if (!bdi->wb_congested)
return -ENOMEM;
+ atomic_set(&bdi->wb_congested->refcnt, 1);
+
err = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL);
if (err) {
- kfree(bdi->wb_congested);
+ wb_congested_put(bdi->wb_congested);
return err;
}
return 0;
}
-static void cgwb_bdi_destroy(struct backing_dev_info *bdi) { }
+static void cgwb_bdi_destroy(struct backing_dev_info *bdi)
+{
+ wb_congested_put(bdi->wb_congested);
+}
#endif /* CONFIG_CGROUP_WRITEBACK */
}
EXPORT_SYMBOL(bdi_register_dev);
+int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner)
+{
+ int rc;
+
+ rc = bdi_register(bdi, NULL, "%u:%u", MAJOR(owner->devt),
+ MINOR(owner->devt));
+ if (rc)
+ return rc;
+ bdi->owner = owner;
+ get_device(owner);
+ return 0;
+}
+EXPORT_SYMBOL(bdi_register_owner);
+
/*
* Remove bdi from bdi_list, and ensure that it is no longer visible
*/
device_unregister(bdi->dev);
bdi->dev = NULL;
}
+
+ if (bdi->owner) {
+ put_device(bdi->owner);
+ bdi->owner = NULL;
+ }
}
void bdi_exit(struct backing_dev_info *bdi)
* jiffies for either a BDI to exit congestion of the given @sync queue
* or a write to complete.
*
- * In the absence of zone congestion, cond_resched() is called to yield
- * the processor if necessary but otherwise does not sleep.
+ * In the absence of zone congestion, a short sleep or a cond_resched is
+ * performed to yield the processor and to allow other subsystems to make
+ * a forward progress.
*
* The return value is 0 if the sleep is for the full timeout. Otherwise,
* it is the number of jiffies that were still remaining when the function
*/
if (atomic_read(&nr_wb_congested[sync]) == 0 ||
!test_bit(ZONE_CONGESTED, &zone->flags)) {
- cond_resched();
+
+ /*
+ * Memory allocation/reclaim might be called from a WQ
+ * context and the current implementation of the WQ
+ * concurrency control doesn't recognize that a particular
+ * WQ is congested if the worker thread is looping without
+ * ever sleeping. Therefore we have to do a short sleep
+ * here rather than calling cond_resched().
+ */
+ if (current->flags & PF_WQ_WORKER)
+ schedule_timeout_uninterruptible(1);
+ else
+ cond_resched();
/* In case we scheduled, work out time remaining */
ret = timeout - (jiffies - start);