From patchwork Fri Sep 10 12:39:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vasily Averin X-Patchwork-Id: 12485101 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AAEBFC433EF for ; Fri, 10 Sep 2021 12:39:35 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1807E60E94 for ; Fri, 10 Sep 2021 12:39:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1807E60E94 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=virtuozzo.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 41DD66B0071; Fri, 10 Sep 2021 08:39:34 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3CD1B900002; Fri, 10 Sep 2021 08:39:34 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2BB9A6B0073; Fri, 10 Sep 2021 08:39:34 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0077.hostedemail.com [216.40.44.77]) by kanga.kvack.org (Postfix) with ESMTP id 1CB5B6B0071 for ; Fri, 10 Sep 2021 08:39:34 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id CA5448249980 for ; Fri, 10 Sep 2021 12:39:33 +0000 (UTC) X-FDA: 78571619826.06.A4163EA Received: from relay.sw.ru (relay.sw.ru [185.231.240.75]) by imf30.hostedemail.com (Postfix) with ESMTP id 385F2E0016B0 for ; Fri, 10 Sep 2021 12:39:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=Content-Type:MIME-Version:Date:Message-ID:Subject :From; bh=uX26lHcEDEEEDF7IL0qVhsYLGM0hoO2eLUbDvhlRdtw=; b=h43ebg4SmVjbGOYRO+L BoV3O7RDbVzBij44DK/UBOq2B5Qe1i3YEmSZOZEX5mdSkqGDsIpSnGXB47D8BZ3LeITSlIUNjYOwg yURpuDjMmDFXE8CGx0Lau0ZXHjf9L8LPvclhzutmdAC5lkTKuE6PfjCHUepjuhUQdw9t+y+iT0Q=; Received: from [10.93.0.56] by relay.sw.ru with esmtp (Exim 4.94.2) (envelope-from ) id 1mOfoW-001Unm-Lj; Fri, 10 Sep 2021 15:39:28 +0300 From: Vasily Averin Subject: [PATCH memcg] memcg: prohibit unconditional exceeding the limit of dying tasks To: Michal Hocko , Johannes Weiner , Vladimir Davydov , Andrew Morton , Tetsuo Handa Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Message-ID: <5b06a490-55bc-a6a0-6c85-690254f86fad@virtuozzo.com> Date: Fri, 10 Sep 2021 15:39:28 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 Content-Language: en-US X-Stat-Signature: ysrd4fpthptbnjfqddyptm5unf6djk3c Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=virtuozzo.com header.s=relay header.b=h43ebg4S; dmarc=pass (policy=quarantine) header.from=virtuozzo.com; spf=pass (imf30.hostedemail.com: domain of vvs@virtuozzo.com designates 185.231.240.75 as permitted sender) smtp.mailfrom=vvs@virtuozzo.com X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 385F2E0016B0 X-HE-Tag: 1631277573-358394 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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. Signed-off-by: Vasily Averin --- 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;