Messages in this thread Patch in this message | | | Subject | Re: [REGRESSION] 6.7.1: md: raid5 hang and unresponsive system; successfully bisected | From | Yu Kuai <> | Date | Fri, 15 Mar 2024 09:17:56 +0800 |
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Hi,
在 2024/03/15 0:12, Dan Moulding 写道: >> How about the following patch? >> >> Thanks, >> Kuai >> >> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c >> index 3ad5f3c7f91e..0b2e6060f2c9 100644 >> --- a/drivers/md/raid5.c >> +++ b/drivers/md/raid5.c >> @@ -6720,7 +6720,6 @@ static void raid5d(struct md_thread *thread) >> >> md_check_recovery(mddev); >> >> - blk_start_plug(&plug); >> handled = 0; >> spin_lock_irq(&conf->device_lock); >> while (1) { >> @@ -6728,6 +6727,14 @@ static void raid5d(struct md_thread *thread) >> int batch_size, released; >> unsigned int offset; >> >> + /* >> + * md_check_recovery() can't clear sb_flags, usually >> because of >> + * 'reconfig_mutex' can't be grabbed, wait for >> mddev_unlock() to >> + * wake up raid5d(). >> + */ >> + if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) >> + goto skip; >> + >> released = release_stripe_list(conf, >> conf->temp_inactive_list); >> if (released) >> clear_bit(R5_DID_ALLOC, &conf->cache_state); >> @@ -6766,8 +6773,8 @@ static void raid5d(struct md_thread *thread) >> spin_lock_irq(&conf->device_lock); >> } >> } >> +skip: >> pr_debug("%d stripes handled\n", handled); >> - >> spin_unlock_irq(&conf->device_lock); >> if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) && >> mutex_trylock(&conf->cache_size_mutex)) { >> @@ -6779,6 +6786,7 @@ static void raid5d(struct md_thread *thread) >> mutex_unlock(&conf->cache_size_mutex); >> } >> >> + blk_start_plug(&plug); >> flush_deferred_bios(conf); >> >> r5l_flush_stripe_to_raid(conf->log); > > I can confirm that this patch also works. I'm unable to reproduce the > hang after applying this instead of the first patch provided by > Junxiao. So looks like both ways are succesful in avoiding the hang. >
Thanks a lot for the testing! Can you also give following patch a try? It removes the change to blk_plug, because Dan and Song are worried about performance degradation, so we need to verify the performance before consider that patch.
Anyway, I think following patch can fix this problem as well.
Thanks, Kuai
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 3ad5f3c7f91e..ae8665be9940 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -6728,6 +6728,9 @@ static void raid5d(struct md_thread *thread) int batch_size, released; unsigned int offset;
+ if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) + goto skip; + released = release_stripe_list(conf, conf->temp_inactive_list); if (released) clear_bit(R5_DID_ALLOC, &conf->cache_state); @@ -6766,6 +6769,7 @@ static void raid5d(struct md_thread *thread) spin_lock_irq(&conf->device_lock); } } +skip: pr_debug("%d stripes handled\n", handled);
spin_unlock_irq(&conf->device_lock);
> -- Dan > . >
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