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Thu, 13 Aug 2026 09:51:33 +0000 X-Migadu-Flow: FLOW_OUT Message-ID: Date: Thu, 13 Aug 2026 17:51:29 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/oom_kill: simplify remaining RCU sections with guard(rcu) To: Michal Hocko Cc: Andrew Morton , Ye Liu , David Rientjes , Shakeel Butt , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260813032634.344946-1-ye.liu@linux.dev> Content-Language: en-US From: Ye Liu In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 07E8B100008 X-Stat-Signature: t7n9nwxmsha4s1h8mccsm8zn7wyx3ib8 X-Rspam-User: X-HE-Tag: 1786614695-783553 X-HE-Meta: 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 fFRwgp1g 175EgyPjX/Ik3ehUAqZxWWDL930e/oi1f7dCfoO8C6MGrKPvm+UC3NzXn9GG2Q0B6QzqaGXSxd/ZS7r4dbyqYMZUxWRveINh5A474x3sCIvOZ6Ncm+BZYpldEGMMX46V8pstvwbdRSeaGVini6GtTHPYuvUtl/huZZ56+VapIk7GXWVLYOHd0Xe9FlMCq73+pD7sgFa+tVtLp+HlyMU/pn+ASTvuVV3bnZo8Z2lvGf5cs00hkEKoddzrnucrK7+ohw4YaGEUcLgv0AgkcL6Q2qmAYOeN96PK7QOb9pDd+AkckjkwoyFZuQ2Ln3lkVP+N1tHyK6Tcwej6BS9goGBpax4f2tSDJYMAqEQgE Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 在 2026/8/13 16:49, Michal Hocko 写道: > On Thu 13-08-26 11:26:33, Ye Liu wrote: >> From: Ye Liu >> >> Replace the remaining manual rcu_read_lock()/rcu_read_unlock() pairs >> in oom_cpuset_eligible(), select_bad_process(), dump_tasks(), >> task_will_free_mem(), and __oom_kill_process() with guard(rcu)() for >> consistency and simpler control flow. > > Could you use scoped_guard instead? While all these functions do not > perform anything pas the for loop this might change in the future and I > find it more obvious what the actual scope for the RCU is rather than > the full function one. >> Thanks for the suggestion, I've updated to V2. >> Signed-off-by: Ye Liu >> --- >> mm/oom_kill.c | 15 +++++---------- >> 1 file changed, 5 insertions(+), 10 deletions(-) >> >> diff --git a/mm/oom_kill.c b/mm/oom_kill.c >> index 4b5c70aaece4..8bbb5ca00bb6 100644 >> --- a/mm/oom_kill.c >> +++ b/mm/oom_kill.c >> @@ -94,7 +94,7 @@ static bool oom_cpuset_eligible(struct task_struct *start, >> bool ret = false; >> const nodemask_t *mask = oc->nodemask; >> >> - rcu_read_lock(); >> + guard(rcu)(); >> for_each_thread(start, tsk) { >> if (mask) { >> /* >> @@ -114,7 +114,6 @@ static bool oom_cpuset_eligible(struct task_struct *start, >> if (ret) >> break; >> } >> - rcu_read_unlock(); >> >> return ret; >> } >> @@ -368,11 +367,10 @@ static void select_bad_process(struct oom_control *oc) >> else { >> struct task_struct *p; >> >> - rcu_read_lock(); >> + guard(rcu)(); >> for_each_process(p) >> if (oom_evaluate_task(p, oc)) >> break; >> - rcu_read_unlock(); >> } >> } >> >> @@ -430,14 +428,13 @@ static void dump_tasks(struct oom_control *oc) >> struct task_struct *p; >> int i = 0; >> >> - rcu_read_lock(); >> + guard(rcu)(); >> for_each_process(p) { >> /* Avoid potential softlockup warning */ >> if ((++i & 1023) == 0) >> touch_softlockup_watchdog(); >> dump_task(p, oc); >> } >> - rcu_read_unlock(); >> } >> } >> >> @@ -894,7 +891,7 @@ 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(); >> + guard(rcu)(); >> for_each_process(p) { >> if (!process_shares_mm(p, mm)) >> continue; >> @@ -904,7 +901,6 @@ static bool task_will_free_mem(struct task_struct *task) >> if (!ret) >> break; >> } >> - rcu_read_unlock(); >> >> return ret; >> } >> @@ -960,7 +956,7 @@ 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(); >> + guard(rcu)(); >> for_each_process(p) { >> if (!process_shares_mm(p, mm)) >> continue; >> @@ -982,7 +978,6 @@ 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 > -- Thanks, Ye Liu