diff options
| author | Guoju Fang <fangguoju@gmail.com> | 2018-09-27 23:41:46 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-09-27 09:47:01 -0600 |
| commit | 0f843e65d9eef4936929bb036c5f771fb261eea4 (patch) | |
| tree | b02f7ba31960169e8789a54b3c546d50834b0da9 | |
| parent | f151ba989d149bbdfc90e5405724bbea094f9b17 (diff) | |
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 <fangguoju@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/md/bcache/bcache.h | 1 | ||||
| -rw-r--r-- | drivers/md/bcache/journal.c | 6 | ||||
| -rw-r--r-- | drivers/md/bcache/super.c | 8 |
3 files changed, 12 insertions, 3 deletions
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index 83504dd8100a..954dad29e6e8 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -965,6 +965,7 @@ void bch_prio_write(struct cache *ca); void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent); extern struct workqueue_struct *bcache_wq; +extern struct workqueue_struct *bch_journal_wq; extern struct mutex bch_register_lock; extern struct list_head bch_cache_sets; 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; } diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 94c756c66bd7..30ba9aeb5ee8 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -47,6 +47,7 @@ static int bcache_major; static DEFINE_IDA(bcache_device_idx); static wait_queue_head_t unregister_wait; struct workqueue_struct *bcache_wq; +struct workqueue_struct *bch_journal_wq; #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE) /* limitation of partitions number on single bcache device */ @@ -2341,6 +2342,9 @@ static void bcache_exit(void) kobject_put(bcache_kobj); if (bcache_wq) destroy_workqueue(bcache_wq); + if (bch_journal_wq) + destroy_workqueue(bch_journal_wq); + if (bcache_major) unregister_blkdev(bcache_major, "bcache"); unregister_reboot_notifier(&reboot); @@ -2370,6 +2374,10 @@ static int __init bcache_init(void) if (!bcache_wq) goto err; + bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0); + if (!bch_journal_wq) + goto err; + bcache_kobj = kobject_create_and_add("bcache", fs_kobj); if (!bcache_kobj) goto err; |