From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-54.mta0.migadu.com [91.218.175.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BF4B04534A9 for ; Mon, 21 Sep 2026 09:21:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.54 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789982517; cv=none; b=YEON819bmSVc7o0Q2J29HTwBAD9xIUkR9hq0ce7Yrhb/7HMIPkAN/CJmD6AiAUQudE+VM+7IW2RJYn5cBJynm/28SnrtUS00F2KMn0yHg9EUm+A2DcUiZ6nnYXOwcnoUXFuaFFiA3g9Qk1bT2YubDVDIIRudzMjtRhXHv4NiQ+s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789982517; c=relaxed/simple; bh=ftt2VmSueNigEmRUzim7RcAInXHUvUyDkJasA+sP/sI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=XOtGeorUdmfBtLsCGJN8Rfgy8flxeRWnmybxU1oMLLwzsrbvxzHEDo9kAqlrur+3k6uzEvvdZXyQAFUFoonXII+r8sw4M48qFsedlnjrXzqB/M9S2Q87Z6QKf/VC9Lg5bESHOrjBKGTVs6Eu3VmU59h0fCZulPVwaD172S7W8b8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=jWsbvQJn; arc=none smtp.client-ip=91.218.175.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="jWsbvQJn" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=ftt2VmSueNigEmRUzim7RcAInXHUvUyDkJasA+sP/sI=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1789982513; v=1; x=1790587313; b=jWsbvQJno9CuCyQVTZB9lhN7qsOidsqwQTyAIOnMC7/GD/rn2vKIe+LgRS26jI5FcznCU58R mIUL3pOsfkgA9Jr6AuJrp73cNcmcaSTvjS0o1R5wKXId1z/TjWu1fFmM0N1QApAjsWPJrdeFXv3 L2EIteOtnYoad3rIZ50U9dg0= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 63f02883ed771dab; Mon, 21 Sep 2026 09:21:53 +0000 X-Mizu-Trace-ID: 63f02883ed771dab X-Migadu-Flow: FLOW_OUT From: Ye Liu To: Michal Hocko , Andrew Morton Cc: Ye Liu , SJ Park , Gregory Price , Lorenzo Stoakes , peterz@infradead.org, paulmck@kernel.org, mingo@redhat.com, rostedt@goodmis.org, jpoimboe@kernel.org, mic@digikod.net, oleg@redhat.com, tglx@kernel.org, david@kernel.org, linmiaohe@huawei.com, nao.horiguchi@gmail.com, rafael@kernel.org, gnoack3000@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, rcu@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, rientjes@google.com, shakeel.butt@linux.dev, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, will@kernel.org, boqun@kernel.org, frederic@kernel.org, neeraj.upadhyay@kernel.org, joelagnelf@nvidia.com, josh@joshtriplett.org, urezki@gmail.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, tony.luck@intel.com, reinette.chatre@intel.com, x86@kernel.org, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, pavel@kernel.org, lance.yang@linux.dev, mhiramat@kernel.org, pmladek@suse.com, longman@redhat.com, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, qiang.zhang@linux.dev, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, kprateek.nayak@amd.com, mark.rutland@arm.com, Dave.Martin@arm.com, james.morse@arm.com, babu.moger@amd.com Subject: [PATCH v4 02/15] mm/oom_kill: convert process/thread iterators to for_each_*_rculock Date: Mon, 21 Sep 2026 17:20:48 +0800 Message-Id: <20260921092101.89285-3-ye.liu@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20260921092101.89285-1-ye.liu@linux.dev> References: <20260921092101.89285-1-ye.liu@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Ye Liu Replace the manual rcu_read_lock()/rcu_read_unlock() pairs wrapping for_each_process()/for_each_thread() loops with for_each_process_rculock() and for_each_thread_rculock(), which scope the RCU read lock to the loop body via scoped_guard(rcu). No functional change. Signed-off-by: Ye Liu Acked-by: Michal Hocko Reviewed-by: SJ Park Reviewed-by: Gregory Price (Meta) Reviewed-by: Lorenzo Stoakes (ARM) --- mm/oom_kill.c | 20 +++++--------------- 1 file changed, 5 insertions(+), 15 deletions(-) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 5f372f6e26fa..ef2e1c423c1d 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -94,8 +94,7 @@ static bool oom_cpuset_eligible(struct task_struct *start, bool ret = false; const nodemask_t *mask = oc->nodemask; - rcu_read_lock(); - for_each_thread(start, tsk) { + for_each_thread_rculock(start, tsk) { if (mask) { /* * If this is a mempolicy constrained oom, tsk's @@ -114,7 +113,6 @@ static bool oom_cpuset_eligible(struct task_struct *start, if (ret) break; } - rcu_read_unlock(); return ret; } @@ -368,11 +366,9 @@ static void select_bad_process(struct oom_control *oc) else { struct task_struct *p; - rcu_read_lock(); - for_each_process(p) + for_each_process_rculock(p) if (oom_evaluate_task(p, oc)) break; - rcu_read_unlock(); } } @@ -430,14 +426,12 @@ static void dump_tasks(struct oom_control *oc) struct task_struct *p; int i = 0; - rcu_read_lock(); - for_each_process(p) { + for_each_process_rculock(p) { /* Avoid potential softlockup warning */ if ((++i & 1023) == 0) touch_softlockup_watchdog(); dump_task(p, oc); } - rcu_read_unlock(); } } @@ -894,8 +888,7 @@ static bool task_will_free_mem(struct task_struct *task) * are dying as well to make sure that a) nobody pins its mm and * b) the task is also reapable by the oom reaper. */ - rcu_read_lock(); - for_each_process(p) { + for_each_process_rculock(p) { if (!process_shares_mm(p, mm)) continue; if (same_thread_group(task, p)) @@ -904,7 +897,6 @@ static bool task_will_free_mem(struct task_struct *task) if (!ret) break; } - rcu_read_unlock(); return ret; } @@ -960,8 +952,7 @@ static void __oom_kill_process(struct task_struct *victim, const char *message) * That thread will now get access to memory reserves since it has a * pending fatal signal. */ - rcu_read_lock(); - for_each_process(p) { + for_each_process_rculock(p) { if (!process_shares_mm(p, mm)) continue; if (same_thread_group(p, victim)) @@ -982,7 +973,6 @@ static void __oom_kill_process(struct task_struct *victim, const char *message) continue; do_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_TGID); } - rcu_read_unlock(); if (can_oom_reap) queue_oom_reaper(victim); -- 2.25.1