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Fri, 04 Sep 2026 08:30:35 +0000 X-Mizu-Trace-ID: 4c1715947a22fdab X-Migadu-Flow: FLOW_OUT From: Ye Liu To: Michal Hocko , Andrew Morton Cc: Ye Liu , David Rientjes , Shakeel Butt , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/8] mm/oom_kill: convert process/thread iterators to for_each_*_rcu Date: Fri, 4 Sep 2026 16:29:54 +0800 Message-Id: <20260904083001.553587-3-ye.liu@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20260904083001.553587-1-ye.liu@linux.dev> References: <20260904083001.553587-1-ye.liu@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: bg6r7678us6u46xkprd4g4bybstqs1ta X-Rspamd-Queue-Id: CB9FB4000A X-Rspamd-Server: rspam02 X-Rspam-User: X-HE-Tag: 1788510636-609067 X-HE-Meta: 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 NK2+3qOw QBqGEgAM4FaF1N/bACmv6vw4600ulHfYcv2b+HAqPEpEGftDEocjWPFwH6m2MKvhOq+E9dr7d576xKvOr8rofOi3i8jjXZX0Fs+PqAPR6m0DAAJkhh27XZJmQH2AUw2WYogZGnvMx6eFNZFc/efLiXVMZ2ZG6xQsYrzPaabLnlOcxIQR612Eii1tMtYtnKpgUIoO10Vvo+ynDvDGf8/MxNM92xHyTE9u62Uk6Xn2UDYUb/WmxzJPnMtFwL9Iegu7cx0PvUGG7zeGv6lGSYWEbC38leg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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_rcu() and for_each_thread_rcu(), so that the RCU read-side critical section is scoped to the loop body. No functional change. Signed-off-by: Ye Liu --- 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..8dd025965810 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_rcu(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_rcu(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_rcu(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_rcu(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_rcu(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