* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (55 commits)
workqueue: mark init_workqueues() as early_initcall()
workqueue: explain for_each_*cwq_cpu() iterators
fscache: fix build on !CONFIG_SYSCTL
slow-work: kill it
gfs2: use workqueue instead of slow-work
drm: use workqueue instead of slow-work
cifs: use workqueue instead of slow-work
fscache: drop references to slow-work
fscache: convert operation to use workqueue instead of slow-work
fscache: convert object to use workqueue instead of slow-work
workqueue: fix how cpu number is stored in work->data
workqueue: fix mayday_mask handling on UP
workqueue: fix build problem on !CONFIG_SMP
workqueue: fix locking in retry path of maybe_create_worker()
async: use workqueue for worker pool
workqueue: remove WQ_SINGLE_CPU and use WQ_UNBOUND instead
workqueue: implement unbound workqueue
workqueue: prepare for WQ_UNBOUND implementation
libata: take advantage of cmwq and remove concurrency limitations
workqueue: fix worker management invocation without pending works
...
Fixed up conflicts in fs/cifs/* as per Tejun. Other trivial conflicts in
include/linux/workqueue.h, kernel/trace/Kconfig and kernel/workqueue.c
[root@andromeda ~]# head /proc/fs/fscache/objects
OBJECT PARENT STAT CHLDN OPS OOP IPR EX READS EM EV F S | NETFS_COOKIE_DEF TY FL NETFS_DATA OBJECT_KEY, AUX_DATA
======== ======== ==== ===== === === === == ===== == == = = | ================ == == ================ ================
- 17e4b 2 ACTV 0 0 0 0 0 0 7b 4 0 8 | NFS.fh DT 0 ffff88001dd82820 010006017edcf8bbc93b43298fdfbe71e50b57b13a172c0117f38472, e567634700000000000000000000000063f2404a000000000000000000000000c9030000000000000000000063f2404a
- 1693a 2 ACTV 0 0 0 0 0 0 7b 4 0 8 | NFS.fh DT 0 ffff88002db23380 010006017edcf8bbc93b43298fdfbe71e50b57b1e0162c01a2df0ea6, 420ebc4a000000000000000000000000420ebc4a0000000000000000000000000e1801000000000000000000420ebc4a
+ 17e4b 2 ACTV 0 0 0 0 0 0 7b 4 0 0 | NFS.fh DT 0 ffff88001dd82820 010006017edcf8bbc93b43298fdfbe71e50b57b13a172c0117f38472, e567634700000000000000000000000063f2404a000000000000000000000000c9030000000000000000000063f2404a
+ 1693a 2 ACTV 0 0 0 0 0 0 7b 4 0 0 | NFS.fh DT 0 ffff88002db23380 010006017edcf8bbc93b43298fdfbe71e50b57b1e0162c01a2df0ea6, 420ebc4a000000000000000000000000420ebc4a0000000000000000000000000e1801000000000000000000420ebc4a
where the first set of columns before the '|' describe the object:
EM Object's event mask
EV Events raised on this object
F Object flags
- S Object slow-work work item flags
+ S Object work item busy state mask (1:pending 2:running)
and the second set of columns describe the object's cookie, if present:
w Show objects that don't have pending writes
R Show objects that have outstanding reads
r Show objects that don't have outstanding reads
- S Show objects that have slow work queued
- s Show objects that don't have slow work queued
+ S Show objects that have work queued
+ s Show objects that don't have work queued
If neither side of a letter pair is given, then both are implied. For example:
+++ /dev/null
- ====================================
- SLOW WORK ITEM EXECUTION THREAD POOL
- ====================================
-
-By: David Howells <dhowells@redhat.com>
-
-The slow work item execution thread pool is a pool of threads for performing
-things that take a relatively long time, such as making mkdir calls.
-Typically, when processing something, these items will spend a lot of time
-blocking a thread on I/O, thus making that thread unavailable for doing other
-work.
-
-The standard workqueue model is unsuitable for this class of work item as that
-limits the owner to a single thread or a single thread per CPU. For some
-tasks, however, more threads - or fewer - are required.
-
-There is just one pool per system. It contains no threads unless something
-wants to use it - and that something must register its interest first. When
-the pool is active, the number of threads it contains is dynamic, varying
-between a maximum and minimum setting, depending on the load.
-
-
-====================
-CLASSES OF WORK ITEM
-====================
-
-This pool support two classes of work items:
-
- (*) Slow work items.
-
- (*) Very slow work items.
-
-The former are expected to finish much quicker than the latter.
-
-An operation of the very slow class may do a batch combination of several
-lookups, mkdirs, and a create for instance.
-
-An operation of the ordinarily slow class may, for example, write stuff or
-expand files, provided the time taken to do so isn't too long.
-
-Operations of both types may sleep during execution, thus tying up the thread
-loaned to it.
-
-A further class of work item is available, based on the slow work item class:
-
- (*) Delayed slow work items.
-
-These are slow work items that have a timer to defer queueing of the item for
-a while.
-
-
-THREAD-TO-CLASS ALLOCATION
---------------------------
-
-Not all the threads in the pool are available to work on very slow work items.
-The number will be between one and one fewer than the number of active threads.
-This is configurable (see the "Pool Configuration" section).
-
-All the threads are available to work on ordinarily slow work items, but a
-percentage of the threads will prefer to work on very slow work items.
-
-The configuration ensures that at least one thread will be available to work on
-very slow work items, and at least one thread will be available that won't work
-on very slow work items at all.
-
-
-=====================
-USING SLOW WORK ITEMS
-=====================
-
-Firstly, a module or subsystem wanting to make use of slow work items must
-register its interest:
-
- int ret = slow_work_register_user(struct module *module);
-
-This will return 0 if successful, or a -ve error upon failure. The module
-pointer should be the module interested in using this facility (almost
-certainly THIS_MODULE).
-
-
-Slow work items may then be set up by:
-
- (1) Declaring a slow_work struct type variable:
-
- #include <linux/slow-work.h>
-
- struct slow_work myitem;
-
- (2) Declaring the operations to be used for this item:
-
- struct slow_work_ops myitem_ops = {
- .get_ref = myitem_get_ref,
- .put_ref = myitem_put_ref,
- .execute = myitem_execute,
- };
-
- [*] For a description of the ops, see section "Item Operations".
-
- (3) Initialising the item:
-
- slow_work_init(&myitem, &myitem_ops);
-
- or:
-
- delayed_slow_work_init(&myitem, &myitem_ops);
-
- or:
-
- vslow_work_init(&myitem, &myitem_ops);
-
- depending on its class.
-
-A suitably set up work item can then be enqueued for processing:
-
- int ret = slow_work_enqueue(&myitem);
-
-This will return a -ve error if the thread pool is unable to gain a reference
-on the item, 0 otherwise, or (for delayed work):
-
- int ret = delayed_slow_work_enqueue(&myitem, my_jiffy_delay);
-
-
-The items are reference counted, so there ought to be no need for a flush
-operation. But as the reference counting is optional, means to cancel
-existing work items are also included:
-
- cancel_slow_work(&myitem);
- cancel_delayed_slow_work(&myitem);
-
-can be used to cancel pending work. The above cancel function waits for
-existing work to have been executed (or prevent execution of them, depending
-on timing).
-
-
-When all a module's slow work items have been processed, and the
-module has no further interest in the facility, it should unregister its
-interest:
-
- slow_work_unregister_user(struct module *module);
-
-The module pointer is used to wait for all outstanding work items for that
-module before completing the unregistration. This prevents the put_ref() code
-from being taken away before it completes. module should almost certainly be
-THIS_MODULE.
-
-
-================
-HELPER FUNCTIONS
-================
-
-The slow-work facility provides a function by which it can be determined
-whether or not an item is queued for later execution:
-
- bool queued = slow_work_is_queued(struct slow_work *work);
-
-If it returns false, then the item is not on the queue (it may be executing
-with a requeue pending). This can be used to work out whether an item on which
-another depends is on the queue, thus allowing a dependent item to be queued
-after it.
-
-If the above shows an item on which another depends not to be queued, then the
-owner of the dependent item might need to wait. However, to avoid locking up
-the threads unnecessarily be sleeping in them, it can make sense under some
-circumstances to return the work item to the queue, thus deferring it until
-some other items have had a chance to make use of the yielded thread.
-
-To yield a thread and defer an item, the work function should simply enqueue
-the work item again and return. However, this doesn't work if there's nothing
-actually on the queue, as the thread just vacated will jump straight back into
-the item's work function, thus busy waiting on a CPU.
-
-Instead, the item should use the thread to wait for the dependency to go away,
-but rather than using schedule() or schedule_timeout() to sleep, it should use
-the following function:
-
- bool requeue = slow_work_sleep_till_thread_needed(
- struct slow_work *work,
- signed long *_timeout);
-
-This will add a second wait and then sleep, such that it will be woken up if
-either something appears on the queue that could usefully make use of the
-thread - and behind which this item can be queued, or if the event the caller
-set up to wait for happens. True will be returned if something else appeared
-on the queue and this work function should perhaps return, of false if
-something else woke it up. The timeout is as for schedule_timeout().
-
-For example:
-
- wq = bit_waitqueue(&my_flags, MY_BIT);
- init_wait(&wait);
- requeue = false;
- do {
- prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
- if (!test_bit(MY_BIT, &my_flags))
- break;
- requeue = slow_work_sleep_till_thread_needed(&my_work,
- &timeout);
- } while (timeout > 0 && !requeue);
- finish_wait(wq, &wait);
- if (!test_bit(MY_BIT, &my_flags)
- goto do_my_thing;
- if (requeue)
- return; // to slow_work
-
-
-===============
-ITEM OPERATIONS
-===============
-
-Each work item requires a table of operations of type struct slow_work_ops.
-Only ->execute() is required; the getting and putting of a reference and the
-describing of an item are all optional.
-
- (*) Get a reference on an item:
-
- int (*get_ref)(struct slow_work *work);
-
- This allows the thread pool to attempt to pin an item by getting a
- reference on it. This function should return 0 if the reference was
- granted, or a -ve error otherwise. If an error is returned,
- slow_work_enqueue() will fail.
-
- The reference is held whilst the item is queued and whilst it is being
- executed. The item may then be requeued with the same reference held, or
- the reference will be released.
-
- (*) Release a reference on an item:
-
- void (*put_ref)(struct slow_work *work);
-
- This allows the thread pool to unpin an item by releasing the reference on
- it. The thread pool will not touch the item again once this has been
- called.
-
- (*) Execute an item:
-
- void (*execute)(struct slow_work *work);
-
- This should perform the work required of the item. It may sleep, it may
- perform disk I/O and it may wait for locks.
-
- (*) View an item through /proc:
-
- void (*desc)(struct slow_work *work, struct seq_file *m);
-
- If supplied, this should print to 'm' a small string describing the work
- the item is to do. This should be no more than about 40 characters, and
- shouldn't include a newline character.
-
- See the 'Viewing executing and queued items' section below.
-
-
-==================
-POOL CONFIGURATION
-==================
-
-The slow-work thread pool has a number of configurables:
-
- (*) /proc/sys/kernel/slow-work/min-threads
-
- The minimum number of threads that should be in the pool whilst it is in
- use. This may be anywhere between 2 and max-threads.
-
- (*) /proc/sys/kernel/slow-work/max-threads
-
- The maximum number of threads that should in the pool. This may be
- anywhere between min-threads and 255 or NR_CPUS * 2, whichever is greater.
-
- (*) /proc/sys/kernel/slow-work/vslow-percentage
-
- The percentage of active threads in the pool that may be used to execute
- very slow work items. This may be between 1 and 99. The resultant number
- is bounded to between 1 and one fewer than the number of active threads.
- This ensures there is always at least one thread that can process very
- slow work items, and always at least one thread that won't.
-
-
-==================================
-VIEWING EXECUTING AND QUEUED ITEMS
-==================================
-
-If CONFIG_SLOW_WORK_DEBUG is enabled, a debugfs file is made available:
-
- /sys/kernel/debug/slow_work/runqueue
-
-through which the list of work items being executed and the queues of items to
-be executed may be viewed. The owner of a work item is given the chance to
-add some information of its own.
-
-The contents look something like the following:
-
- THR PID ITEM ADDR FL MARK DESC
- === ===== ================ == ===== ==========
- 0 3005 ffff880023f52348 a 952ms FSC: OBJ17d3: LOOK
- 1 3006 ffff880024e33668 2 160ms FSC: OBJ17e5 OP60d3b: Write1/Store fl=2
- 2 3165 ffff8800296dd180 a 424ms FSC: OBJ17e4: LOOK
- 3 4089 ffff8800262c8d78 a 212ms FSC: OBJ17ea: CRTN
- 4 4090 ffff88002792bed8 2 388ms FSC: OBJ17e8 OP60d36: Write1/Store fl=2
- 5 4092 ffff88002a0ef308 2 388ms FSC: OBJ17e7 OP60d2e: Write1/Store fl=2
- 6 4094 ffff88002abaf4b8 2 132ms FSC: OBJ17e2 OP60d4e: Write1/Store fl=2
- 7 4095 ffff88002bb188e0 a 388ms FSC: OBJ17e9: CRTN
- vsq - ffff880023d99668 1 308ms FSC: OBJ17e0 OP60f91: Write1/EnQ fl=2
- vsq - ffff8800295d1740 1 212ms FSC: OBJ16be OP4d4b6: Write1/EnQ fl=2
- vsq - ffff880025ba3308 1 160ms FSC: OBJ179a OP58dec: Write1/EnQ fl=2
- vsq - ffff880024ec83e0 1 160ms FSC: OBJ17ae OP599f2: Write1/EnQ fl=2
- vsq - ffff880026618e00 1 160ms FSC: OBJ17e6 OP60d33: Write1/EnQ fl=2
- vsq - ffff880025a2a4b8 1 132ms FSC: OBJ16a2 OP4d583: Write1/EnQ fl=2
- vsq - ffff880023cbe6d8 9 212ms FSC: OBJ17eb: LOOK
- vsq - ffff880024d37590 9 212ms FSC: OBJ17ec: LOOK
- vsq - ffff880027746cb0 9 212ms FSC: OBJ17ed: LOOK
- vsq - ffff880024d37ae8 9 212ms FSC: OBJ17ee: LOOK
- vsq - ffff880024d37cb0 9 212ms FSC: OBJ17ef: LOOK
- vsq - ffff880025036550 9 212ms FSC: OBJ17f0: LOOK
- vsq - ffff8800250368e0 9 212ms FSC: OBJ17f1: LOOK
- vsq - ffff880025036aa8 9 212ms FSC: OBJ17f2: LOOK
-
-In the 'THR' column, executing items show the thread they're occupying and
-queued threads indicate which queue they're on. 'PID' shows the process ID of
-a slow-work thread that's executing something. 'FL' shows the work item flags.
-'MARK' indicates how long since an item was queued or began executing. Lastly,
-the 'DESC' column permits the owner of an item to give some information.
-
/*
* We can't use kernel_thread since we must avoid to reschedule the child.
*/
- if (!keventd_up() || current_is_keventd())
+ if (!keventd_up())
c_idle.work.func(&c_idle.work);
else {
schedule_work(&c_idle.work);
goto do_rest;
}
- if (!keventd_up() || current_is_keventd())
+ if (!keventd_up())
c_idle.work.func(&c_idle.work);
else {
schedule_work(&c_idle.work);
return AE_OK;
}
-static void bind_to_cpu0(struct work_struct *work)
-{
- set_cpus_allowed_ptr(current, cpumask_of(0));
- kfree(work);
-}
-
-static void bind_workqueue(struct workqueue_struct *wq)
-{
- struct work_struct *work;
-
- work = kzalloc(sizeof(struct work_struct), GFP_KERNEL);
- INIT_WORK(work, bind_to_cpu0);
- queue_work(wq, work);
-}
-
acpi_status acpi_os_initialize1(void)
{
- /*
- * On some machines, a software-initiated SMI causes corruption unless
- * the SMI runs on CPU 0. An SMI can be initiated by any AML, but
- * typically it's done in GPE-related methods that are run via
- * workqueues, so we can avoid the known corruption cases by binding
- * the workqueues to CPU 0.
- */
- kacpid_wq = create_singlethread_workqueue("kacpid");
- bind_workqueue(kacpid_wq);
- kacpi_notify_wq = create_singlethread_workqueue("kacpi_notify");
- bind_workqueue(kacpi_notify_wq);
- kacpi_hotplug_wq = create_singlethread_workqueue("kacpi_hotplug");
- bind_workqueue(kacpi_hotplug_wq);
+ kacpid_wq = create_workqueue("kacpid");
+ kacpi_notify_wq = create_workqueue("kacpi_notify");
+ kacpi_hotplug_wq = create_workqueue("kacpi_hotplug");
BUG_ON(!kacpid_wq);
BUG_ON(!kacpi_notify_wq);
BUG_ON(!kacpi_hotplug_wq);
else
INIT_WORK(&dpc->work, acpi_os_execute_deferred);
- ret = queue_work(queue, &dpc->work);
+ /*
+ * On some machines, a software-initiated SMI causes corruption unless
+ * the SMI runs on CPU 0. An SMI can be initiated by any AML, but
+ * typically it's done in GPE-related methods that are run via
+ * workqueues, so we can avoid the known corruption cases by always
+ * queueing on CPU 0.
+ */
+ ret = queue_work_on(0, queue, &dpc->work);
if (!ret) {
printk(KERN_ERR PREFIX
unsigned int ata_print_id = 1;
-struct workqueue_struct *ata_aux_wq;
-
struct ata_force_param {
const char *name;
unsigned int cbl;
ap->msg_enable = ATA_MSG_DRV | ATA_MSG_ERR | ATA_MSG_WARN;
#endif
+ mutex_init(&ap->scsi_scan_mutex);
INIT_DELAYED_WORK(&ap->hotplug_task, ata_scsi_hotplug);
INIT_WORK(&ap->scsi_rescan_task, ata_scsi_dev_rescan);
INIT_LIST_HEAD(&ap->eh_done_q);
ata_parse_force_param();
- ata_aux_wq = create_singlethread_workqueue("ata_aux");
- if (!ata_aux_wq)
- goto fail;
-
rc = ata_sff_init();
- if (rc)
- goto fail;
+ if (rc) {
+ kfree(ata_force_tbl);
+ return rc;
+ }
printk(KERN_DEBUG "libata version " DRV_VERSION " loaded.\n");
return 0;
-
-fail:
- kfree(ata_force_tbl);
- if (ata_aux_wq)
- destroy_workqueue(ata_aux_wq);
- return rc;
}
static void __exit ata_exit(void)
{
ata_sff_exit();
kfree(ata_force_tbl);
- destroy_workqueue(ata_aux_wq);
}
subsys_initcall(ata_init);
if (ap->pflags & ATA_PFLAG_LOADING)
ap->pflags &= ~ATA_PFLAG_LOADING;
else if (ap->pflags & ATA_PFLAG_SCSI_HOTPLUG)
- queue_delayed_work(ata_aux_wq, &ap->hotplug_task, 0);
+ schedule_delayed_work(&ap->hotplug_task, 0);
if (ap->pflags & ATA_PFLAG_RECOVERED)
ata_port_printk(ap, KERN_INFO, "EH complete\n");
ehc->i.flags |= ATA_EHI_SETMODE;
/* schedule the scsi_rescan_device() here */
- queue_work(ata_aux_wq, &(ap->scsi_rescan_task));
+ schedule_work(&(ap->scsi_rescan_task));
} else if (dev->class == ATA_DEV_UNKNOWN &&
ehc->tries[dev->devno] &&
ata_class_enabled(ehc->classes[dev->devno])) {
" switching to async\n");
}
- queue_delayed_work(ata_aux_wq, &ap->hotplug_task,
+ queue_delayed_work(system_long_wq, &ap->hotplug_task,
round_jiffies_relative(HZ));
}
}
DPRINTK("ENTER\n");
+ mutex_lock(&ap->scsi_scan_mutex);
/* Unplug detached devices. We cannot use link iterator here
* because PMP links have to be scanned even if PMP is
/* scan for new ones */
ata_scsi_scan_host(ap, 0);
+ mutex_unlock(&ap->scsi_scan_mutex);
DPRINTK("EXIT\n");
}
* @work: Pointer to ATA port to perform scsi_rescan_device()
*
* After ATA pass thru (SAT) commands are executed successfully,
- * libata need to propagate the changes to SCSI layer. This
- * function must be executed from ata_aux_wq such that sdev
- * attach/detach don't race with rescan.
+ * libata need to propagate the changes to SCSI layer.
*
* LOCKING:
* Kernel thread context (may sleep).
struct ata_device *dev;
unsigned long flags;
+ mutex_lock(&ap->scsi_scan_mutex);
spin_lock_irqsave(ap->lock, flags);
ata_for_each_link(link, ap, EDGE) {
}
spin_unlock_irqrestore(ap->lock, flags);
+ mutex_unlock(&ap->scsi_scan_mutex);
}
/**
int __init ata_sff_init(void)
{
- /*
- * FIXME: In UP case, there is only one workqueue thread and if you
- * have more than one PIO device, latency is bloody awful, with
- * occasional multi-second "hiccups" as one PIO device waits for
- * another. It's an ugly wart that users DO occasionally complain
- * about; luckily most users have at most one PIO polled device.
- */
- ata_sff_wq = create_workqueue("ata_sff");
+ ata_sff_wq = alloc_workqueue("ata_sff", WQ_RESCUER, WQ_MAX_ACTIVE);
if (!ata_sff_wq)
return -ENOMEM;
};
extern unsigned int ata_print_id;
-extern struct workqueue_struct *ata_aux_wq;
extern int atapi_passthru16;
extern int libata_fua;
extern int libata_noacpi;
}
EXPORT_SYMBOL(drm_helper_resume_force_mode);
-static struct slow_work_ops output_poll_ops;
-
#define DRM_OUTPUT_POLL_PERIOD (10*HZ)
-static void output_poll_execute(struct slow_work *work)
+static void output_poll_execute(struct work_struct *work)
{
- struct delayed_slow_work *delayed_work = container_of(work, struct delayed_slow_work, work);
- struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_slow_work);
+ struct delayed_work *delayed_work = to_delayed_work(work);
+ struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_work);
struct drm_connector *connector;
enum drm_connector_status old_status, status;
bool repoll = false, changed = false;
}
if (repoll) {
- ret = delayed_slow_work_enqueue(delayed_work, DRM_OUTPUT_POLL_PERIOD);
+ ret = queue_delayed_work(system_nrt_wq, delayed_work, DRM_OUTPUT_POLL_PERIOD);
if (ret)
DRM_ERROR("delayed enqueue failed %d\n", ret);
}
{
if (!dev->mode_config.poll_enabled)
return;
- delayed_slow_work_cancel(&dev->mode_config.output_poll_slow_work);
+ cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
}
EXPORT_SYMBOL(drm_kms_helper_poll_disable);
}
if (poll) {
- ret = delayed_slow_work_enqueue(&dev->mode_config.output_poll_slow_work, DRM_OUTPUT_POLL_PERIOD);
+ ret = queue_delayed_work(system_nrt_wq, &dev->mode_config.output_poll_work, DRM_OUTPUT_POLL_PERIOD);
if (ret)
DRM_ERROR("delayed enqueue failed %d\n", ret);
}
void drm_kms_helper_poll_init(struct drm_device *dev)
{
- slow_work_register_user(THIS_MODULE);
- delayed_slow_work_init(&dev->mode_config.output_poll_slow_work,
- &output_poll_ops);
+ INIT_DELAYED_WORK(&dev->mode_config.output_poll_work, output_poll_execute);
dev->mode_config.poll_enabled = true;
drm_kms_helper_poll_enable(dev);
void drm_kms_helper_poll_fini(struct drm_device *dev)
{
drm_kms_helper_poll_disable(dev);
- slow_work_unregister_user(THIS_MODULE);
}
EXPORT_SYMBOL(drm_kms_helper_poll_fini);
{
if (!dev->mode_config.poll_enabled)
return;
- delayed_slow_work_cancel(&dev->mode_config.output_poll_slow_work);
- /* schedule a slow work asap */
- delayed_slow_work_enqueue(&dev->mode_config.output_poll_slow_work, 0);
+ /* kill timer and schedule immediate execution, this doesn't block */
+ cancel_delayed_work(&dev->mode_config.output_poll_work);
+ queue_delayed_work(system_nrt_wq, &dev->mode_config.output_poll_work, 0);
}
EXPORT_SYMBOL(drm_helper_hpd_irq_event);
-
-static struct slow_work_ops output_poll_ops = {
- .execute = output_poll_execute,
-};
*/
static int __devinit ivtv_init_struct1(struct ivtv *itv)
{
+ struct sched_param param = { .sched_priority = 99 };
+
itv->base_addr = pci_resource_start(itv->pdev, 0);
itv->enc_mbox.max_mbox = 2; /* the encoder has 3 mailboxes (0-2) */
itv->dec_mbox.max_mbox = 1; /* the decoder has 2 mailboxes (0-1) */
spin_lock_init(&itv->lock);
spin_lock_init(&itv->dma_reg_lock);
- itv->irq_work_queues = create_singlethread_workqueue(itv->v4l2_dev.name);
- if (itv->irq_work_queues == NULL) {
- IVTV_ERR("Could not create ivtv workqueue\n");
+ init_kthread_worker(&itv->irq_worker);
+ itv->irq_worker_task = kthread_run(kthread_worker_fn, &itv->irq_worker,
+ itv->v4l2_dev.name);
+ if (IS_ERR(itv->irq_worker_task)) {
+ IVTV_ERR("Could not create ivtv task\n");
return -1;
}
+ /* must use the FIFO scheduler as it is realtime sensitive */
+ sched_setscheduler(itv->irq_worker_task, SCHED_FIFO, ¶m);
- INIT_WORK(&itv->irq_work_queue, ivtv_irq_work_handler);
+ init_kthread_work(&itv->irq_work, ivtv_irq_work_handler);
/* start counting open_id at 1 */
itv->open_id = 1;
/* PCI Device Setup */
retval = ivtv_setup_pci(itv, pdev, pci_id);
if (retval == -EIO)
- goto free_workqueue;
+ goto free_worker;
if (retval == -ENXIO)
goto free_mem;
release_mem_region(itv->base_addr + IVTV_REG_OFFSET, IVTV_REG_SIZE);
if (itv->has_cx23415)
release_mem_region(itv->base_addr + IVTV_DECODER_OFFSET, IVTV_DECODER_SIZE);
-free_workqueue:
- destroy_workqueue(itv->irq_work_queues);
+free_worker:
+ kthread_stop(itv->irq_worker_task);
err:
if (retval == 0)
retval = -ENODEV;
ivtv_set_irq_mask(itv, 0xffffffff);
del_timer_sync(&itv->dma_timer);
- /* Stop all Work Queues */
- flush_workqueue(itv->irq_work_queues);
- destroy_workqueue(itv->irq_work_queues);
+ /* Kill irq worker */
+ flush_kthread_worker(&itv->irq_worker);
+ kthread_stop(itv->irq_worker_task);
ivtv_streams_cleanup(itv, 1);
ivtv_udma_free(itv);
#include <linux/unistd.h>
#include <linux/pagemap.h>
#include <linux/scatterlist.h>
-#include <linux/workqueue.h>
+#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#define IVTV_F_I_DEC_PAUSED 20 /* the decoder is paused */
#define IVTV_F_I_INITED 21 /* set after first open */
#define IVTV_F_I_FAILED 22 /* set if first open failed */
-#define IVTV_F_I_WORK_INITED 23 /* worker thread was initialized */
/* Event notifications */
#define IVTV_F_I_EV_DEC_STOPPED 28 /* decoder stopped event */
/* Interrupts & DMA */
u32 irqmask; /* active interrupts */
u32 irq_rr_idx; /* round-robin stream index */
- struct workqueue_struct *irq_work_queues; /* workqueue for PIO/YUV/VBI actions */
- struct work_struct irq_work_queue; /* work entry */
+ struct kthread_worker irq_worker; /* kthread worker for PIO/YUV/VBI actions */
+ struct task_struct *irq_worker_task; /* task for irq_worker */
+ struct kthread_work irq_work; /* kthread work entry */
spinlock_t dma_reg_lock; /* lock access to DMA engine registers */
int cur_dma_stream; /* index of current stream doing DMA (-1 if none) */
int cur_pio_stream; /* index of current stream doing PIO (-1 if none) */
write_reg(IVTV_IRQ_ENC_PIO_COMPLETE, 0x44);
}
-void ivtv_irq_work_handler(struct work_struct *work)
+void ivtv_irq_work_handler(struct kthread_work *work)
{
- struct ivtv *itv = container_of(work, struct ivtv, irq_work_queue);
+ struct ivtv *itv = container_of(work, struct ivtv, irq_work);
- DEFINE_WAIT(wait);
-
- if (test_and_clear_bit(IVTV_F_I_WORK_INITED, &itv->i_flags)) {
- struct sched_param param = { .sched_priority = 99 };
-
- /* This thread must use the FIFO scheduler as it
- is realtime sensitive. */
- sched_setscheduler(current, SCHED_FIFO, ¶m);
- }
if (test_and_clear_bit(IVTV_F_I_WORK_HANDLER_PIO, &itv->i_flags))
ivtv_pio_work_handler(itv);
}
if (test_and_clear_bit(IVTV_F_I_HAVE_WORK, &itv->i_flags)) {
- queue_work(itv->irq_work_queues, &itv->irq_work_queue);
+ queue_kthread_work(&itv->irq_worker, &itv->irq_work);
}
spin_unlock(&itv->dma_reg_lock);
irqreturn_t ivtv_irq_handler(int irq, void *dev_id);
-void ivtv_irq_work_handler(struct work_struct *work);
+void ivtv_irq_work_handler(struct kthread_work *work);
void ivtv_dma_stream_dec_prepare(struct ivtv_stream *s, u32 offset, int lock);
void ivtv_unfinished_dma(unsigned long arg);
printk(KERN_ERR "%sobject: OBJ%x\n",
prefix, object->fscache.debug_id);
- printk(KERN_ERR "%sobjstate=%s fl=%lx swfl=%lx ev=%lx[%lx]\n",
+ printk(KERN_ERR "%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n",
prefix, fscache_object_states[object->fscache.state],
- object->fscache.flags, object->fscache.work.flags,
+ object->fscache.flags, work_busy(&object->fscache.work),
object->fscache.events,
object->fscache.event_mask & FSCACHE_OBJECT_EVENTS_MASK);
printk(KERN_ERR "%sops=%u inp=%u exc=%u\n",
/* if the object we're waiting for is queued for processing,
* then just put ourselves on the queue behind it */
- if (slow_work_is_queued(&xobject->fscache.work)) {
+ if (work_pending(&xobject->fscache.work)) {
_debug("queue OBJ%x behind OBJ%x immediately",
object->fscache.debug_id,
xobject->fscache.debug_id);
}
/* otherwise we sleep until either the object we're waiting for
- * is done, or the slow-work facility wants the thread back to
- * do other work */
+ * is done, or the fscache_object is congested */
wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE);
init_wait(&wait);
requeue = false;
prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags))
break;
- requeue = slow_work_sleep_till_thread_needed(
- &object->fscache.work, &timeout);
+
+ requeue = fscache_object_sleep_till_congested(&timeout);
} while (timeout > 0 && !requeue);
finish_wait(wq, &wait);
shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;
op->op.flags &= FSCACHE_OP_KEEP_FLAGS;
- op->op.flags |= FSCACHE_OP_FAST;
+ op->op.flags |= FSCACHE_OP_ASYNC;
op->op.processor = cachefiles_read_copier;
pagevec_init(&pagevec, 0);
pagevec_init(&pagevec, 0);
op->op.flags &= FSCACHE_OP_KEEP_FLAGS;
- op->op.flags |= FSCACHE_OP_FAST;
+ op->op.flags |= FSCACHE_OP_ASYNC;
op->op.processor = cachefiles_read_copier;
INIT_LIST_HEAD(&backpages);
tristate "CIFS support (advanced network filesystem, SMBFS successor)"
depends on INET
select NLS
- select SLOW_WORK
help
This is the client VFS module for the Common Internet File System
(CIFS) protocol which is the successor to the Server Message Block
if (rc)
goto out_unregister_key_type;
#endif
- rc = slow_work_register_user(THIS_MODULE);
- if (rc)
- goto out_unregister_resolver_key;
return 0;
- out_unregister_resolver_key:
#ifdef CONFIG_CIFS_DFS_UPCALL
- cifs_exit_dns_resolver();
out_unregister_key_type:
#endif
#ifdef CONFIG_CIFS_UPCALL
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/slab.h>
-#include <linux/slow-work.h>
+#include <linux/workqueue.h>
#include "cifs_fs_sb.h"
#include "cifsacl.h"
/*
atomic_t count; /* reference count */
struct mutex fh_mutex; /* prevents reopen race after dead ses*/
struct cifs_search_info srch_inf;
- struct slow_work oplock_break; /* slow_work job for oplock breaks */
+ struct work_struct oplock_break; /* work for oplock breaks */
};
/* Take a reference on the file private data */
GLOBAL_EXTERN unsigned int cifs_min_small; /* min size of small buf pool */
GLOBAL_EXTERN unsigned int cifs_max_pending; /* MAX requests at once to server*/
+void cifs_oplock_break(struct work_struct *work);
+void cifs_oplock_break_get(struct cifsFileInfo *cfile);
+void cifs_oplock_break_put(struct cifsFileInfo *cfile);
+
extern const struct slow_work_ops cifs_oplock_break_ops;
#endif /* _CIFS_GLOB_H */
mutex_init(&pCifsFile->lock_mutex);
INIT_LIST_HEAD(&pCifsFile->llist);
atomic_set(&pCifsFile->count, 1);
- slow_work_init(&pCifsFile->oplock_break, &cifs_oplock_break_ops);
+ INIT_WORK(&pCifsFile->oplock_break, cifs_oplock_break);
write_lock(&GlobalSMBSeslock);
list_add(&pCifsFile->tlist, &cifs_sb->tcon->openFileList);
cifs_fscache_invalidate_page(page, &cifsi->vfs_inode);
}
-static void
-cifs_oplock_break(struct slow_work *work)
+void cifs_oplock_break(struct work_struct *work)
{
struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
oplock_break);
LOCKING_ANDX_OPLOCK_RELEASE, false);
cFYI(1, "Oplock release rc = %d", rc);
}
+
+ /*
+ * We might have kicked in before is_valid_oplock_break()
+ * finished grabbing reference for us. Make sure it's done by
+ * waiting for GlobalSMSSeslock.
+ */
+ write_lock(&GlobalSMBSeslock);
+ write_unlock(&GlobalSMBSeslock);
+
+ cifs_oplock_break_put(cfile);
}
-static int
-cifs_oplock_break_get(struct slow_work *work)
+void cifs_oplock_break_get(struct cifsFileInfo *cfile)
{
- struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
- oplock_break);
mntget(cfile->mnt);
cifsFileInfo_get(cfile);
- return 0;
}
-static void
-cifs_oplock_break_put(struct slow_work *work)
+void cifs_oplock_break_put(struct cifsFileInfo *cfile)
{
- struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
- oplock_break);
mntput(cfile->mnt);
cifsFileInfo_put(cfile);
}
-const struct slow_work_ops cifs_oplock_break_ops = {
- .get_ref = cifs_oplock_break_get,
- .put_ref = cifs_oplock_break_put,
- .execute = cifs_oplock_break,
-};
-
const struct address_space_operations cifs_addr_ops = {
.readpage = cifs_readpage,
.readpages = cifs_readpages,
struct cifsTconInfo *tcon;
struct cifsInodeInfo *pCifsInode;
struct cifsFileInfo *netfile;
- int rc;
cFYI(1, "Checking for oplock break or dnotify response");
if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
pCifsInode->clientCanCacheAll = false;
if (pSMB->OplockLevel == 0)
pCifsInode->clientCanCacheRead = false;
- rc = slow_work_enqueue(&netfile->oplock_break);
- if (rc) {
- cERROR(1, "failed to enqueue oplock "
- "break: %d\n", rc);
- } else {
- netfile->oplock_break_cancelled = false;
- }
+
+ /*
+ * cifs_oplock_break_put() can't be called
+ * from here. Get reference after queueing
+ * succeeded. cifs_oplock_break() will
+ * synchronize using GlobalSMSSeslock.
+ */
+ if (queue_work(system_nrt_wq,
+ &netfile->oplock_break))
+ cifs_oplock_break_get(netfile);
+ netfile->oplock_break_cancelled = false;
+
read_unlock(&GlobalSMBSeslock);
read_unlock(&cifs_tcp_ses_lock);
return true;
config FSCACHE
tristate "General filesystem local caching manager"
- select SLOW_WORK
help
This option enables a generic filesystem caching manager that can be
used by various network and other filesystems to cache data locally.
extern unsigned fscache_defer_create;
extern unsigned fscache_debug;
extern struct kobject *fscache_root;
+extern struct workqueue_struct *fscache_object_wq;
+extern struct workqueue_struct *fscache_op_wq;
+DECLARE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
+
+static inline bool fscache_object_congested(void)
+{
+ return workqueue_congested(WORK_CPU_UNBOUND, fscache_object_wq);
+}
extern int fscache_wait_bit(void *);
extern int fscache_wait_bit_interruptible(void *);
#include <linux/sched.h>
#include <linux/completion.h>
#include <linux/slab.h>
+#include <linux/seq_file.h>
#include "internal.h"
MODULE_DESCRIPTION("FS Cache Manager");
"FS-Cache debugging mask");
struct kobject *fscache_root;
+struct workqueue_struct *fscache_object_wq;
+struct workqueue_struct *fscache_op_wq;
+
+DEFINE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
+
+/* these values serve as lower bounds, will be adjusted in fscache_init() */
+static unsigned fscache_object_max_active = 4;
+static unsigned fscache_op_max_active = 2;
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table_header *fscache_sysctl_header;
+
+static int fscache_max_active_sysctl(struct ctl_table *table, int write,
+ void __user *buffer,
+ size_t *lenp, loff_t *ppos)
+{
+ struct workqueue_struct **wqp = table->extra1;
+ unsigned int *datap = table->data;
+ int ret;
+
+ ret = proc_dointvec(table, write, buffer, lenp, ppos);
+ if (ret == 0)
+ workqueue_set_max_active(*wqp, *datap);
+ return ret;
+}
+
+ctl_table fscache_sysctls[] = {
+ {
+ .procname = "object_max_active",
+ .data = &fscache_object_max_active,
+ .maxlen = sizeof(unsigned),
+ .mode = 0644,
+ .proc_handler = fscache_max_active_sysctl,
+ .extra1 = &fscache_object_wq,
+ },
+ {
+ .procname = "operation_max_active",
+ .data = &fscache_op_max_active,
+ .maxlen = sizeof(unsigned),
+ .mode = 0644,
+ .proc_handler = fscache_max_active_sysctl,
+ .extra1 = &fscache_op_wq,
+ },
+ {}
+};
+
+ctl_table fscache_sysctls_root[] = {
+ {
+ .procname = "fscache",
+ .mode = 0555,
+ .child = fscache_sysctls,
+ },
+ {}
+};
+#endif
/*
* initialise the fs caching module
*/
static int __init fscache_init(void)
{
+ unsigned int nr_cpus = num_possible_cpus();
+ unsigned int cpu;
int ret;
- ret = slow_work_register_user(THIS_MODULE);
- if (ret < 0)
- goto error_slow_work;
+ fscache_object_max_active =
+ clamp_val(nr_cpus,
+ fscache_object_max_active, WQ_UNBOUND_MAX_ACTIVE);
+
+ ret = -ENOMEM;
+ fscache_object_wq = alloc_workqueue("fscache_object", WQ_UNBOUND,
+ fscache_object_max_active);
+ if (!fscache_object_wq)
+ goto error_object_wq;
+
+ fscache_op_max_active =
+ clamp_val(fscache_object_max_active / 2,
+ fscache_op_max_active, WQ_UNBOUND_MAX_ACTIVE);
+
+ ret = -ENOMEM;
+ fscache_op_wq = alloc_workqueue("fscache_operation", WQ_UNBOUND,
+ fscache_op_max_active);
+ if (!fscache_op_wq)
+ goto error_op_wq;
+
+ for_each_possible_cpu(cpu)
+ init_waitqueue_head(&per_cpu(fscache_object_cong_wait, cpu));
ret = fscache_proc_init();
if (ret < 0)
goto error_proc;
+#ifdef CONFIG_SYSCTL
+ ret = -ENOMEM;
+ fscache_sysctl_header = register_sysctl_table(fscache_sysctls_root);
+ if (!fscache_sysctl_header)
+ goto error_sysctl;
+#endif
+
fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar",
sizeof(struct fscache_cookie),
0,
error_kobj:
kmem_cache_destroy(fscache_cookie_jar);
error_cookie_jar:
+#ifdef CONFIG_SYSCTL
+ unregister_sysctl_table(fscache_sysctl_header);
+error_sysctl:
+#endif
fscache_proc_cleanup();
error_proc:
- slow_work_unregister_user(THIS_MODULE);
-error_slow_work:
+ destroy_workqueue(fscache_op_wq);
+error_op_wq:
+ destroy_workqueue(fscache_object_wq);
+error_object_wq:
return ret;
}
kobject_put(fscache_root);
kmem_cache_destroy(fscache_cookie_jar);
+#ifdef CONFIG_SYSCTL
+ unregister_sysctl_table(fscache_sysctl_header);
+#endif
fscache_proc_cleanup();
- slow_work_unregister_user(THIS_MODULE);
+ destroy_workqueue(fscache_op_wq);
+ destroy_workqueue(fscache_object_wq);
printk(KERN_NOTICE "FS-Cache: Unloaded\n");
}
#define FSCACHE_OBJLIST_CONFIG_NOREADS 0x00000200 /* show objects without active reads */
#define FSCACHE_OBJLIST_CONFIG_EVENTS 0x00000400 /* show objects with events */
#define FSCACHE_OBJLIST_CONFIG_NOEVENTS 0x00000800 /* show objects without no events */
-#define FSCACHE_OBJLIST_CONFIG_WORK 0x00001000 /* show objects with slow work */
-#define FSCACHE_OBJLIST_CONFIG_NOWORK 0x00002000 /* show objects without slow work */
+#define FSCACHE_OBJLIST_CONFIG_WORK 0x00001000 /* show objects with work */
+#define FSCACHE_OBJLIST_CONFIG_NOWORK 0x00002000 /* show objects without work */
u8 buf[512]; /* key and aux data buffer */
};
READS, NOREADS);
FILTER(obj->events & obj->event_mask,
EVENTS, NOEVENTS);
- FILTER(obj->work.flags & ~(1UL << SLOW_WORK_VERY_SLOW),
- WORK, NOWORK);
+ FILTER(work_busy(&obj->work), WORK, NOWORK);
}
seq_printf(m,
- "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %1lx %1lx | ",
+ "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %1lx %1x | ",
obj->debug_id,
obj->parent ? obj->parent->debug_id : -1,
fscache_object_states_short[obj->state],
obj->event_mask & FSCACHE_OBJECT_EVENTS_MASK,
obj->events,
obj->flags,
- obj->work.flags);
+ work_busy(&obj->work));
no_cookie = true;
keylen = auxlen = 0;
#define FSCACHE_DEBUG_LEVEL COOKIE
#include <linux/module.h>
-#include <linux/seq_file.h>
#include "internal.h"
const char *fscache_object_states[FSCACHE_OBJECT__NSTATES] = {
[FSCACHE_OBJECT_DEAD] = "DEAD",
};
-static void fscache_object_slow_work_put_ref(struct slow_work *);
-static int fscache_object_slow_work_get_ref(struct slow_work *);
-static void fscache_object_slow_work_execute(struct slow_work *);
-#ifdef CONFIG_SLOW_WORK_DEBUG
-static void fscache_object_slow_work_desc(struct slow_work *, struct seq_file *);
-#endif
+static int fscache_get_object(struct fscache_object *);
+static void fscache_put_object(struct fscache_object *);
static void fscache_initialise_object(struct fscache_object *);
static void fscache_lookup_object(struct fscache_object *);
static void fscache_object_available(struct fscache_object *);
static void fscache_enqueue_dependents(struct fscache_object *);
static void fscache_dequeue_object(struct fscache_object *);
-const struct slow_work_ops fscache_object_slow_work_ops = {
- .owner = THIS_MODULE,
- .get_ref = fscache_object_slow_work_get_ref,
- .put_ref = fscache_object_slow_work_put_ref,
- .execute = fscache_object_slow_work_execute,
-#ifdef CONFIG_SLOW_WORK_DEBUG
- .desc = fscache_object_slow_work_desc,
-#endif
-};
-EXPORT_SYMBOL(fscache_object_slow_work_ops);
-
/*
* we need to notify the parent when an op completes that we had outstanding
* upon it
/*
* execute an object
*/
-static void fscache_object_slow_work_execute(struct slow_work *work)
+void fscache_object_work_func(struct work_struct *work)
{
struct fscache_object *object =
container_of(work, struct fscache_object, work);
if (object->events & object->event_mask)
fscache_enqueue_object(object);
clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
+ fscache_put_object(object);
}
-
-/*
- * describe an object for slow-work debugging
- */
-#ifdef CONFIG_SLOW_WORK_DEBUG
-static void fscache_object_slow_work_desc(struct slow_work *work,
- struct seq_file *m)
-{
- struct fscache_object *object =
- container_of(work, struct fscache_object, work);
-
- seq_printf(m, "FSC: OBJ%x: %s",
- object->debug_id,
- fscache_object_states_short[object->state]);
-}
-#endif
+EXPORT_SYMBOL(fscache_object_work_func);
/*
* initialise an object
_enter("");
ASSERT(object->cookie != NULL);
ASSERT(object->cookie->parent != NULL);
- ASSERT(list_empty(&object->work.link));
if (object->events & ((1 << FSCACHE_OBJECT_EV_ERROR) |
(1 << FSCACHE_OBJECT_EV_RELEASE) |
object->parent = NULL;
}
- /* this just shifts the object release to the slow work processor */
- fscache_stat(&fscache_n_cop_put_object);
- object->cache->ops->put_object(object);
- fscache_stat_d(&fscache_n_cop_put_object);
+ /* this just shifts the object release to the work processor */
+ fscache_put_object(object);
_leave("");
}
}
/*
- * allow the slow work item processor to get a ref on an object
+ * get a ref on an object
*/
-static int fscache_object_slow_work_get_ref(struct slow_work *work)
+static int fscache_get_object(struct fscache_object *object)
{
- struct fscache_object *object =
- container_of(work, struct fscache_object, work);
int ret;
fscache_stat(&fscache_n_cop_grab_object);
}
/*
- * allow the slow work item processor to discard a ref on a work item
+ * discard a ref on a work item
*/
-static void fscache_object_slow_work_put_ref(struct slow_work *work)
+static void fscache_put_object(struct fscache_object *object)
{
- struct fscache_object *object =
- container_of(work, struct fscache_object, work);
-
fscache_stat(&fscache_n_cop_put_object);
object->cache->ops->put_object(object);
fscache_stat_d(&fscache_n_cop_put_object);
{
_enter("{OBJ%x}", object->debug_id);
- slow_work_enqueue(&object->work);
+ if (fscache_get_object(object) >= 0) {
+ wait_queue_head_t *cong_wq =
+ &get_cpu_var(fscache_object_cong_wait);
+
+ if (queue_work(fscache_object_wq, &object->work)) {
+ if (fscache_object_congested())
+ wake_up(cong_wq);
+ } else
+ fscache_put_object(object);
+
+ put_cpu_var(fscache_object_cong_wait);
+ }
+}
+
+/**
+ * fscache_object_sleep_till_congested - Sleep until object wq is congested
+ * @timoutp: Scheduler sleep timeout
+ *
+ * Allow an object handler to sleep until the object workqueue is congested.
+ *
+ * The caller must set up a wake up event before calling this and must have set
+ * the appropriate sleep mode (such as TASK_UNINTERRUPTIBLE) and tested its own
+ * condition before calling this function as no test is made here.
+ *
+ * %true is returned if the object wq is congested, %false otherwise.
+ */
+bool fscache_object_sleep_till_congested(signed long *timeoutp)
+{
+ wait_queue_head_t *cong_wq = &__get_cpu_var(fscache_object_cong_wait);
+ DEFINE_WAIT(wait);
+
+ if (fscache_object_congested())
+ return true;
+
+ add_wait_queue_exclusive(cong_wq, &wait);
+ if (!fscache_object_congested())
+ *timeoutp = schedule_timeout(*timeoutp);
+ finish_wait(cong_wq, &wait);
+
+ return fscache_object_congested();
}
+EXPORT_SYMBOL_GPL(fscache_object_sleep_till_congested);
/*
* enqueue the dependents of an object for metadata-type processing
/* sort onto appropriate lists */
fscache_enqueue_object(dep);
- fscache_stat(&fscache_n_cop_put_object);
- dep->cache->ops->put_object(dep);
- fscache_stat_d(&fscache_n_cop_put_object);
+ fscache_put_object(dep);
if (!list_empty(&object->dependents))
cond_resched_lock(&object->lock);
fscache_stat(&fscache_n_op_enqueue);
switch (op->flags & FSCACHE_OP_TYPE) {
- case FSCACHE_OP_FAST:
- _debug("queue fast");
+ case FSCACHE_OP_ASYNC:
+ _debug("queue async");
atomic_inc(&op->usage);
- if (!schedule_work(&op->fast_work))
+ if (!queue_work(fscache_op_wq, &op->work))
fscache_put_operation(op);
break;
- case FSCACHE_OP_SLOW:
- _debug("queue slow");
- slow_work_enqueue(&op->slow_work);
- break;
case FSCACHE_OP_MYTHREAD:
_debug("queue for caller's attention");
break;
}
/*
- * allow the slow work item processor to get a ref on an operation
- */
-static int fscache_op_get_ref(struct slow_work *work)
-{
- struct fscache_operation *op =
- container_of(work, struct fscache_operation, slow_work);
-
- atomic_inc(&op->usage);
- return 0;
-}
-
-/*
- * allow the slow work item processor to discard a ref on an operation
- */
-static void fscache_op_put_ref(struct slow_work *work)
-{
- struct fscache_operation *op =
- container_of(work, struct fscache_operation, slow_work);
-
- fscache_put_operation(op);
-}
-
-/*
- * execute an operation using the slow thread pool to provide processing context
- * - the caller holds a ref to this object, so we don't need to hold one
+ * execute an operation using fs_op_wq to provide processing context -
+ * the caller holds a ref to this object, so we don't need to hold one
*/
-static void fscache_op_execute(struct slow_work *work)
+void fscache_op_work_func(struct work_struct *work)
{
struct fscache_operation *op =
- container_of(work, struct fscache_operation, slow_work);
+ container_of(work, struct fscache_operation, work);
unsigned long start;
_enter("{OBJ%x OP%x,%d}",
start = jiffies;
op->processor(op);
fscache_hist(fscache_ops_histogram, start);
+ fscache_put_operation(op);
_leave("");
}
-
-/*
- * describe an operation for slow-work debugging
- */
-#ifdef CONFIG_SLOW_WORK_DEBUG
-static void fscache_op_desc(struct slow_work *work, struct seq_file *m)
-{
- struct fscache_operation *op =
- container_of(work, struct fscache_operation, slow_work);
-
- seq_printf(m, "FSC: OBJ%x OP%x: %s/%s fl=%lx",
- op->object->debug_id, op->debug_id,
- op->name, op->state, op->flags);
-}
-#endif
-
-const struct slow_work_ops fscache_op_slow_work_ops = {
- .owner = THIS_MODULE,
- .get_ref = fscache_op_get_ref,
- .put_ref = fscache_op_put_ref,
- .execute = fscache_op_execute,
-#ifdef CONFIG_SLOW_WORK_DEBUG
- .desc = fscache_op_desc,
-#endif
-};
page_busy:
/* we might want to wait here, but that could deadlock the allocator as
- * the slow-work threads writing to the cache may all end up sleeping
+ * the work threads writing to the cache may all end up sleeping
* on memory allocation */
fscache_stat(&fscache_n_store_vmscan_busy);
return false;
return -ENOMEM;
}
- fscache_operation_init(op, NULL);
- fscache_operation_init_slow(op, fscache_attr_changed_op);
- op->flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_EXCLUSIVE);
+ fscache_operation_init(op, fscache_attr_changed_op, NULL);
+ op->flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_EXCLUSIVE);
fscache_set_op_name(op, "Attr");
spin_lock(&cookie->lock);
}
EXPORT_SYMBOL(__fscache_attr_changed);
-/*
- * handle secondary execution given to a retrieval op on behalf of the
- * cache
- */
-static void fscache_retrieval_work(struct work_struct *work)
-{
- struct fscache_retrieval *op =
- container_of(work, struct fscache_retrieval, op.fast_work);
- unsigned long start;
-
- _enter("{OP%x}", op->op.debug_id);
-
- start = jiffies;
- op->op.processor(&op->op);
- fscache_hist(fscache_ops_histogram, start);
- fscache_put_operation(&op->op);
-}
-
/*
* release a retrieval op reference
*/
return NULL;
}
- fscache_operation_init(&op->op, fscache_release_retrieval_op);
+ fscache_operation_init(&op->op, NULL, fscache_release_retrieval_op);
op->op.flags = FSCACHE_OP_MYTHREAD | (1 << FSCACHE_OP_WAITING);
op->mapping = mapping;
op->end_io_func = end_io_func;
op->context = context;
op->start_time = jiffies;
- INIT_WORK(&op->op.fast_work, fscache_retrieval_work);
INIT_LIST_HEAD(&op->to_do);
fscache_set_op_name(&op->op, "Retr");
return op;
if (!op)
goto nomem;
- fscache_operation_init(&op->op, fscache_release_write_op);
- fscache_operation_init_slow(&op->op, fscache_write_op);
- op->op.flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_WAITING);
+ fscache_operation_init(&op->op, fscache_write_op,
+ fscache_release_write_op);
+ op->op.flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_WAITING);
fscache_set_op_name(&op->op, "Write1");
ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM);
fscache_stat(&fscache_n_store_ops);
fscache_stat(&fscache_n_stores_ok);
- /* the slow work queue now carries its own ref on the object */
+ /* the work queue now carries its own ref on the object */
fscache_put_operation(&op->op);
_leave(" = 0");
return 0;
select IP_SCTP if DLM_SCTP
select FS_POSIX_ACL
select CRC32
- select SLOW_WORK
select QUOTACTL
help
A cluster filesystem.
#include <linux/fs.h>
#include <linux/workqueue.h>
-#include <linux/slow-work.h>
#include <linux/dlm.h>
#include <linux/buffer_head.h>
struct gfs2_jdesc {
struct list_head jd_list;
struct list_head extent_list;
- struct slow_work jd_work;
+ struct work_struct jd_work;
struct inode *jd_inode;
unsigned long jd_flags;
#define JDF_RECOVERY 1
#include <linux/init.h>
#include <linux/gfs2_ondisk.h>
#include <asm/atomic.h>
-#include <linux/slow-work.h>
#include "gfs2.h"
#include "incore.h"
#include "util.h"
#include "glock.h"
#include "quota.h"
+#include "recovery.h"
static struct shrinker qd_shrinker = {
.shrink = gfs2_shrink_qd_memory,
if (error)
goto fail_unregister;
- error = slow_work_register_user(THIS_MODULE);
- if (error)
- goto fail_slow;
+ error = -ENOMEM;
+ gfs_recovery_wq = alloc_workqueue("gfs_recovery",
+ WQ_NON_REENTRANT | WQ_RESCUER, 0);
+ if (!gfs_recovery_wq)
+ goto fail_wq;
gfs2_register_debugfs();
return 0;
-fail_slow:
+fail_wq:
unregister_filesystem(&gfs2meta_fs_type);
fail_unregister:
unregister_filesystem(&gfs2_fs_type);
gfs2_unregister_debugfs();
unregister_filesystem(&gfs2_fs_type);
unregister_filesystem(&gfs2meta_fs_type);
- slow_work_unregister_user(THIS_MODULE);
+ destroy_workqueue(gfs_recovery_wq);
kmem_cache_destroy(gfs2_quotad_cachep);
kmem_cache_destroy(gfs2_rgrpd_cachep);
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/gfs2_ondisk.h>
-#include <linux/slow-work.h>
#include <linux/quotaops.h>
#include "gfs2.h"
break;
INIT_LIST_HEAD(&jd->extent_list);
- slow_work_init(&jd->jd_work, &gfs2_recover_ops);
+ INIT_WORK(&jd->jd_work, gfs2_recover_func);
jd->jd_inode = gfs2_lookupi(sdp->sd_jindex, &name, 1);
if (!jd->jd_inode || IS_ERR(jd->jd_inode)) {
if (!jd->jd_inode)
if (sdp->sd_lockstruct.ls_first) {
unsigned int x;
for (x = 0; x < sdp->sd_journals; x++) {
- error = gfs2_recover_journal(gfs2_jdesc_find(sdp, x));
+ error = gfs2_recover_journal(gfs2_jdesc_find(sdp, x),
+ true);
if (error) {
fs_err(sdp, "error recovering journal %u: %d\n",
x, error);
gfs2_others_may_mount(sdp);
} else if (!sdp->sd_args.ar_spectator) {
- error = gfs2_recover_journal(sdp->sd_jdesc);
+ error = gfs2_recover_journal(sdp->sd_jdesc, true);
if (error) {
fs_err(sdp, "error recovering my journal: %d\n", error);
goto fail_jinode_gh;
#include <linux/buffer_head.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>
-#include <linux/slow-work.h>
#include "gfs2.h"
#include "incore.h"
#include "util.h"
#include "dir.h"
+struct workqueue_struct *gfs_recovery_wq;
+
int gfs2_replay_read_block(struct gfs2_jdesc *jd, unsigned int blk,
struct buffer_head **bh)
{
kobject_uevent_env(&sdp->sd_kobj, KOBJ_CHANGE, envp);
}
-static int gfs2_recover_get_ref(struct slow_work *work)
-{
- struct gfs2_jdesc *jd = container_of(work, struct gfs2_jdesc, jd_work);
- if (test_and_set_bit(JDF_RECOVERY, &jd->jd_flags))
- return -EBUSY;
- return 0;
-}
-
-static void gfs2_recover_put_ref(struct slow_work *work)
-{
- struct gfs2_jdesc *jd = container_of(work, struct gfs2_jdesc, jd_work);
- clear_bit(JDF_RECOVERY, &jd->jd_flags);
- smp_mb__after_clear_bit();
- wake_up_bit(&jd->jd_flags, JDF_RECOVERY);
-}
-
-static void gfs2_recover_work(struct slow_work *work)
+void gfs2_recover_func(struct work_struct *work)
{
struct gfs2_jdesc *jd = container_of(work, struct gfs2_jdesc, jd_work);
struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
gfs2_glock_dq_uninit(&j_gh);
fs_info(sdp, "jid=%u: Done\n", jd->jd_jid);
- return;
+ goto done;
fail_gunlock_tr:
gfs2_glock_dq_uninit(&t_gh);
}
fs_info(sdp, "jid=%u: %s\n", jd->jd_jid, (error) ? "Failed" : "Done");
-
fail:
gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_GAVEUP);
+done:
+ clear_bit(JDF_RECOVERY, &jd->jd_flags);
+ smp_mb__after_clear_bit();
+ wake_up_bit(&jd->jd_flags, JDF_RECOVERY);
}
-struct slow_work_ops gfs2_recover_ops = {
- .owner = THIS_MODULE,
- .get_ref = gfs2_recover_get_ref,
- .put_ref = gfs2_recover_put_ref,
- .execute = gfs2_recover_work,
-};
-
-
static int gfs2_recovery_wait(void *word)
{
schedule();
return 0;
}
-int gfs2_recover_journal(struct gfs2_jdesc *jd)
+int gfs2_recover_journal(struct gfs2_jdesc *jd, bool wait)
{
int rv;
- rv = slow_work_enqueue(&jd->jd_work);
- if (rv)
- return rv;
- wait_on_bit(&jd->jd_flags, JDF_RECOVERY, gfs2_recovery_wait, TASK_UNINTERRUPTIBLE);
+
+ if (test_and_set_bit(JDF_RECOVERY, &jd->jd_flags))
+ return -EBUSY;
+
+ /* we have JDF_RECOVERY, queue should always succeed */
+ rv = queue_work(gfs_recovery_wq, &jd->jd_work);
+ BUG_ON(!rv);
+
+ if (wait)
+ wait_on_bit(&jd->jd_flags, JDF_RECOVERY, gfs2_recovery_wait,
+ TASK_UNINTERRUPTIBLE);
+
return 0;
}
#include "incore.h"
+extern struct workqueue_struct *gfs_recovery_wq;
+
static inline void gfs2_replay_incr_blk(struct gfs2_sbd *sdp, unsigned int *blk)
{
if (++*blk == sdp->sd_jdesc->jd_blocks)
extern int gfs2_find_jhead(struct gfs2_jdesc *jd,
struct gfs2_log_header_host *head);
-extern int gfs2_recover_journal(struct gfs2_jdesc *gfs2_jd);
-extern struct slow_work_ops gfs2_recover_ops;
+extern int gfs2_recover_journal(struct gfs2_jdesc *gfs2_jd, bool wait);
+extern void gfs2_recover_func(struct work_struct *work);
#endif /* __RECOVERY_DOT_H__ */
#include "quota.h"
#include "util.h"
#include "glops.h"
+#include "recovery.h"
struct gfs2_attr {
struct attribute attr;
list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
if (jd->jd_jid != jid)
continue;
- rv = slow_work_enqueue(&jd->jd_work);
+ rv = gfs2_recover_journal(jd, false);
break;
}
out:
#include <linux/idr.h>
#include <linux/fb.h>
-#include <linux/slow-work.h>
struct drm_device;
struct drm_mode_set;
/* output poll support */
bool poll_enabled;
- struct delayed_slow_work output_poll_slow_work;
+ struct delayed_work output_poll_work;
/* pointers to standard properties */
struct list_head property_blob_list;
/* migration should happen before other stuff but after perf */
CPU_PRI_PERF = 20,
CPU_PRI_MIGRATION = 10,
+ /* prepare workqueues for other notifiers */
+ CPU_PRI_WORKQUEUE = 5,
};
#ifdef CONFIG_SMP
#include <linux/fscache.h>
#include <linux/sched.h>
-#include <linux/slow-work.h>
+#include <linux/workqueue.h>
#define NR_MAXCACHES BITS_PER_LONG
typedef void (*fscache_operation_processor_t)(struct fscache_operation *op);
struct fscache_operation {
- union {
- struct work_struct fast_work; /* record for fast ops */
- struct slow_work slow_work; /* record for (very) slow ops */
- };
+ struct work_struct work; /* record for async ops */
struct list_head pend_link; /* link in object->pending_ops */
struct fscache_object *object; /* object to be operated upon */
unsigned long flags;
#define FSCACHE_OP_TYPE 0x000f /* operation type */
-#define FSCACHE_OP_FAST 0x0001 /* - fast op, processor may not sleep for disk */
-#define FSCACHE_OP_SLOW 0x0002 /* - (very) slow op, processor may sleep for disk */
-#define FSCACHE_OP_MYTHREAD 0x0003 /* - processing is done be issuing thread, not pool */
+#define FSCACHE_OP_ASYNC 0x0001 /* - async op, processor may sleep for disk */
+#define FSCACHE_OP_MYTHREAD 0x0002 /* - processing is done be issuing thread, not pool */
#define FSCACHE_OP_WAITING 4 /* cleared when op is woken */
#define FSCACHE_OP_EXCLUSIVE 5 /* exclusive op, other ops must wait */
#define FSCACHE_OP_DEAD 6 /* op is now dead */
/* operation releaser */
fscache_operation_release_t release;
-#ifdef CONFIG_SLOW_WORK_DEBUG
+#ifdef CONFIG_WORKQUEUE_DEBUGFS
+ struct work_struct put_work; /* work to delay operation put */
const char *name; /* operation name */
const char *state; /* operation state */
#define fscache_set_op_name(OP, N) do { (OP)->name = (N); } while(0)
};
extern atomic_t fscache_op_debug_id;
-extern const struct slow_work_ops fscache_op_slow_work_ops;
+extern void fscache_op_work_func(struct work_struct *work);
extern void fscache_enqueue_operation(struct fscache_operation *);
extern void fscache_put_operation(struct fscache_operation *);
* @release: The release function to assign
*
* Do basic initialisation of an operation. The caller must still set flags,
- * object, either fast_work or slow_work if necessary, and processor if needed.
+ * object and processor if needed.
*/
static inline void fscache_operation_init(struct fscache_operation *op,
- fscache_operation_release_t release)
+ fscache_operation_processor_t processor,
+ fscache_operation_release_t release)
{
+ INIT_WORK(&op->work, fscache_op_work_func);
atomic_set(&op->usage, 1);
op->debug_id = atomic_inc_return(&fscache_op_debug_id);
+ op->processor = processor;
op->release = release;
INIT_LIST_HEAD(&op->pend_link);
fscache_set_op_state(op, "Init");
}
-/**
- * fscache_operation_init_slow - Do additional initialisation of a slow op
- * @op: The operation to initialise
- * @processor: The processor function to assign
- *
- * Do additional initialisation of an operation as required for slow work.
- */
-static inline
-void fscache_operation_init_slow(struct fscache_operation *op,
- fscache_operation_processor_t processor)
-{
- op->processor = processor;
- slow_work_init(&op->slow_work, &fscache_op_slow_work_ops);
-}
-
/*
* data read operation
*/
struct fscache_cache *cache; /* cache that supplied this object */
struct fscache_cookie *cookie; /* netfs's file/index object */
struct fscache_object *parent; /* parent object */
- struct slow_work work; /* attention scheduling record */
+ struct work_struct work; /* attention scheduling record */
struct list_head dependents; /* FIFO of dependent objects */
struct list_head dep_link; /* link in parent's dependents list */
struct list_head pending_ops; /* unstarted operations on this object */
(test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \
(obj)->state >= FSCACHE_OBJECT_DYING)
-extern const struct slow_work_ops fscache_object_slow_work_ops;
+extern void fscache_object_work_func(struct work_struct *work);
/**
* fscache_object_init - Initialise a cache object description
spin_lock_init(&object->lock);
INIT_LIST_HEAD(&object->cache_link);
INIT_HLIST_NODE(&object->cookie_link);
- vslow_work_init(&object->work, &fscache_object_slow_work_ops);
+ INIT_WORK(&object->work, fscache_object_work_func);
INIT_LIST_HEAD(&object->dependents);
INIT_LIST_HEAD(&object->dep_link);
INIT_LIST_HEAD(&object->pending_ops);
extern void fscache_mark_pages_cached(struct fscache_retrieval *op,
struct pagevec *pagevec);
+extern bool fscache_object_sleep_till_congested(signed long *timeoutp);
+
extern enum fscache_checkaux fscache_check_aux(struct fscache_object *object,
const void *data,
uint16_t datalen);
void kthread_bind(struct task_struct *k, unsigned int cpu);
int kthread_stop(struct task_struct *k);
int kthread_should_stop(void);
+void *kthread_data(struct task_struct *k);
int kthreadd(void *unused);
extern struct task_struct *kthreadd_task;
+/*
+ * Simple work processor based on kthread.
+ *
+ * This provides easier way to make use of kthreads. A kthread_work
+ * can be queued and flushed using queue/flush_kthread_work()
+ * respectively. Queued kthread_works are processed by a kthread
+ * running kthread_worker_fn().
+ *
+ * A kthread_work can't be freed while it is executing.
+ */
+struct kthread_work;
+typedef void (*kthread_work_func_t)(struct kthread_work *work);
+
+struct kthread_worker {
+ spinlock_t lock;
+ struct list_head work_list;
+ struct task_struct *task;
+};
+
+struct kthread_work {
+ struct list_head node;
+ kthread_work_func_t func;
+ wait_queue_head_t done;
+ atomic_t flushing;
+ int queue_seq;
+ int done_seq;
+};
+
+#define KTHREAD_WORKER_INIT(worker) { \
+ .lock = SPIN_LOCK_UNLOCKED, \
+ .work_list = LIST_HEAD_INIT((worker).work_list), \
+ }
+
+#define KTHREAD_WORK_INIT(work, fn) { \
+ .node = LIST_HEAD_INIT((work).node), \
+ .func = (fn), \
+ .done = __WAIT_QUEUE_HEAD_INITIALIZER((work).done), \
+ .flushing = ATOMIC_INIT(0), \
+ }
+
+#define DEFINE_KTHREAD_WORKER(worker) \
+ struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
+
+#define DEFINE_KTHREAD_WORK(work, fn) \
+ struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
+
+static inline void init_kthread_worker(struct kthread_worker *worker)
+{
+ *worker = (struct kthread_worker)KTHREAD_WORKER_INIT(*worker);
+}
+
+static inline void init_kthread_work(struct kthread_work *work,
+ kthread_work_func_t fn)
+{
+ *work = (struct kthread_work)KTHREAD_WORK_INIT(*work, fn);
+}
+
+int kthread_worker_fn(void *worker_ptr);
+
+bool queue_kthread_work(struct kthread_worker *worker,
+ struct kthread_work *work);
+void flush_kthread_work(struct kthread_work *work);
+void flush_kthread_worker(struct kthread_worker *worker);
+
#endif /* _LINUX_KTHREAD_H */
struct ata_host *host;
struct device *dev;
+ struct mutex scsi_scan_mutex;
struct delayed_work hotplug_task;
struct work_struct scsi_rescan_task;
+++ /dev/null
-/* Worker thread pool for slow items, such as filesystem lookups or mkdirs
- *
- * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- *
- * See Documentation/slow-work.txt
- */
-
-#ifndef _LINUX_SLOW_WORK_H
-#define _LINUX_SLOW_WORK_H
-
-#ifdef CONFIG_SLOW_WORK
-
-#include <linux/sysctl.h>
-#include <linux/timer.h>
-
-struct slow_work;
-#ifdef CONFIG_SLOW_WORK_DEBUG
-struct seq_file;
-#endif
-
-/*
- * The operations used to support slow work items
- */
-struct slow_work_ops {
- /* owner */
- struct module *owner;
-
- /* get a ref on a work item
- * - return 0 if successful, -ve if not
- */
- int (*get_ref)(struct slow_work *work);
-
- /* discard a ref to a work item */
- void (*put_ref)(struct slow_work *work);
-
- /* execute a work item */
- void (*execute)(struct slow_work *work);
-
-#ifdef CONFIG_SLOW_WORK_DEBUG
- /* describe a work item for debugfs */
- void (*desc)(struct slow_work *work, struct seq_file *m);
-#endif
-};
-
-/*
- * A slow work item
- * - A reference is held on the parent object by the thread pool when it is
- * queued
- */
-struct slow_work {
- struct module *owner; /* the owning module */
- unsigned long flags;
-#define SLOW_WORK_PENDING 0 /* item pending (further) execution */
-#define SLOW_WORK_EXECUTING 1 /* item currently executing */
-#define SLOW_WORK_ENQ_DEFERRED 2 /* item enqueue deferred */
-#define SLOW_WORK_VERY_SLOW 3 /* item is very slow */
-#define SLOW_WORK_CANCELLING 4 /* item is being cancelled, don't enqueue */
-#define SLOW_WORK_DELAYED 5 /* item is struct delayed_slow_work with active timer */
- const struct slow_work_ops *ops; /* operations table for this item */
- struct list_head link; /* link in queue */
-#ifdef CONFIG_SLOW_WORK_DEBUG
- struct timespec mark; /* jiffies at which queued or exec begun */
-#endif
-};
-
-struct delayed_slow_work {
- struct slow_work work;
- struct timer_list timer;
-};
-
-/**
- * slow_work_init - Initialise a slow work item
- * @work: The work item to initialise
- * @ops: The operations to use to handle the slow work item
- *
- * Initialise a slow work item.
- */
-static inline void slow_work_init(struct slow_work *work,
- const struct slow_work_ops *ops)
-{
- work->flags = 0;
- work->ops = ops;
- INIT_LIST_HEAD(&work->link);
-}
-
-/**
- * slow_work_init - Initialise a delayed slow work item
- * @work: The work item to initialise
- * @ops: The operations to use to handle the slow work item
- *
- * Initialise a delayed slow work item.
- */
-static inline void delayed_slow_work_init(struct delayed_slow_work *dwork,
- const struct slow_work_ops *ops)
-{
- init_timer(&dwork->timer);
- slow_work_init(&dwork->work, ops);
-}
-
-/**
- * vslow_work_init - Initialise a very slow work item
- * @work: The work item to initialise
- * @ops: The operations to use to handle the slow work item
- *
- * Initialise a very slow work item. This item will be restricted such that
- * only a certain number of the pool threads will be able to execute items of
- * this type.
- */
-static inline void vslow_work_init(struct slow_work *work,
- const struct slow_work_ops *ops)
-{
- work->flags = 1 << SLOW_WORK_VERY_SLOW;
- work->ops = ops;
- INIT_LIST_HEAD(&work->link);
-}
-
-/**
- * slow_work_is_queued - Determine if a slow work item is on the work queue
- * work: The work item to test
- *
- * Determine if the specified slow-work item is on the work queue. This
- * returns true if it is actually on the queue.
- *
- * If the item is executing and has been marked for requeue when execution
- * finishes, then false will be returned.
- *
- * Anyone wishing to wait for completion of execution can wait on the
- * SLOW_WORK_EXECUTING bit.
- */
-static inline bool slow_work_is_queued(struct slow_work *work)
-{
- unsigned long flags = work->flags;
- return flags & SLOW_WORK_PENDING && !(flags & SLOW_WORK_EXECUTING);
-}
-
-extern int slow_work_enqueue(struct slow_work *work);
-extern void slow_work_cancel(struct slow_work *work);
-extern int slow_work_register_user(struct module *owner);
-extern void slow_work_unregister_user(struct module *owner);
-
-extern int delayed_slow_work_enqueue(struct delayed_slow_work *dwork,
- unsigned long delay);
-
-static inline void delayed_slow_work_cancel(struct delayed_slow_work *dwork)
-{
- slow_work_cancel(&dwork->work);
-}
-
-extern bool slow_work_sleep_till_thread_needed(struct slow_work *work,
- signed long *_timeout);
-
-#ifdef CONFIG_SYSCTL
-extern ctl_table slow_work_sysctls[];
-#endif
-
-#endif /* CONFIG_SLOW_WORK */
-#endif /* _LINUX_SLOW_WORK_H */
#include <linux/linkage.h>
#include <linux/bitops.h>
#include <linux/lockdep.h>
+#include <linux/threads.h>
#include <asm/atomic.h>
struct workqueue_struct;
*/
#define work_data_bits(work) ((unsigned long *)(&(work)->data))
+enum {
+ WORK_STRUCT_PENDING_BIT = 0, /* work item is pending execution */
+ WORK_STRUCT_CWQ_BIT = 1, /* data points to cwq */
+ WORK_STRUCT_LINKED_BIT = 2, /* next work is linked to this one */
+#ifdef CONFIG_DEBUG_OBJECTS_WORK
+ WORK_STRUCT_STATIC_BIT = 3, /* static initializer (debugobjects) */
+ WORK_STRUCT_COLOR_SHIFT = 4, /* color for workqueue flushing */
+#else
+ WORK_STRUCT_COLOR_SHIFT = 3, /* color for workqueue flushing */
+#endif
+
+ WORK_STRUCT_COLOR_BITS = 4,
+
+ WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT,
+ WORK_STRUCT_CWQ = 1 << WORK_STRUCT_CWQ_BIT,
+ WORK_STRUCT_LINKED = 1 << WORK_STRUCT_LINKED_BIT,
+#ifdef CONFIG_DEBUG_OBJECTS_WORK
+ WORK_STRUCT_STATIC = 1 << WORK_STRUCT_STATIC_BIT,
+#else
+ WORK_STRUCT_STATIC = 0,
+#endif
+
+ /*
+ * The last color is no color used for works which don't
+ * participate in workqueue flushing.
+ */
+ WORK_NR_COLORS = (1 << WORK_STRUCT_COLOR_BITS) - 1,
+ WORK_NO_COLOR = WORK_NR_COLORS,
+
+ /* special cpu IDs */
+ WORK_CPU_UNBOUND = NR_CPUS,
+ WORK_CPU_NONE = NR_CPUS + 1,
+ WORK_CPU_LAST = WORK_CPU_NONE,
+
+ /*
+ * Reserve 7 bits off of cwq pointer w/ debugobjects turned
+ * off. This makes cwqs aligned to 128 bytes which isn't too
+ * excessive while allowing 15 workqueue flush colors.
+ */
+ WORK_STRUCT_FLAG_BITS = WORK_STRUCT_COLOR_SHIFT +
+ WORK_STRUCT_COLOR_BITS,
+
+ WORK_STRUCT_FLAG_MASK = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
+ WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
+ WORK_STRUCT_NO_CPU = WORK_CPU_NONE << WORK_STRUCT_FLAG_BITS,
+
+ /* bit mask for work_busy() return values */
+ WORK_BUSY_PENDING = 1 << 0,
+ WORK_BUSY_RUNNING = 1 << 1,
+};
+
struct work_struct {
atomic_long_t data;
-#define WORK_STRUCT_PENDING 0 /* T if work item pending execution */
-#define WORK_STRUCT_STATIC 1 /* static initializer (debugobjects) */
-#define WORK_STRUCT_FLAG_MASK (3UL)
-#define WORK_STRUCT_WQ_DATA_MASK (~WORK_STRUCT_FLAG_MASK)
struct list_head entry;
work_func_t func;
#ifdef CONFIG_LOCKDEP
#endif
};
-#define WORK_DATA_INIT() ATOMIC_LONG_INIT(0)
-#define WORK_DATA_STATIC_INIT() ATOMIC_LONG_INIT(2)
+#define WORK_DATA_INIT() ATOMIC_LONG_INIT(WORK_STRUCT_NO_CPU)
+#define WORK_DATA_STATIC_INIT() \
+ ATOMIC_LONG_INIT(WORK_STRUCT_NO_CPU | WORK_STRUCT_STATIC)
struct delayed_work {
struct work_struct work;
#ifdef CONFIG_DEBUG_OBJECTS_WORK
extern void __init_work(struct work_struct *work, int onstack);
extern void destroy_work_on_stack(struct work_struct *work);
+static inline unsigned int work_static(struct work_struct *work)
+{
+ return *work_data_bits(work) & WORK_STRUCT_STATIC;
+}
#else
static inline void __init_work(struct work_struct *work, int onstack) { }
static inline void destroy_work_on_stack(struct work_struct *work) { }
+static inline unsigned int work_static(struct work_struct *work) { return 0; }
#endif
/*
* @work: The work item in question
*/
#define work_pending(work) \
- test_bit(WORK_STRUCT_PENDING, work_data_bits(work))
+ test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
/**
* delayed_work_pending - Find out whether a delayable work item is currently
* @work: The work item in question
*/
#define work_clear_pending(work) \
- clear_bit(WORK_STRUCT_PENDING, work_data_bits(work))
+ clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
+
+enum {
+ WQ_NON_REENTRANT = 1 << 0, /* guarantee non-reentrance */
+ WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
+ WQ_FREEZEABLE = 1 << 2, /* freeze during suspend */
+ WQ_RESCUER = 1 << 3, /* has an rescue worker */
+ WQ_HIGHPRI = 1 << 4, /* high priority */
+ WQ_CPU_INTENSIVE = 1 << 5, /* cpu instensive workqueue */
+
+ WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
+ WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */
+ WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
+};
+
+/* unbound wq's aren't per-cpu, scale max_active according to #cpus */
+#define WQ_UNBOUND_MAX_ACTIVE \
+ max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
+/*
+ * System-wide workqueues which are always present.
+ *
+ * system_wq is the one used by schedule[_delayed]_work[_on]().
+ * Multi-CPU multi-threaded. There are users which expect relatively
+ * short queue flush time. Don't queue works which can run for too
+ * long.
+ *
+ * system_long_wq is similar to system_wq but may host long running
+ * works. Queue flushing might take relatively long.
+ *
+ * system_nrt_wq is non-reentrant and guarantees that any given work
+ * item is never executed in parallel by multiple CPUs. Queue
+ * flushing might take relatively long.
+ *
+ * system_unbound_wq is unbound workqueue. Workers are not bound to
+ * any specific CPU, not concurrency managed, and all queued works are
+ * executed immediately as long as max_active limit is not reached and
+ * resources are available.
+ */
+extern struct workqueue_struct *system_wq;
+extern struct workqueue_struct *system_long_wq;
+extern struct workqueue_struct *system_nrt_wq;
+extern struct workqueue_struct *system_unbound_wq;
extern struct workqueue_struct *
-__create_workqueue_key(const char *name, int singlethread,
- int freezeable, int rt, struct lock_class_key *key,
- const char *lock_name);
+__alloc_workqueue_key(const char *name, unsigned int flags, int max_active,
+ struct lock_class_key *key, const char *lock_name);
#ifdef CONFIG_LOCKDEP
-#define __create_workqueue(name, singlethread, freezeable, rt) \
+#define alloc_workqueue(name, flags, max_active) \
({ \
static struct lock_class_key __key; \
const char *__lock_name; \
else \
__lock_name = #name; \
\
- __create_workqueue_key((name), (singlethread), \
- (freezeable), (rt), &__key, \
- __lock_name); \
+ __alloc_workqueue_key((name), (flags), (max_active), \
+ &__key, __lock_name); \
})
#else
-#define __create_workqueue(name, singlethread, freezeable, rt) \
- __create_workqueue_key((name), (singlethread), (freezeable), (rt), \
- NULL, NULL)
+#define alloc_workqueue(name, flags, max_active) \
+ __alloc_workqueue_key((name), (flags), (max_active), NULL, NULL)
#endif
-#define create_workqueue(name) __create_workqueue((name), 0, 0, 0)
-#define create_rt_workqueue(name) __create_workqueue((name), 0, 0, 1)
-#define create_freezeable_workqueue(name) __create_workqueue((name), 1, 1, 0)
-#define create_singlethread_workqueue(name) __create_workqueue((name), 1, 0, 0)
+#define create_workqueue(name) \
+ alloc_workqueue((name), WQ_RESCUER, 1)
+#define create_freezeable_workqueue(name) \
+ alloc_workqueue((name), WQ_FREEZEABLE | WQ_UNBOUND | WQ_RESCUER, 1)
+#define create_singlethread_workqueue(name) \
+ alloc_workqueue((name), WQ_UNBOUND | WQ_RESCUER, 1)
extern void destroy_workqueue(struct workqueue_struct *wq);
extern int schedule_delayed_work_on(int cpu, struct delayed_work *work,
unsigned long delay);
extern int schedule_on_each_cpu(work_func_t func);
-extern int current_is_keventd(void);
extern int keventd_up(void);
-extern void init_workqueues(void);
int execute_in_process_context(work_func_t fn, struct execute_work *);
extern int flush_work(struct work_struct *work);
-
extern int cancel_work_sync(struct work_struct *work);
+extern void workqueue_set_max_active(struct workqueue_struct *wq,
+ int max_active);
+extern bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq);
+extern unsigned int work_cpu(struct work_struct *work);
+extern unsigned int work_busy(struct work_struct *work);
+
/*
* Kill off a pending schedule_delayed_work(). Note that the work callback
* function may still be running on return from cancel_delayed_work(), unless
long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg);
#endif /* CONFIG_SMP */
+#ifdef CONFIG_FREEZER
+extern void freeze_workqueues_begin(void);
+extern bool freeze_workqueues_busy(void);
+extern void thaw_workqueues(void);
+#endif /* CONFIG_FREEZER */
+
#ifdef CONFIG_LOCKDEP
int in_workqueue_context(struct workqueue_struct *wq);
#endif
+
#endif
+++ /dev/null
-#undef TRACE_SYSTEM
-#define TRACE_SYSTEM workqueue
-
-#if !defined(_TRACE_WORKQUEUE_H) || defined(TRACE_HEADER_MULTI_READ)
-#define _TRACE_WORKQUEUE_H
-
-#include <linux/workqueue.h>
-#include <linux/sched.h>
-#include <linux/tracepoint.h>
-
-DECLARE_EVENT_CLASS(workqueue,
-
- TP_PROTO(struct task_struct *wq_thread, struct work_struct *work),
-
- TP_ARGS(wq_thread, work),
-
- TP_STRUCT__entry(
- __array(char, thread_comm, TASK_COMM_LEN)
- __field(pid_t, thread_pid)
- __field(work_func_t, func)
- ),
-
- TP_fast_assign(
- memcpy(__entry->thread_comm, wq_thread->comm, TASK_COMM_LEN);
- __entry->thread_pid = wq_thread->pid;
- __entry->func = work->func;
- ),
-
- TP_printk("thread=%s:%d func=%pf", __entry->thread_comm,
- __entry->thread_pid, __entry->func)
-);
-
-DEFINE_EVENT(workqueue, workqueue_insertion,
-
- TP_PROTO(struct task_struct *wq_thread, struct work_struct *work),
-
- TP_ARGS(wq_thread, work)
-);
-
-DEFINE_EVENT(workqueue, workqueue_execution,
-
- TP_PROTO(struct task_struct *wq_thread, struct work_struct *work),
-
- TP_ARGS(wq_thread, work)
-);
-
-/* Trace the creation of one workqueue thread on a cpu */
-TRACE_EVENT(workqueue_creation,
-
- TP_PROTO(struct task_struct *wq_thread, int cpu),
-
- TP_ARGS(wq_thread, cpu),
-
- TP_STRUCT__entry(
- __array(char, thread_comm, TASK_COMM_LEN)
- __field(pid_t, thread_pid)
- __field(int, cpu)
- ),
-
- TP_fast_assign(
- memcpy(__entry->thread_comm, wq_thread->comm, TASK_COMM_LEN);
- __entry->thread_pid = wq_thread->pid;
- __entry->cpu = cpu;
- ),
-
- TP_printk("thread=%s:%d cpu=%d", __entry->thread_comm,
- __entry->thread_pid, __entry->cpu)
-);
-
-TRACE_EVENT(workqueue_destruction,
-
- TP_PROTO(struct task_struct *wq_thread),
-
- TP_ARGS(wq_thread),
-
- TP_STRUCT__entry(
- __array(char, thread_comm, TASK_COMM_LEN)
- __field(pid_t, thread_pid)
- ),
-
- TP_fast_assign(
- memcpy(__entry->thread_comm, wq_thread->comm, TASK_COMM_LEN);
- __entry->thread_pid = wq_thread->pid;
- ),
-
- TP_printk("thread=%s:%d", __entry->thread_comm, __entry->thread_pid)
-);
-
-#endif /* _TRACE_WORKQUEUE_H */
-
-/* This part must be outside protection */
-#include <trace/define_trace.h>
source "arch/Kconfig"
-config SLOW_WORK
- default n
- bool
- help
- The slow work thread pool provides a number of dynamically allocated
- threads that can be used by the kernel to perform operations that
- take a relatively long time.
-
- An example of this would be CacheFiles doing a path lookup followed
- by a series of mkdirs and a create call, all of which have to touch
- disk.
-
- See Documentation/slow-work.txt.
-
-config SLOW_WORK_DEBUG
- bool "Slow work debugging through debugfs"
- default n
- depends on SLOW_WORK && DEBUG_FS
- help
- Display the contents of the slow work run queue through debugfs,
- including items currently executing.
-
- See Documentation/slow-work.txt.
-
endmenu # General setup
config HAVE_GENERIC_DMA_COHERENT
#include <linux/start_kernel.h>
#include <linux/security.h>
#include <linux/smp.h>
-#include <linux/workqueue.h>
#include <linux/profile.h>
#include <linux/rcupdate.h>
#include <linux/moduleparam.h>
*/
static void __init do_basic_setup(void)
{
- init_workqueues();
cpuset_init_smp();
usermodehelper_init();
init_tmpfs();
obj-$(CONFIG_X86_DS) += trace/
obj-$(CONFIG_RING_BUFFER) += trace/
obj-$(CONFIG_SMP) += sched_cpupri.o
-obj-$(CONFIG_SLOW_WORK) += slow-work.o
-obj-$(CONFIG_SLOW_WORK_DEBUG) += slow-work-debugfs.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o
*/
#include <linux/async.h>
-#include <linux/bug.h>
#include <linux/module.h>
#include <linux/wait.h>
#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/kthread.h>
-#include <linux/delay.h>
#include <linux/slab.h>
+#include <linux/workqueue.h>
#include <asm/atomic.h>
static async_cookie_t next_cookie = 1;
-#define MAX_THREADS 256
#define MAX_WORK 32768
static LIST_HEAD(async_pending);
static LIST_HEAD(async_running);
static DEFINE_SPINLOCK(async_lock);
-static int async_enabled = 0;
-
struct async_entry {
- struct list_head list;
- async_cookie_t cookie;
- async_func_ptr *func;
- void *data;
- struct list_head *running;
+ struct list_head list;
+ struct work_struct work;
+ async_cookie_t cookie;
+ async_func_ptr *func;
+ void *data;
+ struct list_head *running;
};
static DECLARE_WAIT_QUEUE_HEAD(async_done);
-static DECLARE_WAIT_QUEUE_HEAD(async_new);
static atomic_t entry_count;
-static atomic_t thread_count;
extern int initcall_debug;
spin_unlock_irqrestore(&async_lock, flags);
return ret;
}
+
/*
* pick the first pending entry and run it
*/
-static void run_one_entry(void)
+static void async_run_entry_fn(struct work_struct *work)
{
+ struct async_entry *entry =
+ container_of(work, struct async_entry, work);
unsigned long flags;
- struct async_entry *entry;
ktime_t calltime, delta, rettime;
- /* 1) pick one task from the pending queue */
-
+ /* 1) move self to the running queue */
spin_lock_irqsave(&async_lock, flags);
- if (list_empty(&async_pending))
- goto out;
- entry = list_first_entry(&async_pending, struct async_entry, list);
-
- /* 2) move it to the running queue */
list_move_tail(&entry->list, entry->running);
spin_unlock_irqrestore(&async_lock, flags);
- /* 3) run it (and print duration)*/
+ /* 2) run (and print duration) */
if (initcall_debug && system_state == SYSTEM_BOOTING) {
printk("calling %lli_%pF @ %i\n", (long long)entry->cookie,
entry->func, task_pid_nr(current));
(long long)ktime_to_ns(delta) >> 10);
}
- /* 4) remove it from the running queue */
+ /* 3) remove self from the running queue */
spin_lock_irqsave(&async_lock, flags);
list_del(&entry->list);
- /* 5) free the entry */
+ /* 4) free the entry */
kfree(entry);
atomic_dec(&entry_count);
spin_unlock_irqrestore(&async_lock, flags);
- /* 6) wake up any waiters. */
+ /* 5) wake up any waiters */
wake_up(&async_done);
- return;
-
-out:
- spin_unlock_irqrestore(&async_lock, flags);
}
-
static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct list_head *running)
{
struct async_entry *entry;
unsigned long flags;
async_cookie_t newcookie;
-
/* allow irq-off callers */
entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC);
* If we're out of memory or if there's too much work
* pending already, we execute synchronously.
*/
- if (!async_enabled || !entry || atomic_read(&entry_count) > MAX_WORK) {
+ if (!entry || atomic_read(&entry_count) > MAX_WORK) {
kfree(entry);
spin_lock_irqsave(&async_lock, flags);
newcookie = next_cookie++;
ptr(data, newcookie);
return newcookie;
}
+ INIT_WORK(&entry->work, async_run_entry_fn);
entry->func = ptr;
entry->data = data;
entry->running = running;
list_add_tail(&entry->list, &async_pending);
atomic_inc(&entry_count);
spin_unlock_irqrestore(&async_lock, flags);
- wake_up(&async_new);
+
+ /* schedule for execution */
+ queue_work(system_unbound_wq, &entry->work);
+
return newcookie;
}
async_synchronize_cookie_domain(cookie, &async_running);
}
EXPORT_SYMBOL_GPL(async_synchronize_cookie);
-
-
-static int async_thread(void *unused)
-{
- DECLARE_WAITQUEUE(wq, current);
- add_wait_queue(&async_new, &wq);
-
- while (!kthread_should_stop()) {
- int ret = HZ;
- set_current_state(TASK_INTERRUPTIBLE);
- /*
- * check the list head without lock.. false positives
- * are dealt with inside run_one_entry() while holding
- * the lock.
- */
- rmb();
- if (!list_empty(&async_pending))
- run_one_entry();
- else
- ret = schedule_timeout(HZ);
-
- if (ret == 0) {
- /*
- * we timed out, this means we as thread are redundant.
- * we sign off and die, but we to avoid any races there
- * is a last-straw check to see if work snuck in.
- */
- atomic_dec(&thread_count);
- wmb(); /* manager must see our departure first */
- if (list_empty(&async_pending))
- break;
- /*
- * woops work came in between us timing out and us
- * signing off; we need to stay alive and keep working.
- */
- atomic_inc(&thread_count);
- }
- }
- remove_wait_queue(&async_new, &wq);
-
- return 0;
-}
-
-static int async_manager_thread(void *unused)
-{
- DECLARE_WAITQUEUE(wq, current);
- add_wait_queue(&async_new, &wq);
-
- while (!kthread_should_stop()) {
- int tc, ec;
-
- set_current_state(TASK_INTERRUPTIBLE);
-
- tc = atomic_read(&thread_count);
- rmb();
- ec = atomic_read(&entry_count);
-
- while (tc < ec && tc < MAX_THREADS) {
- if (IS_ERR(kthread_run(async_thread, NULL, "async/%i",
- tc))) {
- msleep(100);
- continue;
- }
- atomic_inc(&thread_count);
- tc++;
- }
-
- schedule();
- }
- remove_wait_queue(&async_new, &wq);
-
- return 0;
-}
-
-static int __init async_init(void)
-{
- async_enabled =
- !IS_ERR(kthread_run(async_manager_thread, NULL, "async/mgr"));
-
- WARN_ON(!async_enabled);
- return 0;
-}
-
-core_initcall(async_init);
#include <linux/file.h>
#include <linux/module.h>
#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/freezer.h>
#include <trace/events/sched.h>
static DEFINE_SPINLOCK(kthread_create_lock);
struct kthread {
int should_stop;
+ void *data;
struct completion exited;
};
}
EXPORT_SYMBOL(kthread_should_stop);
+/**
+ * kthread_data - return data value specified on kthread creation
+ * @task: kthread task in question
+ *
+ * Return the data value specified when kthread @task was created.
+ * The caller is responsible for ensuring the validity of @task when
+ * calling this function.
+ */
+void *kthread_data(struct task_struct *task)
+{
+ return to_kthread(task)->data;
+}
+
static int kthread(void *_create)
{
/* Copy data: it's on kthread's stack */
int ret;
self.should_stop = 0;
+ self.data = data;
init_completion(&self.exited);
current->vfork_done = &self.exited;
return 0;
}
+
+/**
+ * kthread_worker_fn - kthread function to process kthread_worker
+ * @worker_ptr: pointer to initialized kthread_worker
+ *
+ * This function can be used as @threadfn to kthread_create() or
+ * kthread_run() with @worker_ptr argument pointing to an initialized
+ * kthread_worker. The started kthread will process work_list until
+ * the it is stopped with kthread_stop(). A kthread can also call
+ * this function directly after extra initialization.
+ *
+ * Different kthreads can be used for the same kthread_worker as long
+ * as there's only one kthread attached to it at any given time. A
+ * kthread_worker without an attached kthread simply collects queued
+ * kthread_works.
+ */
+int kthread_worker_fn(void *worker_ptr)
+{
+ struct kthread_worker *worker = worker_ptr;
+ struct kthread_work *work;
+
+ WARN_ON(worker->task);
+ worker->task = current;
+repeat:
+ set_current_state(TASK_INTERRUPTIBLE); /* mb paired w/ kthread_stop */
+
+ if (kthread_should_stop()) {
+ __set_current_state(TASK_RUNNING);
+ spin_lock_irq(&worker->lock);
+ worker->task = NULL;
+ spin_unlock_irq(&worker->lock);
+ return 0;
+ }
+
+ work = NULL;
+ spin_lock_irq(&worker->lock);
+ if (!list_empty(&worker->work_list)) {
+ work = list_first_entry(&worker->work_list,
+ struct kthread_work, node);
+ list_del_init(&work->node);
+ }
+ spin_unlock_irq(&worker->lock);
+
+ if (work) {
+ __set_current_state(TASK_RUNNING);
+ work->func(work);
+ smp_wmb(); /* wmb worker-b0 paired with flush-b1 */
+ work->done_seq = work->queue_seq;
+ smp_mb(); /* mb worker-b1 paired with flush-b0 */
+ if (atomic_read(&work->flushing))
+ wake_up_all(&work->done);
+ } else if (!freezing(current))
+ schedule();
+
+ try_to_freeze();
+ goto repeat;
+}
+EXPORT_SYMBOL_GPL(kthread_worker_fn);
+
+/**
+ * queue_kthread_work - queue a kthread_work
+ * @worker: target kthread_worker
+ * @work: kthread_work to queue
+ *
+ * Queue @work to work processor @task for async execution. @task
+ * must have been created with kthread_worker_create(). Returns %true
+ * if @work was successfully queued, %false if it was already pending.
+ */
+bool queue_kthread_work(struct kthread_worker *worker,
+ struct kthread_work *work)
+{
+ bool ret = false;
+ unsigned long flags;
+
+ spin_lock_irqsave(&worker->lock, flags);
+ if (list_empty(&work->node)) {
+ list_add_tail(&work->node, &worker->work_list);
+ work->queue_seq++;
+ if (likely(worker->task))
+ wake_up_process(worker->task);
+ ret = true;
+ }
+ spin_unlock_irqrestore(&worker->lock, flags);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(queue_kthread_work);
+
+/**
+ * flush_kthread_work - flush a kthread_work
+ * @work: work to flush
+ *
+ * If @work is queued or executing, wait for it to finish execution.
+ */
+void flush_kthread_work(struct kthread_work *work)
+{
+ int seq = work->queue_seq;
+
+ atomic_inc(&work->flushing);
+
+ /*
+ * mb flush-b0 paired with worker-b1, to make sure either
+ * worker sees the above increment or we see done_seq update.
+ */
+ smp_mb__after_atomic_inc();
+
+ /* A - B <= 0 tests whether B is in front of A regardless of overflow */
+ wait_event(work->done, seq - work->done_seq <= 0);
+ atomic_dec(&work->flushing);
+
+ /*
+ * rmb flush-b1 paired with worker-b0, to make sure our caller
+ * sees every change made by work->func().
+ */
+ smp_mb__after_atomic_dec();
+}
+EXPORT_SYMBOL_GPL(flush_kthread_work);
+
+struct kthread_flush_work {
+ struct kthread_work work;
+ struct completion done;
+};
+
+static void kthread_flush_work_fn(struct kthread_work *work)
+{
+ struct kthread_flush_work *fwork =
+ container_of(work, struct kthread_flush_work, work);
+ complete(&fwork->done);
+}
+
+/**
+ * flush_kthread_worker - flush all current works on a kthread_worker
+ * @worker: worker to flush
+ *
+ * Wait until all currently executing or pending works on @worker are
+ * finished.
+ */
+void flush_kthread_worker(struct kthread_worker *worker)
+{
+ struct kthread_flush_work fwork = {
+ KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),
+ COMPLETION_INITIALIZER_ONSTACK(fwork.done),
+ };
+
+ queue_kthread_work(worker, &fwork.work);
+ wait_for_completion(&fwork.done);
+}
+EXPORT_SYMBOL_GPL(flush_kthread_worker);
#include <linux/syscalls.h>
#include <linux/freezer.h>
#include <linux/delay.h>
+#include <linux/workqueue.h>
/*
* Timeout for stopping processes
struct task_struct *g, *p;
unsigned long end_time;
unsigned int todo;
+ bool wq_busy = false;
struct timeval start, end;
u64 elapsed_csecs64;
unsigned int elapsed_csecs;
do_gettimeofday(&start);
end_time = jiffies + TIMEOUT;
+
+ if (!sig_only)
+ freeze_workqueues_begin();
+
while (true) {
todo = 0;
read_lock(&tasklist_lock);
todo++;
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
+
+ if (!sig_only) {
+ wq_busy = freeze_workqueues_busy();
+ todo += wq_busy;
+ }
+
if (!todo || time_after(jiffies, end_time))
break;
*/
printk("\n");
printk(KERN_ERR "Freezing of tasks failed after %d.%02d seconds "
- "(%d tasks refusing to freeze):\n",
- elapsed_csecs / 100, elapsed_csecs % 100, todo);
+ "(%d tasks refusing to freeze, wq_busy=%d):\n",
+ elapsed_csecs / 100, elapsed_csecs % 100,
+ todo - wq_busy, wq_busy);
+
+ thaw_workqueues();
+
read_lock(&tasklist_lock);
do_each_thread(g, p) {
task_lock(p);
oom_killer_enable();
printk("Restarting tasks ... ");
+ thaw_workqueues();
thaw_tasks(true);
thaw_tasks(false);
schedule();
+++ /dev/null
-/* Slow work debugging
- *
- * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-
-#include <linux/module.h>
-#include <linux/slow-work.h>
-#include <linux/fs.h>
-#include <linux/time.h>
-#include <linux/seq_file.h>
-#include "slow-work.h"
-
-#define ITERATOR_SHIFT (BITS_PER_LONG - 4)
-#define ITERATOR_SELECTOR (0xfUL << ITERATOR_SHIFT)
-#define ITERATOR_COUNTER (~ITERATOR_SELECTOR)
-
-void slow_work_new_thread_desc(struct slow_work *work, struct seq_file *m)
-{
- seq_puts(m, "Slow-work: New thread");
-}
-
-/*
- * Render the time mark field on a work item into a 5-char time with units plus
- * a space
- */
-static void slow_work_print_mark(struct seq_file *m, struct slow_work *work)
-{
- struct timespec now, diff;
-
- now = CURRENT_TIME;
- diff = timespec_sub(now, work->mark);
-
- if (diff.tv_sec < 0)
- seq_puts(m, " -ve ");
- else if (diff.tv_sec == 0 && diff.tv_nsec < 1000)
- seq_printf(m, "%3luns ", diff.tv_nsec);
- else if (diff.tv_sec == 0 && diff.tv_nsec < 1000000)
- seq_printf(m, "%3luus ", diff.tv_nsec / 1000);
- else if (diff.tv_sec == 0 && diff.tv_nsec < 1000000000)
- seq_printf(m, "%3lums ", diff.tv_nsec / 1000000);
- else if (diff.tv_sec <= 1)
- seq_puts(m, " 1s ");
- else if (diff.tv_sec < 60)
- seq_printf(m, "%4lus ", diff.tv_sec);
- else if (diff.tv_sec < 60 * 60)
- seq_printf(m, "%4lum ", diff.tv_sec / 60);
- else if (diff.tv_sec < 60 * 60 * 24)
- seq_printf(m, "%4luh ", diff.tv_sec / 3600);
- else
- seq_puts(m, "exces ");
-}
-
-/*
- * Describe a slow work item for debugfs
- */
-static int slow_work_runqueue_show(struct seq_file *m, void *v)
-{
- struct slow_work *work;
- struct list_head *p = v;
- unsigned long id;
-
- switch ((unsigned long) v) {
- case 1:
- seq_puts(m, "THR PID ITEM ADDR FL MARK DESC\n");
- return 0;
- case 2:
- seq_puts(m, "=== ===== ================ == ===== ==========\n");
- return 0;
-
- case 3 ... 3 + SLOW_WORK_THREAD_LIMIT - 1:
- id = (unsigned long) v - 3;
-
- read_lock(&slow_work_execs_lock);
- work = slow_work_execs[id];
- if (work) {
- smp_read_barrier_depends();
-
- seq_printf(m, "%3lu %5d %16p %2lx ",
- id, slow_work_pids[id], work, work->flags);
- slow_work_print_mark(m, work);
-
- if (work->ops->desc)
- work->ops->desc(work, m);
- seq_putc(m, '\n');
- }
- read_unlock(&slow_work_execs_lock);
- return 0;
-
- default:
- work = list_entry(p, struct slow_work, link);
- seq_printf(m, "%3s - %16p %2lx ",
- work->flags & SLOW_WORK_VERY_SLOW ? "vsq" : "sq",
- work, work->flags);
- slow_work_print_mark(m, work);
-
- if (work->ops->desc)
- work->ops->desc(work, m);
- seq_putc(m, '\n');
- return 0;
- }
-}
-
-/*
- * map the iterator to a work item
- */
-static void *slow_work_runqueue_index(struct seq_file *m, loff_t *_pos)
-{
- struct list_head *p;
- unsigned long count, id;
-
- switch (*_pos >> ITERATOR_SHIFT) {
- case 0x0:
- if (*_pos == 0)
- *_pos = 1;
- if (*_pos < 3)
- return (void *)(unsigned long) *_pos;
- if (*_pos < 3 + SLOW_WORK_THREAD_LIMIT)
- for (id = *_pos - 3;
- id < SLOW_WORK_THREAD_LIMIT;
- id++, (*_pos)++)
- if (slow_work_execs[id])
- return (void *)(unsigned long) *_pos;
- *_pos = 0x1UL << ITERATOR_SHIFT;
-
- case 0x1:
- count = *_pos & ITERATOR_COUNTER;
- list_for_each(p, &slow_work_queue) {
- if (count == 0)
- return p;
- count--;
- }
- *_pos = 0x2UL << ITERATOR_SHIFT;
-
- case 0x2:
- count = *_pos & ITERATOR_COUNTER;
- list_for_each(p, &vslow_work_queue) {
- if (count == 0)
- return p;
- count--;
- }
- *_pos = 0x3UL << ITERATOR_SHIFT;
-
- default:
- return NULL;
- }
-}
-
-/*
- * set up the iterator to start reading from the first line
- */
-static void *slow_work_runqueue_start(struct seq_file *m, loff_t *_pos)
-{
- spin_lock_irq(&slow_work_queue_lock);
- return slow_work_runqueue_index(m, _pos);
-}
-
-/*
- * move to the next line
- */
-static void *slow_work_runqueue_next(struct seq_file *m, void *v, loff_t *_pos)
-{
- struct list_head *p = v;
- unsigned long selector = *_pos >> ITERATOR_SHIFT;
-
- (*_pos)++;
- switch (selector) {
- case 0x0:
- return slow_work_runqueue_index(m, _pos);
-
- case 0x1:
- if (*_pos >> ITERATOR_SHIFT == 0x1) {
- p = p->next;
- if (p != &slow_work_queue)
- return p;
- }
- *_pos = 0x2UL << ITERATOR_SHIFT;
- p = &vslow_work_queue;
-
- case 0x2:
- if (*_pos >> ITERATOR_SHIFT == 0x2) {
- p = p->next;
- if (p != &vslow_work_queue)
- return p;
- }
- *_pos = 0x3UL << ITERATOR_SHIFT;
-
- default:
- return NULL;
- }
-}
-
-/*
- * clean up after reading
- */
-static void slow_work_runqueue_stop(struct seq_file *m, void *v)
-{
- spin_unlock_irq(&slow_work_queue_lock);
-}
-
-static const struct seq_operations slow_work_runqueue_ops = {
- .start = slow_work_runqueue_start,
- .stop = slow_work_runqueue_stop,
- .next = slow_work_runqueue_next,
- .show = slow_work_runqueue_show,
-};
-
-/*
- * open "/sys/kernel/debug/slow_work/runqueue" to list queue contents
- */
-static int slow_work_runqueue_open(struct inode *inode, struct file *file)
-{
- return seq_open(file, &slow_work_runqueue_ops);
-}
-
-const struct file_operations slow_work_runqueue_fops = {
- .owner = THIS_MODULE,
- .open = slow_work_runqueue_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = seq_release,
-};
+++ /dev/null
-/* Worker thread pool for slow items, such as filesystem lookups or mkdirs
- *
- * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- *
- * See Documentation/slow-work.txt
- */
-
-#include <linux/module.h>
-#include <linux/slow-work.h>
-#include <linux/kthread.h>
-#include <linux/freezer.h>
-#include <linux/wait.h>
-#include <linux/debugfs.h>
-#include "slow-work.h"
-
-static void slow_work_cull_timeout(unsigned long);
-static void slow_work_oom_timeout(unsigned long);
-
-#ifdef CONFIG_SYSCTL
-static int slow_work_min_threads_sysctl(struct ctl_table *, int,
- void __user *, size_t *, loff_t *);
-
-static int slow_work_max_threads_sysctl(struct ctl_table *, int ,
- void __user *, size_t *, loff_t *);
-#endif
-
-/*
- * The pool of threads has at least min threads in it as long as someone is
- * using the facility, and may have as many as max.
- *
- * A portion of the pool may be processing very slow operations.
- */
-static unsigned slow_work_min_threads = 2;
-static unsigned slow_work_max_threads = 4;
-static unsigned vslow_work_proportion = 50; /* % of threads that may process
- * very slow work */
-
-#ifdef CONFIG_SYSCTL
-static const int slow_work_min_min_threads = 2;
-static int slow_work_max_max_threads = SLOW_WORK_THREAD_LIMIT;
-static const int slow_work_min_vslow = 1;
-static const int slow_work_max_vslow = 99;
-
-ctl_table slow_work_sysctls[] = {
- {
- .procname = "min-threads",
- .data = &slow_work_min_threads,
- .maxlen = sizeof(unsigned),
- .mode = 0644,
- .proc_handler = slow_work_min_threads_sysctl,
- .extra1 = (void *) &slow_work_min_min_threads,
- .extra2 = &slow_work_max_threads,
- },
- {
- .procname = "max-threads",
- .data = &slow_work_max_threads,
- .maxlen = sizeof(unsigned),
- .mode = 0644,
- .proc_handler = slow_work_max_threads_sysctl,
- .extra1 = &slow_work_min_threads,
- .extra2 = (void *) &slow_work_max_max_threads,
- },
- {
- .procname = "vslow-percentage",
- .data = &vslow_work_proportion,
- .maxlen = sizeof(unsigned),
- .mode = 0644,
- .proc_handler = proc_dointvec_minmax,
- .extra1 = (void *) &slow_work_min_vslow,
- .extra2 = (void *) &slow_work_max_vslow,
- },
- {}
-};
-#endif
-
-/*
- * The active state of the thread pool
- */
-static atomic_t slow_work_thread_count;
-static atomic_t vslow_work_executing_count;
-
-static bool slow_work_may_not_start_new_thread;
-static bool slow_work_cull; /* cull a thread due to lack of activity */
-static DEFINE_TIMER(slow_work_cull_timer, slow_work_cull_timeout, 0, 0);
-static DEFINE_TIMER(slow_work_oom_timer, slow_work_oom_timeout, 0, 0);
-static struct slow_work slow_work_new_thread; /* new thread starter */
-
-/*
- * slow work ID allocation (use slow_work_queue_lock)
- */
-static DECLARE_BITMAP(slow_work_ids, SLOW_WORK_THREAD_LIMIT);
-
-/*
- * Unregistration tracking to prevent put_ref() from disappearing during module
- * unload
- */
-#ifdef CONFIG_MODULES
-static struct module *slow_work_thread_processing[SLOW_WORK_THREAD_LIMIT];
-static struct module *slow_work_unreg_module;
-static struct slow_work *slow_work_unreg_work_item;
-static DECLARE_WAIT_QUEUE_HEAD(slow_work_unreg_wq);
-static DEFINE_MUTEX(slow_work_unreg_sync_lock);
-
-static void slow_work_set_thread_processing(int id, struct slow_work *work)
-{
- if (work)
- slow_work_thread_processing[id] = work->owner;
-}
-static void slow_work_done_thread_processing(int id, struct slow_work *work)
-{
- struct module *module = slow_work_thread_processing[id];
-
- slow_work_thread_processing[id] = NULL;
- smp_mb();
- if (slow_work_unreg_work_item == work ||
- slow_work_unreg_module == module)
- wake_up_all(&slow_work_unreg_wq);
-}
-static void slow_work_clear_thread_processing(int id)
-{
- slow_work_thread_processing[id] = NULL;
-}
-#else
-static void slow_work_set_thread_processing(int id, struct slow_work *work) {}
-static void slow_work_done_thread_processing(int id, struct slow_work *work) {}
-static void slow_work_clear_thread_processing(int id) {}
-#endif
-
-/*
- * Data for tracking currently executing items for indication through /proc
- */
-#ifdef CONFIG_SLOW_WORK_DEBUG
-struct slow_work *slow_work_execs[SLOW_WORK_THREAD_LIMIT];
-pid_t slow_work_pids[SLOW_WORK_THREAD_LIMIT];
-DEFINE_RWLOCK(slow_work_execs_lock);
-#endif
-
-/*
- * The queues of work items and the lock governing access to them. These are
- * shared between all the CPUs. It doesn't make sense to have per-CPU queues
- * as the number of threads bears no relation to the number of CPUs.
- *
- * There are two queues of work items: one for slow work items, and one for
- * very slow work items.
- */
-LIST_HEAD(slow_work_queue);
-LIST_HEAD(vslow_work_queue);
-DEFINE_SPINLOCK(slow_work_queue_lock);
-
-/*
- * The following are two wait queues that get pinged when a work item is placed
- * on an empty queue. These allow work items that are hogging a thread by
- * sleeping in a way that could be deferred to yield their thread and enqueue
- * themselves.
- */
-static DECLARE_WAIT_QUEUE_HEAD(slow_work_queue_waits_for_occupation);
-static DECLARE_WAIT_QUEUE_HEAD(vslow_work_queue_waits_for_occupation);
-
-/*
- * The thread controls. A variable used to signal to the threads that they
- * should exit when the queue is empty, a waitqueue used by the threads to wait
- * for signals, and a completion set by the last thread to exit.
- */
-static bool slow_work_threads_should_exit;
-static DECLARE_WAIT_QUEUE_HEAD(slow_work_thread_wq);
-static DECLARE_COMPLETION(slow_work_last_thread_exited);
-
-/*
- * The number of users of the thread pool and its lock. Whilst this is zero we
- * have no threads hanging around, and when this reaches zero, we wait for all
- * active or queued work items to complete and kill all the threads we do have.
- */
-static int slow_work_user_count;
-static DEFINE_MUTEX(slow_work_user_lock);
-
-static inline int slow_work_get_ref(struct slow_work *work)
-{
- if (work->ops->get_ref)
- return work->ops->get_ref(work);
-
- return 0;
-}
-
-static inline void slow_work_put_ref(struct slow_work *work)
-{
- if (work->ops->put_ref)
- work->ops->put_ref(work);
-}
-
-/*
- * Calculate the maximum number of active threads in the pool that are
- * permitted to process very slow work items.
- *
- * The answer is rounded up to at least 1, but may not equal or exceed the
- * maximum number of the threads in the pool. This means we always have at
- * least one thread that can process slow work items, and we always have at
- * least one thread that won't get tied up doing so.
- */
-static unsigned slow_work_calc_vsmax(void)
-{
- unsigned vsmax;
-
- vsmax = atomic_read(&slow_work_thread_count) * vslow_work_proportion;
- vsmax /= 100;
- vsmax = max(vsmax, 1U);
- return min(vsmax, slow_work_max_threads - 1);
-}
-
-/*
- * Attempt to execute stuff queued on a slow thread. Return true if we managed
- * it, false if there was nothing to do.
- */
-static noinline bool slow_work_execute(int id)
-{
- struct slow_work *work = NULL;
- unsigned vsmax;
- bool very_slow;
-
- vsmax = slow_work_calc_vsmax();
-
- /* see if we can schedule a new thread to be started if we're not
- * keeping up with the work */
- if (!waitqueue_active(&slow_work_thread_wq) &&
- (!list_empty(&slow_work_queue) || !list_empty(&vslow_work_queue)) &&
- atomic_read(&slow_work_thread_count) < slow_work_max_threads &&
- !slow_work_may_not_start_new_thread)
- slow_work_enqueue(&slow_work_new_thread);
-
- /* find something to execute */
- spin_lock_irq(&slow_work_queue_lock);
- if (!list_empty(&vslow_work_queue) &&
- atomic_read(&vslow_work_executing_count) < vsmax) {
- work = list_entry(vslow_work_queue.next,
- struct slow_work, link);
- if (test_and_set_bit_lock(SLOW_WORK_EXECUTING, &work->flags))
- BUG();
- list_del_init(&work->link);
- atomic_inc(&vslow_work_executing_count);
- very_slow = true;
- } else if (!list_empty(&slow_work_queue)) {
- work = list_entry(slow_work_queue.next,
- struct slow_work, link);
- if (test_and_set_bit_lock(SLOW_WORK_EXECUTING, &work->flags))
- BUG();
- list_del_init(&work->link);
- very_slow = false;
- } else {
- very_slow = false; /* avoid the compiler warning */
- }
-
- slow_work_set_thread_processing(id, work);
- if (work) {
- slow_work_mark_time(work);
- slow_work_begin_exec(id, work);
- }
-
- spin_unlock_irq(&slow_work_queue_lock);
-
- if (!work)
- return false;
-
- if (!test_and_clear_bit(SLOW_WORK_PENDING, &work->flags))
- BUG();
-
- /* don't execute if the work is in the process of being cancelled */
- if (!test_bit(SLOW_WORK_CANCELLING, &work->flags))
- work->ops->execute(work);
-
- if (very_slow)
- atomic_dec(&vslow_work_executing_count);
- clear_bit_unlock(SLOW_WORK_EXECUTING, &work->flags);
-
- /* wake up anyone waiting for this work to be complete */
- wake_up_bit(&work->flags, SLOW_WORK_EXECUTING);
-
- slow_work_end_exec(id, work);
-
- /* if someone tried to enqueue the item whilst we were executing it,
- * then it'll be left unenqueued to avoid multiple threads trying to
- * execute it simultaneously
- *
- * there is, however, a race between us testing the pending flag and
- * getting the spinlock, and between the enqueuer setting the pending
- * flag and getting the spinlock, so we use a deferral bit to tell us
- * if the enqueuer got there first
- */
- if (test_bit(SLOW_WORK_PENDING, &work->flags)) {
- spin_lock_irq(&slow_work_queue_lock);
-
- if (!test_bit(SLOW_WORK_EXECUTING, &work->flags) &&
- test_and_clear_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags))
- goto auto_requeue;
-
- spin_unlock_irq(&slow_work_queue_lock);
- }
-
- /* sort out the race between module unloading and put_ref() */
- slow_work_put_ref(work);
- slow_work_done_thread_processing(id, work);
-
- return true;
-
-auto_requeue:
- /* we must complete the enqueue operation
- * - we transfer our ref on the item back to the appropriate queue
- * - don't wake another thread up as we're awake already
- */
- slow_work_mark_time(work);
- if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags))
- list_add_tail(&work->link, &vslow_work_queue);
- else
- list_add_tail(&work->link, &slow_work_queue);
- spin_unlock_irq(&slow_work_queue_lock);
- slow_work_clear_thread_processing(id);
- return true;
-}
-
-/**
- * slow_work_sleep_till_thread_needed - Sleep till thread needed by other work
- * work: The work item under execution that wants to sleep
- * _timeout: Scheduler sleep timeout
- *
- * Allow a requeueable work item to sleep on a slow-work processor thread until
- * that thread is needed to do some other work or the sleep is interrupted by
- * some other event.
- *
- * The caller must set up a wake up event before calling this and must have set
- * the appropriate sleep mode (such as TASK_UNINTERRUPTIBLE) and tested its own
- * condition before calling this function as no test is made here.
- *
- * False is returned if there is nothing on the queue; true is returned if the
- * work item should be requeued
- */
-bool slow_work_sleep_till_thread_needed(struct slow_work *work,
- signed long *_timeout)
-{
- wait_queue_head_t *wfo_wq;
- struct list_head *queue;
-
- DEFINE_WAIT(wait);
-
- if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) {
- wfo_wq = &vslow_work_queue_waits_for_occupation;
- queue = &vslow_work_queue;
- } else {
- wfo_wq = &slow_work_queue_waits_for_occupation;
- queue = &slow_work_queue;
- }
-
- if (!list_empty(queue))
- return true;
-
- add_wait_queue_exclusive(wfo_wq, &wait);
- if (list_empty(queue))
- *_timeout = schedule_timeout(*_timeout);
- finish_wait(wfo_wq, &wait);
-
- return !list_empty(queue);
-}
-EXPORT_SYMBOL(slow_work_sleep_till_thread_needed);
-
-/**
- * slow_work_enqueue - Schedule a slow work item for processing
- * @work: The work item to queue
- *
- * Schedule a slow work item for processing. If the item is already undergoing
- * execution, this guarantees not to re-enter the execution routine until the
- * first execution finishes.
- *
- * The item is pinned by this function as it retains a reference to it, managed
- * through the item operations. The item is unpinned once it has been
- * executed.
- *
- * An item may hog the thread that is running it for a relatively large amount
- * of time, sufficient, for example, to perform several lookup, mkdir, create
- * and setxattr operations. It may sleep on I/O and may sleep to obtain locks.
- *
- * Conversely, if a number of items are awaiting processing, it may take some
- * time before any given item is given attention. The number of threads in the
- * pool may be increased to deal with demand, but only up to a limit.
- *
- * If SLOW_WORK_VERY_SLOW is set on the work item, then it will be placed in
- * the very slow queue, from which only a portion of the threads will be
- * allowed to pick items to execute. This ensures that very slow items won't
- * overly block ones that are just ordinarily slow.
- *
- * Returns 0 if successful, -EAGAIN if not (or -ECANCELED if cancelled work is
- * attempted queued)
- */
-int slow_work_enqueue(struct slow_work *work)
-{
- wait_queue_head_t *wfo_wq;
- struct list_head *queue;
- unsigned long flags;
- int ret;
-
- if (test_bit(SLOW_WORK_CANCELLING, &work->flags))
- return -ECANCELED;
-
- BUG_ON(slow_work_user_count <= 0);
- BUG_ON(!work);
- BUG_ON(!work->ops);
-
- /* when honouring an enqueue request, we only promise that we will run
- * the work function in the future; we do not promise to run it once
- * per enqueue request
- *
- * we use the PENDING bit to merge together repeat requests without
- * having to disable IRQs and take the spinlock, whilst still
- * maintaining our promise
- */
- if (!test_and_set_bit_lock(SLOW_WORK_PENDING, &work->flags)) {
- if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) {
- wfo_wq = &vslow_work_queue_waits_for_occupation;
- queue = &vslow_work_queue;
- } else {
- wfo_wq = &slow_work_queue_waits_for_occupation;
- queue = &slow_work_queue;
- }
-
- spin_lock_irqsave(&slow_work_queue_lock, flags);
-
- if (unlikely(test_bit(SLOW_WORK_CANCELLING, &work->flags)))
- goto cancelled;
-
- /* we promise that we will not attempt to execute the work
- * function in more than one thread simultaneously
- *
- * this, however, leaves us with a problem if we're asked to
- * enqueue the work whilst someone is executing the work
- * function as simply queueing the work immediately means that
- * another thread may try executing it whilst it is already
- * under execution
- *
- * to deal with this, we set the ENQ_DEFERRED bit instead of
- * enqueueing, and the thread currently executing the work
- * function will enqueue the work item when the work function
- * returns and it has cleared the EXECUTING bit
- */
- if (test_bit(SLOW_WORK_EXECUTING, &work->flags)) {
- set_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags);
- } else {
- ret = slow_work_get_ref(work);
- if (ret < 0)
- goto failed;
- slow_work_mark_time(work);
- list_add_tail(&work->link, queue);
- wake_up(&slow_work_thread_wq);
-
- /* if someone who could be requeued is sleeping on a
- * thread, then ask them to yield their thread */
- if (work->link.prev == queue)
- wake_up(wfo_wq);
- }
-
- spin_unlock_irqrestore(&slow_work_queue_lock, flags);
- }
- return 0;
-
-cancelled:
- ret = -ECANCELED;
-failed:
- spin_unlock_irqrestore(&slow_work_queue_lock, flags);
- return ret;
-}
-EXPORT_SYMBOL(slow_work_enqueue);
-
-static int slow_work_wait(void *word)
-{
- schedule();
- return 0;
-}
-
-/**
- * slow_work_cancel - Cancel a slow work item
- * @work: The work item to cancel
- *
- * This function will cancel a previously enqueued work item. If we cannot
- * cancel the work item, it is guarenteed to have run when this function
- * returns.
- */
-void slow_work_cancel(struct slow_work *work)
-{
- bool wait = true, put = false;
-
- set_bit(SLOW_WORK_CANCELLING, &work->flags);
- smp_mb();
-
- /* if the work item is a delayed work item with an active timer, we
- * need to wait for the timer to finish _before_ getting the spinlock,
- * lest we deadlock against the timer routine
- *
- * the timer routine will leave DELAYED set if it notices the
- * CANCELLING flag in time
- */
- if (test_bit(SLOW_WORK_DELAYED, &work->flags)) {
- struct delayed_slow_work *dwork =
- container_of(work, struct delayed_slow_work, work);
- del_timer_sync(&dwork->timer);
- }
-
- spin_lock_irq(&slow_work_queue_lock);
-
- if (test_bit(SLOW_WORK_DELAYED, &work->flags)) {
- /* the timer routine aborted or never happened, so we are left
- * holding the timer's reference on the item and should just
- * drop the pending flag and wait for any ongoing execution to
- * finish */
- struct delayed_slow_work *dwork =
- container_of(work, struct delayed_slow_work, work);
-
- BUG_ON(timer_pending(&dwork->timer));
- BUG_ON(!list_empty(&work->link));
-
- clear_bit(SLOW_WORK_DELAYED, &work->flags);
- put = true;
- clear_bit(SLOW_WORK_PENDING, &work->flags);
-
- } else if (test_bit(SLOW_WORK_PENDING, &work->flags) &&
- !list_empty(&work->link)) {
- /* the link in the pending queue holds a reference on the item
- * that we will need to release */
- list_del_init(&work->link);
- wait = false;
- put = true;
- clear_bit(SLOW_WORK_PENDING, &work->flags);
-
- } else if (test_and_clear_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags)) {
- /* the executor is holding our only reference on the item, so
- * we merely need to wait for it to finish executing */
- clear_bit(SLOW_WORK_PENDING, &work->flags);
- }
-
- spin_unlock_irq(&slow_work_queue_lock);
-
- /* the EXECUTING flag is set by the executor whilst the spinlock is set
- * and before the item is dequeued - so assuming the above doesn't
- * actually dequeue it, simply waiting for the EXECUTING flag to be
- * released here should be sufficient */
- if (wait)
- wait_on_bit(&work->flags, SLOW_WORK_EXECUTING, slow_work_wait,
- TASK_UNINTERRUPTIBLE);
-
- clear_bit(SLOW_WORK_CANCELLING, &work->flags);
- if (put)
- slow_work_put_ref(work);
-}
-EXPORT_SYMBOL(slow_work_cancel);
-
-/*
- * Handle expiry of the delay timer, indicating that a delayed slow work item
- * should now be queued if not cancelled
- */
-static void delayed_slow_work_timer(unsigned long data)
-{
- wait_queue_head_t *wfo_wq;
- struct list_head *queue;
- struct slow_work *work = (struct slow_work *) data;
- unsigned long flags;
- bool queued = false, put = false, first = false;
-
- if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) {
- wfo_wq = &vslow_work_queue_waits_for_occupation;
- queue = &vslow_work_queue;
- } else {
- wfo_wq = &slow_work_queue_waits_for_occupation;
- queue = &slow_work_queue;
- }
-
- spin_lock_irqsave(&slow_work_queue_lock, flags);
- if (likely(!test_bit(SLOW_WORK_CANCELLING, &work->flags))) {
- clear_bit(SLOW_WORK_DELAYED, &work->flags);
-
- if (test_bit(SLOW_WORK_EXECUTING, &work->flags)) {
- /* we discard the reference the timer was holding in
- * favour of the one the executor holds */
- set_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags);
- put = true;
- } else {
- slow_work_mark_time(work);
- list_add_tail(&work->link, queue);
- queued = true;
- if (work->link.prev == queue)
- first = true;
- }
- }
-
- spin_unlock_irqrestore(&slow_work_queue_lock, flags);
- if (put)
- slow_work_put_ref(work);
- if (first)
- wake_up(wfo_wq);
- if (queued)
- wake_up(&slow_work_thread_wq);
-}
-
-/**
- * delayed_slow_work_enqueue - Schedule a delayed slow work item for processing
- * @dwork: The delayed work item to queue
- * @delay: When to start executing the work, in jiffies from now
- *
- * This is similar to slow_work_enqueue(), but it adds a delay before the work
- * is actually queued for processing.
- *
- * The item can have delayed processing requested on it whilst it is being
- * executed. The delay will begin immediately, and if it expires before the
- * item finishes executing, the item will be placed back on the queue when it
- * has done executing.
- */
-int delayed_slow_work_enqueue(struct delayed_slow_work *dwork,
- unsigned long delay)
-{
- struct slow_work *work = &dwork->work;
- unsigned long flags;
- int ret;
-
- if (delay == 0)
- return slow_work_enqueue(&dwork->work);
-
- BUG_ON(slow_work_user_count <= 0);
- BUG_ON(!work);
- BUG_ON(!work->ops);
-
- if (test_bit(SLOW_WORK_CANCELLING, &work->flags))
- return -ECANCELED;
-
- if (!test_and_set_bit_lock(SLOW_WORK_PENDING, &work->flags)) {
- spin_lock_irqsave(&slow_work_queue_lock, flags);
-
- if (test_bit(SLOW_WORK_CANCELLING, &work->flags))
- goto cancelled;
-
- /* the timer holds a reference whilst it is pending */
- ret = slow_work_get_ref(work);
- if (ret < 0)
- goto cant_get_ref;
-
- if (test_and_set_bit(SLOW_WORK_DELAYED, &work->flags))
- BUG();
- dwork->timer.expires = jiffies + delay;
- dwork->timer.data = (unsigned long) work;
- dwork->timer.function = delayed_slow_work_timer;
- add_timer(&dwork->timer);
-
- spin_unlock_irqrestore(&slow_work_queue_lock, flags);
- }
-
- return 0;
-
-cancelled:
- ret = -ECANCELED;
-cant_get_ref:
- spin_unlock_irqrestore(&slow_work_queue_lock, flags);
- return ret;
-}
-EXPORT_SYMBOL(delayed_slow_work_enqueue);
-
-/*
- * Schedule a cull of the thread pool at some time in the near future
- */
-static void slow_work_schedule_cull(void)
-{
- mod_timer(&slow_work_cull_timer,
- round_jiffies(jiffies + SLOW_WORK_CULL_TIMEOUT));
-}
-
-/*
- * Worker thread culling algorithm
- */
-static bool slow_work_cull_thread(void)
-{
- unsigned long flags;
- bool do_cull = false;
-
- spin_lock_irqsave(&slow_work_queue_lock, flags);
-
- if (slow_work_cull) {
- slow_work_cull = false;
-
- if (list_empty(&slow_work_queue) &&
- list_empty(&vslow_work_queue) &&
- atomic_read(&slow_work_thread_count) >
- slow_work_min_threads) {
- slow_work_schedule_cull();
- do_cull = true;
- }
- }
-
- spin_unlock_irqrestore(&slow_work_queue_lock, flags);
- return do_cull;
-}
-
-/*
- * Determine if there is slow work available for dispatch
- */
-static inline bool slow_work_available(int vsmax)
-{
- return !list_empty(&slow_work_queue) ||
- (!list_empty(&vslow_work_queue) &&
- atomic_read(&vslow_work_executing_count) < vsmax);
-}
-
-/*
- * Worker thread dispatcher
- */
-static int slow_work_thread(void *_data)
-{
- int vsmax, id;
-
- DEFINE_WAIT(wait);
-
- set_freezable();
- set_user_nice(current, -5);
-
- /* allocate ourselves an ID */
- spin_lock_irq(&slow_work_queue_lock);
- id = find_first_zero_bit(slow_work_ids, SLOW_WORK_THREAD_LIMIT);
- BUG_ON(id < 0 || id >= SLOW_WORK_THREAD_LIMIT);
- __set_bit(id, slow_work_ids);
- slow_work_set_thread_pid(id, current->pid);
- spin_unlock_irq(&slow_work_queue_lock);
-
- sprintf(current->comm, "kslowd%03u", id);
-
- for (;;) {
- vsmax = vslow_work_proportion;
- vsmax *= atomic_read(&slow_work_thread_count);
- vsmax /= 100;
-
- prepare_to_wait_exclusive(&slow_work_thread_wq, &wait,
- TASK_INTERRUPTIBLE);
- if (!freezing(current) &&
- !slow_work_threads_should_exit &&
- !slow_work_available(vsmax) &&
- !slow_work_cull)
- schedule();
- finish_wait(&slow_work_thread_wq, &wait);
-
- try_to_freeze();
-
- vsmax = vslow_work_proportion;
- vsmax *= atomic_read(&slow_work_thread_count);
- vsmax /= 100;
-
- if (slow_work_available(vsmax) && slow_work_execute(id)) {
- cond_resched();
- if (list_empty(&slow_work_queue) &&
- list_empty(&vslow_work_queue) &&
- atomic_read(&slow_work_thread_count) >
- slow_work_min_threads)
- slow_work_schedule_cull();
- continue;
- }
-
- if (slow_work_threads_should_exit)
- break;
-
- if (slow_work_cull && slow_work_cull_thread())
- break;
- }
-
- spin_lock_irq(&slow_work_queue_lock);
- slow_work_set_thread_pid(id, 0);
- __clear_bit(id, slow_work_ids);
- spin_unlock_irq(&slow_work_queue_lock);
-
- if (atomic_dec_and_test(&slow_work_thread_count))
- complete_and_exit(&slow_work_last_thread_exited, 0);
- return 0;
-}
-
-/*
- * Handle thread cull timer expiration
- */
-static void slow_work_cull_timeout(unsigned long data)
-{
- slow_work_cull = true;
- wake_up(&slow_work_thread_wq);
-}
-
-/*
- * Start a new slow work thread
- */
-static void slow_work_new_thread_execute(struct slow_work *work)
-{
- struct task_struct *p;
-
- if (slow_work_threads_should_exit)
- return;
-
- if (atomic_read(&slow_work_thread_count) >= slow_work_max_threads)
- return;
-
- if (!mutex_trylock(&slow_work_user_lock))
- return;
-
- slow_work_may_not_start_new_thread = true;
- atomic_inc(&slow_work_thread_count);
- p = kthread_run(slow_work_thread, NULL, "kslowd");
- if (IS_ERR(p)) {
- printk(KERN_DEBUG "Slow work thread pool: OOM\n");
- if (atomic_dec_and_test(&slow_work_thread_count))
- BUG(); /* we're running on a slow work thread... */
- mod_timer(&slow_work_oom_timer,
- round_jiffies(jiffies + SLOW_WORK_OOM_TIMEOUT));
- } else {
- /* ratelimit the starting of new threads */
- mod_timer(&slow_work_oom_timer, jiffies + 1);
- }
-
- mutex_unlock(&slow_work_user_lock);
-}
-
-static const struct slow_work_ops slow_work_new_thread_ops = {
- .owner = THIS_MODULE,
- .execute = slow_work_new_thread_execute,
-#ifdef CONFIG_SLOW_WORK_DEBUG
- .desc = slow_work_new_thread_desc,
-#endif
-};
-
-/*
- * post-OOM new thread start suppression expiration
- */
-static void slow_work_oom_timeout(unsigned long data)
-{
- slow_work_may_not_start_new_thread = false;
-}
-
-#ifdef CONFIG_SYSCTL
-/*
- * Handle adjustment of the minimum number of threads
- */
-static int slow_work_min_threads_sysctl(struct ctl_table *table, int write,
- void __user *buffer,
- size_t *lenp, loff_t *ppos)
-{
- int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
- int n;
-
- if (ret == 0) {
- mutex_lock(&slow_work_user_lock);
- if (slow_work_user_count > 0) {
- /* see if we need to start or stop threads */
- n = atomic_read(&slow_work_thread_count) -
- slow_work_min_threads;
-
- if (n < 0 && !slow_work_may_not_start_new_thread)
- slow_work_enqueue(&slow_work_new_thread);
- else if (n > 0)
- slow_work_schedule_cull();
- }
- mutex_unlock(&slow_work_user_lock);
- }
-
- return ret;
-}
-
-/*
- * Handle adjustment of the maximum number of threads
- */
-static int slow_work_max_threads_sysctl(struct ctl_table *table, int write,
- void __user *buffer,
- size_t *lenp, loff_t *ppos)
-{
- int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
- int n;
-
- if (ret == 0) {
- mutex_lock(&slow_work_user_lock);
- if (slow_work_user_count > 0) {
- /* see if we need to stop threads */
- n = slow_work_max_threads -
- atomic_read(&slow_work_thread_count);
-
- if (n < 0)
- slow_work_schedule_cull();
- }
- mutex_unlock(&slow_work_user_lock);
- }
-
- return ret;
-}
-#endif /* CONFIG_SYSCTL */
-
-/**
- * slow_work_register_user - Register a user of the facility
- * @module: The module about to make use of the facility
- *
- * Register a user of the facility, starting up the initial threads if there
- * aren't any other users at this point. This will return 0 if successful, or
- * an error if not.
- */
-int slow_work_register_user(struct module *module)
-{
- struct task_struct *p;
- int loop;
-
- mutex_lock(&slow_work_user_lock);
-
- if (slow_work_user_count == 0) {
- printk(KERN_NOTICE "Slow work thread pool: Starting up\n");
- init_completion(&slow_work_last_thread_exited);
-
- slow_work_threads_should_exit = false;
- slow_work_init(&slow_work_new_thread,
- &slow_work_new_thread_ops);
- slow_work_may_not_start_new_thread = false;
- slow_work_cull = false;
-
- /* start the minimum number of threads */
- for (loop = 0; loop < slow_work_min_threads; loop++) {
- atomic_inc(&slow_work_thread_count);
- p = kthread_run(slow_work_thread, NULL, "kslowd");
- if (IS_ERR(p))
- goto error;
- }
- printk(KERN_NOTICE "Slow work thread pool: Ready\n");
- }
-
- slow_work_user_count++;
- mutex_unlock(&slow_work_user_lock);
- return 0;
-
-error:
- if (atomic_dec_and_test(&slow_work_thread_count))
- complete(&slow_work_last_thread_exited);
- if (loop > 0) {
- printk(KERN_ERR "Slow work thread pool:"
- " Aborting startup on ENOMEM\n");
- slow_work_threads_should_exit = true;
- wake_up_all(&slow_work_thread_wq);
- wait_for_completion(&slow_work_last_thread_exited);
- printk(KERN_ERR "Slow work thread pool: Aborted\n");
- }
- mutex_unlock(&slow_work_user_lock);
- return PTR_ERR(p);
-}
-EXPORT_SYMBOL(slow_work_register_user);
-
-/*
- * wait for all outstanding items from the calling module to complete
- * - note that more items may be queued whilst we're waiting
- */
-static void slow_work_wait_for_items(struct module *module)
-{
-#ifdef CONFIG_MODULES
- DECLARE_WAITQUEUE(myself, current);
- struct slow_work *work;
- int loop;
-
- mutex_lock(&slow_work_unreg_sync_lock);
- add_wait_queue(&slow_work_unreg_wq, &myself);
-
- for (;;) {
- spin_lock_irq(&slow_work_queue_lock);
-
- /* first of all, we wait for the last queued item in each list
- * to be processed */
- list_for_each_entry_reverse(work, &vslow_work_queue, link) {
- if (work->owner == module) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- slow_work_unreg_work_item = work;
- goto do_wait;
- }
- }
- list_for_each_entry_reverse(work, &slow_work_queue, link) {
- if (work->owner == module) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- slow_work_unreg_work_item = work;
- goto do_wait;
- }
- }
-
- /* then we wait for the items being processed to finish */
- slow_work_unreg_module = module;
- smp_mb();
- for (loop = 0; loop < SLOW_WORK_THREAD_LIMIT; loop++) {
- if (slow_work_thread_processing[loop] == module)
- goto do_wait;
- }
- spin_unlock_irq(&slow_work_queue_lock);
- break; /* okay, we're done */
-
- do_wait:
- spin_unlock_irq(&slow_work_queue_lock);
- schedule();
- slow_work_unreg_work_item = NULL;
- slow_work_unreg_module = NULL;
- }
-
- remove_wait_queue(&slow_work_unreg_wq, &myself);
- mutex_unlock(&slow_work_unreg_sync_lock);
-#endif /* CONFIG_MODULES */
-}
-
-/**
- * slow_work_unregister_user - Unregister a user of the facility
- * @module: The module whose items should be cleared
- *
- * Unregister a user of the facility, killing all the threads if this was the
- * last one.
- *
- * This waits for all the work items belonging to the nominated module to go
- * away before proceeding.
- */
-void slow_work_unregister_user(struct module *module)
-{
- /* first of all, wait for all outstanding items from the calling module
- * to complete */
- if (module)
- slow_work_wait_for_items(module);
-
- /* then we can actually go about shutting down the facility if need
- * be */
- mutex_lock(&slow_work_user_lock);
-
- BUG_ON(slow_work_user_count <= 0);
-
- slow_work_user_count--;
- if (slow_work_user_count == 0) {
- printk(KERN_NOTICE "Slow work thread pool: Shutting down\n");
- slow_work_threads_should_exit = true;
- del_timer_sync(&slow_work_cull_timer);
- del_timer_sync(&slow_work_oom_timer);
- wake_up_all(&slow_work_thread_wq);
- wait_for_completion(&slow_work_last_thread_exited);
- printk(KERN_NOTICE "Slow work thread pool:"
- " Shut down complete\n");
- }
-
- mutex_unlock(&slow_work_user_lock);
-}
-EXPORT_SYMBOL(slow_work_unregister_user);
-
-/*
- * Initialise the slow work facility
- */
-static int __init init_slow_work(void)
-{
- unsigned nr_cpus = num_possible_cpus();
-
- if (slow_work_max_threads < nr_cpus)
- slow_work_max_threads = nr_cpus;
-#ifdef CONFIG_SYSCTL
- if (slow_work_max_max_threads < nr_cpus * 2)
- slow_work_max_max_threads = nr_cpus * 2;
-#endif
-#ifdef CONFIG_SLOW_WORK_DEBUG
- {
- struct dentry *dbdir;
-
- dbdir = debugfs_create_dir("slow_work", NULL);
- if (dbdir && !IS_ERR(dbdir))
- debugfs_create_file("runqueue", S_IFREG | 0400, dbdir,
- NULL, &slow_work_runqueue_fops);
- }
-#endif
- return 0;
-}
-
-subsys_initcall(init_slow_work);
+++ /dev/null
-/* Slow work private definitions
- *
- * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-
-#define SLOW_WORK_CULL_TIMEOUT (5 * HZ) /* cull threads 5s after running out of
- * things to do */
-#define SLOW_WORK_OOM_TIMEOUT (5 * HZ) /* can't start new threads for 5s after
- * OOM */
-
-#define SLOW_WORK_THREAD_LIMIT 255 /* abs maximum number of slow-work threads */
-
-/*
- * slow-work.c
- */
-#ifdef CONFIG_SLOW_WORK_DEBUG
-extern struct slow_work *slow_work_execs[];
-extern pid_t slow_work_pids[];
-extern rwlock_t slow_work_execs_lock;
-#endif
-
-extern struct list_head slow_work_queue;
-extern struct list_head vslow_work_queue;
-extern spinlock_t slow_work_queue_lock;
-
-/*
- * slow-work-debugfs.c
- */
-#ifdef CONFIG_SLOW_WORK_DEBUG
-extern const struct file_operations slow_work_runqueue_fops;
-
-extern void slow_work_new_thread_desc(struct slow_work *, struct seq_file *);
-#endif
-
-/*
- * Helper functions
- */
-static inline void slow_work_set_thread_pid(int id, pid_t pid)
-{
-#ifdef CONFIG_SLOW_WORK_DEBUG
- slow_work_pids[id] = pid;
-#endif
-}
-
-static inline void slow_work_mark_time(struct slow_work *work)
-{
-#ifdef CONFIG_SLOW_WORK_DEBUG
- work->mark = CURRENT_TIME;
-#endif
-}
-
-static inline void slow_work_begin_exec(int id, struct slow_work *work)
-{
-#ifdef CONFIG_SLOW_WORK_DEBUG
- slow_work_execs[id] = work;
-#endif
-}
-
-static inline void slow_work_end_exec(int id, struct slow_work *work)
-{
-#ifdef CONFIG_SLOW_WORK_DEBUG
- write_lock(&slow_work_execs_lock);
- slow_work_execs[id] = NULL;
- write_unlock(&slow_work_execs_lock);
-#endif
-}
#include <linux/acpi.h>
#include <linux/reboot.h>
#include <linux/ftrace.h>
-#include <linux/slow-work.h>
#include <linux/perf_event.h>
#include <linux/kprobes.h>
#include <linux/pipe_fs_i.h>
.proc_handler = proc_dointvec,
},
#endif
-#ifdef CONFIG_SLOW_WORK
- {
- .procname = "slow-work",
- .mode = 0555,
- .child = slow_work_sysctls,
- },
-#endif
#ifdef CONFIG_PERF_EVENTS
{
.procname = "perf_event_paranoid",
Say N if unsure.
-config WORKQUEUE_TRACER
- bool "Trace workqueues"
- select GENERIC_TRACER
- help
- The workqueue tracer provides some statistical information
- about each cpu workqueue thread such as the number of the
- works inserted and executed since their creation. It can help
- to evaluate the amount of work each of them has to perform.
- For example it can help a developer to decide whether he should
- choose a per-cpu workqueue instead of a singlethreaded one.
-
config BLK_DEV_IO_TRACE
bool "Support for tracing block IO actions"
depends on SYSFS
#include <linux/kallsyms.h>
#include <linux/debug_locks.h>
#include <linux/lockdep.h>
-#define CREATE_TRACE_POINTS
-#include <trace/events/workqueue.h>
+#include <linux/idr.h>
+
+#include "workqueue_sched.h"
+
+enum {
+ /* global_cwq flags */
+ GCWQ_MANAGE_WORKERS = 1 << 0, /* need to manage workers */
+ GCWQ_MANAGING_WORKERS = 1 << 1, /* managing workers */
+ GCWQ_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */
+ GCWQ_FREEZING = 1 << 3, /* freeze in progress */
+ GCWQ_HIGHPRI_PENDING = 1 << 4, /* highpri works on queue */
+
+ /* worker flags */
+ WORKER_STARTED = 1 << 0, /* started */
+ WORKER_DIE = 1 << 1, /* die die die */
+ WORKER_IDLE = 1 << 2, /* is idle */
+ WORKER_PREP = 1 << 3, /* preparing to run works */
+ WORKER_ROGUE = 1 << 4, /* not bound to any cpu */
+ WORKER_REBIND = 1 << 5, /* mom is home, come back */
+ WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */
+ WORKER_UNBOUND = 1 << 7, /* worker is unbound */
+
+ WORKER_NOT_RUNNING = WORKER_PREP | WORKER_ROGUE | WORKER_REBIND |
+ WORKER_CPU_INTENSIVE | WORKER_UNBOUND,
+
+ /* gcwq->trustee_state */
+ TRUSTEE_START = 0, /* start */
+ TRUSTEE_IN_CHARGE = 1, /* trustee in charge of gcwq */
+ TRUSTEE_BUTCHER = 2, /* butcher workers */
+ TRUSTEE_RELEASE = 3, /* release workers */
+ TRUSTEE_DONE = 4, /* trustee is done */
+
+ BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */
+ BUSY_WORKER_HASH_SIZE = 1 << BUSY_WORKER_HASH_ORDER,
+ BUSY_WORKER_HASH_MASK = BUSY_WORKER_HASH_SIZE - 1,
+
+ MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */
+ IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */
+
+ MAYDAY_INITIAL_TIMEOUT = HZ / 100, /* call for help after 10ms */
+ MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */
+ CREATE_COOLDOWN = HZ, /* time to breath after fail */
+ TRUSTEE_COOLDOWN = HZ / 10, /* for trustee draining */
+
+ /*
+ * Rescue workers are used only on emergencies and shared by
+ * all cpus. Give -20.
+ */
+ RESCUER_NICE_LEVEL = -20,
+};
/*
- * The per-CPU workqueue (if single thread, we always use the first
- * possible cpu).
+ * Structure fields follow one of the following exclusion rules.
+ *
+ * I: Set during initialization and read-only afterwards.
+ *
+ * P: Preemption protected. Disabling preemption is enough and should
+ * only be modified and accessed from the local cpu.
+ *
+ * L: gcwq->lock protected. Access with gcwq->lock held.
+ *
+ * X: During normal operation, modification requires gcwq->lock and
+ * should be done only from local cpu. Either disabling preemption
+ * on local cpu or grabbing gcwq->lock is enough for read access.
+ * If GCWQ_DISASSOCIATED is set, it's identical to L.
+ *
+ * F: wq->flush_mutex protected.
+ *
+ * W: workqueue_lock protected.
*/
-struct cpu_workqueue_struct {
- spinlock_t lock;
+struct global_cwq;
- struct list_head worklist;
- wait_queue_head_t more_work;
- struct work_struct *current_work;
+/*
+ * The poor guys doing the actual heavy lifting. All on-duty workers
+ * are either serving the manager role, on idle list or on busy hash.
+ */
+struct worker {
+ /* on idle list while idle, on busy hash table while busy */
+ union {
+ struct list_head entry; /* L: while idle */
+ struct hlist_node hentry; /* L: while busy */
+ };
- struct workqueue_struct *wq;
- struct task_struct *thread;
-} ____cacheline_aligned;
+ struct work_struct *current_work; /* L: work being processed */
+ struct cpu_workqueue_struct *current_cwq; /* L: current_work's cwq */
+ struct list_head scheduled; /* L: scheduled works */
+ struct task_struct *task; /* I: worker task */
+ struct global_cwq *gcwq; /* I: the associated gcwq */
+ /* 64 bytes boundary on 64bit, 32 on 32bit */
+ unsigned long last_active; /* L: last active timestamp */
+ unsigned int flags; /* X: flags */
+ int id; /* I: worker id */
+ struct work_struct rebind_work; /* L: rebind worker to cpu */
+};
+
+/*
+ * Global per-cpu workqueue. There's one and only one for each cpu
+ * and all works are queued and processed here regardless of their
+ * target workqueues.
+ */
+struct global_cwq {
+ spinlock_t lock; /* the gcwq lock */
+ struct list_head worklist; /* L: list of pending works */
+ unsigned int cpu; /* I: the associated cpu */
+ unsigned int flags; /* L: GCWQ_* flags */
+
+ int nr_workers; /* L: total number of workers */
+ int nr_idle; /* L: currently idle ones */
+
+ /* workers are chained either in the idle_list or busy_hash */
+ struct list_head idle_list; /* X: list of idle workers */
+ struct hlist_head busy_hash[BUSY_WORKER_HASH_SIZE];
+ /* L: hash of busy workers */
+
+ struct timer_list idle_timer; /* L: worker idle timeout */
+ struct timer_list mayday_timer; /* L: SOS timer for dworkers */
+
+ struct ida worker_ida; /* L: for worker IDs */
+
+ struct task_struct *trustee; /* L: for gcwq shutdown */
+ unsigned int trustee_state; /* L: trustee state */
+ wait_queue_head_t trustee_wait; /* trustee wait */
+ struct worker *first_idle; /* L: first idle worker */
+} ____cacheline_aligned_in_smp;
+
+/*
+ * The per-CPU workqueue. The lower WORK_STRUCT_FLAG_BITS of
+ * work_struct->data are used for flags and thus cwqs need to be
+ * aligned at two's power of the number of flag bits.
+ */
+struct cpu_workqueue_struct {
+ struct global_cwq *gcwq; /* I: the associated gcwq */
+ struct workqueue_struct *wq; /* I: the owning workqueue */
+ int work_color; /* L: current color */
+ int flush_color; /* L: flushing color */
+ int nr_in_flight[WORK_NR_COLORS];
+ /* L: nr of in_flight works */
+ int nr_active; /* L: nr of active works */
+ int max_active; /* L: max active works */
+ struct list_head delayed_works; /* L: delayed works */
+};
+
+/*
+ * Structure used to wait for workqueue flush.
+ */
+struct wq_flusher {
+ struct list_head list; /* F: list of flushers */
+ int flush_color; /* F: flush color waiting for */
+ struct completion done; /* flush completion */
+};
+
+/*
+ * All cpumasks are assumed to be always set on UP and thus can't be
+ * used to determine whether there's something to be done.
+ */
+#ifdef CONFIG_SMP
+typedef cpumask_var_t mayday_mask_t;
+#define mayday_test_and_set_cpu(cpu, mask) \
+ cpumask_test_and_set_cpu((cpu), (mask))
+#define mayday_clear_cpu(cpu, mask) cpumask_clear_cpu((cpu), (mask))
+#define for_each_mayday_cpu(cpu, mask) for_each_cpu((cpu), (mask))
+#define alloc_mayday_mask(maskp, gfp) alloc_cpumask_var((maskp), (gfp))
+#define free_mayday_mask(mask) free_cpumask_var((mask))
+#else
+typedef unsigned long mayday_mask_t;
+#define mayday_test_and_set_cpu(cpu, mask) test_and_set_bit(0, &(mask))
+#define mayday_clear_cpu(cpu, mask) clear_bit(0, &(mask))
+#define for_each_mayday_cpu(cpu, mask) if ((cpu) = 0, (mask))
+#define alloc_mayday_mask(maskp, gfp) true
+#define free_mayday_mask(mask) do { } while (0)
+#endif
/*
* The externally visible workqueue abstraction is an array of
* per-CPU workqueues:
*/
struct workqueue_struct {
- struct cpu_workqueue_struct *cpu_wq;
- struct list_head list;
- const char *name;
- int singlethread;
- int freezeable; /* Freeze threads during suspend */
- int rt;
+ unsigned int flags; /* I: WQ_* flags */
+ union {
+ struct cpu_workqueue_struct __percpu *pcpu;
+ struct cpu_workqueue_struct *single;
+ unsigned long v;
+ } cpu_wq; /* I: cwq's */
+ struct list_head list; /* W: list of all workqueues */
+
+ struct mutex flush_mutex; /* protects wq flushing */
+ int work_color; /* F: current work color */
+ int flush_color; /* F: current flush color */
+ atomic_t nr_cwqs_to_flush; /* flush in progress */
+ struct wq_flusher *first_flusher; /* F: first flusher */
+ struct list_head flusher_queue; /* F: flush waiters */
+ struct list_head flusher_overflow; /* F: flush overflow list */
+
+ mayday_mask_t mayday_mask; /* cpus requesting rescue */
+ struct worker *rescuer; /* I: rescue worker */
+
+ int saved_max_active; /* W: saved cwq max_active */
+ const char *name; /* I: workqueue name */
#ifdef CONFIG_LOCKDEP
- struct lockdep_map lockdep_map;
+ struct lockdep_map lockdep_map;
#endif
};
+struct workqueue_struct *system_wq __read_mostly;
+struct workqueue_struct *system_long_wq __read_mostly;
+struct workqueue_struct *system_nrt_wq __read_mostly;
+struct workqueue_struct *system_unbound_wq __read_mostly;
+EXPORT_SYMBOL_GPL(system_wq);
+EXPORT_SYMBOL_GPL(system_long_wq);
+EXPORT_SYMBOL_GPL(system_nrt_wq);
+EXPORT_SYMBOL_GPL(system_unbound_wq);
+
+#define for_each_busy_worker(worker, i, pos, gcwq) \
+ for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) \
+ hlist_for_each_entry(worker, pos, &gcwq->busy_hash[i], hentry)
+
+static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask,
+ unsigned int sw)
+{
+ if (cpu < nr_cpu_ids) {
+ if (sw & 1) {
+ cpu = cpumask_next(cpu, mask);
+ if (cpu < nr_cpu_ids)
+ return cpu;
+ }
+ if (sw & 2)
+ return WORK_CPU_UNBOUND;
+ }
+ return WORK_CPU_NONE;
+}
+
+static inline int __next_wq_cpu(int cpu, const struct cpumask *mask,
+ struct workqueue_struct *wq)
+{
+ return __next_gcwq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2);
+}
+
+/*
+ * CPU iterators
+ *
+ * An extra gcwq is defined for an invalid cpu number
+ * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any
+ * specific CPU. The following iterators are similar to
+ * for_each_*_cpu() iterators but also considers the unbound gcwq.
+ *
+ * for_each_gcwq_cpu() : possible CPUs + WORK_CPU_UNBOUND
+ * for_each_online_gcwq_cpu() : online CPUs + WORK_CPU_UNBOUND
+ * for_each_cwq_cpu() : possible CPUs for bound workqueues,
+ * WORK_CPU_UNBOUND for unbound workqueues
+ */
+#define for_each_gcwq_cpu(cpu) \
+ for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3); \
+ (cpu) < WORK_CPU_NONE; \
+ (cpu) = __next_gcwq_cpu((cpu), cpu_possible_mask, 3))
+
+#define for_each_online_gcwq_cpu(cpu) \
+ for ((cpu) = __next_gcwq_cpu(-1, cpu_online_mask, 3); \
+ (cpu) < WORK_CPU_NONE; \
+ (cpu) = __next_gcwq_cpu((cpu), cpu_online_mask, 3))
+
+#define for_each_cwq_cpu(cpu, wq) \
+ for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, (wq)); \
+ (cpu) < WORK_CPU_NONE; \
+ (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, (wq)))
+
#ifdef CONFIG_LOCKDEP
/**
* in_workqueue_context() - in context of specified workqueue?
* statically initialized. We just make sure that it
* is tracked in the object tracker.
*/
- if (test_bit(WORK_STRUCT_STATIC, work_data_bits(work))) {
+ if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) {
debug_object_init(work, &work_debug_descr);
debug_object_activate(work, &work_debug_descr);
return 0;
/* Serializes the accesses to the list of workqueues. */
static DEFINE_SPINLOCK(workqueue_lock);
static LIST_HEAD(workqueues);
+static bool workqueue_freezing; /* W: have wqs started freezing? */
+
+/*
+ * The almighty global cpu workqueues. nr_running is the only field
+ * which is expected to be used frequently by other cpus via
+ * try_to_wake_up(). Put it in a separate cacheline.
+ */
+static DEFINE_PER_CPU(struct global_cwq, global_cwq);
+static DEFINE_PER_CPU_SHARED_ALIGNED(atomic_t, gcwq_nr_running);
+
+/*
+ * Global cpu workqueue and nr_running counter for unbound gcwq. The
+ * gcwq is always online, has GCWQ_DISASSOCIATED set, and all its
+ * workers have WORKER_UNBOUND set.
+ */
+static struct global_cwq unbound_global_cwq;
+static atomic_t unbound_gcwq_nr_running = ATOMIC_INIT(0); /* always 0 */
+
+static int worker_thread(void *__worker);
+
+static struct global_cwq *get_gcwq(unsigned int cpu)
+{
+ if (cpu != WORK_CPU_UNBOUND)
+ return &per_cpu(global_cwq, cpu);
+ else
+ return &unbound_global_cwq;
+}
+
+static atomic_t *get_gcwq_nr_running(unsigned int cpu)
+{
+ if (cpu != WORK_CPU_UNBOUND)
+ return &per_cpu(gcwq_nr_running, cpu);
+ else
+ return &unbound_gcwq_nr_running;
+}
+
+static struct cpu_workqueue_struct *get_cwq(unsigned int cpu,
+ struct workqueue_struct *wq)
+{
+ if (!(wq->flags & WQ_UNBOUND)) {
+ if (likely(cpu < nr_cpu_ids)) {
+#ifdef CONFIG_SMP
+ return per_cpu_ptr(wq->cpu_wq.pcpu, cpu);
+#else
+ return wq->cpu_wq.single;
+#endif
+ }
+ } else if (likely(cpu == WORK_CPU_UNBOUND))
+ return wq->cpu_wq.single;
+ return NULL;
+}
+
+static unsigned int work_color_to_flags(int color)
+{
+ return color << WORK_STRUCT_COLOR_SHIFT;
+}
+
+static int get_work_color(struct work_struct *work)
+{
+ return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) &
+ ((1 << WORK_STRUCT_COLOR_BITS) - 1);
+}
+
+static int work_next_color(int color)
+{
+ return (color + 1) % WORK_NR_COLORS;
+}
-static int singlethread_cpu __read_mostly;
-static const struct cpumask *cpu_singlethread_map __read_mostly;
/*
- * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD
- * flushes cwq->worklist. This means that flush_workqueue/wait_on_work
- * which comes in between can't use for_each_online_cpu(). We could
- * use cpu_possible_map, the cpumask below is more a documentation
- * than optimization.
+ * A work's data points to the cwq with WORK_STRUCT_CWQ set while the
+ * work is on queue. Once execution starts, WORK_STRUCT_CWQ is
+ * cleared and the work data contains the cpu number it was last on.
+ *
+ * set_work_{cwq|cpu}() and clear_work_data() can be used to set the
+ * cwq, cpu or clear work->data. These functions should only be
+ * called while the work is owned - ie. while the PENDING bit is set.
+ *
+ * get_work_[g]cwq() can be used to obtain the gcwq or cwq
+ * corresponding to a work. gcwq is available once the work has been
+ * queued anywhere after initialization. cwq is available only from
+ * queueing until execution starts.
*/
-static cpumask_var_t cpu_populated_map __read_mostly;
+static inline void set_work_data(struct work_struct *work, unsigned long data,
+ unsigned long flags)
+{
+ BUG_ON(!work_pending(work));
+ atomic_long_set(&work->data, data | flags | work_static(work));
+}
+
+static void set_work_cwq(struct work_struct *work,
+ struct cpu_workqueue_struct *cwq,
+ unsigned long extra_flags)
+{
+ set_work_data(work, (unsigned long)cwq,
+ WORK_STRUCT_PENDING | WORK_STRUCT_CWQ | extra_flags);
+}
+
+static void set_work_cpu(struct work_struct *work, unsigned int cpu)
+{
+ set_work_data(work, cpu << WORK_STRUCT_FLAG_BITS, WORK_STRUCT_PENDING);
+}
-/* If it's single threaded, it isn't in the list of workqueues. */
-static inline int is_wq_single_threaded(struct workqueue_struct *wq)
+static void clear_work_data(struct work_struct *work)
{
- return wq->singlethread;
+ set_work_data(work, WORK_STRUCT_NO_CPU, 0);
}
-static const struct cpumask *wq_cpu_map(struct workqueue_struct *wq)
+static struct cpu_workqueue_struct *get_work_cwq(struct work_struct *work)
{
- return is_wq_single_threaded(wq)
- ? cpu_singlethread_map : cpu_populated_map;
+ unsigned long data = atomic_long_read(&work->data);
+
+ if (data & WORK_STRUCT_CWQ)
+ return (void *)(data & WORK_STRUCT_WQ_DATA_MASK);
+ else
+ return NULL;
+}
+
+static struct global_cwq *get_work_gcwq(struct work_struct *work)
+{
+ unsigned long data = atomic_long_read(&work->data);
+ unsigned int cpu;
+
+ if (data & WORK_STRUCT_CWQ)
+ return ((struct cpu_workqueue_struct *)
+ (data & WORK_STRUCT_WQ_DATA_MASK))->gcwq;
+
+ cpu = data >> WORK_STRUCT_FLAG_BITS;
+ if (cpu == WORK_CPU_NONE)
+ return NULL;
+
+ BUG_ON(cpu >= nr_cpu_ids && cpu != WORK_CPU_UNBOUND);
+ return get_gcwq(cpu);
}
-static
-struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu)
+/*
+ * Policy functions. These define the policies on how the global
+ * worker pool is managed. Unless noted otherwise, these functions
+ * assume that they're being called with gcwq->lock held.
+ */
+
+static bool __need_more_worker(struct global_cwq *gcwq)
{
- if (unlikely(is_wq_single_threaded(wq)))
- cpu = singlethread_cpu;
- return per_cpu_ptr(wq->cpu_wq, cpu);
+ return !atomic_read(get_gcwq_nr_running(gcwq->cpu)) ||
+ gcwq->flags & GCWQ_HIGHPRI_PENDING;
}
/*
- * Set the workqueue on which a work item is to be run
- * - Must *only* be called if the pending flag is set
+ * Need to wake up a worker? Called from anything but currently
+ * running workers.
*/
-static inline void set_wq_data(struct work_struct *work,
- struct cpu_workqueue_struct *cwq)
+static bool need_more_worker(struct global_cwq *gcwq)
{
- unsigned long new;
+ return !list_empty(&gcwq->worklist) && __need_more_worker(gcwq);
+}
- BUG_ON(!work_pending(work));
+/* Can I start working? Called from busy but !running workers. */
+static bool may_start_working(struct global_cwq *gcwq)
+{
+ return gcwq->nr_idle;
+}
+
+/* Do I need to keep working? Called from currently running workers. */
+static bool keep_working(struct global_cwq *gcwq)
+{
+ atomic_t *nr_running = get_gcwq_nr_running(gcwq->cpu);
+
+ return !list_empty(&gcwq->worklist) && atomic_read(nr_running) <= 1;
+}
+
+/* Do we need a new worker? Called from manager. */
+static bool need_to_create_worker(struct global_cwq *gcwq)
+{
+ return need_more_worker(gcwq) && !may_start_working(gcwq);
+}
- new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING);
- new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work);
- atomic_long_set(&work->data, new);
+/* Do I need to be the manager? */
+static bool need_to_manage_workers(struct global_cwq *gcwq)
+{
+ return need_to_create_worker(gcwq) || gcwq->flags & GCWQ_MANAGE_WORKERS;
+}
+
+/* Do we have too many workers and should some go away? */
+static bool too_many_workers(struct global_cwq *gcwq)
+{
+ bool managing = gcwq->flags & GCWQ_MANAGING_WORKERS;
+ int nr_idle = gcwq->nr_idle + managing; /* manager is considered idle */
+ int nr_busy = gcwq->nr_workers - nr_idle;
+
+ return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy;
}
/*
- * Clear WORK_STRUCT_PENDING and the workqueue on which it was queued.
+ * Wake up functions.
+ */
+
+/* Return the first worker. Safe with preemption disabled */
+static struct worker *first_worker(struct global_cwq *gcwq)
+{
+ if (unlikely(list_empty(&gcwq->idle_list)))
+ return NULL;
+
+ return list_first_entry(&gcwq->idle_list, struct worker, entry);
+}
+
+/**
+ * wake_up_worker - wake up an idle worker
+ * @gcwq: gcwq to wake worker for
+ *
+ * Wake up the first idle worker of @gcwq.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void wake_up_worker(struct global_cwq *gcwq)
+{
+ struct worker *worker = first_worker(gcwq);
+
+ if (likely(worker))
+ wake_up_process(worker->task);
+}
+
+/**
+ * wq_worker_waking_up - a worker is waking up
+ * @task: task waking up
+ * @cpu: CPU @task is waking up to
+ *
+ * This function is called during try_to_wake_up() when a worker is
+ * being awoken.
+ *
+ * CONTEXT:
+ * spin_lock_irq(rq->lock)
+ */
+void wq_worker_waking_up(struct task_struct *task, unsigned int cpu)
+{
+ struct worker *worker = kthread_data(task);
+
+ if (likely(!(worker->flags & WORKER_NOT_RUNNING)))
+ atomic_inc(get_gcwq_nr_running(cpu));
+}
+
+/**
+ * wq_worker_sleeping - a worker is going to sleep
+ * @task: task going to sleep
+ * @cpu: CPU in question, must be the current CPU number
+ *
+ * This function is called during schedule() when a busy worker is
+ * going to sleep. Worker on the same cpu can be woken up by
+ * returning pointer to its task.
+ *
+ * CONTEXT:
+ * spin_lock_irq(rq->lock)
+ *
+ * RETURNS:
+ * Worker task on @cpu to wake up, %NULL if none.
+ */
+struct task_struct *wq_worker_sleeping(struct task_struct *task,
+ unsigned int cpu)
+{
+ struct worker *worker = kthread_data(task), *to_wakeup = NULL;
+ struct global_cwq *gcwq = get_gcwq(cpu);
+ atomic_t *nr_running = get_gcwq_nr_running(cpu);
+
+ if (unlikely(worker->flags & WORKER_NOT_RUNNING))
+ return NULL;
+
+ /* this can only happen on the local cpu */
+ BUG_ON(cpu != raw_smp_processor_id());
+
+ /*
+ * The counterpart of the following dec_and_test, implied mb,
+ * worklist not empty test sequence is in insert_work().
+ * Please read comment there.
+ *
+ * NOT_RUNNING is clear. This means that trustee is not in
+ * charge and we're running on the local cpu w/ rq lock held
+ * and preemption disabled, which in turn means that none else
+ * could be manipulating idle_list, so dereferencing idle_list
+ * without gcwq lock is safe.
+ */
+ if (atomic_dec_and_test(nr_running) && !list_empty(&gcwq->worklist))
+ to_wakeup = first_worker(gcwq);
+ return to_wakeup ? to_wakeup->task : NULL;
+}
+
+/**
+ * worker_set_flags - set worker flags and adjust nr_running accordingly
+ * @worker: self
+ * @flags: flags to set
+ * @wakeup: wakeup an idle worker if necessary
+ *
+ * Set @flags in @worker->flags and adjust nr_running accordingly. If
+ * nr_running becomes zero and @wakeup is %true, an idle worker is
+ * woken up.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock)
+ */
+static inline void worker_set_flags(struct worker *worker, unsigned int flags,
+ bool wakeup)
+{
+ struct global_cwq *gcwq = worker->gcwq;
+
+ WARN_ON_ONCE(worker->task != current);
+
+ /*
+ * If transitioning into NOT_RUNNING, adjust nr_running and
+ * wake up an idle worker as necessary if requested by
+ * @wakeup.
+ */
+ if ((flags & WORKER_NOT_RUNNING) &&
+ !(worker->flags & WORKER_NOT_RUNNING)) {
+ atomic_t *nr_running = get_gcwq_nr_running(gcwq->cpu);
+
+ if (wakeup) {
+ if (atomic_dec_and_test(nr_running) &&
+ !list_empty(&gcwq->worklist))
+ wake_up_worker(gcwq);
+ } else
+ atomic_dec(nr_running);
+ }
+
+ worker->flags |= flags;
+}
+
+/**
+ * worker_clr_flags - clear worker flags and adjust nr_running accordingly
+ * @worker: self
+ * @flags: flags to clear
+ *
+ * Clear @flags in @worker->flags and adjust nr_running accordingly.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock)
+ */
+static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
+{
+ struct global_cwq *gcwq = worker->gcwq;
+ unsigned int oflags = worker->flags;
+
+ WARN_ON_ONCE(worker->task != current);
+
+ worker->flags &= ~flags;
+
+ /* if transitioning out of NOT_RUNNING, increment nr_running */
+ if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING))
+ if (!(worker->flags & WORKER_NOT_RUNNING))
+ atomic_inc(get_gcwq_nr_running(gcwq->cpu));
+}
+
+/**
+ * busy_worker_head - return the busy hash head for a work
+ * @gcwq: gcwq of interest
+ * @work: work to be hashed
+ *
+ * Return hash head of @gcwq for @work.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ *
+ * RETURNS:
+ * Pointer to the hash head.
+ */
+static struct hlist_head *busy_worker_head(struct global_cwq *gcwq,
+ struct work_struct *work)
+{
+ const int base_shift = ilog2(sizeof(struct work_struct));
+ unsigned long v = (unsigned long)work;
+
+ /* simple shift and fold hash, do we need something better? */
+ v >>= base_shift;
+ v += v >> BUSY_WORKER_HASH_ORDER;
+ v &= BUSY_WORKER_HASH_MASK;
+
+ return &gcwq->busy_hash[v];
+}
+
+/**
+ * __find_worker_executing_work - find worker which is executing a work
+ * @gcwq: gcwq of interest
+ * @bwh: hash head as returned by busy_worker_head()
+ * @work: work to find worker for
+ *
+ * Find a worker which is executing @work on @gcwq. @bwh should be
+ * the hash head obtained by calling busy_worker_head() with the same
+ * work.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ *
+ * RETURNS:
+ * Pointer to worker which is executing @work if found, NULL
+ * otherwise.
+ */
+static struct worker *__find_worker_executing_work(struct global_cwq *gcwq,
+ struct hlist_head *bwh,
+ struct work_struct *work)
+{
+ struct worker *worker;
+ struct hlist_node *tmp;
+
+ hlist_for_each_entry(worker, tmp, bwh, hentry)
+ if (worker->current_work == work)
+ return worker;
+ return NULL;
+}
+
+/**
+ * find_worker_executing_work - find worker which is executing a work
+ * @gcwq: gcwq of interest
+ * @work: work to find worker for
+ *
+ * Find a worker which is executing @work on @gcwq. This function is
+ * identical to __find_worker_executing_work() except that this
+ * function calculates @bwh itself.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ *
+ * RETURNS:
+ * Pointer to worker which is executing @work if found, NULL
+ * otherwise.
*/
-static inline void clear_wq_data(struct work_struct *work)
+static struct worker *find_worker_executing_work(struct global_cwq *gcwq,
+ struct work_struct *work)
{
- unsigned long flags = *work_data_bits(work) &
- (1UL << WORK_STRUCT_STATIC);
- atomic_long_set(&work->data, flags);
+ return __find_worker_executing_work(gcwq, busy_worker_head(gcwq, work),
+ work);
}
-static inline
-struct cpu_workqueue_struct *get_wq_data(struct work_struct *work)
+/**
+ * gcwq_determine_ins_pos - find insertion position
+ * @gcwq: gcwq of interest
+ * @cwq: cwq a work is being queued for
+ *
+ * A work for @cwq is about to be queued on @gcwq, determine insertion
+ * position for the work. If @cwq is for HIGHPRI wq, the work is
+ * queued at the head of the queue but in FIFO order with respect to
+ * other HIGHPRI works; otherwise, at the end of the queue. This
+ * function also sets GCWQ_HIGHPRI_PENDING flag to hint @gcwq that
+ * there are HIGHPRI works pending.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ *
+ * RETURNS:
+ * Pointer to inserstion position.
+ */
+static inline struct list_head *gcwq_determine_ins_pos(struct global_cwq *gcwq,
+ struct cpu_workqueue_struct *cwq)
{
- return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK);
+ struct work_struct *twork;
+
+ if (likely(!(cwq->wq->flags & WQ_HIGHPRI)))
+ return &gcwq->worklist;
+
+ list_for_each_entry(twork, &gcwq->worklist, entry) {
+ struct cpu_workqueue_struct *tcwq = get_work_cwq(twork);
+
+ if (!(tcwq->wq->flags & WQ_HIGHPRI))
+ break;
+ }
+
+ gcwq->flags |= GCWQ_HIGHPRI_PENDING;
+ return &twork->entry;
}
+/**
+ * insert_work - insert a work into gcwq
+ * @cwq: cwq @work belongs to
+ * @work: work to insert
+ * @head: insertion point
+ * @extra_flags: extra WORK_STRUCT_* flags to set
+ *
+ * Insert @work which belongs to @cwq into @gcwq after @head.
+ * @extra_flags is or'd to work_struct flags.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
static void insert_work(struct cpu_workqueue_struct *cwq,
- struct work_struct *work, struct list_head *head)
+ struct work_struct *work, struct list_head *head,
+ unsigned int extra_flags)
{
- trace_workqueue_insertion(cwq->thread, work);
+ struct global_cwq *gcwq = cwq->gcwq;
+
+ /* we own @work, set data and link */
+ set_work_cwq(work, cwq, extra_flags);
- set_wq_data(work, cwq);
/*
* Ensure that we get the right work->data if we see the
* result of list_add() below, see try_to_grab_pending().
*/
smp_wmb();
+
list_add_tail(&work->entry, head);
- wake_up(&cwq->more_work);
+
+ /*
+ * Ensure either worker_sched_deactivated() sees the above
+ * list_add_tail() or we see zero nr_running to avoid workers
+ * lying around lazily while there are works to be processed.
+ */
+ smp_mb();
+
+ if (__need_more_worker(gcwq))
+ wake_up_worker(gcwq);
}
-static void __queue_work(struct cpu_workqueue_struct *cwq,
+static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
struct work_struct *work)
{
+ struct global_cwq *gcwq;
+ struct cpu_workqueue_struct *cwq;
+ struct list_head *worklist;
unsigned long flags;
debug_work_activate(work);
- spin_lock_irqsave(&cwq->lock, flags);
- insert_work(cwq, work, &cwq->worklist);
- spin_unlock_irqrestore(&cwq->lock, flags);
+
+ /* determine gcwq to use */
+ if (!(wq->flags & WQ_UNBOUND)) {
+ struct global_cwq *last_gcwq;
+
+ if (unlikely(cpu == WORK_CPU_UNBOUND))
+ cpu = raw_smp_processor_id();
+
+ /*
+ * It's multi cpu. If @wq is non-reentrant and @work
+ * was previously on a different cpu, it might still
+ * be running there, in which case the work needs to
+ * be queued on that cpu to guarantee non-reentrance.
+ */
+ gcwq = get_gcwq(cpu);
+ if (wq->flags & WQ_NON_REENTRANT &&
+ (last_gcwq = get_work_gcwq(work)) && last_gcwq != gcwq) {
+ struct worker *worker;
+
+ spin_lock_irqsave(&last_gcwq->lock, flags);
+
+ worker = find_worker_executing_work(last_gcwq, work);
+
+ if (worker && worker->current_cwq->wq == wq)
+ gcwq = last_gcwq;
+ else {
+ /* meh... not running there, queue here */
+ spin_unlock_irqrestore(&last_gcwq->lock, flags);
+ spin_lock_irqsave(&gcwq->lock, flags);
+ }
+ } else
+ spin_lock_irqsave(&gcwq->lock, flags);
+ } else {
+ gcwq = get_gcwq(WORK_CPU_UNBOUND);
+ spin_lock_irqsave(&gcwq->lock, flags);
+ }
+
+ /* gcwq determined, get cwq and queue */
+ cwq = get_cwq(gcwq->cpu, wq);
+
+ BUG_ON(!list_empty(&work->entry));
+
+ cwq->nr_in_flight[cwq->work_color]++;
+
+ if (likely(cwq->nr_active < cwq->max_active)) {
+ cwq->nr_active++;
+ worklist = gcwq_determine_ins_pos(gcwq, cwq);
+ } else
+ worklist = &cwq->delayed_works;
+
+ insert_work(cwq, work, worklist, work_color_to_flags(cwq->work_color));
+
+ spin_unlock_irqrestore(&gcwq->lock, flags);
}
/**
{
int ret = 0;
- if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
- BUG_ON(!list_empty(&work->entry));
- __queue_work(wq_per_cpu(wq, cpu), work);
+ if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+ __queue_work(cpu, wq, work);
ret = 1;
}
return ret;
static void delayed_work_timer_fn(unsigned long __data)
{
struct delayed_work *dwork = (struct delayed_work *)__data;
- struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work);
- struct workqueue_struct *wq = cwq->wq;
+ struct cpu_workqueue_struct *cwq = get_work_cwq(&dwork->work);
- __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work);
+ __queue_work(smp_processor_id(), cwq->wq, &dwork->work);
}
/**
struct timer_list *timer = &dwork->timer;
struct work_struct *work = &dwork->work;
- if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
+ if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+ unsigned int lcpu;
+
BUG_ON(timer_pending(timer));
BUG_ON(!list_empty(&work->entry));
timer_stats_timer_set_start_info(&dwork->timer);
- /* This stores cwq for the moment, for the timer_fn */
- set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id()));
+ /*
+ * This stores cwq for the moment, for the timer_fn.
+ * Note that the work's gcwq is preserved to allow
+ * reentrance detection for delayed works.
+ */
+ if (!(wq->flags & WQ_UNBOUND)) {
+ struct global_cwq *gcwq = get_work_gcwq(work);
+
+ if (gcwq && gcwq->cpu != WORK_CPU_UNBOUND)
+ lcpu = gcwq->cpu;
+ else
+ lcpu = raw_smp_processor_id();
+ } else
+ lcpu = WORK_CPU_UNBOUND;
+
+ set_work_cwq(work, get_cwq(lcpu, wq), 0);
+
timer->expires = jiffies + delay;
timer->data = (unsigned long)dwork;
timer->function = delayed_work_timer_fn;
}
EXPORT_SYMBOL_GPL(queue_delayed_work_on);
-static void run_workqueue(struct cpu_workqueue_struct *cwq)
+/**
+ * worker_enter_idle - enter idle state
+ * @worker: worker which is entering idle state
+ *
+ * @worker is entering idle state. Update stats and idle timer if
+ * necessary.
+ *
+ * LOCKING:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void worker_enter_idle(struct worker *worker)
{
- spin_lock_irq(&cwq->lock);
- while (!list_empty(&cwq->worklist)) {
- struct work_struct *work = list_entry(cwq->worklist.next,
- struct work_struct, entry);
- work_func_t f = work->func;
-#ifdef CONFIG_LOCKDEP
+ struct global_cwq *gcwq = worker->gcwq;
+
+ BUG_ON(worker->flags & WORKER_IDLE);
+ BUG_ON(!list_empty(&worker->entry) &&
+ (worker->hentry.next || worker->hentry.pprev));
+
+ /* can't use worker_set_flags(), also called from start_worker() */
+ worker->flags |= WORKER_IDLE;
+ gcwq->nr_idle++;
+ worker->last_active = jiffies;
+
+ /* idle_list is LIFO */
+ list_add(&worker->entry, &gcwq->idle_list);
+
+ if (likely(!(worker->flags & WORKER_ROGUE))) {
+ if (too_many_workers(gcwq) && !timer_pending(&gcwq->idle_timer))
+ mod_timer(&gcwq->idle_timer,
+ jiffies + IDLE_WORKER_TIMEOUT);
+ } else
+ wake_up_all(&gcwq->trustee_wait);
+
+ /* sanity check nr_running */
+ WARN_ON_ONCE(gcwq->nr_workers == gcwq->nr_idle &&
+ atomic_read(get_gcwq_nr_running(gcwq->cpu)));
+}
+
+/**
+ * worker_leave_idle - leave idle state
+ * @worker: worker which is leaving idle state
+ *
+ * @worker is leaving idle state. Update stats.
+ *
+ * LOCKING:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void worker_leave_idle(struct worker *worker)
+{
+ struct global_cwq *gcwq = worker->gcwq;
+
+ BUG_ON(!(worker->flags & WORKER_IDLE));
+ worker_clr_flags(worker, WORKER_IDLE);
+ gcwq->nr_idle--;
+ list_del_init(&worker->entry);
+}
+
+/**
+ * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock gcwq
+ * @worker: self
+ *
+ * Works which are scheduled while the cpu is online must at least be
+ * scheduled to a worker which is bound to the cpu so that if they are
+ * flushed from cpu callbacks while cpu is going down, they are
+ * guaranteed to execute on the cpu.
+ *
+ * This function is to be used by rogue workers and rescuers to bind
+ * themselves to the target cpu and may race with cpu going down or
+ * coming online. kthread_bind() can't be used because it may put the
+ * worker to already dead cpu and set_cpus_allowed_ptr() can't be used
+ * verbatim as it's best effort and blocking and gcwq may be
+ * [dis]associated in the meantime.
+ *
+ * This function tries set_cpus_allowed() and locks gcwq and verifies
+ * the binding against GCWQ_DISASSOCIATED which is set during
+ * CPU_DYING and cleared during CPU_ONLINE, so if the worker enters
+ * idle state or fetches works without dropping lock, it can guarantee
+ * the scheduling requirement described in the first paragraph.
+ *
+ * CONTEXT:
+ * Might sleep. Called without any lock but returns with gcwq->lock
+ * held.
+ *
+ * RETURNS:
+ * %true if the associated gcwq is online (@worker is successfully
+ * bound), %false if offline.
+ */
+static bool worker_maybe_bind_and_lock(struct worker *worker)
+{
+ struct global_cwq *gcwq = worker->gcwq;
+ struct task_struct *task = worker->task;
+
+ while (true) {
/*
- * It is permissible to free the struct work_struct
- * from inside the function that is called from it,
- * this we need to take into account for lockdep too.
- * To avoid bogus "held lock freed" warnings as well
- * as problems when looking into work->lockdep_map,
- * make a copy and use that here.
+ * The following call may fail, succeed or succeed
+ * without actually migrating the task to the cpu if
+ * it races with cpu hotunplug operation. Verify
+ * against GCWQ_DISASSOCIATED.
*/
- struct lockdep_map lockdep_map = work->lockdep_map;
-#endif
- trace_workqueue_execution(cwq->thread, work);
- debug_work_deactivate(work);
- cwq->current_work = work;
- list_del_init(cwq->worklist.next);
- spin_unlock_irq(&cwq->lock);
-
- BUG_ON(get_wq_data(work) != cwq);
- work_clear_pending(work);
- lock_map_acquire(&cwq->wq->lockdep_map);
- lock_map_acquire(&lockdep_map);
- f(work);
- lock_map_release(&lockdep_map);
- lock_map_release(&cwq->wq->lockdep_map);
-
- if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
- printk(KERN_ERR "BUG: workqueue leaked lock or atomic: "
- "%s/0x%08x/%d\n",
- current->comm, preempt_count(),
- task_pid_nr(current));
- printk(KERN_ERR " last function: ");
- print_symbol("%s\n", (unsigned long)f);
- debug_show_held_locks(current);
- dump_stack();
+ if (!(gcwq->flags & GCWQ_DISASSOCIATED))
+ set_cpus_allowed_ptr(task, get_cpu_mask(gcwq->cpu));
+
+ spin_lock_irq(&gcwq->lock);
+ if (gcwq->flags & GCWQ_DISASSOCIATED)
+ return false;
+ if (task_cpu(task) == gcwq->cpu &&
+ cpumask_equal(¤t->cpus_allowed,
+ get_cpu_mask(gcwq->cpu)))
+ return true;
+ spin_unlock_irq(&gcwq->lock);
+
+ /* CPU has come up inbetween, retry migration */
+ cpu_relax();
+ }
+}
+
+/*
+ * Function for worker->rebind_work used to rebind rogue busy workers
+ * to the associated cpu which is coming back online. This is
+ * scheduled by cpu up but can race with other cpu hotplug operations
+ * and may be executed twice without intervening cpu down.
+ */
+static void worker_rebind_fn(struct work_struct *work)
+{
+ struct worker *worker = container_of(work, struct worker, rebind_work);
+ struct global_cwq *gcwq = worker->gcwq;
+
+ if (worker_maybe_bind_and_lock(worker))
+ worker_clr_flags(worker, WORKER_REBIND);
+
+ spin_unlock_irq(&gcwq->lock);
+}
+
+static struct worker *alloc_worker(void)
+{
+ struct worker *worker;
+
+ worker = kzalloc(sizeof(*worker), GFP_KERNEL);
+ if (worker) {
+ INIT_LIST_HEAD(&worker->entry);
+ INIT_LIST_HEAD(&worker->scheduled);
+ INIT_WORK(&worker->rebind_work, worker_rebind_fn);
+ /* on creation a worker is in !idle && prep state */
+ worker->flags = WORKER_PREP;
+ }
+ return worker;
+}
+
+/**
+ * create_worker - create a new workqueue worker
+ * @gcwq: gcwq the new worker will belong to
+ * @bind: whether to set affinity to @cpu or not
+ *
+ * Create a new worker which is bound to @gcwq. The returned worker
+ * can be started by calling start_worker() or destroyed using
+ * destroy_worker().
+ *
+ * CONTEXT:
+ * Might sleep. Does GFP_KERNEL allocations.
+ *
+ * RETURNS:
+ * Pointer to the newly created worker.
+ */
+static struct worker *create_worker(struct global_cwq *gcwq, bool bind)
+{
+ bool on_unbound_cpu = gcwq->cpu == WORK_CPU_UNBOUND;
+ struct worker *worker = NULL;
+ int id = -1;
+
+ spin_lock_irq(&gcwq->lock);
+ while (ida_get_new(&gcwq->worker_ida, &id)) {
+ spin_unlock_irq(&gcwq->lock);
+ if (!ida_pre_get(&gcwq->worker_ida, GFP_KERNEL))
+ goto fail;
+ spin_lock_irq(&gcwq->lock);
+ }
+ spin_unlock_irq(&gcwq->lock);
+
+ worker = alloc_worker();
+ if (!worker)
+ goto fail;
+
+ worker->gcwq = gcwq;
+ worker->id = id;
+
+ if (!on_unbound_cpu)
+ worker->task = kthread_create(worker_thread, worker,
+ "kworker/%u:%d", gcwq->cpu, id);
+ else
+ worker->task = kthread_create(worker_thread, worker,
+ "kworker/u:%d", id);
+ if (IS_ERR(worker->task))
+ goto fail;
+
+ /*
+ * A rogue worker will become a regular one if CPU comes
+ * online later on. Make sure every worker has
+ * PF_THREAD_BOUND set.
+ */
+ if (bind && !on_unbound_cpu)
+ kthread_bind(worker->task, gcwq->cpu);
+ else {
+ worker->task->flags |= PF_THREAD_BOUND;
+ if (on_unbound_cpu)
+ worker->flags |= WORKER_UNBOUND;
+ }
+
+ return worker;
+fail:
+ if (id >= 0) {
+ spin_lock_irq(&gcwq->lock);
+ ida_remove(&gcwq->worker_ida, id);
+ spin_unlock_irq(&gcwq->lock);
+ }
+ kfree(worker);
+ return NULL;
+}
+
+/**
+ * start_worker - start a newly created worker
+ * @worker: worker to start
+ *
+ * Make the gcwq aware of @worker and start it.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void start_worker(struct worker *worker)
+{
+ worker->flags |= WORKER_STARTED;
+ worker->gcwq->nr_workers++;
+ worker_enter_idle(worker);
+ wake_up_process(worker->task);
+}
+
+/**
+ * destroy_worker - destroy a workqueue worker
+ * @worker: worker to be destroyed
+ *
+ * Destroy @worker and adjust @gcwq stats accordingly.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which is released and regrabbed.
+ */
+static void destroy_worker(struct worker *worker)
+{
+ struct global_cwq *gcwq = worker->gcwq;
+ int id = worker->id;
+
+ /* sanity check frenzy */
+ BUG_ON(worker->current_work);
+ BUG_ON(!list_empty(&worker->scheduled));
+
+ if (worker->flags & WORKER_STARTED)
+ gcwq->nr_workers--;
+ if (worker->flags & WORKER_IDLE)
+ gcwq->nr_idle--;
+
+ list_del_init(&worker->entry);
+ worker->flags |= WORKER_DIE;
+
+ spin_unlock_irq(&gcwq->lock);
+
+ kthread_stop(worker->task);
+ kfree(worker);
+
+ spin_lock_irq(&gcwq->lock);
+ ida_remove(&gcwq->worker_ida, id);
+}
+
+static void idle_worker_timeout(unsigned long __gcwq)
+{
+ struct global_cwq *gcwq = (void *)__gcwq;
+
+ spin_lock_irq(&gcwq->lock);
+
+ if (too_many_workers(gcwq)) {
+ struct worker *worker;
+ unsigned long expires;
+
+ /* idle_list is kept in LIFO order, check the last one */
+ worker = list_entry(gcwq->idle_list.prev, struct worker, entry);
+ expires = worker->last_active + IDLE_WORKER_TIMEOUT;
+
+ if (time_before(jiffies, expires))
+ mod_timer(&gcwq->idle_timer, expires);
+ else {
+ /* it's been idle for too long, wake up manager */
+ gcwq->flags |= GCWQ_MANAGE_WORKERS;
+ wake_up_worker(gcwq);
}
+ }
+
+ spin_unlock_irq(&gcwq->lock);
+}
- spin_lock_irq(&cwq->lock);
- cwq->current_work = NULL;
+static bool send_mayday(struct work_struct *work)
+{
+ struct cpu_workqueue_struct *cwq = get_work_cwq(work);
+ struct workqueue_struct *wq = cwq->wq;
+ unsigned int cpu;
+
+ if (!(wq->flags & WQ_RESCUER))
+ return false;
+
+ /* mayday mayday mayday */
+ cpu = cwq->gcwq->cpu;
+ /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */
+ if (cpu == WORK_CPU_UNBOUND)
+ cpu = 0;
+ if (!mayday_test_and_set_cpu(cpu, wq->mayday_mask))
+ wake_up_process(wq->rescuer->task);
+ return true;
+}
+
+static void gcwq_mayday_timeout(unsigned long __gcwq)
+{
+ struct global_cwq *gcwq = (void *)__gcwq;
+ struct work_struct *work;
+
+ spin_lock_irq(&gcwq->lock);
+
+ if (need_to_create_worker(gcwq)) {
+ /*
+ * We've been trying to create a new worker but
+ * haven't been successful. We might be hitting an
+ * allocation deadlock. Send distress signals to
+ * rescuers.
+ */
+ list_for_each_entry(work, &gcwq->worklist, entry)
+ send_mayday(work);
}
- spin_unlock_irq(&cwq->lock);
+
+ spin_unlock_irq(&gcwq->lock);
+
+ mod_timer(&gcwq->mayday_timer, jiffies + MAYDAY_INTERVAL);
}
-static int worker_thread(void *__cwq)
+/**
+ * maybe_create_worker - create a new worker if necessary
+ * @gcwq: gcwq to create a new worker for
+ *
+ * Create a new worker for @gcwq if necessary. @gcwq is guaranteed to
+ * have at least one idle worker on return from this function. If
+ * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is
+ * sent to all rescuers with works scheduled on @gcwq to resolve
+ * possible allocation deadlock.
+ *
+ * On return, need_to_create_worker() is guaranteed to be false and
+ * may_start_working() true.
+ *
+ * LOCKING:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times. Does GFP_KERNEL allocations. Called only from
+ * manager.
+ *
+ * RETURNS:
+ * false if no action was taken and gcwq->lock stayed locked, true
+ * otherwise.
+ */
+static bool maybe_create_worker(struct global_cwq *gcwq)
{
- struct cpu_workqueue_struct *cwq = __cwq;
- DEFINE_WAIT(wait);
+ if (!need_to_create_worker(gcwq))
+ return false;
+restart:
+ spin_unlock_irq(&gcwq->lock);
+
+ /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */
+ mod_timer(&gcwq->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT);
+
+ while (true) {
+ struct worker *worker;
+
+ worker = create_worker(gcwq, true);
+ if (worker) {
+ del_timer_sync(&gcwq->mayday_timer);
+ spin_lock_irq(&gcwq->lock);
+ start_worker(worker);
+ BUG_ON(need_to_create_worker(gcwq));
+ return true;
+ }
+
+ if (!need_to_create_worker(gcwq))
+ break;
- if (cwq->wq->freezeable)
- set_freezable();
+ __set_current_state(TASK_INTERRUPTIBLE);
+ schedule_timeout(CREATE_COOLDOWN);
+
+ if (!need_to_create_worker(gcwq))
+ break;
+ }
+
+ del_timer_sync(&gcwq->mayday_timer);
+ spin_lock_irq(&gcwq->lock);
+ if (need_to_create_worker(gcwq))
+ goto restart;
+ return true;
+}
+
+/**
+ * maybe_destroy_worker - destroy workers which have been idle for a while
+ * @gcwq: gcwq to destroy workers for
+ *
+ * Destroy @gcwq workers which have been idle for longer than
+ * IDLE_WORKER_TIMEOUT.
+ *
+ * LOCKING:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times. Called only from manager.
+ *
+ * RETURNS:
+ * false if no action was taken and gcwq->lock stayed locked, true
+ * otherwise.
+ */
+static bool maybe_destroy_workers(struct global_cwq *gcwq)
+{
+ bool ret = false;
- for (;;) {
- prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE);
- if (!freezing(current) &&
- !kthread_should_stop() &&
- list_empty(&cwq->worklist))
- schedule();
- finish_wait(&cwq->more_work, &wait);
+ while (too_many_workers(gcwq)) {
+ struct worker *worker;
+ unsigned long expires;
- try_to_freeze();
+ worker = list_entry(gcwq->idle_list.prev, struct worker, entry);
+ expires = worker->last_active + IDLE_WORKER_TIMEOUT;
- if (kthread_should_stop())
+ if (time_before(jiffies, expires)) {
+ mod_timer(&gcwq->idle_timer, expires);
break;
+ }
- run_workqueue(cwq);
+ destroy_worker(worker);
+ ret = true;
}
- return 0;
+ return ret;
+}
+
+/**
+ * manage_workers - manage worker pool
+ * @worker: self
+ *
+ * Assume the manager role and manage gcwq worker pool @worker belongs
+ * to. At any given time, there can be only zero or one manager per
+ * gcwq. The exclusion is handled automatically by this function.
+ *
+ * The caller can safely start processing works on false return. On
+ * true return, it's guaranteed that need_to_create_worker() is false
+ * and may_start_working() is true.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times. Does GFP_KERNEL allocations.
+ *
+ * RETURNS:
+ * false if no action was taken and gcwq->lock stayed locked, true if
+ * some action was taken.
+ */
+static bool manage_workers(struct worker *worker)
+{
+ struct global_cwq *gcwq = worker->gcwq;
+ bool ret = false;
+
+ if (gcwq->flags & GCWQ_MANAGING_WORKERS)
+ return ret;
+
+ gcwq->flags &= ~GCWQ_MANAGE_WORKERS;
+ gcwq->flags |= GCWQ_MANAGING_WORKERS;
+
+ /*
+ * Destroy and then create so that may_start_working() is true
+ * on return.
+ */
+ ret |= maybe_destroy_workers(gcwq);
+ ret |= maybe_create_worker(gcwq);
+
+ gcwq->flags &= ~GCWQ_MANAGING_WORKERS;
+
+ /*
+ * The trustee might be waiting to take over the manager
+ * position, tell it we're done.
+ */
+ if (unlikely(gcwq->trustee))
+ wake_up_all(&gcwq->trustee_wait);
+
+ return ret;
+}
+
+/**
+ * move_linked_works - move linked works to a list
+ * @work: start of series of works to be scheduled
+ * @head: target list to append @work to
+ * @nextp: out paramter for nested worklist walking
+ *
+ * Schedule linked works starting from @work to @head. Work series to
+ * be scheduled starts at @work and includes any consecutive work with
+ * WORK_STRUCT_LINKED set in its predecessor.
+ *
+ * If @nextp is not NULL, it's updated to point to the next work of
+ * the last scheduled work. This allows move_linked_works() to be
+ * nested inside outer list_for_each_entry_safe().
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void move_linked_works(struct work_struct *work, struct list_head *head,
+ struct work_struct **nextp)
+{
+ struct work_struct *n;
+
+ /*
+ * Linked worklist will always end before the end of the list,
+ * use NULL for list head.
+ */
+ list_for_each_entry_safe_from(work, n, NULL, entry) {
+ list_move_tail(&work->entry, head);
+ if (!(*work_data_bits(work) & WORK_STRUCT_LINKED))
+ break;
+ }
+
+ /*
+ * If we're already inside safe list traversal and have moved
+ * multiple works to the scheduled queue, the next position
+ * needs to be updated.
+ */
+ if (nextp)
+ *nextp = n;
+}
+
+static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq)
+{
+ struct work_struct *work = list_first_entry(&cwq->delayed_works,
+ struct work_struct, entry);
+ struct list_head *pos = gcwq_determine_ins_pos(cwq->gcwq, cwq);
+
+ move_linked_works(work, pos, NULL);
+ cwq->nr_active++;
+}
+
+/**
+ * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight
+ * @cwq: cwq of interest
+ * @color: color of work which left the queue
+ *
+ * A work either has completed or is removed from pending queue,
+ * decrement nr_in_flight of its cwq and handle workqueue flushing.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color)
+{
+ /* ignore uncolored works */
+ if (color == WORK_NO_COLOR)
+ return;
+
+ cwq->nr_in_flight[color]--;
+ cwq->nr_active--;
+
+ if (!list_empty(&cwq->delayed_works)) {
+ /* one down, submit a delayed one */
+ if (cwq->nr_active < cwq->max_active)
+ cwq_activate_first_delayed(cwq);
+ }
+
+ /* is flush in progress and are we at the flushing tip? */
+ if (likely(cwq->flush_color != color))
+ return;
+
+ /* are there still in-flight works? */
+ if (cwq->nr_in_flight[color])
+ return;
+
+ /* this cwq is done, clear flush_color */
+ cwq->flush_color = -1;
+
+ /*
+ * If this was the last cwq, wake up the first flusher. It
+ * will handle the rest.
+ */
+ if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush))
+ complete(&cwq->wq->first_flusher->done);
+}
+
+/**
+ * process_one_work - process single work
+ * @worker: self
+ * @work: work to process
+ *
+ * Process @work. This function contains all the logics necessary to
+ * process a single work including synchronization against and
+ * interaction with other workers on the same cpu, queueing and
+ * flushing. As long as context requirement is met, any worker can
+ * call this function to process a work.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which is released and regrabbed.
+ */
+static void process_one_work(struct worker *worker, struct work_struct *work)
+{
+ struct cpu_workqueue_struct *cwq = get_work_cwq(work);
+ struct global_cwq *gcwq = cwq->gcwq;
+ struct hlist_head *bwh = busy_worker_head(gcwq, work);
+ bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE;
+ work_func_t f = work->func;
+ int work_color;
+ struct worker *collision;
+#ifdef CONFIG_LOCKDEP
+ /*
+ * It is permissible to free the struct work_struct from
+ * inside the function that is called from it, this we need to
+ * take into account for lockdep too. To avoid bogus "held
+ * lock freed" warnings as well as problems when looking into
+ * work->lockdep_map, make a copy and use that here.
+ */
+ struct lockdep_map lockdep_map = work->lockdep_map;
+#endif
+ /*
+ * A single work shouldn't be executed concurrently by
+ * multiple workers on a single cpu. Check whether anyone is
+ * already processing the work. If so, defer the work to the
+ * currently executing one.
+ */
+ collision = __find_worker_executing_work(gcwq, bwh, work);
+ if (unlikely(collision)) {
+ move_linked_works(work, &collision->scheduled, NULL);
+ return;
+ }
+
+ /* claim and process */
+ debug_work_deactivate(work);
+ hlist_add_head(&worker->hentry, bwh);
+ worker->current_work = work;
+ worker->current_cwq = cwq;
+ work_color = get_work_color(work);
+
+ /* record the current cpu number in the work data and dequeue */
+ set_work_cpu(work, gcwq->cpu);
+ list_del_init(&work->entry);
+
+ /*
+ * If HIGHPRI_PENDING, check the next work, and, if HIGHPRI,
+ * wake up another worker; otherwise, clear HIGHPRI_PENDING.
+ */
+ if (unlikely(gcwq->flags & GCWQ_HIGHPRI_PENDING)) {
+ struct work_struct *nwork = list_first_entry(&gcwq->worklist,
+ struct work_struct, entry);
+
+ if (!list_empty(&gcwq->worklist) &&
+ get_work_cwq(nwork)->wq->flags & WQ_HIGHPRI)
+ wake_up_worker(gcwq);
+ else
+ gcwq->flags &= ~GCWQ_HIGHPRI_PENDING;
+ }
+
+ /*
+ * CPU intensive works don't participate in concurrency
+ * management. They're the scheduler's responsibility.
+ */
+ if (unlikely(cpu_intensive))
+ worker_set_flags(worker, WORKER_CPU_INTENSIVE, true);
+
+ spin_unlock_irq(&gcwq->lock);
+
+ work_clear_pending(work);
+ lock_map_acquire(&cwq->wq->lockdep_map);
+ lock_map_acquire(&lockdep_map);
+ f(work);
+ lock_map_release(&lockdep_map);
+ lock_map_release(&cwq->wq->lockdep_map);
+
+ if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
+ printk(KERN_ERR "BUG: workqueue leaked lock or atomic: "
+ "%s/0x%08x/%d\n",
+ current->comm, preempt_count(), task_pid_nr(current));
+ printk(KERN_ERR " last function: ");
+ print_symbol("%s\n", (unsigned long)f);
+ debug_show_held_locks(current);
+ dump_stack();
+ }
+
+ spin_lock_irq(&gcwq->lock);
+
+ /* clear cpu intensive status */
+ if (unlikely(cpu_intensive))
+ worker_clr_flags(worker, WORKER_CPU_INTENSIVE);
+
+ /* we're done with it, release */
+ hlist_del_init(&worker->hentry);
+ worker->current_work = NULL;
+ worker->current_cwq = NULL;
+ cwq_dec_nr_in_flight(cwq, work_color);
+}
+
+/**
+ * process_scheduled_works - process scheduled works
+ * @worker: self
+ *
+ * Process all scheduled works. Please note that the scheduled list
+ * may change while processing a work, so this function repeatedly
+ * fetches a work from the top and executes it.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times.
+ */
+static void process_scheduled_works(struct worker *worker)
+{
+ while (!list_empty(&worker->scheduled)) {
+ struct work_struct *work = list_first_entry(&worker->scheduled,
+ struct work_struct, entry);
+ process_one_work(worker, work);
+ }
+}
+
+/**
+ * worker_thread - the worker thread function
+ * @__worker: self
+ *
+ * The gcwq worker thread function. There's a single dynamic pool of
+ * these per each cpu. These workers process all works regardless of
+ * their specific target workqueue. The only exception is works which
+ * belong to workqueues with a rescuer which will be explained in
+ * rescuer_thread().
+ */
+static int worker_thread(void *__worker)
+{
+ struct worker *worker = __worker;
+ struct global_cwq *gcwq = worker->gcwq;
+
+ /* tell the scheduler that this is a workqueue worker */
+ worker->task->flags |= PF_WQ_WORKER;
+woke_up:
+ spin_lock_irq(&gcwq->lock);
+
+ /* DIE can be set only while we're idle, checking here is enough */
+ if (worker->flags & WORKER_DIE) {
+ spin_unlock_irq(&gcwq->lock);
+ worker->task->flags &= ~PF_WQ_WORKER;
+ return 0;
+ }
+
+ worker_leave_idle(worker);
+recheck:
+ /* no more worker necessary? */
+ if (!need_more_worker(gcwq))
+ goto sleep;
+
+ /* do we need to manage? */
+ if (unlikely(!may_start_working(gcwq)) && manage_workers(worker))
+ goto recheck;
+
+ /*
+ * ->scheduled list can only be filled while a worker is
+ * preparing to process a work or actually processing it.
+ * Make sure nobody diddled with it while I was sleeping.
+ */
+ BUG_ON(!list_empty(&worker->scheduled));
+
+ /*
+ * When control reaches this point, we're guaranteed to have
+ * at least one idle worker or that someone else has already
+ * assumed the manager role.
+ */
+ worker_clr_flags(worker, WORKER_PREP);
+
+ do {
+ struct work_struct *work =
+ list_first_entry(&gcwq->worklist,
+ struct work_struct, entry);
+
+ if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) {
+ /* optimization path, not strictly necessary */
+ process_one_work(worker, work);
+ if (unlikely(!list_empty(&worker->scheduled)))
+ process_scheduled_works(worker);
+ } else {
+ move_linked_works(work, &worker->scheduled, NULL);
+ process_scheduled_works(worker);
+ }
+ } while (keep_working(gcwq));
+
+ worker_set_flags(worker, WORKER_PREP, false);
+sleep:
+ if (unlikely(need_to_manage_workers(gcwq)) && manage_workers(worker))
+ goto recheck;
+
+ /*
+ * gcwq->lock is held and there's no work to process and no
+ * need to manage, sleep. Workers are woken up only while
+ * holding gcwq->lock or from local cpu, so setting the
+ * current state before releasing gcwq->lock is enough to
+ * prevent losing any event.
+ */
+ worker_enter_idle(worker);
+ __set_current_state(TASK_INTERRUPTIBLE);
+ spin_unlock_irq(&gcwq->lock);
+ schedule();
+ goto woke_up;
+}
+
+/**
+ * rescuer_thread - the rescuer thread function
+ * @__wq: the associated workqueue
+ *
+ * Workqueue rescuer thread function. There's one rescuer for each
+ * workqueue which has WQ_RESCUER set.
+ *
+ * Regular work processing on a gcwq may block trying to create a new
+ * worker which uses GFP_KERNEL allocation which has slight chance of
+ * developing into deadlock if some works currently on the same queue
+ * need to be processed to satisfy the GFP_KERNEL allocation. This is
+ * the problem rescuer solves.
+ *
+ * When such condition is possible, the gcwq summons rescuers of all
+ * workqueues which have works queued on the gcwq and let them process
+ * those works so that forward progress can be guaranteed.
+ *
+ * This should happen rarely.
+ */
+static int rescuer_thread(void *__wq)
+{
+ struct workqueue_struct *wq = __wq;
+ struct worker *rescuer = wq->rescuer;
+ struct list_head *scheduled = &rescuer->scheduled;
+ bool is_unbound = wq->flags & WQ_UNBOUND;
+ unsigned int cpu;
+
+ set_user_nice(current, RESCUER_NICE_LEVEL);
+repeat:
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ if (kthread_should_stop())
+ return 0;
+
+ /*
+ * See whether any cpu is asking for help. Unbounded
+ * workqueues use cpu 0 in mayday_mask for CPU_UNBOUND.
+ */
+ for_each_mayday_cpu(cpu, wq->mayday_mask) {
+ unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu;
+ struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq);
+ struct global_cwq *gcwq = cwq->gcwq;
+ struct work_struct *work, *n;
+
+ __set_current_state(TASK_RUNNING);
+ mayday_clear_cpu(cpu, wq->mayday_mask);
+
+ /* migrate to the target cpu if possible */
+ rescuer->gcwq = gcwq;
+ worker_maybe_bind_and_lock(rescuer);
+
+ /*
+ * Slurp in all works issued via this workqueue and
+ * process'em.
+ */
+ BUG_ON(!list_empty(&rescuer->scheduled));
+ list_for_each_entry_safe(work, n, &gcwq->worklist, entry)
+ if (get_work_cwq(work) == cwq)
+ move_linked_works(work, scheduled, &n);
+
+ process_scheduled_works(rescuer);
+ spin_unlock_irq(&gcwq->lock);
+ }
+
+ schedule();
+ goto repeat;
}
struct wq_barrier {
complete(&barr->done);
}
+/**
+ * insert_wq_barrier - insert a barrier work
+ * @cwq: cwq to insert barrier into
+ * @barr: wq_barrier to insert
+ * @target: target work to attach @barr to
+ * @worker: worker currently executing @target, NULL if @target is not executing
+ *
+ * @barr is linked to @target such that @barr is completed only after
+ * @target finishes execution. Please note that the ordering
+ * guarantee is observed only with respect to @target and on the local
+ * cpu.
+ *
+ * Currently, a queued barrier can't be canceled. This is because
+ * try_to_grab_pending() can't determine whether the work to be
+ * grabbed is at the head of the queue and thus can't clear LINKED
+ * flag of the previous work while there must be a valid next work
+ * after a work with LINKED flag set.
+ *
+ * Note that when @worker is non-NULL, @target may be modified
+ * underneath us, so we can't reliably determine cwq from @target.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
- struct wq_barrier *barr, struct list_head *head)
+ struct wq_barrier *barr,
+ struct work_struct *target, struct worker *worker)
{
+ struct list_head *head;
+ unsigned int linked = 0;
+
/*
- * debugobject calls are safe here even with cwq->lock locked
+ * debugobject calls are safe here even with gcwq->lock locked
* as we know for sure that this will not trigger any of the
* checks and call back into the fixup functions where we
* might deadlock.
*/
INIT_WORK_ON_STACK(&barr->work, wq_barrier_func);
- __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work));
+ __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work));
+ init_completion(&barr->done);
+
+ /*
+ * If @target is currently being executed, schedule the
+ * barrier to the worker; otherwise, put it after @target.
+ */
+ if (worker)
+ head = worker->scheduled.next;
+ else {
+ unsigned long *bits = work_data_bits(target);
+
+ head = target->entry.next;
+ /* there can already be other linked works, inherit and set */
+ linked = *bits & WORK_STRUCT_LINKED;
+ __set_bit(WORK_STRUCT_LINKED_BIT, bits);
+ }
+
+ debug_work_activate(&barr->work);
+ insert_work(cwq, &barr->work, head,
+ work_color_to_flags(WORK_NO_COLOR) | linked);
+}
+
+/**
+ * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing
+ * @wq: workqueue being flushed
+ * @flush_color: new flush color, < 0 for no-op
+ * @work_color: new work color, < 0 for no-op
+ *
+ * Prepare cwqs for workqueue flushing.
+ *
+ * If @flush_color is non-negative, flush_color on all cwqs should be
+ * -1. If no cwq has in-flight commands at the specified color, all
+ * cwq->flush_color's stay at -1 and %false is returned. If any cwq
+ * has in flight commands, its cwq->flush_color is set to
+ * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq
+ * wakeup logic is armed and %true is returned.
+ *
+ * The caller should have initialized @wq->first_flusher prior to
+ * calling this function with non-negative @flush_color. If
+ * @flush_color is negative, no flush color update is done and %false
+ * is returned.
+ *
+ * If @work_color is non-negative, all cwqs should have the same
+ * work_color which is previous to @work_color and all will be
+ * advanced to @work_color.
+ *
+ * CONTEXT:
+ * mutex_lock(wq->flush_mutex).
+ *
+ * RETURNS:
+ * %true if @flush_color >= 0 and there's something to flush. %false
+ * otherwise.
+ */
+static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq,
+ int flush_color, int work_color)
+{
+ bool wait = false;
+ unsigned int cpu;
+
+ if (flush_color >= 0) {
+ BUG_ON(atomic_read(&wq->nr_cwqs_to_flush));
+ atomic_set(&wq->nr_cwqs_to_flush, 1);
+ }
+
+ for_each_cwq_cpu(cpu, wq) {
+ struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+ struct global_cwq *gcwq = cwq->gcwq;
- init_completion(&barr->done);
+ spin_lock_irq(&gcwq->lock);
- debug_work_activate(&barr->work);
- insert_work(cwq, &barr->work, head);
-}
+ if (flush_color >= 0) {
+ BUG_ON(cwq->flush_color != -1);
-static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
-{
- int active = 0;
- struct wq_barrier barr;
+ if (cwq->nr_in_flight[flush_color]) {
+ cwq->flush_color = flush_color;
+ atomic_inc(&wq->nr_cwqs_to_flush);
+ wait = true;
+ }
+ }
- WARN_ON(cwq->thread == current);
+ if (work_color >= 0) {
+ BUG_ON(work_color != work_next_color(cwq->work_color));
+ cwq->work_color = work_color;
+ }
- spin_lock_irq(&cwq->lock);
- if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) {
- insert_wq_barrier(cwq, &barr, &cwq->worklist);
- active = 1;
+ spin_unlock_irq(&gcwq->lock);
}
- spin_unlock_irq(&cwq->lock);
- if (active) {
- wait_for_completion(&barr.done);
- destroy_work_on_stack(&barr.work);
- }
+ if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush))
+ complete(&wq->first_flusher->done);
- return active;
+ return wait;
}
/**
*
* We sleep until all works which were queued on entry have been handled,
* but we are not livelocked by new incoming ones.
- *
- * This function used to run the workqueues itself. Now we just wait for the
- * helper threads to do it.
*/
void flush_workqueue(struct workqueue_struct *wq)
{
- const struct cpumask *cpu_map = wq_cpu_map(wq);
- int cpu;
+ struct wq_flusher this_flusher = {
+ .list = LIST_HEAD_INIT(this_flusher.list),
+ .flush_color = -1,
+ .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done),
+ };
+ int next_color;
- might_sleep();
lock_map_acquire(&wq->lockdep_map);
lock_map_release(&wq->lockdep_map);
- for_each_cpu(cpu, cpu_map)
- flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
+
+ mutex_lock(&wq->flush_mutex);
+
+ /*
+ * Start-to-wait phase
+ */
+ next_color = work_next_color(wq->work_color);
+
+ if (next_color != wq->flush_color) {
+ /*
+ * Color space is not full. The current work_color
+ * becomes our flush_color and work_color is advanced
+ * by one.
+ */
+ BUG_ON(!list_empty(&wq->flusher_overflow));
+ this_flusher.flush_color = wq->work_color;
+ wq->work_color = next_color;
+
+ if (!wq->first_flusher) {
+ /* no flush in progress, become the first flusher */
+ BUG_ON(wq->flush_color != this_flusher.flush_color);
+
+ wq->first_flusher = &this_flusher;
+
+ if (!flush_workqueue_prep_cwqs(wq, wq->flush_color,
+ wq->work_color)) {
+ /* nothing to flush, done */
+ wq->flush_color = next_color;
+ wq->first_flusher = NULL;
+ goto out_unlock;
+ }
+ } else {
+ /* wait in queue */
+ BUG_ON(wq->flush_color == this_flusher.flush_color);
+ list_add_tail(&this_flusher.list, &wq->flusher_queue);
+ flush_workqueue_prep_cwqs(wq, -1, wq->work_color);
+ }
+ } else {
+ /*
+ * Oops, color space is full, wait on overflow queue.
+ * The next flush completion will assign us
+ * flush_color and transfer to flusher_queue.
+ */
+ list_add_tail(&this_flusher.list, &wq->flusher_overflow);
+ }
+
+ mutex_unlock(&wq->flush_mutex);
+
+ wait_for_completion(&this_flusher.done);
+
+ /*
+ * Wake-up-and-cascade phase
+ *
+ * First flushers are responsible for cascading flushes and
+ * handling overflow. Non-first flushers can simply return.
+ */
+ if (wq->first_flusher != &this_flusher)
+ return;
+
+ mutex_lock(&wq->flush_mutex);
+
+ /* we might have raced, check again with mutex held */
+ if (wq->first_flusher != &this_flusher)
+ goto out_unlock;
+
+ wq->first_flusher = NULL;
+
+ BUG_ON(!list_empty(&this_flusher.list));
+ BUG_ON(wq->flush_color != this_flusher.flush_color);
+
+ while (true) {
+ struct wq_flusher *next, *tmp;
+
+ /* complete all the flushers sharing the current flush color */
+ list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) {
+ if (next->flush_color != wq->flush_color)
+ break;
+ list_del_init(&next->list);
+ complete(&next->done);
+ }
+
+ BUG_ON(!list_empty(&wq->flusher_overflow) &&
+ wq->flush_color != work_next_color(wq->work_color));
+
+ /* this flush_color is finished, advance by one */
+ wq->flush_color = work_next_color(wq->flush_color);
+
+ /* one color has been freed, handle overflow queue */
+ if (!list_empty(&wq->flusher_overflow)) {
+ /*
+ * Assign the same color to all overflowed
+ * flushers, advance work_color and append to
+ * flusher_queue. This is the start-to-wait
+ * phase for these overflowed flushers.
+ */
+ list_for_each_entry(tmp, &wq->flusher_overflow, list)
+ tmp->flush_color = wq->work_color;
+
+ wq->work_color = work_next_color(wq->work_color);
+
+ list_splice_tail_init(&wq->flusher_overflow,
+ &wq->flusher_queue);
+ flush_workqueue_prep_cwqs(wq, -1, wq->work_color);
+ }
+
+ if (list_empty(&wq->flusher_queue)) {
+ BUG_ON(wq->flush_color != wq->work_color);
+ break;
+ }
+
+ /*
+ * Need to flush more colors. Make the next flusher
+ * the new first flusher and arm cwqs.
+ */
+ BUG_ON(wq->flush_color == wq->work_color);
+ BUG_ON(wq->flush_color != next->flush_color);
+
+ list_del_init(&next->list);
+ wq->first_flusher = next;
+
+ if (flush_workqueue_prep_cwqs(wq, wq->flush_color, -1))
+ break;
+
+ /*
+ * Meh... this color is already done, clear first
+ * flusher and repeat cascading.
+ */
+ wq->first_flusher = NULL;
+ }
+
+out_unlock:
+ mutex_unlock(&wq->flush_mutex);
}
EXPORT_SYMBOL_GPL(flush_workqueue);
*/
int flush_work(struct work_struct *work)
{
+ struct worker *worker = NULL;
+ struct global_cwq *gcwq;
struct cpu_workqueue_struct *cwq;
- struct list_head *prev;
struct wq_barrier barr;
might_sleep();
- cwq = get_wq_data(work);
- if (!cwq)
+ gcwq = get_work_gcwq(work);
+ if (!gcwq)
return 0;
- lock_map_acquire(&cwq->wq->lockdep_map);
- lock_map_release(&cwq->wq->lockdep_map);
-
- prev = NULL;
- spin_lock_irq(&cwq->lock);
+ spin_lock_irq(&gcwq->lock);
if (!list_empty(&work->entry)) {
/*
* See the comment near try_to_grab_pending()->smp_rmb().
- * If it was re-queued under us we are not going to wait.
+ * If it was re-queued to a different gcwq under us, we
+ * are not going to wait.
*/
smp_rmb();
- if (unlikely(cwq != get_wq_data(work)))
- goto out;
- prev = &work->entry;
+ cwq = get_work_cwq(work);
+ if (unlikely(!cwq || gcwq != cwq->gcwq))
+ goto already_gone;
} else {
- if (cwq->current_work != work)
- goto out;
- prev = &cwq->worklist;
+ worker = find_worker_executing_work(gcwq, work);
+ if (!worker)
+ goto already_gone;
+ cwq = worker->current_cwq;
}
- insert_wq_barrier(cwq, &barr, prev->next);
-out:
- spin_unlock_irq(&cwq->lock);
- if (!prev)
- return 0;
+
+ insert_wq_barrier(cwq, &barr, work, worker);
+ spin_unlock_irq(&gcwq->lock);
+
+ lock_map_acquire(&cwq->wq->lockdep_map);
+ lock_map_release(&cwq->wq->lockdep_map);
wait_for_completion(&barr.done);
destroy_work_on_stack(&barr.work);
return 1;
+already_gone:
+ spin_unlock_irq(&gcwq->lock);
+ return 0;
}
EXPORT_SYMBOL_GPL(flush_work);
*/
static int try_to_grab_pending(struct work_struct *work)
{
- struct cpu_workqueue_struct *cwq;
+ struct global_cwq *gcwq;
int ret = -1;
- if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work)))
+ if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
return 0;
/*
* The queueing is in progress, or it is already queued. Try to
* steal it from ->worklist without clearing WORK_STRUCT_PENDING.
*/
-
- cwq = get_wq_data(work);
- if (!cwq)
+ gcwq = get_work_gcwq(work);
+ if (!gcwq)
return ret;
- spin_lock_irq(&cwq->lock);
+ spin_lock_irq(&gcwq->lock);
if (!list_empty(&work->entry)) {
/*
- * This work is queued, but perhaps we locked the wrong cwq.
+ * This work is queued, but perhaps we locked the wrong gcwq.
* In that case we must see the new value after rmb(), see
* insert_work()->wmb().
*/
smp_rmb();
- if (cwq == get_wq_data(work)) {
+ if (gcwq == get_work_gcwq(work)) {
debug_work_deactivate(work);
list_del_init(&work->entry);
+ cwq_dec_nr_in_flight(get_work_cwq(work),
+ get_work_color(work));
ret = 1;
}
}
- spin_unlock_irq(&cwq->lock);
+ spin_unlock_irq(&gcwq->lock);
return ret;
}
-static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq,
- struct work_struct *work)
+static void wait_on_cpu_work(struct global_cwq *gcwq, struct work_struct *work)
{
struct wq_barrier barr;
- int running = 0;
+ struct worker *worker;
- spin_lock_irq(&cwq->lock);
- if (unlikely(cwq->current_work == work)) {
- insert_wq_barrier(cwq, &barr, cwq->worklist.next);
- running = 1;
- }
- spin_unlock_irq(&cwq->lock);
+ spin_lock_irq(&gcwq->lock);
- if (unlikely(running)) {
+ worker = find_worker_executing_work(gcwq, work);
+ if (unlikely(worker))
+ insert_wq_barrier(worker->current_cwq, &barr, work, worker);
+
+ spin_unlock_irq(&gcwq->lock);
+
+ if (unlikely(worker)) {
wait_for_completion(&barr.done);
destroy_work_on_stack(&barr.work);
}
static void wait_on_work(struct work_struct *work)
{
- struct cpu_workqueue_struct *cwq;
- struct workqueue_struct *wq;
- const struct cpumask *cpu_map;
int cpu;
might_sleep();
lock_map_acquire(&work->lockdep_map);
lock_map_release(&work->lockdep_map);
- cwq = get_wq_data(work);
- if (!cwq)
- return;
-
- wq = cwq->wq;
- cpu_map = wq_cpu_map(wq);
-
- for_each_cpu(cpu, cpu_map)
- wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
+ for_each_gcwq_cpu(cpu)
+ wait_on_cpu_work(get_gcwq(cpu), work);
}
static int __cancel_work_timer(struct work_struct *work,
wait_on_work(work);
} while (unlikely(ret < 0));
- clear_wq_data(work);
+ clear_work_data(work);
return ret;
}
}
EXPORT_SYMBOL(cancel_delayed_work_sync);
-static struct workqueue_struct *keventd_wq __read_mostly;
-
/**
* schedule_work - put work task in global workqueue
* @work: job to be done
*/
int schedule_work(struct work_struct *work)
{
- return queue_work(keventd_wq, work);
+ return queue_work(system_wq, work);
}
EXPORT_SYMBOL(schedule_work);
*/
int schedule_work_on(int cpu, struct work_struct *work)
{
- return queue_work_on(cpu, keventd_wq, work);
+ return queue_work_on(cpu, system_wq, work);
}
EXPORT_SYMBOL(schedule_work_on);
int schedule_delayed_work(struct delayed_work *dwork,
unsigned long delay)
{
- return queue_delayed_work(keventd_wq, dwork, delay);
+ return queue_delayed_work(system_wq, dwork, delay);
}
EXPORT_SYMBOL(schedule_delayed_work);
void flush_delayed_work(struct delayed_work *dwork)
{
if (del_timer_sync(&dwork->timer)) {
- struct cpu_workqueue_struct *cwq;
- cwq = wq_per_cpu(get_wq_data(&dwork->work)->wq, get_cpu());
- __queue_work(cwq, &dwork->work);
+ __queue_work(get_cpu(), get_work_cwq(&dwork->work)->wq,
+ &dwork->work);
put_cpu();
}
flush_work(&dwork->work);
int schedule_delayed_work_on(int cpu,
struct delayed_work *dwork, unsigned long delay)
{
- return queue_delayed_work_on(cpu, keventd_wq, dwork, delay);
+ return queue_delayed_work_on(cpu, system_wq, dwork, delay);
}
EXPORT_SYMBOL(schedule_delayed_work_on);
int schedule_on_each_cpu(work_func_t func)
{
int cpu;
- int orig = -1;
struct work_struct *works;
works = alloc_percpu(struct work_struct);
get_online_cpus();
+ for_each_online_cpu(cpu) {
+ struct work_struct *work = per_cpu_ptr(works, cpu);
+
+ INIT_WORK(work, func);
+ schedule_work_on(cpu, work);
+ }
+
+ for_each_online_cpu(cpu)
+ flush_work(per_cpu_ptr(works, cpu));
+
+ put_online_cpus();
+ free_percpu(works);
+ return 0;
+}
+
+/**
+ * flush_scheduled_work - ensure that any scheduled work has run to completion.
+ *
+ * Forces execution of the kernel-global workqueue and blocks until its
+ * completion.
+ *
+ * Think twice before calling this function! It's very easy to get into
+ * trouble if you don't take great care. Either of the following situations
+ * will lead to deadlock:
+ *
+ * One of the work items currently on the workqueue needs to acquire
+ * a lock held by your code or its caller.
+ *
+ * Your code is running in the context of a work routine.
+ *
+ * They will be detected by lockdep when they occur, but the first might not
+ * occur very often. It depends on what work items are on the workqueue and
+ * what locks they need, which you have no control over.
+ *
+ * In most situations flushing the entire workqueue is overkill; you merely
+ * need to know that a particular work item isn't queued and isn't running.
+ * In such cases you should use cancel_delayed_work_sync() or
+ * cancel_work_sync() instead.
+ */
+void flush_scheduled_work(void)
+{
+ flush_workqueue(system_wq);
+}
+EXPORT_SYMBOL(flush_scheduled_work);
+
+/**
+ * execute_in_process_context - reliably execute the routine with user context
+ * @fn: the function to execute
+ * @ew: guaranteed storage for the execute work structure (must
+ * be available when the work executes)
+ *
+ * Executes the function immediately if process context is available,
+ * otherwise schedules the function for delayed execution.
+ *
+ * Returns: 0 - function was executed
+ * 1 - function was scheduled for execution
+ */
+int execute_in_process_context(work_func_t fn, struct execute_work *ew)
+{
+ if (!in_interrupt()) {
+ fn(&ew->work);
+ return 0;
+ }
+
+ INIT_WORK(&ew->work, fn);
+ schedule_work(&ew->work);
+
+ return 1;
+}
+EXPORT_SYMBOL_GPL(execute_in_process_context);
+
+int keventd_up(void)
+{
+ return system_wq != NULL;
+}
+
+static int alloc_cwqs(struct workqueue_struct *wq)
+{
/*
- * When running in keventd don't schedule a work item on
- * itself. Can just call directly because the work queue is
- * already bound. This also is faster.
+ * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS.
+ * Make sure that the alignment isn't lower than that of
+ * unsigned long long.
*/
- if (current_is_keventd())
- orig = raw_smp_processor_id();
+ const size_t size = sizeof(struct cpu_workqueue_struct);
+ const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS,
+ __alignof__(unsigned long long));
+#ifdef CONFIG_SMP
+ bool percpu = !(wq->flags & WQ_UNBOUND);
+#else
+ bool percpu = false;
+#endif
- for_each_online_cpu(cpu) {
- struct work_struct *work = per_cpu_ptr(works, cpu);
+ if (percpu)
+ wq->cpu_wq.pcpu = __alloc_percpu(size, align);
+ else {
+ void *ptr;
+
+ /*
+ * Allocate enough room to align cwq and put an extra
+ * pointer at the end pointing back to the originally
+ * allocated pointer which will be used for free.
+ */
+ ptr = kzalloc(size + align + sizeof(void *), GFP_KERNEL);
+ if (ptr) {
+ wq->cpu_wq.single = PTR_ALIGN(ptr, align);
+ *(void **)(wq->cpu_wq.single + 1) = ptr;
+ }
+ }
+
+ /* just in case, make sure it's actually aligned */
+ BUG_ON(!IS_ALIGNED(wq->cpu_wq.v, align));
+ return wq->cpu_wq.v ? 0 : -ENOMEM;
+}
+
+static void free_cwqs(struct workqueue_struct *wq)
+{
+#ifdef CONFIG_SMP
+ bool percpu = !(wq->flags & WQ_UNBOUND);
+#else
+ bool percpu = false;
+#endif
+
+ if (percpu)
+ free_percpu(wq->cpu_wq.pcpu);
+ else if (wq->cpu_wq.single) {
+ /* the pointer to free is stored right after the cwq */
+ kfree(*(void **)(wq->cpu_wq.single + 1));
+ }
+}
+
+static int wq_clamp_max_active(int max_active, unsigned int flags,
+ const char *name)
+{
+ int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE;
+
+ if (max_active < 1 || max_active > lim)
+ printk(KERN_WARNING "workqueue: max_active %d requested for %s "
+ "is out of range, clamping between %d and %d\n",
+ max_active, name, 1, lim);
+
+ return clamp_val(max_active, 1, lim);
+}
+
+struct workqueue_struct *__alloc_workqueue_key(const char *name,
+ unsigned int flags,
+ int max_active,
+ struct lock_class_key *key,
+ const char *lock_name)
+{
+ struct workqueue_struct *wq;
+ unsigned int cpu;
+
+ /*
+ * Unbound workqueues aren't concurrency managed and should be
+ * dispatched to workers immediately.
+ */
+ if (flags & WQ_UNBOUND)
+ flags |= WQ_HIGHPRI;
+
+ max_active = max_active ?: WQ_DFL_ACTIVE;
+ max_active = wq_clamp_max_active(max_active, flags, name);
+
+ wq = kzalloc(sizeof(*wq), GFP_KERNEL);
+ if (!wq)
+ goto err;
+
+ wq->flags = flags;
+ wq->saved_max_active = max_active;
+ mutex_init(&wq->flush_mutex);
+ atomic_set(&wq->nr_cwqs_to_flush, 0);
+ INIT_LIST_HEAD(&wq->flusher_queue);
+ INIT_LIST_HEAD(&wq->flusher_overflow);
+
+ wq->name = name;
+ lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
+ INIT_LIST_HEAD(&wq->list);
+
+ if (alloc_cwqs(wq) < 0)
+ goto err;
+
+ for_each_cwq_cpu(cpu, wq) {
+ struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+ struct global_cwq *gcwq = get_gcwq(cpu);
+
+ BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK);
+ cwq->gcwq = gcwq;
+ cwq->wq = wq;
+ cwq->flush_color = -1;
+ cwq->max_active = max_active;
+ INIT_LIST_HEAD(&cwq->delayed_works);
+ }
+
+ if (flags & WQ_RESCUER) {
+ struct worker *rescuer;
+
+ if (!alloc_mayday_mask(&wq->mayday_mask, GFP_KERNEL))
+ goto err;
+
+ wq->rescuer = rescuer = alloc_worker();
+ if (!rescuer)
+ goto err;
+
+ rescuer->task = kthread_create(rescuer_thread, wq, "%s", name);
+ if (IS_ERR(rescuer->task))
+ goto err;
+
+ wq->rescuer = rescuer;
+ rescuer->task->flags |= PF_THREAD_BOUND;
+ wake_up_process(rescuer->task);
+ }
+
+ /*
+ * workqueue_lock protects global freeze state and workqueues
+ * list. Grab it, set max_active accordingly and add the new
+ * workqueue to workqueues list.
+ */
+ spin_lock(&workqueue_lock);
+
+ if (workqueue_freezing && wq->flags & WQ_FREEZEABLE)
+ for_each_cwq_cpu(cpu, wq)
+ get_cwq(cpu, wq)->max_active = 0;
+
+ list_add(&wq->list, &workqueues);
+
+ spin_unlock(&workqueue_lock);
+
+ return wq;
+err:
+ if (wq) {
+ free_cwqs(wq);
+ free_mayday_mask(wq->mayday_mask);
+ kfree(wq->rescuer);
+ kfree(wq);
+ }
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(__alloc_workqueue_key);
+
+/**
+ * destroy_workqueue - safely terminate a workqueue
+ * @wq: target workqueue
+ *
+ * Safely destroy a workqueue. All work currently pending will be done first.
+ */
+void destroy_workqueue(struct workqueue_struct *wq)
+{
+ unsigned int cpu;
+
+ flush_workqueue(wq);
+
+ /*
+ * wq list is used to freeze wq, remove from list after
+ * flushing is complete in case freeze races us.
+ */
+ spin_lock(&workqueue_lock);
+ list_del(&wq->list);
+ spin_unlock(&workqueue_lock);
+
+ /* sanity check */
+ for_each_cwq_cpu(cpu, wq) {
+ struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+ int i;
+
+ for (i = 0; i < WORK_NR_COLORS; i++)
+ BUG_ON(cwq->nr_in_flight[i]);
+ BUG_ON(cwq->nr_active);
+ BUG_ON(!list_empty(&cwq->delayed_works));
+ }
+
+ if (wq->flags & WQ_RESCUER) {
+ kthread_stop(wq->rescuer->task);
+ free_mayday_mask(wq->mayday_mask);
+ }
+
+ free_cwqs(wq);
+ kfree(wq);
+}
+EXPORT_SYMBOL_GPL(destroy_workqueue);
+
+/**
+ * workqueue_set_max_active - adjust max_active of a workqueue
+ * @wq: target workqueue
+ * @max_active: new max_active value.
+ *
+ * Set max_active of @wq to @max_active.
+ *
+ * CONTEXT:
+ * Don't call from IRQ context.
+ */
+void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
+{
+ unsigned int cpu;
+
+ max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
+
+ spin_lock(&workqueue_lock);
+
+ wq->saved_max_active = max_active;
+
+ for_each_cwq_cpu(cpu, wq) {
+ struct global_cwq *gcwq = get_gcwq(cpu);
+
+ spin_lock_irq(&gcwq->lock);
+
+ if (!(wq->flags & WQ_FREEZEABLE) ||
+ !(gcwq->flags & GCWQ_FREEZING))
+ get_cwq(gcwq->cpu, wq)->max_active = max_active;
- INIT_WORK(work, func);
- if (cpu != orig)
- schedule_work_on(cpu, work);
+ spin_unlock_irq(&gcwq->lock);
}
- if (orig >= 0)
- func(per_cpu_ptr(works, orig));
-
- for_each_online_cpu(cpu)
- flush_work(per_cpu_ptr(works, cpu));
- put_online_cpus();
- free_percpu(works);
- return 0;
+ spin_unlock(&workqueue_lock);
}
+EXPORT_SYMBOL_GPL(workqueue_set_max_active);
/**
- * flush_scheduled_work - ensure that any scheduled work has run to completion.
- *
- * Forces execution of the kernel-global workqueue and blocks until its
- * completion.
- *
- * Think twice before calling this function! It's very easy to get into
- * trouble if you don't take great care. Either of the following situations
- * will lead to deadlock:
- *
- * One of the work items currently on the workqueue needs to acquire
- * a lock held by your code or its caller.
- *
- * Your code is running in the context of a work routine.
+ * workqueue_congested - test whether a workqueue is congested
+ * @cpu: CPU in question
+ * @wq: target workqueue
*
- * They will be detected by lockdep when they occur, but the first might not
- * occur very often. It depends on what work items are on the workqueue and
- * what locks they need, which you have no control over.
+ * Test whether @wq's cpu workqueue for @cpu is congested. There is
+ * no synchronization around this function and the test result is
+ * unreliable and only useful as advisory hints or for debugging.
*
- * In most situations flushing the entire workqueue is overkill; you merely
- * need to know that a particular work item isn't queued and isn't running.
- * In such cases you should use cancel_delayed_work_sync() or
- * cancel_work_sync() instead.
+ * RETURNS:
+ * %true if congested, %false otherwise.
*/
-void flush_scheduled_work(void)
+bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq)
{
- flush_workqueue(keventd_wq);
+ struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+
+ return !list_empty(&cwq->delayed_works);
}
-EXPORT_SYMBOL(flush_scheduled_work);
+EXPORT_SYMBOL_GPL(workqueue_congested);
/**
- * execute_in_process_context - reliably execute the routine with user context
- * @fn: the function to execute
- * @ew: guaranteed storage for the execute work structure (must
- * be available when the work executes)
+ * work_cpu - return the last known associated cpu for @work
+ * @work: the work of interest
*
- * Executes the function immediately if process context is available,
- * otherwise schedules the function for delayed execution.
- *
- * Returns: 0 - function was executed
- * 1 - function was scheduled for execution
+ * RETURNS:
+ * CPU number if @work was ever queued. WORK_CPU_NONE otherwise.
*/
-int execute_in_process_context(work_func_t fn, struct execute_work *ew)
+unsigned int work_cpu(struct work_struct *work)
{
- if (!in_interrupt()) {
- fn(&ew->work);
- return 0;
- }
-
- INIT_WORK(&ew->work, fn);
- schedule_work(&ew->work);
+ struct global_cwq *gcwq = get_work_gcwq(work);
- return 1;
+ return gcwq ? gcwq->cpu : WORK_CPU_NONE;
}
-EXPORT_SYMBOL_GPL(execute_in_process_context);
+EXPORT_SYMBOL_GPL(work_cpu);
-int keventd_up(void)
+/**
+ * work_busy - test whether a work is currently pending or running
+ * @work: the work to be tested
+ *
+ * Test whether @work is currently pending or running. There is no
+ * synchronization around this function and the test result is
+ * unreliable and only useful as advisory hints or for debugging.
+ * Especially for reentrant wqs, the pending state might hide the
+ * running state.
+ *
+ * RETURNS:
+ * OR'd bitmask of WORK_BUSY_* bits.
+ */
+unsigned int work_busy(struct work_struct *work)
{
- return keventd_wq != NULL;
-}
+ struct global_cwq *gcwq = get_work_gcwq(work);
+ unsigned long flags;
+ unsigned int ret = 0;
-int current_is_keventd(void)
-{
- struct cpu_workqueue_struct *cwq;
- int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */
- int ret = 0;
+ if (!gcwq)
+ return false;
- BUG_ON(!keventd_wq);
+ spin_lock_irqsave(&gcwq->lock, flags);
- cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu);
- if (current == cwq->thread)
- ret = 1;
+ if (work_pending(work))
+ ret |= WORK_BUSY_PENDING;
+ if (find_worker_executing_work(gcwq, work))
+ ret |= WORK_BUSY_RUNNING;
- return ret;
+ spin_unlock_irqrestore(&gcwq->lock, flags);
+ return ret;
}
+EXPORT_SYMBOL_GPL(work_busy);
-static struct cpu_workqueue_struct *
-init_cpu_workqueue(struct workqueue_struct *wq, int cpu)
-{
- struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
+/*
+ * CPU hotplug.
+ *
+ * There are two challenges in supporting CPU hotplug. Firstly, there
+ * are a lot of assumptions on strong associations among work, cwq and
+ * gcwq which make migrating pending and scheduled works very
+ * difficult to implement without impacting hot paths. Secondly,
+ * gcwqs serve mix of short, long and very long running works making
+ * blocked draining impractical.
+ *
+ * This is solved by allowing a gcwq to be detached from CPU, running
+ * it with unbound (rogue) workers and allowing it to be reattached
+ * later if the cpu comes back online. A separate thread is created
+ * to govern a gcwq in such state and is called the trustee of the
+ * gcwq.
+ *
+ * Trustee states and their descriptions.
+ *
+ * START Command state used on startup. On CPU_DOWN_PREPARE, a
+ * new trustee is started with this state.
+ *
+ * IN_CHARGE Once started, trustee will enter this state after
+ * assuming the manager role and making all existing
+ * workers rogue. DOWN_PREPARE waits for trustee to
+ * enter this state. After reaching IN_CHARGE, trustee
+ * tries to execute the pending worklist until it's empty
+ * and the state is set to BUTCHER, or the state is set
+ * to RELEASE.
+ *
+ * BUTCHER Command state which is set by the cpu callback after
+ * the cpu has went down. Once this state is set trustee
+ * knows that there will be no new works on the worklist
+ * and once the worklist is empty it can proceed to
+ * killing idle workers.
+ *
+ * RELEASE Command state which is set by the cpu callback if the
+ * cpu down has been canceled or it has come online
+ * again. After recognizing this state, trustee stops
+ * trying to drain or butcher and clears ROGUE, rebinds
+ * all remaining workers back to the cpu and releases
+ * manager role.
+ *
+ * DONE Trustee will enter this state after BUTCHER or RELEASE
+ * is complete.
+ *
+ * trustee CPU draining
+ * took over down complete
+ * START -----------> IN_CHARGE -----------> BUTCHER -----------> DONE
+ * | | ^
+ * | CPU is back online v return workers |
+ * ----------------> RELEASE --------------
+ */
- cwq->wq = wq;
- spin_lock_init(&cwq->lock);
- INIT_LIST_HEAD(&cwq->worklist);
- init_waitqueue_head(&cwq->more_work);
+/**
+ * trustee_wait_event_timeout - timed event wait for trustee
+ * @cond: condition to wait for
+ * @timeout: timeout in jiffies
+ *
+ * wait_event_timeout() for trustee to use. Handles locking and
+ * checks for RELEASE request.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times. To be used by trustee.
+ *
+ * RETURNS:
+ * Positive indicating left time if @cond is satisfied, 0 if timed
+ * out, -1 if canceled.
+ */
+#define trustee_wait_event_timeout(cond, timeout) ({ \
+ long __ret = (timeout); \
+ while (!((cond) || (gcwq->trustee_state == TRUSTEE_RELEASE)) && \
+ __ret) { \
+ spin_unlock_irq(&gcwq->lock); \
+ __wait_event_timeout(gcwq->trustee_wait, (cond) || \
+ (gcwq->trustee_state == TRUSTEE_RELEASE), \
+ __ret); \
+ spin_lock_irq(&gcwq->lock); \
+ } \
+ gcwq->trustee_state == TRUSTEE_RELEASE ? -1 : (__ret); \
+})
- return cwq;
-}
+/**
+ * trustee_wait_event - event wait for trustee
+ * @cond: condition to wait for
+ *
+ * wait_event() for trustee to use. Automatically handles locking and
+ * checks for CANCEL request.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times. To be used by trustee.
+ *
+ * RETURNS:
+ * 0 if @cond is satisfied, -1 if canceled.
+ */
+#define trustee_wait_event(cond) ({ \
+ long __ret1; \
+ __ret1 = trustee_wait_event_timeout(cond, MAX_SCHEDULE_TIMEOUT);\
+ __ret1 < 0 ? -1 : 0; \
+})
-static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
+static int __cpuinit trustee_thread(void *__gcwq)
{
- struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
- struct workqueue_struct *wq = cwq->wq;
- const char *fmt = is_wq_single_threaded(wq) ? "%s" : "%s/%d";
- struct task_struct *p;
+ struct global_cwq *gcwq = __gcwq;
+ struct worker *worker;
+ struct work_struct *work;
+ struct hlist_node *pos;
+ long rc;
+ int i;
- p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu);
+ BUG_ON(gcwq->cpu != smp_processor_id());
+
+ spin_lock_irq(&gcwq->lock);
/*
- * Nobody can add the work_struct to this cwq,
- * if (caller is __create_workqueue)
- * nobody should see this wq
- * else // caller is CPU_UP_PREPARE
- * cpu is not on cpu_online_map
- * so we can abort safely.
+ * Claim the manager position and make all workers rogue.
+ * Trustee must be bound to the target cpu and can't be
+ * cancelled.
*/
- if (IS_ERR(p))
- return PTR_ERR(p);
- if (cwq->wq->rt)
- sched_setscheduler_nocheck(p, SCHED_FIFO, ¶m);
- cwq->thread = p;
+ BUG_ON(gcwq->cpu != smp_processor_id());
+ rc = trustee_wait_event(!(gcwq->flags & GCWQ_MANAGING_WORKERS));
+ BUG_ON(rc < 0);
- trace_workqueue_creation(cwq->thread, cpu);
+ gcwq->flags |= GCWQ_MANAGING_WORKERS;
- return 0;
-}
+ list_for_each_entry(worker, &gcwq->idle_list, entry)
+ worker->flags |= WORKER_ROGUE;
-static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
-{
- struct task_struct *p = cwq->thread;
+ for_each_busy_worker(worker, i, pos, gcwq)
+ worker->flags |= WORKER_ROGUE;
- if (p != NULL) {
- if (cpu >= 0)
- kthread_bind(p, cpu);
- wake_up_process(p);
- }
-}
+ /*
+ * Call schedule() so that we cross rq->lock and thus can
+ * guarantee sched callbacks see the rogue flag. This is
+ * necessary as scheduler callbacks may be invoked from other
+ * cpus.
+ */
+ spin_unlock_irq(&gcwq->lock);
+ schedule();
+ spin_lock_irq(&gcwq->lock);
-struct workqueue_struct *__create_workqueue_key(const char *name,
- int singlethread,
- int freezeable,
- int rt,
- struct lock_class_key *key,
- const char *lock_name)
-{
- struct workqueue_struct *wq;
- struct cpu_workqueue_struct *cwq;
- int err = 0, cpu;
+ /*
+ * Sched callbacks are disabled now. Zap nr_running. After
+ * this, nr_running stays zero and need_more_worker() and
+ * keep_working() are always true as long as the worklist is
+ * not empty.
+ */
+ atomic_set(get_gcwq_nr_running(gcwq->cpu), 0);
- wq = kzalloc(sizeof(*wq), GFP_KERNEL);
- if (!wq)
- return NULL;
+ spin_unlock_irq(&gcwq->lock);
+ del_timer_sync(&gcwq->idle_timer);
+ spin_lock_irq(&gcwq->lock);
- wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct);
- if (!wq->cpu_wq) {
- kfree(wq);
- return NULL;
- }
+ /*
+ * We're now in charge. Notify and proceed to drain. We need
+ * to keep the gcwq running during the whole CPU down
+ * procedure as other cpu hotunplug callbacks may need to
+ * flush currently running tasks.
+ */
+ gcwq->trustee_state = TRUSTEE_IN_CHARGE;
+ wake_up_all(&gcwq->trustee_wait);
- wq->name = name;
- lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
- wq->singlethread = singlethread;
- wq->freezeable = freezeable;
- wq->rt = rt;
- INIT_LIST_HEAD(&wq->list);
+ /*
+ * The original cpu is in the process of dying and may go away
+ * anytime now. When that happens, we and all workers would
+ * be migrated to other cpus. Try draining any left work. We
+ * want to get it over with ASAP - spam rescuers, wake up as
+ * many idlers as necessary and create new ones till the
+ * worklist is empty. Note that if the gcwq is frozen, there
+ * may be frozen works in freezeable cwqs. Don't declare
+ * completion while frozen.
+ */
+ while (gcwq->nr_workers != gcwq->nr_idle ||
+ gcwq->flags & GCWQ_FREEZING ||
+ gcwq->trustee_state == TRUSTEE_IN_CHARGE) {
+ int nr_works = 0;
+
+ list_for_each_entry(work, &gcwq->worklist, entry) {
+ send_mayday(work);
+ nr_works++;
+ }
- if (singlethread) {
- cwq = init_cpu_workqueue(wq, singlethread_cpu);
- err = create_workqueue_thread(cwq, singlethread_cpu);
- start_workqueue_thread(cwq, -1);
- } else {
- cpu_maps_update_begin();
- /*
- * We must place this wq on list even if the code below fails.
- * cpu_down(cpu) can remove cpu from cpu_populated_map before
- * destroy_workqueue() takes the lock, in that case we leak
- * cwq[cpu]->thread.
- */
- spin_lock(&workqueue_lock);
- list_add(&wq->list, &workqueues);
- spin_unlock(&workqueue_lock);
- /*
- * We must initialize cwqs for each possible cpu even if we
- * are going to call destroy_workqueue() finally. Otherwise
- * cpu_up() can hit the uninitialized cwq once we drop the
- * lock.
- */
- for_each_possible_cpu(cpu) {
- cwq = init_cpu_workqueue(wq, cpu);
- if (err || !cpu_online(cpu))
- continue;
- err = create_workqueue_thread(cwq, cpu);
- start_workqueue_thread(cwq, cpu);
+ list_for_each_entry(worker, &gcwq->idle_list, entry) {
+ if (!nr_works--)
+ break;
+ wake_up_process(worker->task);
+ }
+
+ if (need_to_create_worker(gcwq)) {
+ spin_unlock_irq(&gcwq->lock);
+ worker = create_worker(gcwq, false);
+ spin_lock_irq(&gcwq->lock);
+ if (worker) {
+ worker->flags |= WORKER_ROGUE;
+ start_worker(worker);
+ }
}
- cpu_maps_update_done();
- }
- if (err) {
- destroy_workqueue(wq);
- wq = NULL;
+ /* give a breather */
+ if (trustee_wait_event_timeout(false, TRUSTEE_COOLDOWN) < 0)
+ break;
}
- return wq;
-}
-EXPORT_SYMBOL_GPL(__create_workqueue_key);
-static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
-{
/*
- * Our caller is either destroy_workqueue() or CPU_POST_DEAD,
- * cpu_add_remove_lock protects cwq->thread.
+ * Either all works have been scheduled and cpu is down, or
+ * cpu down has already been canceled. Wait for and butcher
+ * all workers till we're canceled.
*/
- if (cwq->thread == NULL)
- return;
-
- lock_map_acquire(&cwq->wq->lockdep_map);
- lock_map_release(&cwq->wq->lockdep_map);
+ do {
+ rc = trustee_wait_event(!list_empty(&gcwq->idle_list));
+ while (!list_empty(&gcwq->idle_list))
+ destroy_worker(list_first_entry(&gcwq->idle_list,
+ struct worker, entry));
+ } while (gcwq->nr_workers && rc >= 0);
- flush_cpu_workqueue(cwq);
/*
- * If the caller is CPU_POST_DEAD and cwq->worklist was not empty,
- * a concurrent flush_workqueue() can insert a barrier after us.
- * However, in that case run_workqueue() won't return and check
- * kthread_should_stop() until it flushes all work_struct's.
- * When ->worklist becomes empty it is safe to exit because no
- * more work_structs can be queued on this cwq: flush_workqueue
- * checks list_empty(), and a "normal" queue_work() can't use
- * a dead CPU.
+ * At this point, either draining has completed and no worker
+ * is left, or cpu down has been canceled or the cpu is being
+ * brought back up. There shouldn't be any idle one left.
+ * Tell the remaining busy ones to rebind once it finishes the
+ * currently scheduled works by scheduling the rebind_work.
*/
- trace_workqueue_destruction(cwq->thread);
- kthread_stop(cwq->thread);
- cwq->thread = NULL;
+ WARN_ON(!list_empty(&gcwq->idle_list));
+
+ for_each_busy_worker(worker, i, pos, gcwq) {
+ struct work_struct *rebind_work = &worker->rebind_work;
+
+ /*
+ * Rebind_work may race with future cpu hotplug
+ * operations. Use a separate flag to mark that
+ * rebinding is scheduled.
+ */
+ worker->flags |= WORKER_REBIND;
+ worker->flags &= ~WORKER_ROGUE;
+
+ /* queue rebind_work, wq doesn't matter, use the default one */
+ if (test_and_set_bit(WORK_STRUCT_PENDING_BIT,
+ work_data_bits(rebind_work)))
+ continue;
+
+ debug_work_activate(rebind_work);
+ insert_work(get_cwq(gcwq->cpu, system_wq), rebind_work,
+ worker->scheduled.next,
+ work_color_to_flags(WORK_NO_COLOR));
+ }
+
+ /* relinquish manager role */
+ gcwq->flags &= ~GCWQ_MANAGING_WORKERS;
+
+ /* notify completion */
+ gcwq->trustee = NULL;
+ gcwq->trustee_state = TRUSTEE_DONE;
+ wake_up_all(&gcwq->trustee_wait);
+ spin_unlock_irq(&gcwq->lock);
+ return 0;
}
/**
- * destroy_workqueue - safely terminate a workqueue
- * @wq: target workqueue
+ * wait_trustee_state - wait for trustee to enter the specified state
+ * @gcwq: gcwq the trustee of interest belongs to
+ * @state: target state to wait for
*
- * Safely destroy a workqueue. All work currently pending will be done first.
+ * Wait for the trustee to reach @state. DONE is already matched.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times. To be used by cpu_callback.
*/
-void destroy_workqueue(struct workqueue_struct *wq)
+static void __cpuinit wait_trustee_state(struct global_cwq *gcwq, int state)
{
- const struct cpumask *cpu_map = wq_cpu_map(wq);
- int cpu;
-
- cpu_maps_update_begin();
- spin_lock(&workqueue_lock);
- list_del(&wq->list);
- spin_unlock(&workqueue_lock);
-
- for_each_cpu(cpu, cpu_map)
- cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu));
- cpu_maps_update_done();
-
- free_percpu(wq->cpu_wq);
- kfree(wq);
+ if (!(gcwq->trustee_state == state ||
+ gcwq->trustee_state == TRUSTEE_DONE)) {
+ spin_unlock_irq(&gcwq->lock);
+ __wait_event(gcwq->trustee_wait,
+ gcwq->trustee_state == state ||
+ gcwq->trustee_state == TRUSTEE_DONE);
+ spin_lock_irq(&gcwq->lock);
+ }
}
-EXPORT_SYMBOL_GPL(destroy_workqueue);
static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
unsigned long action,
void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
- struct cpu_workqueue_struct *cwq;
- struct workqueue_struct *wq;
- int err = 0;
+ struct global_cwq *gcwq = get_gcwq(cpu);
+ struct task_struct *new_trustee = NULL;
+ struct worker *uninitialized_var(new_worker);
+ unsigned long flags;
action &= ~CPU_TASKS_FROZEN;
switch (action) {
+ case CPU_DOWN_PREPARE:
+ new_trustee = kthread_create(trustee_thread, gcwq,
+ "workqueue_trustee/%d\n", cpu);
+ if (IS_ERR(new_trustee))
+ return notifier_from_errno(PTR_ERR(new_trustee));
+ kthread_bind(new_trustee, cpu);
+ /* fall through */
case CPU_UP_PREPARE:
- cpumask_set_cpu(cpu, cpu_populated_map);
- }
-undo:
- list_for_each_entry(wq, &workqueues, list) {
- cwq = per_cpu_ptr(wq->cpu_wq, cpu);
-
- switch (action) {
- case CPU_UP_PREPARE:
- err = create_workqueue_thread(cwq, cpu);
- if (!err)
- break;
- printk(KERN_ERR "workqueue [%s] for %i failed\n",
- wq->name, cpu);
- action = CPU_UP_CANCELED;
- err = -ENOMEM;
- goto undo;
-
- case CPU_ONLINE:
- start_workqueue_thread(cwq, cpu);
- break;
-
- case CPU_UP_CANCELED:
- start_workqueue_thread(cwq, -1);
- case CPU_POST_DEAD:
- cleanup_workqueue_thread(cwq);
- break;
+ BUG_ON(gcwq->first_idle);
+ new_worker = create_worker(gcwq, false);
+ if (!new_worker) {
+ if (new_trustee)
+ kthread_stop(new_trustee);
+ return NOTIFY_BAD;
}
}
+ /* some are called w/ irq disabled, don't disturb irq status */
+ spin_lock_irqsave(&gcwq->lock, flags);
+
switch (action) {
- case CPU_UP_CANCELED:
+ case CPU_DOWN_PREPARE:
+ /* initialize trustee and tell it to acquire the gcwq */
+ BUG_ON(gcwq->trustee || gcwq->trustee_state != TRUSTEE_DONE);
+ gcwq->trustee = new_trustee;
+ gcwq->trustee_state = TRUSTEE_START;
+ wake_up_process(gcwq->trustee);
+ wait_trustee_state(gcwq, TRUSTEE_IN_CHARGE);
+ /* fall through */
+ case CPU_UP_PREPARE:
+ BUG_ON(gcwq->first_idle);
+ gcwq->first_idle = new_worker;
+ break;
+
+ case CPU_DYING:
+ /*
+ * Before this, the trustee and all workers except for
+ * the ones which are still executing works from
+ * before the last CPU down must be on the cpu. After
+ * this, they'll all be diasporas.
+ */
+ gcwq->flags |= GCWQ_DISASSOCIATED;
+ break;
+
case CPU_POST_DEAD:
- cpumask_clear_cpu(cpu, cpu_populated_map);
+ gcwq->trustee_state = TRUSTEE_BUTCHER;
+ /* fall through */
+ case CPU_UP_CANCELED:
+ destroy_worker(gcwq->first_idle);
+ gcwq->first_idle = NULL;
+ break;
+
+ case CPU_DOWN_FAILED:
+ case CPU_ONLINE:
+ gcwq->flags &= ~GCWQ_DISASSOCIATED;
+ if (gcwq->trustee_state != TRUSTEE_DONE) {
+ gcwq->trustee_state = TRUSTEE_RELEASE;
+ wake_up_process(gcwq->trustee);
+ wait_trustee_state(gcwq, TRUSTEE_DONE);
+ }
+
+ /*
+ * Trustee is done and there might be no worker left.
+ * Put the first_idle in and request a real manager to
+ * take a look.
+ */
+ spin_unlock_irq(&gcwq->lock);
+ kthread_bind(gcwq->first_idle->task, cpu);
+ spin_lock_irq(&gcwq->lock);
+ gcwq->flags |= GCWQ_MANAGE_WORKERS;
+ start_worker(gcwq->first_idle);
+ gcwq->first_idle = NULL;
+ break;
}
- return notifier_from_errno(err);
+ spin_unlock_irqrestore(&gcwq->lock, flags);
+
+ return notifier_from_errno(0);
}
#ifdef CONFIG_SMP
EXPORT_SYMBOL_GPL(work_on_cpu);
#endif /* CONFIG_SMP */
-void __init init_workqueues(void)
+#ifdef CONFIG_FREEZER
+
+/**
+ * freeze_workqueues_begin - begin freezing workqueues
+ *
+ * Start freezing workqueues. After this function returns, all
+ * freezeable workqueues will queue new works to their frozen_works
+ * list instead of gcwq->worklist.
+ *
+ * CONTEXT:
+ * Grabs and releases workqueue_lock and gcwq->lock's.
+ */
+void freeze_workqueues_begin(void)
+{
+ unsigned int cpu;
+
+ spin_lock(&workqueue_lock);
+
+ BUG_ON(workqueue_freezing);
+ workqueue_freezing = true;
+
+ for_each_gcwq_cpu(cpu) {
+ struct global_cwq *gcwq = get_gcwq(cpu);
+ struct workqueue_struct *wq;
+
+ spin_lock_irq(&gcwq->lock);
+
+ BUG_ON(gcwq->flags & GCWQ_FREEZING);
+ gcwq->flags |= GCWQ_FREEZING;
+
+ list_for_each_entry(wq, &workqueues, list) {
+ struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+
+ if (cwq && wq->flags & WQ_FREEZEABLE)
+ cwq->max_active = 0;
+ }
+
+ spin_unlock_irq(&gcwq->lock);
+ }
+
+ spin_unlock(&workqueue_lock);
+}
+
+/**
+ * freeze_workqueues_busy - are freezeable workqueues still busy?
+ *
+ * Check whether freezing is complete. This function must be called
+ * between freeze_workqueues_begin() and thaw_workqueues().
+ *
+ * CONTEXT:
+ * Grabs and releases workqueue_lock.
+ *
+ * RETURNS:
+ * %true if some freezeable workqueues are still busy. %false if
+ * freezing is complete.
+ */
+bool freeze_workqueues_busy(void)
+{
+ unsigned int cpu;
+ bool busy = false;
+
+ spin_lock(&workqueue_lock);
+
+ BUG_ON(!workqueue_freezing);
+
+ for_each_gcwq_cpu(cpu) {
+ struct workqueue_struct *wq;
+ /*
+ * nr_active is monotonically decreasing. It's safe
+ * to peek without lock.
+ */
+ list_for_each_entry(wq, &workqueues, list) {
+ struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+
+ if (!cwq || !(wq->flags & WQ_FREEZEABLE))
+ continue;
+
+ BUG_ON(cwq->nr_active < 0);
+ if (cwq->nr_active) {
+ busy = true;
+ goto out_unlock;
+ }
+ }
+ }
+out_unlock:
+ spin_unlock(&workqueue_lock);
+ return busy;
+}
+
+/**
+ * thaw_workqueues - thaw workqueues
+ *
+ * Thaw workqueues. Normal queueing is restored and all collected
+ * frozen works are transferred to their respective gcwq worklists.
+ *
+ * CONTEXT:
+ * Grabs and releases workqueue_lock and gcwq->lock's.
+ */
+void thaw_workqueues(void)
+{
+ unsigned int cpu;
+
+ spin_lock(&workqueue_lock);
+
+ if (!workqueue_freezing)
+ goto out_unlock;
+
+ for_each_gcwq_cpu(cpu) {
+ struct global_cwq *gcwq = get_gcwq(cpu);
+ struct workqueue_struct *wq;
+
+ spin_lock_irq(&gcwq->lock);
+
+ BUG_ON(!(gcwq->flags & GCWQ_FREEZING));
+ gcwq->flags &= ~GCWQ_FREEZING;
+
+ list_for_each_entry(wq, &workqueues, list) {
+ struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+
+ if (!cwq || !(wq->flags & WQ_FREEZEABLE))
+ continue;
+
+ /* restore max_active and repopulate worklist */
+ cwq->max_active = wq->saved_max_active;
+
+ while (!list_empty(&cwq->delayed_works) &&
+ cwq->nr_active < cwq->max_active)
+ cwq_activate_first_delayed(cwq);
+ }
+
+ wake_up_worker(gcwq);
+
+ spin_unlock_irq(&gcwq->lock);
+ }
+
+ workqueue_freezing = false;
+out_unlock:
+ spin_unlock(&workqueue_lock);
+}
+#endif /* CONFIG_FREEZER */
+
+static int __init init_workqueues(void)
{
- alloc_cpumask_var(&cpu_populated_map, GFP_KERNEL);
+ unsigned int cpu;
+ int i;
+
+ hotcpu_notifier(workqueue_cpu_callback, CPU_PRI_WORKQUEUE);
+
+ /* initialize gcwqs */
+ for_each_gcwq_cpu(cpu) {
+ struct global_cwq *gcwq = get_gcwq(cpu);
+
+ spin_lock_init(&gcwq->lock);
+ INIT_LIST_HEAD(&gcwq->worklist);
+ gcwq->cpu = cpu;
+ if (cpu == WORK_CPU_UNBOUND)
+ gcwq->flags |= GCWQ_DISASSOCIATED;
+
+ INIT_LIST_HEAD(&gcwq->idle_list);
+ for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++)
+ INIT_HLIST_HEAD(&gcwq->busy_hash[i]);
+
+ init_timer_deferrable(&gcwq->idle_timer);
+ gcwq->idle_timer.function = idle_worker_timeout;
+ gcwq->idle_timer.data = (unsigned long)gcwq;
- cpumask_copy(cpu_populated_map, cpu_online_mask);
- singlethread_cpu = cpumask_first(cpu_possible_mask);
- cpu_singlethread_map = cpumask_of(singlethread_cpu);
- hotcpu_notifier(workqueue_cpu_callback, 0);
- keventd_wq = create_workqueue("events");
- BUG_ON(!keventd_wq);
+ setup_timer(&gcwq->mayday_timer, gcwq_mayday_timeout,
+ (unsigned long)gcwq);
+
+ ida_init(&gcwq->worker_ida);
+
+ gcwq->trustee_state = TRUSTEE_DONE;
+ init_waitqueue_head(&gcwq->trustee_wait);
+ }
+
+ /* create the initial worker */
+ for_each_online_gcwq_cpu(cpu) {
+ struct global_cwq *gcwq = get_gcwq(cpu);
+ struct worker *worker;
+
+ worker = create_worker(gcwq, true);
+ BUG_ON(!worker);
+ spin_lock_irq(&gcwq->lock);
+ start_worker(worker);
+ spin_unlock_irq(&gcwq->lock);
+ }
+
+ system_wq = alloc_workqueue("events", 0, 0);
+ system_long_wq = alloc_workqueue("events_long", 0, 0);
+ system_nrt_wq = alloc_workqueue("events_nrt", WQ_NON_REENTRANT, 0);
+ system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND,
+ WQ_UNBOUND_MAX_ACTIVE);
+ BUG_ON(!system_wq || !system_long_wq || !system_nrt_wq);
+ return 0;
}
+early_initcall(init_workqueues);
* Scheduler hooks for concurrency managed workqueue. Only to be
* included from sched.c and workqueue.c.
*/
-static inline void wq_worker_waking_up(struct task_struct *task,
- unsigned int cpu)
-{
-}
-
-static inline struct task_struct *wq_worker_sleeping(struct task_struct *task,
- unsigned int cpu)
-{
- return NULL;
-}
+void wq_worker_waking_up(struct task_struct *task, unsigned int cpu);
+struct task_struct *wq_worker_sleeping(struct task_struct *task,
+ unsigned int cpu);
projects / firefly-linux-kernel-4.4.55.git / commitdiff