From: Vasily Averin <vvs@virtuozzo.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Michal Hocko <mhocko@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH memcg] memcg: prohibit unconditional exceeding the limit of dying tasks
Date: Fri, 10 Sep 2021 16:20:58 +0300 [thread overview]
Message-ID: <4a407474-ff7a-9e4f-d314-ab85f0eeaadf@virtuozzo.com> (raw)
In-Reply-To: <099aa0db-045a-e5b8-6df7-b7c3fc4d3caa@i-love.sakura.ne.jp>
On 9/10/21 4:04 PM, Tetsuo Handa wrote:
> On 2021/09/10 21:39, Vasily Averin wrote:
>> The kernel currently allows dying tasks to exceed the memcg limits.
>> The allocation is expected to be the last one and the occupied memory
>> will be freed soon.
>> This is not always true because it can be part of the huge vmalloc
>> allocation. Allowed once, they will repeat over and over again.
>> Moreover lifetime of the allocated object can differ from
>> In addition the lifetime of the dying task.
>
> Can't we add fatal_signal_pending(current) test to vmalloc() loop?
1) this has been done in the past but has been reverted later.
2) any vmalloc changes will affect non-memcg allocations too.
If we're doing memcg-related checks it's better to do it in one place.
3) it is not vmalloc-only issue. Huge number of kmalloc page allocations
from N concurrent threads will lead to the same problem.
>> Multiple such allocations running concurrently can not only overuse
>> the memcg limit, but can lead to a global out of memory and,
>> in the worst case, cause the host to panic.
>>
>> Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
WARNING: multiple messages have this Message-ID (diff)
From: Vasily Averin <vvs-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>
To: Tetsuo Handa
<penguin-kernel-1yMVhJb1mP/7nzcFbJAaVXf5DAMn2ifp@public.gmane.org>
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
Vladimir Davydov
<vdavydov.dev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Subject: Re: [PATCH memcg] memcg: prohibit unconditional exceeding the limit of dying tasks
Date: Fri, 10 Sep 2021 16:20:58 +0300 [thread overview]
Message-ID: <4a407474-ff7a-9e4f-d314-ab85f0eeaadf@virtuozzo.com> (raw)
In-Reply-To: <099aa0db-045a-e5b8-6df7-b7c3fc4d3caa-1yMVhJb1mP/7nzcFbJAaVXf5DAMn2ifp@public.gmane.org>
On 9/10/21 4:04 PM, Tetsuo Handa wrote:
> On 2021/09/10 21:39, Vasily Averin wrote:
>> The kernel currently allows dying tasks to exceed the memcg limits.
>> The allocation is expected to be the last one and the occupied memory
>> will be freed soon.
>> This is not always true because it can be part of the huge vmalloc
>> allocation. Allowed once, they will repeat over and over again.
>> Moreover lifetime of the allocated object can differ from
>> In addition the lifetime of the dying task.
>
> Can't we add fatal_signal_pending(current) test to vmalloc() loop?
1) this has been done in the past but has been reverted later.
2) any vmalloc changes will affect non-memcg allocations too.
If we're doing memcg-related checks it's better to do it in one place.
3) it is not vmalloc-only issue. Huge number of kmalloc page allocations
from N concurrent threads will lead to the same problem.
>> Multiple such allocations running concurrently can not only overuse
>> the memcg limit, but can lead to a global out of memory and,
>> in the worst case, cause the host to panic.
>>
>> Signed-off-by: Vasily Averin <vvs-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>
next prev parent reply other threads:[~2021-09-10 13:21 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-10 12:39 [PATCH memcg] memcg: prohibit unconditional exceeding the limit of dying tasks Vasily Averin
2021-09-10 13:04 ` Tetsuo Handa
2021-09-10 13:04 ` Tetsuo Handa
2021-09-10 13:20 ` Vasily Averin [this message]
2021-09-10 13:20 ` Vasily Averin
2021-09-10 14:55 ` Michal Hocko
2021-09-13 8:29 ` Vasily Averin
2021-09-13 8:29 ` Vasily Averin
2021-09-13 8:42 ` Michal Hocko
2021-09-13 8:42 ` Michal Hocko
2021-09-17 8:06 ` [PATCH mm] vmalloc: back off when the current task is OOM-killed Vasily Averin
2021-09-17 8:06 ` Vasily Averin
2021-09-19 23:31 ` Andrew Morton
2021-09-19 23:31 ` Andrew Morton
2021-09-20 1:22 ` Tetsuo Handa
2021-09-20 10:59 ` Vasily Averin
2021-09-20 10:59 ` Vasily Averin
2021-09-21 18:55 ` Andrew Morton
2021-09-22 6:18 ` Vasily Averin
2021-09-22 12:27 ` Michal Hocko
2021-09-22 12:27 ` Michal Hocko
2021-09-23 6:49 ` Vasily Averin
2021-09-23 6:49 ` Vasily Averin
2021-09-24 7:55 ` Michal Hocko
2021-09-24 7:55 ` Michal Hocko
2021-09-27 9:36 ` Vasily Averin
2021-09-27 9:36 ` Vasily Averin
2021-09-27 11:08 ` Michal Hocko
2021-09-27 11:08 ` Michal Hocko
2021-10-05 13:52 ` [PATCH mm v2] " Vasily Averin
2021-10-05 13:52 ` Vasily Averin
2021-10-05 14:00 ` Vasily Averin
2021-10-05 14:00 ` Vasily Averin
2021-10-07 10:47 ` Michal Hocko
2021-10-07 10:47 ` Michal Hocko
2021-10-07 19:55 ` Andrew Morton
2021-10-07 19:55 ` Andrew Morton
2021-09-10 13:07 ` [PATCH memcg] memcg: prohibit unconditional exceeding the limit of dying tasks Vasily Averin
2021-09-10 13:07 ` Vasily Averin
2021-09-13 7:51 ` Vasily Averin
2021-09-13 7:51 ` Vasily Averin
2021-09-13 8:39 ` Michal Hocko
2021-09-13 8:39 ` Michal Hocko
2021-09-13 9:37 ` Vasily Averin
2021-09-13 9:37 ` Vasily Averin
2021-09-13 10:10 ` Michal Hocko
2021-09-13 10:10 ` Michal Hocko
2021-09-13 8:53 ` Michal Hocko
2021-09-13 10:35 ` Vasily Averin
2021-09-13 10:35 ` Vasily Averin
2021-09-13 10:55 ` Michal Hocko
2021-09-13 10:55 ` Michal Hocko
2021-09-14 10:01 ` Vasily Averin
2021-09-14 10:01 ` Vasily Averin
2021-09-14 10:10 ` [PATCH memcg v2] " Vasily Averin
2021-09-14 10:10 ` Vasily Averin
2021-09-16 12:55 ` Michal Hocko
2021-09-16 12:55 ` Michal Hocko
2021-10-05 13:52 ` [PATCH memcg v3] " Vasily Averin
2021-10-05 13:52 ` Vasily Averin
2021-10-05 14:55 ` Michal Hocko
2021-10-05 14:55 ` Michal Hocko
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