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| author |   John Pittman <jpittman@redhat.com> | 2018-08-06 15:53:12 -0400 |
|---|---|---|
| committer |   Mike Snitzer <snitzer@redhat.com> | 2018-08-08 09:16:24 -0400 |
| commit | 784c9a29e99eb40b842c29ecf1cc3a79e00fb629 (patch) | |
| tree | ce11f4e06591c991e0fea624392b23a45b8b05c1 /drivers/md/dm-kcopyd.c | |
| parent | dm cache metadata: save in-core policy_hint_size to on-disk superblock (diff) | |
| download | linux-dev-784c9a29e99eb40b842c29ecf1cc3a79e00fb629.tar.xz linux-dev-784c9a29e99eb40b842c29ecf1cc3a79e00fb629.zip | |
dm kcopyd: avoid softlockup in run_complete_job
It was reported that softlockups occur when using dm-snapshot ontop of
slow (rbd) storage. E.g.:
[ 4047.990647] watchdog: BUG: soft lockup - CPU#10 stuck for 22s! [kworker/10:23:26177]
...
[ 4048.034151] Workqueue: kcopyd do_work [dm_mod]
[ 4048.034156] RIP: 0010:copy_callback+0x41/0x160 [dm_snapshot]
...
[ 4048.034190] Call Trace:
[ 4048.034196] ? __chunk_is_tracked+0x70/0x70 [dm_snapshot]
[ 4048.034200] run_complete_job+0x5f/0xb0 [dm_mod]
[ 4048.034205] process_jobs+0x91/0x220 [dm_mod]
[ 4048.034210] ? kcopyd_put_pages+0x40/0x40 [dm_mod]
[ 4048.034214] do_work+0x46/0xa0 [dm_mod]
[ 4048.034219] process_one_work+0x171/0x370
[ 4048.034221] worker_thread+0x1fc/0x3f0
[ 4048.034224] kthread+0xf8/0x130
[ 4048.034226] ? max_active_store+0x80/0x80
[ 4048.034227] ? kthread_bind+0x10/0x10
[ 4048.034231] ret_from_fork+0x35/0x40
[ 4048.034233] Kernel panic - not syncing: softlockup: hung tasks
Fix this by calling cond_resched() after run_complete_job()'s callout to
the dm_kcopyd_notify_fn (which is dm-snap.c:copy_callback in the above
trace).
Signed-off-by: John Pittman <jpittman@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-kcopyd.c')
| -rw-r--r-- | drivers/md/dm-kcopyd.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c index cc101f3ec42c..2fc4213e02b5 100644 --- a/drivers/md/dm-kcopyd.c +++ b/drivers/md/dm-kcopyd.c @@ -487,6 +487,8 @@ static int run_complete_job(struct kcopyd_job *job) if (atomic_dec_and_test(&kc->nr_jobs)) wake_up(&kc->destroyq); + cond_resched(); + return 0; } |