linux-kernel - [PATCH 4/5] mm: vmscan: remove shrinker_rwsem from synchronize

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 20 Feb 2023 17:16:36 +0800
From:   Qi Zheng <zhengqi.arch@...edance.com>
To:     akpm@...ux-foundation.org, hannes@...xchg.org, shakeelb@...gle.com,
        mhocko@...nel.org, roman.gushchin@...ux.dev, muchun.song@...ux.dev,
        david@...hat.com, shy828301@...il.com
Cc:     tkhai@...ru, sultan@...neltoast.com, dave@...olabs.net,
        penguin-kernel@...ove.SAKURA.ne.jp, paulmck@...nel.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Qi Zheng <zhengqi.arch@...edance.com>
Subject: [PATCH 4/5] mm: vmscan: remove shrinker_rwsem from synchronize_shrinkers()

Now there are no readers of shrinker_rwsem, so
synchronize_shrinkers() does not need to hold the
writer of shrinker_rwsem to wait for all running
shinkers to complete, synchronize_srcu() is enough.

Signed-off-by: Qi Zheng <zhengqi.arch@...edance.com>
---
 mm/vmscan.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index dc47396ecd0e..b8da56beba96 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -787,15 +787,11 @@ EXPORT_SYMBOL(unregister_shrinker);
 /**
  * synchronize_shrinkers - Wait for all running shrinkers to complete.
  *
- * This is equivalent to calling unregister_shrink() and register_shrinker(),
- * but atomically and with less overhead. This is useful to guarantee that all
- * shrinker invocations have seen an update, before freeing memory, similar to
- * rcu.
+ * This is useful to guarantee that all shrinker invocations have seen an
+ * update, before freeing memory.
  */
 void synchronize_shrinkers(void)
 {
-	down_write(&shrinker_rwsem);
-	up_write(&shrinker_rwsem);
 	synchronize_srcu(&shrinker_srcu);
 }
 EXPORT_SYMBOL(synchronize_shrinkers);
-- 
2.20.1