From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D709EC433F5 for ; Wed, 20 Oct 2021 12:14:53 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 65DF86135E for ; Wed, 20 Oct 2021 12:14:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 65DF86135E 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 069A66B0072; Wed, 20 Oct 2021 08:14:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F34AB900002; Wed, 20 Oct 2021 08:14:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DFD736B0074; Wed, 20 Oct 2021 08:14:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0238.hostedemail.com [216.40.44.238]) by kanga.kvack.org (Postfix) with ESMTP id D0FAF6B0072 for ; Wed, 20 Oct 2021 08:14:52 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 918961EA19 for ; Wed, 20 Oct 2021 12:14:52 +0000 (UTC) X-FDA: 78716709624.20.8B91785 Received: from relay.sw.ru (relay.sw.ru [185.231.240.75]) by imf24.hostedemail.com (Postfix) with ESMTP id 9B5F7B0000A7 for ; Wed, 20 Oct 2021 12:14:49 +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=vKfgRv2zJEAoAS/QMp8Ojy3ytr5x5Kwda6HCzY+o9dY=; b=piFq4YJOVCzthmB9i6b NgU9AF9sxMXuXUshwNGUqc8UUt7jOsEyjWpz7crmMVUVecu7tMqQloOLCOHVflMvVpfVsy94enpjs 38aVbuXoEwvwIBMuS1SZMSPcfMeMLX5W7o9phEpjbW/bnnHEfFKouHYb3wZ6hDngTOJJSojLDVQ=; Received: from [172.29.1.17] by relay.sw.ru with esmtp (Exim 4.94.2) (envelope-from ) id 1mdAUa-006bCw-9o; Wed, 20 Oct 2021 15:14:48 +0300 From: Vasily Averin Subject: [PATCH memcg 3/3] memcg: handle memcg oom failures To: Michal Hocko , Johannes Weiner , Vladimir Davydov , Andrew Morton Cc: Roman Gushchin , Uladzislau Rezki , Vlastimil Babka , Shakeel Butt , Mel Gorman , Tetsuo Handa , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel@openvz.org References: Message-ID: Date: Wed, 20 Oct 2021 15:14:27 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 9B5F7B0000A7 X-Stat-Signature: knx3datbx8z4z7wuppcnysubg4h49uxr Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=virtuozzo.com header.s=relay header.b=piFq4YJO; spf=pass (imf24.hostedemail.com: domain of vvs@virtuozzo.com designates 185.231.240.75 as permitted sender) smtp.mailfrom=vvs@virtuozzo.com; dmarc=pass (policy=quarantine) header.from=virtuozzo.com X-HE-Tag: 1634732089-822772 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: mem_cgroup_oom() can fail if current task was marked unkillable and oom killer cannot find any victim. Currently we force memcg charge for such allocations, however it allow memcg-limited userspace task in to overuse assigned limits and potentially trigger the global memory shortage. Let's fail the memory charge in such cases. This failure should be somehow recognised in #PF context, so let's use current->memcg_in_oom == (struct mem_cgroup *)OOM_FAILED ToDo: what is the best way to notify pagefault_out_of_memory() about mem_cgroup_out_of_memory failure ? Signed-off-by: Vasily Averin --- mm/memcontrol.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 74a7379dbac1..b09d3c64f63f 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1810,11 +1810,21 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int mem_cgroup_oom_notify(memcg); mem_cgroup_unmark_under_oom(memcg); - if (mem_cgroup_out_of_memory(memcg, mask, order)) + if (mem_cgroup_out_of_memory(memcg, mask, order)) { ret = OOM_SUCCESS; - else + } else { ret = OOM_FAILED; - + /* + * In some rare cases mem_cgroup_out_of_memory() can return false. + * If it was called from #PF it forces handle_mm_fault() + * return VM_FAULT_OOM and executes pagefault_out_of_memory(). + * memcg_in_oom is set here to notify pagefault_out_of_memory() + * that it was a memcg-related failure and not allow to run + * global OOM. + */ + if (current->in_user_fault) + current->memcg_in_oom = (struct mem_cgroup *)ret; + } if (locked) mem_cgroup_oom_unlock(memcg); @@ -1848,6 +1858,15 @@ bool mem_cgroup_oom_synchronize(bool handle) if (!memcg) return false; + /* OOM is memcg, however out_of_memory() found no victim */ + if (memcg == (struct mem_cgroup *)OOM_FAILED) { + /* + * Should be called from pagefault_out_of_memory() only, + * where it is used to prevent false global OOM. + */ + current->memcg_in_oom = NULL; + return true; + } if (!handle) goto cleanup; @@ -2633,15 +2652,10 @@ 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) { passed_oom = true; nr_retries = MAX_RECLAIM_RETRIES; goto retry; - case OOM_FAILED: - goto force; - default: - goto nomem; } nomem: if (!(gfp_mask & __GFP_NOFAIL)) -- 2.32.0