diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 7441bd93b732..8fe3ebd6ac00 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -412,6 +412,7 @@ static void wb_exit(struct bdi_writeback *wb) * protected. */ static DEFINE_SPINLOCK(cgwb_lock); +static struct workqueue_struct *cgwb_release_wq; /** * wb_congested_get_create - get or create a wb_congested @@ -522,7 +523,7 @@ static void cgwb_release(struct percpu_ref *refcnt) { struct bdi_writeback *wb = container_of(refcnt, struct bdi_writeback, refcnt); - schedule_work(&wb->release_work); + queue_work(cgwb_release_wq, &wb->release_work); } static void cgwb_kill(struct bdi_writeback *wb) @@ -784,6 +785,21 @@ static void cgwb_bdi_register(struct backing_dev_info *bdi) spin_unlock_irq(&cgwb_lock); } +static int __init cgwb_init(void) +{ + /* + * There can be many concurrent release work items overwhelming + * system_wq. Put them in a separate wq and limit concurrency. + * There's no point in executing many of these in parallel. + */ + cgwb_release_wq = alloc_workqueue("cgwb_release", 0, 1); + if (!cgwb_release_wq) + return -ENOMEM; + + return 0; +} +subsys_initcall(cgwb_init); + #else /* CONFIG_CGROUP_WRITEBACK */ static int cgwb_bdi_init(struct backing_dev_info *bdi)