From: Vasily Averin <vvs@virtuozzo.com>
To: Michal Hocko <mhocko@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH memcg] memcg: prohibit unconditional exceeding the limit of dying tasks
Date: Fri, 10 Sep 2021 16:07:08 +0300 [thread overview]
Message-ID: <4d61c7fd-ee33-4dc9-0ab1-8eca4d3297b0@virtuozzo.com> (raw)
In-Reply-To: <5b06a490-55bc-a6a0-6c85-690254f86fad@virtuozzo.com>
On 9/10/21 3:39 PM, 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.
> 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.
btw should_force_charge() function name become wrong with this.
Is it make sense to replace it by something like is_task_dying() ?
> Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
> ---
> mm/memcontrol.c | 23 +++++------------------
> 1 file changed, 5 insertions(+), 18 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 389b5766e74f..67195fcfbddf 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1834,6 +1834,9 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int
> return OOM_ASYNC;
> }
>
> + if (should_force_charge())
> + return OOM_SKIPPED;
> +
> mem_cgroup_mark_under_oom(memcg);
>
> locked = mem_cgroup_oom_trylock(memcg);
> @@ -2622,15 +2625,6 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
> if (gfp_mask & __GFP_ATOMIC)
> goto force;
>
> - /*
> - * Unlike in global OOM situations, memcg is not in a physical
> - * memory shortage. Allow dying and OOM-killed tasks to
> - * bypass the last charges so that they can exit quickly and
> - * free their memory.
> - */
> - if (unlikely(should_force_charge()))
> - goto force;
> -
> /*
> * Prevent unbounded recursion when reclaim operations need to
> * allocate memory. This might exceed the limits temporarily,
> @@ -2688,9 +2682,6 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
> if (gfp_mask & __GFP_RETRY_MAYFAIL)
> goto nomem;
>
> - if (fatal_signal_pending(current))
> - goto force;
> -
> /*
> * keep retrying as long as the memcg oom killer is able to make
> * a forward progress or bypass the charge if the oom killer
> @@ -2698,15 +2689,11 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
> */
> oom_status = mem_cgroup_oom(mem_over_limit, gfp_mask,
> get_order(nr_pages * PAGE_SIZE));
> - switch (oom_status) {
> - case OOM_SUCCESS:
> + if (oom_status == OOM_SUCCESS) {
> nr_retries = MAX_RECLAIM_RETRIES;
> goto retry;
> - case OOM_FAILED:
> + } else if (oom_status == OOM_FAILED)
> goto force;
> - default:
> - goto nomem;
> - }
> nomem:
> if (!(gfp_mask & __GFP_NOFAIL))
> return -ENOMEM;
>
next prev parent reply other threads:[~2021-09-10 13:07 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
2021-09-10 13:07 ` Vasily Averin [this message]
2021-09-13 7:51 ` [PATCH memcg] memcg: prohibit unconditional exceeding the limit of dying tasks 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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