diff options
| author | Jan Kara <jack@suse.cz> | 2023-10-04 16:32:01 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-10-20 00:05:33 +0300 |
| commit | 56e96b38d2f7cd95b3c30eb70decac7233915e0a (patch) | |
| tree | 5421e5f969acd933b1504874e0fdb8cd6b526df7 /include/linux | |
| parent | 28ddc1e0b898291323b62d770b1b931de131a528 (diff) | |
| download | linux-56e96b38d2f7cd95b3c30eb70decac7233915e0a.tar.xz | |
quota: Fix slow quotaoff
commit 869b6ea1609f655a43251bf41757aa44e5350a8f upstream.
Eric has reported that commit dabc8b207566 ("quota: fix dqput() to
follow the guarantees dquot_srcu should provide") heavily increases
runtime of generic/270 xfstest for ext4 in nojournal mode. The reason
for this is that ext4 in nojournal mode leaves dquots dirty until the last
dqput() and thus the cleanup done in quota_release_workfn() has to write
them all. Due to the way quota_release_workfn() is written this results
in synchronize_srcu() call for each dirty dquot which makes the dquot
cleanup when turning quotas off extremely slow.
To be able to avoid synchronize_srcu() for each dirty dquot we need to
rework how we track dquots to be cleaned up. Instead of keeping the last
dquot reference while it is on releasing_dquots list, we drop it right
away and mark the dquot with new DQ_RELEASING_B bit instead. This way we
can we can remove dquot from releasing_dquots list when new reference to
it is acquired and thus there's no need to call synchronize_srcu() each
time we drop dq_list_lock.
References: https://lore.kernel.org/all/ZRytn6CxFK2oECUt@debian-BULLSEYE-live-builder-AMD64
Reported-by: Eric Whitney <enwlinux@gmail.com>
Fixes: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide")
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/quota.h | 4 | ||||
| -rw-r--r-- | include/linux/quotaops.h | 2 |
2 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/quota.h b/include/linux/quota.h index 18ebd39c9487..fc52cd623d29 100644 --- a/include/linux/quota.h +++ b/include/linux/quota.h @@ -285,7 +285,9 @@ static inline void dqstats_dec(unsigned int type) #define DQ_FAKE_B 3 /* no limits only usage */ #define DQ_READ_B 4 /* dquot was read into memory */ #define DQ_ACTIVE_B 5 /* dquot is active (dquot_release not called) */ -#define DQ_LASTSET_B 6 /* Following 6 bits (see QIF_) are reserved\ +#define DQ_RELEASING_B 6 /* dquot is in releasing_dquots list waiting + * to be cleaned up */ +#define DQ_LASTSET_B 7 /* Following 6 bits (see QIF_) are reserved\ * for the mask of entries set via SETQUOTA\ * quotactl. They are set under dq_data_lock\ * and the quota format handling dquot can\ diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h index a0f6668924d3..4bc8ff2a6614 100644 --- a/include/linux/quotaops.h +++ b/include/linux/quotaops.h @@ -56,7 +56,7 @@ static inline bool dquot_is_busy(struct dquot *dquot) { if (test_bit(DQ_MOD_B, &dquot->dq_flags)) return true; - if (atomic_read(&dquot->dq_count) > 1) + if (atomic_read(&dquot->dq_count) > 0) return true; return false; } |