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h=Date:From:To:Cc:Subject:References:In-Reply-To; b=GlDV0UdXoMomtP016qtWdfhBcTL8gmddP/0T8F0MWrDwpxDQN2f4ko1Wocil4V+4O HDiMG6LHFKKijrMY/6TKhDx5a+XeTmjTLFpH0R+2E9I8zmfOpIeOP4jpVvD1J6oiqt r4zAGJtuddnX283jMvfQv5eopopQhFXVQCU400y1oiJe42/dF2HXBZZCpIA4/dAma5 G+MTqCyVIBxJ6lyqxpV6OxjC1tom5XFf6lhGhYlL8trsEjwuKFseaDN3Hy/1563AfD idwFSfRBZGSexeqpYIZYA+bgizGrZT+uFCrKyDnUZ9DJRIT+UUNAEz6HFLpSLUqWu/ NFtqaJWO8/eKg== Date: Mon, 7 Sep 2026 09:35:39 +0100 From: "Lorenzo Stoakes (ARM)" To: Ye Liu Cc: Michal Hocko , Andrew Morton , Ye Liu , SJ Park , 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, 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, 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 Subject: Re: [PATCH v2 2/8] mm/oom_kill: convert process/thread iterators to for_each_*_rculock Message-ID: References: <20260907081334.1152889-1-ye.liu@linux.dev> <20260907081334.1152889-3-ye.liu@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260907081334.1152889-3-ye.liu@linux.dev> X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: C839A140004 X-Stat-Signature: kbueuemtri46f7j5xbwepnr4bayae8qk X-Rspam-User: X-HE-Tag: 1788770155-862680 X-HE-Meta: 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 fSE4s4Md LmKUNZK0cXO89BkplDnJ0ajNWM3xAZTlQ9N5gV8LpOJ++ZgecIwTtm6IhEWLkTTF5q9nN5m+F3PcbOkHCLeQZP6AWCLr9T5/QbAVzofQxSttESH9oVkppLQJH6vpoNbCpgJgxAQ1Ju9NxHlg2sMs7Uq8z3mW5VflK8IgVXeueq0opnBOU4kfS4BPO1cF+hmR4T7qlcgrmXjmoY1DdkUErAKkpPlNha2xNSXR7seaJo++77jgjvohz3AcVA3y3ocbgsjvo0wfY0UbRaEPnH4RvtGb/GmCQiQre0prsntF4NX4epsbzWtTDITmldn+eVrLGheAdLXJylcqxMzbKYppb5u+LY4RWrA0ArR2DphRBWsD3UF/KZliW4z2ch2PgpjcDYSPR00fmGR5Jj47gmd2FLIIBE0A55XgPyCJzfWYmh8jUi5ZTaeJiU7Aq+wxfRwqTKrtZ/zA+R2Skh1g= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Sep 07, 2026 at 04:13:28PM +0800, Ye Liu wrote: > 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 LGTM so: Reviewed-by: Lorenzo Stoakes (ARM) > --- > Changes in v2: > - Rename *_rcu to *_rculock > 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 > -- Cheers, Lorenzo