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 X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 CAA66C433DB for ; Mon, 1 Mar 2021 12:16:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E15764E31 for ; Mon, 1 Mar 2021 12:16:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233731AbhCAMPy (ORCPT ); Mon, 1 Mar 2021 07:15:54 -0500 Received: from mx2.suse.de ([195.135.220.15]:40020 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232836AbhCAMPt (ORCPT ); Mon, 1 Mar 2021 07:15:49 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1614600903; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=KsLZ5Y4Ek3DADqn5FApSaLdnl0AlNSLh5qu8paQS2MA=; b=h51r4GoWiVVRKIf3kAFyA2IuXEPrk/XF/HNpzik1F6Zr3+5QYBzL5XY5rKVapq8i4wk3eb A9sEJX6VS1HLEnqxhXYzDIWFgafBF170CMwAXOHUPITdULmCIw6QM8isThOY/K7qkqhR4h 9XpzD5LMZMqJwGnvcnZhtusom/LyST8= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 3FB38AC24; Mon, 1 Mar 2021 12:15:03 +0000 (UTC) Date: Mon, 1 Mar 2021 13:15:02 +0100 From: Michal Hocko To: Yang Shi Cc: Johannes Weiner , Roman Gushchin , Shakeel Butt , Andrew Morton , Jonathan Corbet , Linux MM , Linux Kernel Mailing List Subject: Re: [PATCH] doc: memcontrol: add description for oom_kill Message-ID: References: <20210226021254.3980-1-shy828301@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 26-02-21 08:42:29, Yang Shi wrote: > On Thu, Feb 25, 2021 at 11:30 PM Michal Hocko wrote: > > > > On Thu 25-02-21 18:12:54, Yang Shi wrote: > > > When debugging an oom issue, I found the oom_kill counter of memcg is > > > confusing. At the first glance without checking document, I thought it > > > just counts for memcg oom, but it turns out it counts both global and > > > memcg oom. > > > > Yes, this is the case indeed. The point of the counter was to count oom > > victims from the memcg rather than matching that to the source of the > > oom. Rememeber that this could have been a memcg oom up in the > > hierarchy as well. Counting victims on the oom origin could be equally > > Yes, it is updated hierarchically on v2, but not on v1. I'm supposed > this is because v1 may work in non-hierarchcal mode? If this is the > only reason we may be able to remove this to get aligned with v2 since > non-hierarchal mode is no longer supported. I believe the reson is that v1 can have tasks in the intermediate (non-leaf) memcgs. So you wouldn't have a way to tell whether the oom kill has happened in such a memcg or somewhere down the hierarchy. -- Michal Hocko SUSE Labs