diff options
| author | Jan Kara <jack@suse.cz> | 2017-03-23 01:36:58 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2017-03-22 20:11:30 -0600 |
| commit | 4514451e79ae5baabb85d22ba3523602e59d5218 (patch) | |
| tree | 41e4e68dee3cd706fa2ceb026c27f9db6f5c78f7 /mm/backing-dev.c | |
| parent | 5318ce7d46866e1dbc20ab9349b93753edba0b3e (diff) | |
| download | lwn-4514451e79ae5baabb85d22ba3523602e59d5218.tar.gz lwn-4514451e79ae5baabb85d22ba3523602e59d5218.zip | |
bdi: Do not wait for cgwbs release in bdi_unregister()
Currently we wait for all cgwbs to get released in cgwb_bdi_destroy()
(called from bdi_unregister()). That is however unnecessary now when
cgwb->bdi is a proper refcounted reference (thus bdi cannot get
released before all cgwbs are released) and when cgwb_bdi_destroy()
shuts down writeback directly.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'mm/backing-dev.c')
| -rw-r--r-- | mm/backing-dev.c | 22 |
1 files changed, 1 insertions, 21 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c index b67be4fc12c4..8c30b1a7aae5 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -406,11 +406,9 @@ static void wb_exit(struct bdi_writeback *wb) /* * cgwb_lock protects bdi->cgwb_tree, bdi->cgwb_congested_tree, * blkcg->cgwb_list, and memcg->cgwb_list. bdi->cgwb_tree is also RCU - * protected. cgwb_release_wait is used to wait for the completion of cgwb - * releases from bdi destruction path. + * protected. */ static DEFINE_SPINLOCK(cgwb_lock); -static DECLARE_WAIT_QUEUE_HEAD(cgwb_release_wait); /** * wb_congested_get_create - get or create a wb_congested @@ -505,7 +503,6 @@ static void cgwb_release_workfn(struct work_struct *work) { struct bdi_writeback *wb = container_of(work, struct bdi_writeback, release_work); - struct backing_dev_info *bdi = wb->bdi; wb_shutdown(wb); @@ -516,9 +513,6 @@ static void cgwb_release_workfn(struct work_struct *work) percpu_ref_exit(&wb->refcnt); wb_exit(wb); kfree_rcu(wb, rcu); - - if (atomic_dec_and_test(&bdi->usage_cnt)) - wake_up_all(&cgwb_release_wait); } static void cgwb_release(struct percpu_ref *refcnt) @@ -608,7 +602,6 @@ static int cgwb_create(struct backing_dev_info *bdi, /* we might have raced another instance of this function */ ret = radix_tree_insert(&bdi->cgwb_tree, memcg_css->id, wb); if (!ret) { - atomic_inc(&bdi->usage_cnt); list_add_tail_rcu(&wb->bdi_node, &bdi->wb_list); list_add(&wb->memcg_node, memcg_cgwb_list); list_add(&wb->blkcg_node, blkcg_cgwb_list); @@ -698,7 +691,6 @@ static int cgwb_bdi_init(struct backing_dev_info *bdi) INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC); bdi->cgwb_congested_tree = RB_ROOT; - atomic_set(&bdi->usage_cnt, 1); ret = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL); if (!ret) { @@ -728,18 +720,6 @@ static void cgwb_bdi_destroy(struct backing_dev_info *bdi) spin_lock_irq(&cgwb_lock); } spin_unlock_irq(&cgwb_lock); - - /* - * All cgwb's must be shutdown and released before returning. Drain - * the usage counter to wait for all cgwb's ever created on @bdi. - */ - atomic_dec(&bdi->usage_cnt); - wait_event(cgwb_release_wait, !atomic_read(&bdi->usage_cnt)); - /* - * Grab back our reference so that we hold it when @bdi gets - * re-registered. - */ - atomic_inc(&bdi->usage_cnt); } /** |