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 /drivers/md/bcache/super.c | |
| parent | xen/blkfront: When purging persistent grants, keep them in the buffer (diff) | |
| download | linux-dev-0f843e65d9eef4936929bb036c5f771fb261eea4.tar.xz linux-dev-0f843e65d9eef4936929bb036c5f771fb261eea4.zip | |
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>
Diffstat (limited to '')
| -rw-r--r-- | drivers/md/bcache/super.c | 8 |
1 files changed, 8 insertions, 0 deletions
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; |