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From: Andrew Morton <akpm@linux-foundation.org>
To: Vasily Averin <vvs@virtuozzo.com>
Cc: Michal Hocko <mhocko@kernel.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Vladimir Davydov <vdavydov.dev@gmail.com>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	cgroups@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, kernel@openvz.org
Subject: Re: [PATCH mm v2] vmalloc: back off when the current task is OOM-killed
Date: Thu, 7 Oct 2021 12:55:41 -0700	[thread overview]
Message-ID: <20211007125541.db0f3ff2bdbd8fa7dc1db03d@linux-foundation.org> (raw)
In-Reply-To: <83efc664-3a65-2adb-d7c4-2885784cf109@virtuozzo.com>

On Tue, 5 Oct 2021 16:52:40 +0300 Vasily Averin <vvs@virtuozzo.com> wrote:

> Huge vmalloc allocation on heavy loaded node can lead to a global
> memory shortage. Task called vmalloc can have worst badness and
> be selected by OOM-killer, however taken fatal signal does not
> interrupt allocation cycle. Vmalloc repeat page allocaions
> again and again, exacerbating the crisis and consuming the memory
> freed up by another killed tasks.
> 
> After a successful completion of the allocation procedure, a fatal
> signal will be processed and task will be destroyed finally.
> However it may not release the consumed memory, since the allocated
> object may have a lifetime unrelated to the completed task.
> In the worst case, this can lead to the host will panic
> due to "Out of memory and no killable processes..."
> 
> This patch allows OOM-killer to break vmalloc cycle, makes OOM more
> effective and avoid host panic. It does not check oom condition directly,
> however, and breaks page allocation cycle when fatal signal was received.
> 
> This may trigger some hidden problems, when caller does not handle
> vmalloc failures, or when rollaback after failed vmalloc calls own
> vmallocs inside. However all of these scenarios are incorrect:
> vmalloc does not guarantee successful allocation, it has never been called
> with __GFP_NOFAIL and threfore either should not be used for any rollbacks
> or should handle such errors correctly and not lead to critical
> failures.
> 

This needed a little rework due to
https://lkml.kernel.org/r/20210928121040.2547407-1-chenwandun@huawei.com.
Please check and retest sometime?

--- a/mm/vmalloc.c~vmalloc-back-off-when-the-current-task-is-oom-killed
+++ a/mm/vmalloc.c
@@ -2887,6 +2887,9 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
 
 	page = NULL;
 	while (nr_allocated < nr_pages) {
+		if (fatal_signal_pending(current))
+			break;
+
 		if (nid == NUMA_NO_NODE)
 			page = alloc_pages(gfp, order);
 		else
_



  parent reply	other threads:[~2021-10-07 19:55 UTC|newest]

Thread overview: 34+ 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 13:20   ` Vasily Averin
2021-09-10 14:55     ` Michal Hocko
2021-09-13  8:29       ` Vasily Averin
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
2021-09-19 23:31             ` Andrew Morton
2021-09-20  1:22               ` Tetsuo Handa
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
2021-09-23  6:49               ` Vasily Averin
2021-09-24  7:55                 ` Michal Hocko
2021-09-27  9:36                   ` Vasily Averin
2021-09-27 11:08                     ` Michal Hocko
2021-10-05 13:52                       ` [PATCH mm v2] " Vasily Averin
2021-10-05 14:00                         ` Vasily Averin
2021-10-07 10:47                         ` Michal Hocko
2021-10-07 19:55                         ` Andrew Morton [this message]
2021-09-10 13:07 ` [PATCH memcg] memcg: prohibit unconditional exceeding the limit of dying tasks Vasily Averin
2021-09-13  7:51 ` Vasily Averin
2021-09-13  8:39   ` Michal Hocko
2021-09-13  9:37     ` Vasily Averin
2021-09-13 10:10       ` Michal Hocko
2021-09-13  8:53 ` Michal Hocko
2021-09-13 10:35   ` Vasily Averin
2021-09-13 10:55     ` Michal Hocko
2021-09-14 10:01       ` Vasily Averin
2021-09-14 10:10         ` [PATCH memcg v2] " Vasily Averin
2021-09-16 12:55           ` Michal Hocko
2021-10-05 13:52             ` [PATCH memcg v3] " Vasily Averin
2021-10-05 14:55               ` Michal Hocko

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