/* Throttling is performed over 100ms slice and after that slice is renewed */
static unsigned long throtl_slice = HZ/10; /* 100 ms */
+static struct blkcg_policy blkcg_policy_throtl;
+
/* A workqueue to queue throttle related work */
static struct workqueue_struct *kthrotld_workqueue;
static void throtl_schedule_delayed_work(struct throtl_data *td,
#define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node)
+/* Per-cpu group stats */
+struct tg_stats_cpu {
+ /* total bytes transferred */
+ struct blkg_rwstat service_bytes;
+ /* total IOs serviced, post merge */
+ struct blkg_rwstat serviced;
+};
+
struct throtl_grp {
- /* List of throtl groups on the request queue*/
- struct hlist_node tg_node;
+ /* must be the first member */
+ struct blkg_policy_data pd;
/* active throtl group service_tree member */
struct rb_node rb_node;
*/
unsigned long disptime;
- struct blkio_group blkg;
- atomic_t ref;
unsigned int flags;
/* Two lists for READ and WRITE */
/* Some throttle limits got updated for the group */
int limits_changed;
- struct rcu_head rcu_head;
+ /* Per cpu stats pointer */
+ struct tg_stats_cpu __percpu *stats_cpu;
+
+ /* List of tgs waiting for per cpu stats memory to be allocated */
+ struct list_head stats_alloc_node;
};
struct throtl_data
{
- /* List of throtl groups */
- struct hlist_head tg_list;
-
/* service tree for active throtl groups */
struct throtl_rb_root tg_service_tree;
- struct throtl_grp *root_tg;
struct request_queue *queue;
/* Total Number of queued bios on READ and WRITE lists */
int limits_changed;
};
+/* list and work item to allocate percpu group stats */
+static DEFINE_SPINLOCK(tg_stats_alloc_lock);
+static LIST_HEAD(tg_stats_alloc_list);
+
+static void tg_stats_alloc_fn(struct work_struct *);
+static DECLARE_DELAYED_WORK(tg_stats_alloc_work, tg_stats_alloc_fn);
+
+static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd)
+{
+ return pd ? container_of(pd, struct throtl_grp, pd) : NULL;
+}
+
+static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg)
+{
+ return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl));
+}
+
+static inline struct blkcg_gq *tg_to_blkg(struct throtl_grp *tg)
+{
+ return pd_to_blkg(&tg->pd);
+}
+
+static inline struct throtl_grp *td_root_tg(struct throtl_data *td)
+{
+ return blkg_to_tg(td->queue->root_blkg);
+}
+
enum tg_state_flags {
THROTL_TG_FLAG_on_rr = 0, /* on round-robin busy list */
};
THROTL_TG_FNS(on_rr);
-#define throtl_log_tg(td, tg, fmt, args...) \
- blk_add_trace_msg((td)->queue, "throtl %s " fmt, \
- blkg_path(&(tg)->blkg), ##args); \
+#define throtl_log_tg(td, tg, fmt, args...) do { \
+ char __pbuf[128]; \
+ \
+ blkg_path(tg_to_blkg(tg), __pbuf, sizeof(__pbuf)); \
+ blk_add_trace_msg((td)->queue, "throtl %s " fmt, __pbuf, ##args); \
+} while (0)
#define throtl_log(td, fmt, args...) \
blk_add_trace_msg((td)->queue, "throtl " fmt, ##args)
-static inline struct throtl_grp *tg_of_blkg(struct blkio_group *blkg)
-{
- if (blkg)
- return container_of(blkg, struct throtl_grp, blkg);
-
- return NULL;
-}
-
static inline unsigned int total_nr_queued(struct throtl_data *td)
{
return td->nr_queued[0] + td->nr_queued[1];
}
-static inline struct throtl_grp *throtl_ref_get_tg(struct throtl_grp *tg)
-{
- atomic_inc(&tg->ref);
- return tg;
-}
-
-static void throtl_free_tg(struct rcu_head *head)
+/*
+ * Worker for allocating per cpu stat for tgs. This is scheduled on the
+ * system_nrt_wq once there are some groups on the alloc_list waiting for
+ * allocation.
+ */
+static void tg_stats_alloc_fn(struct work_struct *work)
{
- struct throtl_grp *tg;
+ static struct tg_stats_cpu *stats_cpu; /* this fn is non-reentrant */
+ struct delayed_work *dwork = to_delayed_work(work);
+ bool empty = false;
+
+alloc_stats:
+ if (!stats_cpu) {
+ stats_cpu = alloc_percpu(struct tg_stats_cpu);
+ if (!stats_cpu) {
+ /* allocation failed, try again after some time */
+ queue_delayed_work(system_nrt_wq, dwork,
+ msecs_to_jiffies(10));
+ return;
+ }
+ }
- tg = container_of(head, struct throtl_grp, rcu_head);
- free_percpu(tg->blkg.stats_cpu);
- kfree(tg);
-}
+ spin_lock_irq(&tg_stats_alloc_lock);
-static void throtl_put_tg(struct throtl_grp *tg)
-{
- BUG_ON(atomic_read(&tg->ref) <= 0);
- if (!atomic_dec_and_test(&tg->ref))
- return;
+ if (!list_empty(&tg_stats_alloc_list)) {
+ struct throtl_grp *tg = list_first_entry(&tg_stats_alloc_list,
+ struct throtl_grp,
+ stats_alloc_node);
+ swap(tg->stats_cpu, stats_cpu);
+ list_del_init(&tg->stats_alloc_node);
+ }
- /*
- * A group is freed in rcu manner. But having an rcu lock does not
- * mean that one can access all the fields of blkg and assume these
- * are valid. For example, don't try to follow throtl_data and
- * request queue links.
- *
- * Having a reference to blkg under an rcu allows acess to only
- * values local to groups like group stats and group rate limits
- */
- call_rcu(&tg->rcu_head, throtl_free_tg);
+ empty = list_empty(&tg_stats_alloc_list);
+ spin_unlock_irq(&tg_stats_alloc_lock);
+ if (!empty)
+ goto alloc_stats;
}
-static void throtl_init_group(struct throtl_grp *tg)
+static void throtl_pd_init(struct blkcg_gq *blkg)
{
- INIT_HLIST_NODE(&tg->tg_node);
+ struct throtl_grp *tg = blkg_to_tg(blkg);
+ unsigned long flags;
+
RB_CLEAR_NODE(&tg->rb_node);
bio_list_init(&tg->bio_lists[0]);
bio_list_init(&tg->bio_lists[1]);
tg->limits_changed = false;
- /* Practically unlimited BW */
- tg->bps[0] = tg->bps[1] = -1;
- tg->iops[0] = tg->iops[1] = -1;
+ tg->bps[READ] = -1;
+ tg->bps[WRITE] = -1;
+ tg->iops[READ] = -1;
+ tg->iops[WRITE] = -1;
/*
- * Take the initial reference that will be released on destroy
- * This can be thought of a joint reference by cgroup and
- * request queue which will be dropped by either request queue
- * exit or cgroup deletion path depending on who is exiting first.
+ * Ugh... We need to perform per-cpu allocation for tg->stats_cpu
+ * but percpu allocator can't be called from IO path. Queue tg on
+ * tg_stats_alloc_list and allocate from work item.
*/
- atomic_set(&tg->ref, 1);
+ spin_lock_irqsave(&tg_stats_alloc_lock, flags);
+ list_add(&tg->stats_alloc_node, &tg_stats_alloc_list);
+ queue_delayed_work(system_nrt_wq, &tg_stats_alloc_work, 0);
+ spin_unlock_irqrestore(&tg_stats_alloc_lock, flags);
}
-/* Should be called with rcu read lock held (needed for blkcg) */
-static void
-throtl_add_group_to_td_list(struct throtl_data *td, struct throtl_grp *tg)
+static void throtl_pd_exit(struct blkcg_gq *blkg)
{
- hlist_add_head(&tg->tg_node, &td->tg_list);
- td->nr_undestroyed_grps++;
-}
-
-static void
-__throtl_tg_fill_dev_details(struct throtl_data *td, struct throtl_grp *tg)
-{
- struct backing_dev_info *bdi = &td->queue->backing_dev_info;
- unsigned int major, minor;
-
- if (!tg || tg->blkg.dev)
- return;
-
- /*
- * Fill in device details for a group which might not have been
- * filled at group creation time as queue was being instantiated
- * and driver had not attached a device yet
- */
- if (bdi->dev && dev_name(bdi->dev)) {
- sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
- tg->blkg.dev = MKDEV(major, minor);
- }
-}
-
-/*
- * Should be called with without queue lock held. Here queue lock will be
- * taken rarely. It will be taken only once during life time of a group
- * if need be
- */
-static void
-throtl_tg_fill_dev_details(struct throtl_data *td, struct throtl_grp *tg)
-{
- if (!tg || tg->blkg.dev)
- return;
-
- spin_lock_irq(td->queue->queue_lock);
- __throtl_tg_fill_dev_details(td, tg);
- spin_unlock_irq(td->queue->queue_lock);
-}
-
-static void throtl_init_add_tg_lists(struct throtl_data *td,
- struct throtl_grp *tg, struct blkio_cgroup *blkcg)
-{
- __throtl_tg_fill_dev_details(td, tg);
-
- /* Add group onto cgroup list */
- blkiocg_add_blkio_group(blkcg, &tg->blkg, (void *)td,
- tg->blkg.dev, BLKIO_POLICY_THROTL);
+ struct throtl_grp *tg = blkg_to_tg(blkg);
+ unsigned long flags;
- tg->bps[READ] = blkcg_get_read_bps(blkcg, tg->blkg.dev);
- tg->bps[WRITE] = blkcg_get_write_bps(blkcg, tg->blkg.dev);
- tg->iops[READ] = blkcg_get_read_iops(blkcg, tg->blkg.dev);
- tg->iops[WRITE] = blkcg_get_write_iops(blkcg, tg->blkg.dev);
+ spin_lock_irqsave(&tg_stats_alloc_lock, flags);
+ list_del_init(&tg->stats_alloc_node);
+ spin_unlock_irqrestore(&tg_stats_alloc_lock, flags);
- throtl_add_group_to_td_list(td, tg);
+ free_percpu(tg->stats_cpu);
}
-/* Should be called without queue lock and outside of rcu period */
-static struct throtl_grp *throtl_alloc_tg(struct throtl_data *td)
+static void throtl_pd_reset_stats(struct blkcg_gq *blkg)
{
- struct throtl_grp *tg = NULL;
- int ret;
+ struct throtl_grp *tg = blkg_to_tg(blkg);
+ int cpu;
- tg = kzalloc_node(sizeof(*tg), GFP_ATOMIC, td->queue->node);
- if (!tg)
- return NULL;
+ if (tg->stats_cpu == NULL)
+ return;
- ret = blkio_alloc_blkg_stats(&tg->blkg);
+ for_each_possible_cpu(cpu) {
+ struct tg_stats_cpu *sc = per_cpu_ptr(tg->stats_cpu, cpu);
- if (ret) {
- kfree(tg);
- return NULL;
+ blkg_rwstat_reset(&sc->service_bytes);
+ blkg_rwstat_reset(&sc->serviced);
}
-
- throtl_init_group(tg);
- return tg;
}
-static struct
-throtl_grp *throtl_find_tg(struct throtl_data *td, struct blkio_cgroup *blkcg)
+static struct throtl_grp *throtl_lookup_tg(struct throtl_data *td,
+ struct blkcg *blkcg)
{
- struct throtl_grp *tg = NULL;
- void *key = td;
-
/*
- * This is the common case when there are no blkio cgroups.
- * Avoid lookup in this case
- */
- if (blkcg == &blkio_root_cgroup)
- tg = td->root_tg;
- else
- tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key));
+ * This is the common case when there are no blkcgs. Avoid lookup
+ * in this case
+ */
+ if (blkcg == &blkcg_root)
+ return td_root_tg(td);
- __throtl_tg_fill_dev_details(td, tg);
- return tg;
+ return blkg_to_tg(blkg_lookup(blkcg, td->queue));
}
-static struct throtl_grp * throtl_get_tg(struct throtl_data *td)
+static struct throtl_grp *throtl_lookup_create_tg(struct throtl_data *td,
+ struct blkcg *blkcg)
{
- struct throtl_grp *tg = NULL, *__tg = NULL;
- struct blkio_cgroup *blkcg;
struct request_queue *q = td->queue;
-
- /* no throttling for dead queue */
- if (unlikely(blk_queue_dead(q)))
- return NULL;
-
- rcu_read_lock();
- blkcg = task_blkio_cgroup(current);
- tg = throtl_find_tg(td, blkcg);
- if (tg) {
- rcu_read_unlock();
- return tg;
- }
-
- /*
- * Need to allocate a group. Allocation of group also needs allocation
- * of per cpu stats which in-turn takes a mutex() and can block. Hence
- * we need to drop rcu lock and queue_lock before we call alloc.
- */
- rcu_read_unlock();
- spin_unlock_irq(q->queue_lock);
-
- tg = throtl_alloc_tg(td);
-
- /* Group allocated and queue is still alive. take the lock */
- spin_lock_irq(q->queue_lock);
-
- /* Make sure @q is still alive */
- if (unlikely(blk_queue_dead(q))) {
- kfree(tg);
- return NULL;
- }
-
- /*
- * Initialize the new group. After sleeping, read the blkcg again.
- */
- rcu_read_lock();
- blkcg = task_blkio_cgroup(current);
+ struct throtl_grp *tg = NULL;
/*
- * If some other thread already allocated the group while we were
- * not holding queue lock, free up the group
+ * This is the common case when there are no blkcgs. Avoid lookup
+ * in this case
*/
- __tg = throtl_find_tg(td, blkcg);
-
- if (__tg) {
- kfree(tg);
- rcu_read_unlock();
- return __tg;
- }
-
- /* Group allocation failed. Account the IO to root group */
- if (!tg) {
- tg = td->root_tg;
- return tg;
+ if (blkcg == &blkcg_root) {
+ tg = td_root_tg(td);
+ } else {
+ struct blkcg_gq *blkg;
+
+ blkg = blkg_lookup_create(blkcg, q);
+
+ /* if %NULL and @q is alive, fall back to root_tg */
+ if (!IS_ERR(blkg))
+ tg = blkg_to_tg(blkg);
+ else if (!blk_queue_dead(q))
+ tg = td_root_tg(td);
}
- throtl_init_add_tg_lists(td, tg, blkcg);
- rcu_read_unlock();
return tg;
}
return 0;
}
+static void throtl_update_dispatch_stats(struct blkcg_gq *blkg, u64 bytes,
+ int rw)
+{
+ struct throtl_grp *tg = blkg_to_tg(blkg);
+ struct tg_stats_cpu *stats_cpu;
+ unsigned long flags;
+
+ /* If per cpu stats are not allocated yet, don't do any accounting. */
+ if (tg->stats_cpu == NULL)
+ return;
+
+ /*
+ * Disabling interrupts to provide mutual exclusion between two
+ * writes on same cpu. It probably is not needed for 64bit. Not
+ * optimizing that case yet.
+ */
+ local_irq_save(flags);
+
+ stats_cpu = this_cpu_ptr(tg->stats_cpu);
+
+ blkg_rwstat_add(&stats_cpu->serviced, rw, 1);
+ blkg_rwstat_add(&stats_cpu->service_bytes, rw, bytes);
+
+ local_irq_restore(flags);
+}
+
static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio)
{
bool rw = bio_data_dir(bio);
- bool sync = rw_is_sync(bio->bi_rw);
/* Charge the bio to the group */
tg->bytes_disp[rw] += bio->bi_size;
tg->io_disp[rw]++;
- blkiocg_update_dispatch_stats(&tg->blkg, bio->bi_size, rw, sync);
+ throtl_update_dispatch_stats(tg_to_blkg(tg), bio->bi_size, bio->bi_rw);
}
static void throtl_add_bio_tg(struct throtl_data *td, struct throtl_grp *tg,
bio_list_add(&tg->bio_lists[rw], bio);
/* Take a bio reference on tg */
- throtl_ref_get_tg(tg);
+ blkg_get(tg_to_blkg(tg));
tg->nr_queued[rw]++;
td->nr_queued[rw]++;
throtl_enqueue_tg(td, tg);
bio = bio_list_pop(&tg->bio_lists[rw]);
tg->nr_queued[rw]--;
- /* Drop bio reference on tg */
- throtl_put_tg(tg);
+ /* Drop bio reference on blkg */
+ blkg_put(tg_to_blkg(tg));
BUG_ON(td->nr_queued[rw] <= 0);
td->nr_queued[rw]--;
static void throtl_process_limit_change(struct throtl_data *td)
{
- struct throtl_grp *tg;
- struct hlist_node *pos, *n;
+ struct request_queue *q = td->queue;
+ struct blkcg_gq *blkg, *n;
if (!td->limits_changed)
return;
throtl_log(td, "limits changed");
- hlist_for_each_entry_safe(tg, pos, n, &td->tg_list, tg_node) {
+ list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) {
+ struct throtl_grp *tg = blkg_to_tg(blkg);
+
if (!tg->limits_changed)
continue;
}
}
-static void
-throtl_destroy_tg(struct throtl_data *td, struct throtl_grp *tg)
+static u64 tg_prfill_cpu_rwstat(struct seq_file *sf,
+ struct blkg_policy_data *pd, int off)
{
- /* Something wrong if we are trying to remove same group twice */
- BUG_ON(hlist_unhashed(&tg->tg_node));
+ struct throtl_grp *tg = pd_to_tg(pd);
+ struct blkg_rwstat rwstat = { }, tmp;
+ int i, cpu;
- hlist_del_init(&tg->tg_node);
+ for_each_possible_cpu(cpu) {
+ struct tg_stats_cpu *sc = per_cpu_ptr(tg->stats_cpu, cpu);
- /*
- * Put the reference taken at the time of creation so that when all
- * queues are gone, group can be destroyed.
- */
- throtl_put_tg(tg);
- td->nr_undestroyed_grps--;
+ tmp = blkg_rwstat_read((void *)sc + off);
+ for (i = 0; i < BLKG_RWSTAT_NR; i++)
+ rwstat.cnt[i] += tmp.cnt[i];
+ }
+
+ return __blkg_prfill_rwstat(sf, pd, &rwstat);
}
-static void throtl_release_tgs(struct throtl_data *td)
+static int tg_print_cpu_rwstat(struct cgroup *cgrp, struct cftype *cft,
+ struct seq_file *sf)
{
- struct hlist_node *pos, *n;
- struct throtl_grp *tg;
+ struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
- hlist_for_each_entry_safe(tg, pos, n, &td->tg_list, tg_node) {
- /*
- * If cgroup removal path got to blk_group first and removed
- * it from cgroup list, then it will take care of destroying
- * cfqg also.
- */
- if (!blkiocg_del_blkio_group(&tg->blkg))
- throtl_destroy_tg(td, tg);
- }
+ blkcg_print_blkgs(sf, blkcg, tg_prfill_cpu_rwstat, &blkcg_policy_throtl,
+ cft->private, true);
+ return 0;
}
-/*
- * Blk cgroup controller notification saying that blkio_group object is being
- * delinked as associated cgroup object is going away. That also means that
- * no new IO will come in this group. So get rid of this group as soon as
- * any pending IO in the group is finished.
- *
- * This function is called under rcu_read_lock(). key is the rcu protected
- * pointer. That means "key" is a valid throtl_data pointer as long as we are
- * rcu read lock.
- *
- * "key" was fetched from blkio_group under blkio_cgroup->lock. That means
- * it should not be NULL as even if queue was going away, cgroup deltion
- * path got to it first.
- */
-void throtl_unlink_blkio_group(void *key, struct blkio_group *blkg)
+static u64 tg_prfill_conf_u64(struct seq_file *sf, struct blkg_policy_data *pd,
+ int off)
{
- unsigned long flags;
- struct throtl_data *td = key;
+ struct throtl_grp *tg = pd_to_tg(pd);
+ u64 v = *(u64 *)((void *)tg + off);
- spin_lock_irqsave(td->queue->queue_lock, flags);
- throtl_destroy_tg(td, tg_of_blkg(blkg));
- spin_unlock_irqrestore(td->queue->queue_lock, flags);
+ if (v == -1)
+ return 0;
+ return __blkg_prfill_u64(sf, pd, v);
}
-static void throtl_update_blkio_group_common(struct throtl_data *td,
- struct throtl_grp *tg)
+static u64 tg_prfill_conf_uint(struct seq_file *sf, struct blkg_policy_data *pd,
+ int off)
{
- xchg(&tg->limits_changed, true);
- xchg(&td->limits_changed, true);
- /* Schedule a work now to process the limit change */
- throtl_schedule_delayed_work(td, 0);
+ struct throtl_grp *tg = pd_to_tg(pd);
+ unsigned int v = *(unsigned int *)((void *)tg + off);
+
+ if (v == -1)
+ return 0;
+ return __blkg_prfill_u64(sf, pd, v);
}
-/*
- * For all update functions, key should be a valid pointer because these
- * update functions are called under blkcg_lock, that means, blkg is
- * valid and in turn key is valid. queue exit path can not race because
- * of blkcg_lock
- *
- * Can not take queue lock in update functions as queue lock under blkcg_lock
- * is not allowed. Under other paths we take blkcg_lock under queue_lock.
- */
-static void throtl_update_blkio_group_read_bps(void *key,
- struct blkio_group *blkg, u64 read_bps)
+static int tg_print_conf_u64(struct cgroup *cgrp, struct cftype *cft,
+ struct seq_file *sf)
{
- struct throtl_data *td = key;
- struct throtl_grp *tg = tg_of_blkg(blkg);
-
- tg->bps[READ] = read_bps;
- throtl_update_blkio_group_common(td, tg);
+ blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp), tg_prfill_conf_u64,
+ &blkcg_policy_throtl, cft->private, false);
+ return 0;
}
-static void throtl_update_blkio_group_write_bps(void *key,
- struct blkio_group *blkg, u64 write_bps)
+static int tg_print_conf_uint(struct cgroup *cgrp, struct cftype *cft,
+ struct seq_file *sf)
{
- struct throtl_data *td = key;
- struct throtl_grp *tg = tg_of_blkg(blkg);
-
- tg->bps[WRITE] = write_bps;
- throtl_update_blkio_group_common(td, tg);
+ blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp), tg_prfill_conf_uint,
+ &blkcg_policy_throtl, cft->private, false);
+ return 0;
}
-static void throtl_update_blkio_group_read_iops(void *key,
- struct blkio_group *blkg, unsigned int read_iops)
+static int tg_set_conf(struct cgroup *cgrp, struct cftype *cft, const char *buf,
+ bool is_u64)
{
- struct throtl_data *td = key;
- struct throtl_grp *tg = tg_of_blkg(blkg);
+ struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
+ struct blkg_conf_ctx ctx;
+ struct throtl_grp *tg;
+ struct throtl_data *td;
+ int ret;
+
+ ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx);
+ if (ret)
+ return ret;
+
+ tg = blkg_to_tg(ctx.blkg);
+ td = ctx.blkg->q->td;
+
+ if (!ctx.v)
+ ctx.v = -1;
+
+ if (is_u64)
+ *(u64 *)((void *)tg + cft->private) = ctx.v;
+ else
+ *(unsigned int *)((void *)tg + cft->private) = ctx.v;
+
+ /* XXX: we don't need the following deferred processing */
+ xchg(&tg->limits_changed, true);
+ xchg(&td->limits_changed, true);
+ throtl_schedule_delayed_work(td, 0);
- tg->iops[READ] = read_iops;
- throtl_update_blkio_group_common(td, tg);
+ blkg_conf_finish(&ctx);
+ return 0;
}
-static void throtl_update_blkio_group_write_iops(void *key,
- struct blkio_group *blkg, unsigned int write_iops)
+static int tg_set_conf_u64(struct cgroup *cgrp, struct cftype *cft,
+ const char *buf)
{
- struct throtl_data *td = key;
- struct throtl_grp *tg = tg_of_blkg(blkg);
+ return tg_set_conf(cgrp, cft, buf, true);
+}
- tg->iops[WRITE] = write_iops;
- throtl_update_blkio_group_common(td, tg);
+static int tg_set_conf_uint(struct cgroup *cgrp, struct cftype *cft,
+ const char *buf)
+{
+ return tg_set_conf(cgrp, cft, buf, false);
}
+static struct cftype throtl_files[] = {
+ {
+ .name = "throttle.read_bps_device",
+ .private = offsetof(struct throtl_grp, bps[READ]),
+ .read_seq_string = tg_print_conf_u64,
+ .write_string = tg_set_conf_u64,
+ .max_write_len = 256,
+ },
+ {
+ .name = "throttle.write_bps_device",
+ .private = offsetof(struct throtl_grp, bps[WRITE]),
+ .read_seq_string = tg_print_conf_u64,
+ .write_string = tg_set_conf_u64,
+ .max_write_len = 256,
+ },
+ {
+ .name = "throttle.read_iops_device",
+ .private = offsetof(struct throtl_grp, iops[READ]),
+ .read_seq_string = tg_print_conf_uint,
+ .write_string = tg_set_conf_uint,
+ .max_write_len = 256,
+ },
+ {
+ .name = "throttle.write_iops_device",
+ .private = offsetof(struct throtl_grp, iops[WRITE]),
+ .read_seq_string = tg_print_conf_uint,
+ .write_string = tg_set_conf_uint,
+ .max_write_len = 256,
+ },
+ {
+ .name = "throttle.io_service_bytes",
+ .private = offsetof(struct tg_stats_cpu, service_bytes),
+ .read_seq_string = tg_print_cpu_rwstat,
+ },
+ {
+ .name = "throttle.io_serviced",
+ .private = offsetof(struct tg_stats_cpu, serviced),
+ .read_seq_string = tg_print_cpu_rwstat,
+ },
+ { } /* terminate */
+};
+
static void throtl_shutdown_wq(struct request_queue *q)
{
struct throtl_data *td = q->td;
cancel_delayed_work_sync(&td->throtl_work);
}
-static struct blkio_policy_type blkio_policy_throtl = {
- .ops = {
- .blkio_unlink_group_fn = throtl_unlink_blkio_group,
- .blkio_update_group_read_bps_fn =
- throtl_update_blkio_group_read_bps,
- .blkio_update_group_write_bps_fn =
- throtl_update_blkio_group_write_bps,
- .blkio_update_group_read_iops_fn =
- throtl_update_blkio_group_read_iops,
- .blkio_update_group_write_iops_fn =
- throtl_update_blkio_group_write_iops,
- },
- .plid = BLKIO_POLICY_THROTL,
+static struct blkcg_policy blkcg_policy_throtl = {
+ .pd_size = sizeof(struct throtl_grp),
+ .cftypes = throtl_files,
+
+ .pd_init_fn = throtl_pd_init,
+ .pd_exit_fn = throtl_pd_exit,
+ .pd_reset_stats_fn = throtl_pd_reset_stats,
};
bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
struct throtl_data *td = q->td;
struct throtl_grp *tg;
bool rw = bio_data_dir(bio), update_disptime = true;
- struct blkio_cgroup *blkcg;
+ struct blkcg *blkcg;
bool throttled = false;
if (bio->bi_rw & REQ_THROTTLED) {
goto out;
}
+ /* bio_associate_current() needs ioc, try creating */
+ create_io_context(GFP_ATOMIC, q->node);
+
/*
* A throtl_grp pointer retrieved under rcu can be used to access
* basic fields like stats and io rates. If a group has no rules,
* just update the dispatch stats in lockless manner and return.
*/
-
rcu_read_lock();
- blkcg = task_blkio_cgroup(current);
- tg = throtl_find_tg(td, blkcg);
+ blkcg = bio_blkcg(bio);
+ tg = throtl_lookup_tg(td, blkcg);
if (tg) {
- throtl_tg_fill_dev_details(td, tg);
-
if (tg_no_rule_group(tg, rw)) {
- blkiocg_update_dispatch_stats(&tg->blkg, bio->bi_size,
- rw, rw_is_sync(bio->bi_rw));
- rcu_read_unlock();
- goto out;
+ throtl_update_dispatch_stats(tg_to_blkg(tg),
+ bio->bi_size, bio->bi_rw);
+ goto out_unlock_rcu;
}
}
- rcu_read_unlock();
/*
* Either group has not been allocated yet or it is not an unlimited
* IO group
*/
spin_lock_irq(q->queue_lock);
- tg = throtl_get_tg(td);
+ tg = throtl_lookup_create_tg(td, blkcg);
if (unlikely(!tg))
goto out_unlock;
tg->io_disp[rw], tg->iops[rw],
tg->nr_queued[READ], tg->nr_queued[WRITE]);
+ bio_associate_current(bio);
throtl_add_bio_tg(q->td, tg, bio);
throttled = true;
out_unlock:
spin_unlock_irq(q->queue_lock);
+out_unlock_rcu:
+ rcu_read_unlock();
out:
return throttled;
}
int blk_throtl_init(struct request_queue *q)
{
struct throtl_data *td;
- struct throtl_grp *tg;
+ int ret;
td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node);
if (!td)
return -ENOMEM;
- INIT_HLIST_HEAD(&td->tg_list);
td->tg_service_tree = THROTL_RB_ROOT;
td->limits_changed = false;
INIT_DELAYED_WORK(&td->throtl_work, blk_throtl_work);
- /* alloc and Init root group. */
+ q->td = td;
td->queue = q;
- tg = throtl_alloc_tg(td);
- if (!tg) {
+ /* activate policy */
+ ret = blkcg_activate_policy(q, &blkcg_policy_throtl);
+ if (ret)
kfree(td);
- return -ENOMEM;
- }
-
- td->root_tg = tg;
-
- rcu_read_lock();
- throtl_init_add_tg_lists(td, tg, &blkio_root_cgroup);
- rcu_read_unlock();
-
- /* Attach throtl data to request queue */
- q->td = td;
- return 0;
+ return ret;
}
void blk_throtl_exit(struct request_queue *q)
{
- struct throtl_data *td = q->td;
- bool wait = false;
-
- BUG_ON(!td);
-
- throtl_shutdown_wq(q);
-
- spin_lock_irq(q->queue_lock);
- throtl_release_tgs(td);
-
- /* If there are other groups */
- if (td->nr_undestroyed_grps > 0)
- wait = true;
-
- spin_unlock_irq(q->queue_lock);
-
- /*
- * Wait for tg->blkg->key accessors to exit their grace periods.
- * Do this wait only if there are other undestroyed groups out
- * there (other than root group). This can happen if cgroup deletion
- * path claimed the responsibility of cleaning up a group before
- * queue cleanup code get to the group.
- *
- * Do not call synchronize_rcu() unconditionally as there are drivers
- * which create/delete request queue hundreds of times during scan/boot
- * and synchronize_rcu() can take significant time and slow down boot.
- */
- if (wait)
- synchronize_rcu();
-
- /*
- * Just being safe to make sure after previous flush if some body did
- * update limits through cgroup and another work got queued, cancel
- * it.
- */
+ BUG_ON(!q->td);
throtl_shutdown_wq(q);
-}
-
-void blk_throtl_release(struct request_queue *q)
-{
+ blkcg_deactivate_policy(q, &blkcg_policy_throtl);
kfree(q->td);
}
if (!kthrotld_workqueue)
panic("Failed to create kthrotld\n");
- blkio_policy_register(&blkio_policy_throtl);
- return 0;
+ return blkcg_policy_register(&blkcg_policy_throtl);
}
module_init(throtl_init);
projects / firefly-linux-kernel-4.4.55.git / blobdiff