From: Qi Zheng <qi.zheng@linux.dev>
To: akpm@linux-foundation.org, tkhai@ya.ru, roman.gushchin@linux.dev,
vbabka@suse.cz, viro@zeniv.linux.org.uk, brauner@kernel.org,
djwong@kernel.org, hughd@google.com, paulmck@kernel.org,
muchun.song@linux.dev
Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org,
Qi Zheng <zhengqi.arch@bytedance.com>
Subject: [PATCH 4/8] fs: shrink only (SB_ACTIVE|SB_BORN) superblocks in super_cache_scan()
Date: Wed, 31 May 2023 09:57:38 +0000 [thread overview]
Message-ID: <20230531095742.2480623-5-qi.zheng@linux.dev> (raw)
In-Reply-To: <20230531095742.2480623-1-qi.zheng@linux.dev>
From: Kirill Tkhai <tkhai@ya.ru>
This patch prepares superblock shrinker for delayed unregistering.
It makes super_cache_scan() avoid shrinking of not active superblocks.
SB_ACTIVE is used as such the indicator. In case of superblock is not
active, super_cache_scan() just exits with SHRINK_STOP as result.
Note, that SB_ACTIVE is cleared in generic_shutdown_super() and this
is made under the write lock of s_umount. Function super_cache_scan()
also takes the read lock of s_umount, so it can't skip this flag cleared.
SB_BORN check is added to super_cache_scan() just for uniformity
with super_cache_count(), while super_cache_count() received SB_ACTIVE
check just for uniformity with super_cache_scan().
After this patch super_cache_scan() becomes to ignore unregistering
superblocks, so this function is OK with splitting unregister_shrinker().
Next patches prepare super_cache_count() to follow this way.
Signed-off-by: Kirill Tkhai <tkhai@ya.ru>
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
fs/super.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/fs/super.c b/fs/super.c
index 2ce4c72720f3..2ce54561e82e 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -79,6 +79,11 @@ static unsigned long super_cache_scan(struct shrinker *shrink,
if (!trylock_super(sb))
return SHRINK_STOP;
+ if ((sb->s_flags & (SB_BORN|SB_ACTIVE)) != (SB_BORN|SB_ACTIVE)) {
+ freed = SHRINK_STOP;
+ goto unlock;
+ }
+
if (sb->s_op->nr_cached_objects)
fs_objects = sb->s_op->nr_cached_objects(sb, sc);
@@ -110,6 +115,7 @@ static unsigned long super_cache_scan(struct shrinker *shrink,
freed += sb->s_op->free_cached_objects(sb, sc);
}
+unlock:
up_read(&sb->s_umount);
return freed;
}
@@ -136,7 +142,7 @@ static unsigned long super_cache_count(struct shrinker *shrink,
* avoid this situation, so do the same here. The memory barrier is
* matched with the one in mount_fs() as we don't hold locks here.
*/
- if (!(sb->s_flags & SB_BORN))
+ if ((sb->s_flags & (SB_BORN|SB_ACTIVE)) != (SB_BORN|SB_ACTIVE))
return 0;
smp_rmb();
--
2.30.2
next prev parent reply other threads:[~2023-05-31 9:58 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-31 9:57 [PATCH 0/8] make unregistration of super_block shrinker more faster Qi Zheng
2023-05-31 9:57 ` [PATCH 1/8] mm: vmscan: move shrinker_debugfs_remove() before synchronize_srcu() Qi Zheng
2023-05-31 10:49 ` Christian Brauner
2023-05-31 12:52 ` Qi Zheng
2023-05-31 9:57 ` [PATCH 2/8] mm: vmscan: split unregister_shrinker() Qi Zheng
2023-05-31 9:57 ` [PATCH 3/8] fs: move list_lru_destroy() to destroy_super_work() Qi Zheng
2023-05-31 9:57 ` Qi Zheng [this message]
2023-05-31 9:57 ` [PATCH 5/8] fs: introduce struct super_operations::destroy_super() callback Qi Zheng
2023-05-31 11:19 ` Christian Brauner
2023-05-31 12:54 ` Qi Zheng
2023-05-31 9:57 ` [PATCH 6/8] xfs: introduce xfs_fs_destroy_super() Qi Zheng
2023-05-31 9:57 ` [PATCH 7/8] shmem: implement shmem_destroy_super() Qi Zheng
2023-05-31 9:57 ` [PATCH 8/8] fs: use unregister_shrinker_delayed_{initiate, finalize} for super_block shrinker Qi Zheng
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