From: Michal Hocko <mhocko@suse.com>
To: Vasily Averin <vvs@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Roman Gushchin <guro@fb.com>, Uladzislau Rezki <urezki@gmail.com>,
Vlastimil Babka <vbabka@suse.cz>,
Shakeel Butt <shakeelb@google.com>,
Mel Gorman <mgorman@techsingularity.net>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, kernel@openvz.org
Subject: Re: [PATCH memcg 0/1] false global OOM triggered by memcg-limited task
Date: Mon, 18 Oct 2021 13:53:43 +0200 [thread overview]
Message-ID: <YW1gRz0rTkJrvc4L@dhcp22.suse.cz> (raw)
In-Reply-To: <6b751abe-aa52-d1d8-2631-ec471975cc3a@virtuozzo.com>
On Mon 18-10-21 13:05:35, Vasily Averin wrote:
> On 18.10.2021 12:04, Michal Hocko wrote:
> > On Mon 18-10-21 11:13:52, Vasily Averin wrote:
> > [...]
> >> How could this happen?
> >>
> >> User-space task inside the memcg-limited container generated a page fault,
> >> its handler do_user_addr_fault() called handle_mm_fault which could not
> >> allocate the page due to exceeding the memcg limit and returned VM_FAULT_OOM.
> >> Then do_user_addr_fault() called pagefault_out_of_memory() which executed
> >> out_of_memory() without set of memcg.
> >>
> >> Partially this problem depends on one of my recent patches, disabled unlimited
> >> memory allocation for dying tasks. However I think the problem can happen
> >> on non-killed tasks too, for example because of kmem limit.
> >
> > Could you be more specific on how this can happen without your patch? I
> > have to say I haven't realized this side effect when discussing it.
>
> We can reach obj_cgroup_charge_pages() for example via
>
> do_user_addr_fault
> handle_mm_fault
> __handle_mm_fault
> p4d_alloc
> __p4d_alloc
> p4d_alloc_one
> get_zeroed_page
> __get_free_pages
> alloc_pages
> __alloc_pages
> __memcg_kmem_charge_page
> obj_cgroup_charge_pages
>
> Here we call try_charge_memcg() that return success and approve the allocation,
> however then we hit into kmem limit and fail the allocation.
Just to make sure I understand this would be for the v1 kmem explicit
limit, correct?
> If required I can try to search how try_charge_memcg() can reject page allocation
> of non-dying task too.
Yes.
> > I will be honest that I am not really happy about pagefault_out_of_memory.
> > I have tried to remove it in the past. Without much success back then,
> > unfortunately[1].
> > Maybe we should get rid of it finally. The OOM is always triggered from
> > inside the allocator where we have much more infromation about the
> > allocation context. A first step would be to skip pagefault_out_of_memory
> > for killed or exiting processes.
>
> I like this idea, however it may be not enough, at least in scenario described above.
I original patch has removed the oom killer completely.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-10-18 11:53 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-18 8:13 [PATCH memcg 0/1] false global OOM triggered by memcg-limited task Vasily Averin
2021-10-18 9:04 ` Michal Hocko
2021-10-18 10:05 ` Vasily Averin
2021-10-18 10:12 ` Vasily Averin
2021-10-18 11:53 ` Michal Hocko [this message]
[not found] ` <27dc0c49-a0d6-875b-49c6-0ef5c0cc3ac8@virtuozzo.com>
2021-10-18 12:27 ` Michal Hocko
2021-10-18 15:07 ` Shakeel Butt
2021-10-18 16:51 ` Michal Hocko
2021-10-18 17:13 ` Shakeel Butt
2021-10-18 18:52 ` Vasily Averin
2021-10-18 19:18 ` Vasily Averin
2021-10-19 5:34 ` Shakeel Butt
2021-10-19 5:33 ` Shakeel Butt
2021-10-19 6:42 ` Vasily Averin
2021-10-19 8:47 ` Michal Hocko
2021-10-19 6:30 ` Vasily Averin
2021-10-19 8:49 ` Michal Hocko
2021-10-19 10:30 ` Vasily Averin
2021-10-19 11:54 ` Michal Hocko
2021-10-19 12:04 ` Michal Hocko
2021-10-19 13:26 ` Vasily Averin
2021-10-19 14:13 ` Michal Hocko
2021-10-19 14:19 ` Michal Hocko
2021-10-19 19:09 ` Vasily Averin
2021-10-20 8:07 ` [PATCH memcg v4] memcg: prohibit unconditional exceeding the limit of dying tasks Vasily Averin
2021-10-20 8:43 ` Michal Hocko
2021-10-20 12:11 ` [PATCH memcg RFC 0/3] " Vasily Averin
[not found] ` <cover.1634730787.git.vvs@virtuozzo.com>
2021-10-20 12:12 ` [PATCH memcg 1/3] mm: do not firce global OOM from inside " Vasily Averin
2021-10-20 12:33 ` Michal Hocko
2021-10-20 13:52 ` Vasily Averin
2021-10-20 12:13 ` [PATCH memcg 2/3] memcg: remove charge forcinig for " Vasily Averin
2021-10-20 12:41 ` Michal Hocko
2021-10-20 14:21 ` Vasily Averin
2021-10-20 14:57 ` Michal Hocko
2021-10-20 15:20 ` Tetsuo Handa
2021-10-21 10:03 ` Michal Hocko
2021-10-20 12:14 ` [PATCH memcg 3/3] memcg: handle memcg oom failures Vasily Averin
2021-10-20 13:02 ` Michal Hocko
2021-10-20 15:46 ` Vasily Averin
2021-10-21 11:49 ` Michal Hocko
2021-10-21 15:05 ` Vasily Averin
2021-10-21 16:47 ` Michal Hocko
2021-10-22 8:10 ` [PATCH memcg v2 0/2] memcg: prohibit unconditional exceeding the limit of dying tasks Vasily Averin
[not found] ` <cover.1634889066.git.vvs@virtuozzo.com>
2021-10-22 8:11 ` [PATCH memcg v2 1/2] mm, oom: do not trigger out_of_memory from the #PF Vasily Averin
2021-10-22 8:55 ` Michal Hocko
2021-10-22 8:11 ` [PATCH memcg v2 2/2] memcg: prohibit unconditional exceeding the limit of dying tasks Vasily Averin
2021-10-22 9:10 ` Michal Hocko
2021-10-23 13:18 ` [PATCH memcg v3 0/3] " Vasily Averin
[not found] ` <cover.1634994605.git.vvs@virtuozzo.com>
2021-10-23 13:19 ` [PATCH memcg v3 1/3] mm, oom: pagefault_out_of_memory: don't force global OOM for " Vasily Averin
2021-10-25 9:27 ` Michal Hocko
2021-10-23 13:20 ` [PATCH memcg v3 2/3] mm, oom: do not trigger out_of_memory from the #PF Vasily Averin
2021-10-23 15:01 ` Tetsuo Handa
2021-10-23 19:15 ` Vasily Averin
2021-10-25 8:04 ` Michal Hocko
2021-10-26 13:56 ` Tetsuo Handa
2021-10-26 14:07 ` Michal Hocko
2021-10-25 9:34 ` Michal Hocko
2021-10-23 13:20 ` [PATCH memcg v3 3/3] memcg: prohibit unconditional exceeding the limit of dying tasks Vasily Averin
2021-10-25 9:36 ` Michal Hocko
2021-10-27 22:36 ` Andrew Morton
2021-10-28 7:22 ` Vasily Averin
2021-10-29 7:46 ` Greg Kroah-Hartman
2021-10-29 7:58 ` Michal Hocko
2021-10-21 8:03 ` [PATCH memcg 0/1] false global OOM triggered by memcg-limited task Vasily Averin
2021-10-21 11:49 ` Michal Hocko
2021-10-21 13:24 ` Vasily Averin
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