From 0f843e65d9eef4936929bb036c5f771fb261eea4 Mon Sep 17 00:00:00 2001 From: Guoju Fang Date: Thu, 27 Sep 2018 23:41:46 +0800 Subject: bcache: add separate workqueue for journal_write to avoid deadlock After write SSD completed, bcache schedules journal_write work to system_wq, which is a public workqueue in system, without WQ_MEM_RECLAIM flag. system_wq is also a bound wq, and there may be no idle kworker on current processor. Creating a new kworker may unfortunately need to reclaim memory first, by shrinking cache and slab used by vfs, which depends on bcache device. That's a deadlock. This patch create a new workqueue for journal_write with WQ_MEM_RECLAIM flag. It's rescuer thread will work to avoid the deadlock. Signed-off-by: Guoju Fang Cc: stable@vger.kernel.org Signed-off-by: Coly Li Signed-off-by: Jens Axboe --- drivers/md/bcache/journal.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/md/bcache/journal.c') diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c index 6116bbf870d8..522c7426f3a0 100644 --- a/drivers/md/bcache/journal.c +++ b/drivers/md/bcache/journal.c @@ -485,7 +485,7 @@ static void do_journal_discard(struct cache *ca) closure_get(&ca->set->cl); INIT_WORK(&ja->discard_work, journal_discard_work); - schedule_work(&ja->discard_work); + queue_work(bch_journal_wq, &ja->discard_work); } } @@ -592,7 +592,7 @@ static void journal_write_done(struct closure *cl) : &j->w[0]; __closure_wake_up(&w->wait); - continue_at_nobarrier(cl, journal_write, system_wq); + continue_at_nobarrier(cl, journal_write, bch_journal_wq); } static void journal_write_unlock(struct closure *cl) @@ -627,7 +627,7 @@ static void journal_write_unlocked(struct closure *cl) spin_unlock(&c->journal.lock); btree_flush_write(c); - continue_at(cl, journal_write, system_wq); + continue_at(cl, journal_write, bch_journal_wq); return; } -- cgit v1.2.3-59-g8ed1b