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 8401AC433F5 for ; Sat, 23 Oct 2021 13:19:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AF8360FDA for ; Sat, 23 Oct 2021 13:19:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231331AbhJWNWO (ORCPT ); Sat, 23 Oct 2021 09:22:14 -0400 Received: from relay.sw.ru ([185.231.240.75]:56520 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230476AbhJWNWK (ORCPT ); Sat, 23 Oct 2021 09:22:10 -0400 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=DX974UacjLa5B8lLKBDGYPr0ueCh9q/0PqGjv1EsfYw=; b=Qqybfz2pU+1i6qU1cl+ n1/Ryq+c0MgrgrTKsIr+zAZ1FcRW64LaQxmTNiUdj22yblJrcLgq8hzUJ6nLnvPsVJAJt72LMbhfw +odGC3WfLkhI4RMty6rnyhpI2Nrq4jD4t5JdjGwt3X6OlFXMtqtk18+4yM2yEuiOzojbz5hH3hs=; Received: from [172.29.1.17] by relay.sw.ru with esmtp (Exim 4.94.2) (envelope-from ) id 1meGw9-006vQI-Bm; Sat, 23 Oct 2021 16:19:49 +0300 From: Vasily Averin Subject: [PATCH memcg v3 1/3] mm, oom: pagefault_out_of_memory: don't force global OOM for dying tasks 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: <0828a149-786e-7c06-b70a-52d086818ea3@virtuozzo.com> Date: Sat, 23 Oct 2021 16:19:28 +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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Any allocation failure during the #PF path will return with VM_FAULT_OOM which in turn results in pagefault_out_of_memory which in own turn executes out_out_memory() and can kill a random task. An allocation might fail when the current task is the oom victim and there are no memory reserves left. The OOM killer is already handled at the page allocator level for the global OOM and at the charging level for the memcg one. Both have much more information about the scope of allocation/charge request. This means that either the OOM killer has been invoked properly and didn't lead to the allocation success or it has been skipped because it couldn't have been invoked. In both cases triggering it from here is pointless and even harmful. It makes much more sense to let the killed task die rather than to wake up an eternally hungry oom-killer and send him to choose a fatter victim for breakfast. Suggested-by: Michal Hocko Signed-off-by: Vasily Averin --- mm/oom_kill.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 831340e7ad8b..1deef8c7a71b 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -1137,6 +1137,9 @@ void pagefault_out_of_memory(void) if (mem_cgroup_oom_synchronize(true)) return; + if (fatal_signal_pending(current)) + return; + if (!mutex_trylock(&oom_lock)) return; out_of_memory(&oc); -- 2.32.0