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From: zhongjinji <zhongjinji@honor.com>
To: <mhocko@suse.com>
Cc: <akpm@linux-foundation.org>, <andrealmeid@igalia.com>,
	<dave@stgolabs.net>, <dvhart@infradead.org>, <feng.han@honor.com>,
	<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
	<liulu.liu@honor.com>, <mingo@redhat.com>, <npache@redhat.com>,
	<peterz@infradead.org>, <rientjes@google.com>,
	<shakeel.butt@linux.dev>, <tglx@linutronix.de>,
	<zhongjinji@honor.com>
Subject: Re: [[PATCH v2] 2/2] futex: Only delay OOM reaper for processes using robust futex
Date: Mon, 4 Aug 2025 19:50:37 +0800	[thread overview]
Message-ID: <20250804115037.19690-1-zhongjinji@honor.com> (raw)
In-Reply-To: <aJBKijr1nR1CleBL@tiehlicka>

>On Fri 01-08-25 23:36:49, zhongjinji@honor.com wrote:
>> From: zhongjinji <zhongjinji@honor.com>
>> 
>> After merging the patch
>> https://lore.kernel.org/all/20220414144042.677008-1-npache@redhat.com/T/#u,
>> the OOM reaper runs less frequently because many processes exit within 2 seconds.
>> 
>> However, when a process is killed, timely handling by the OOM reaper allows
>> its memory to be freed faster.
>> 
>> Since relatively few processes use robust futex, delaying the OOM reaper for
>> all processes is undesirable, as many killed processes cannot release memory
>> more quickly.
>
>Could you elaborate more about why this is really needed? OOM should be
>a very slow path. Why do you care about this potential improvement in
>that situation? In other words what is the usecase?

Well, We are using the cgroup v1 freezer. When a frozen process is
killed, it cannot exit immediately and is blocked in __refrigerator until
it is thawed. When the process cannot be thawed in time, it will result in 
increased system memory pressure.



  reply	other threads:[~2025-08-04 11:50 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-01 15:36 [[PATCH v2] 1/2] futex: Add check_robust_futex to verify process usage of robust_futex zhongjinji
2025-08-01 15:36 ` [[PATCH v2] 2/2] futex: Only delay OOM reaper for processes using robust futex zhongjinji
2025-08-04  5:52   ` Michal Hocko
2025-08-04 11:50     ` zhongjinji [this message]
2025-08-04 12:01       ` Michal Hocko
2025-08-05  6:18         ` Michal Hocko
2025-08-05 14:55           ` zhongjinji
2025-08-05 13:19         ` zhongjinji
2025-08-05 16:02 ` [[PATCH v2] 1/2] futex: Add check_robust_futex to verify process usage of robust_futex Thomas Gleixner
2025-08-12 13:21   ` zhongjinji

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