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Mon, 11 May 2026 01:18:47 -0700 (PDT) Received: from intel.company.local ([210.184.73.204]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-367beac5b48sm2631245a91.11.2026.05.11.01.18.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 May 2026 01:18:46 -0700 (PDT) From: Wandun Chen X-Google-Original-From: Wandun Chen To: longman@redhat.com, chenridong@huaweicloud.com, tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] cgroup/cpuset: skip hardwall ancestor scan in cpuset v2 in cpuset_current_node_allowed() Date: Mon, 11 May 2026 16:18:38 +0800 Message-ID: <20260511081838.862889-1-chenwandun@lixiang.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Chen Wandun Cgroup v2 doesn't have the concept of memory hardwall, only top_cpuset has CS_MEM_EXCLUSIVE/CS_MEM_HARDWALL flags, nearest_hardwall_ancestor always returns top_cpuset with all nodes set, so no need to acquire callback_lock and scan up cpuset. Suggested-by: Michal Koutn=C3=BD Signed-off-by: Chen Wandun --- v1 --> v2: use cpuset_v2 instead of is_in_v2_mode, suggested by Tejun. --- kernel/cgroup/cpuset.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index a48901a0416a..cbd9e7fc800e 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -4231,6 +4231,9 @@ bool cpuset_current_node_allowed(int node, gfp_t gfp_= mask) if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */ return false; =20 + if (cpuset_v2()) + return true; + /* Not hardwall and node outside mems_allowed: scan up cpusets */ spin_lock_irqsave(&callback_lock, flags); =20 --=20 2.43.0