linux-kernel - [PATCH 1/3] cpuset: Don't always flush cpuset_migrate_mm_wq in cpuset_write

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]

Message-Id: <20250904074505.1722678-2-zhouchuyi@bytedance.com>
Date: Thu,  4 Sep 2025 15:45:03 +0800
From: Chuyi Zhou <zhouchuyi@...edance.com>
To: tj@...nel.org,
	mkoutny@...e.com,
	hannes@...xchg.org,
	longman@...hat.com
Cc: linux-kernel@...r.kernel.org,
	Chuyi Zhou <zhouchuyi@...edance.com>
Subject: [PATCH 1/3] cpuset: Don't always flush cpuset_migrate_mm_wq in cpuset_write_resmask

It is unnecessary to always wait for the flush operation of
cpuset_migrate_mm_wq to complete in cpuset_write_resmask, as modifying
cpuset.cpus or cpuset.exclusive does not trigger mm migrations. The
flush_workqueue can be executed only when cpuset.mems is modified.

Signed-off-by: Chuyi Zhou <zhouchuyi@...edance.com>
---
 kernel/cgroup/cpuset.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 27adb04df675d..3d8492581c8c4 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -3256,7 +3256,8 @@ ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
 out_unlock:
 	mutex_unlock(&cpuset_mutex);
 	cpus_read_unlock();
-	flush_workqueue(cpuset_migrate_mm_wq);
+	if (of_cft(of)->private == FILE_MEMLIST)
+		flush_workqueue(cpuset_migrate_mm_wq);
 	return retval ?: nbytes;
 }
 
-- 
2.20.1