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([2601:188:c180:4250:ecbe:130d:668d:951d]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4b48f77d6c4sm29848671cf.36.2025.09.04.08.12.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 04 Sep 2025 08:12:44 -0700 (PDT) From: Waiman Long X-Google-Original-From: Waiman Long Message-ID: <5e9efe12-0f59-4836-81cd-d39805f3b243@redhat.com> Date: Thu, 4 Sep 2025 11:12:43 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/3] cpuset: Don't always flush cpuset_migrate_mm_wq in cpuset_write_resmask To: Chuyi Zhou , tj@kernel.org, mkoutny@suse.com, hannes@cmpxchg.org Cc: linux-kernel@vger.kernel.org References: <20250904074505.1722678-1-zhouchuyi@bytedance.com> <20250904074505.1722678-2-zhouchuyi@bytedance.com> Content-Language: en-US In-Reply-To: <20250904074505.1722678-2-zhouchuyi@bytedance.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 9/4/25 3:45 AM, Chuyi Zhou wrote: > 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 > --- > 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; > } > LGTM Reviewed-by:  Waiman Long