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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4509C4332F for ; Thu, 15 Dec 2022 18:18:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230059AbiLOSSM (ORCPT ); Thu, 15 Dec 2022 13:18:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229929AbiLOSSI (ORCPT ); Thu, 15 Dec 2022 13:18:08 -0500 Received: from mail-pj1-x104a.google.com (mail-pj1-x104a.google.com [IPv6:2607:f8b0:4864:20::104a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1DEA547314 for ; Thu, 15 Dec 2022 10:18:08 -0800 (PST) Received: by mail-pj1-x104a.google.com with SMTP id md9-20020a17090b23c900b00218fa3308a9so6172335pjb.8 for ; Thu, 15 Dec 2022 10:18:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=2zYd8pjM+h9ZXywEkUSyHttrKqV0HoqJqNzSbDuyoPU=; b=QEecPBb/5PjJcWOAy10Z7ojCqt+SK1vQNF17KM+NZE4XAeHuudIMyBAP5bZoCg4SfS zq8wQjHHa0IE8Y7IHsQVhfTw2IEXrOqTCQzZYXUOT4QNgJlewLWLijpZlDp56GIU4CAH Z5+Yk474Fhto01x4AIjhTig4Hr0kw27aL2RNBhzM27TUvoiYBxWXmbgk4Os4G7SVibJl Yiy14r5WEKWK7TLITUwQ6PdLDah3yXbJb4EYyB42AFzq/FbZAre5xEBJrlO69bIL9B6F erJ5Nj7adcQ25emu3FWWjJjAI+wWAAs0e29AR3ra2OiHhxHXKUVhmu7G23HHnbNxAXBC ADnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=2zYd8pjM+h9ZXywEkUSyHttrKqV0HoqJqNzSbDuyoPU=; b=p3RYVLwKgYyUKOtFNuzjAhPqMf7QKXfyJn00KN2BTyMZ8ZVwGU+mGIEj+DE5EHk7Ap ery+aSbRM4xFpUkX9+kplPzhS8w0fe3xjEWRf3FbfLMLuOsI+bklkONxXQph+RN60wQa PAD48LXL+nIREZnAmAHNRo6l3gIW4oYzgBwIALwh60xS723srwBY+09E6tHBLOQ1YPYe Q9Mi/uQloYamE3J3N5Vdar1Hw9c7ZX0UAKQS0a9MPngvbgtnAdaUpE4cGbJ7lEcBGanM DBzzwi8Aw8RnmV+1Meu/qn9vGfuBhxHo+NC4Tao0YFOu+B3hvupvSlQTj9kQ5jPHWi9D ZI4g== X-Gm-Message-State: ANoB5pmZEb3bFltHDKNS2n4Q5Vw3eBZxCJnE4dmOL6mkJdGUP4X8IHdb 4uaMEByNHNplNbnR3tLopwaEN+s/HrbEwg== X-Google-Smtp-Source: AA0mqf5jnzmQSpwE0GvclzeEATSymmXibKDumwzmrbSfLhBcsjQyxZITSBd/SenLherKv8wSZEHbd0GBjsUZSA== X-Received: from shakeelb.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:262e]) (user=shakeelb job=sendgmr) by 2002:aa7:9acc:0:b0:577:81cb:4761 with SMTP id x12-20020aa79acc000000b0057781cb4761mr8441913pfp.46.1671128287622; Thu, 15 Dec 2022 10:18:07 -0800 (PST) Date: Thu, 15 Dec 2022 18:18:03 +0000 In-Reply-To: <20221215091907.763801-1-haifeng.xu@shopee.com> Mime-Version: 1.0 References: <20221215091907.763801-1-haifeng.xu@shopee.com> Message-ID: <20221215181803.ome46pkh6g7qu3t4@google.com> Subject: Re: [PATCH] mm/memcontrol: Skip root memcg in memcg_memory_event_mm From: Shakeel Butt To: Haifeng Xu Cc: akpm@linux-foundation.org, roman.gushchin@linux.dev, songmuchun@bytedance.com, hannes@cmpxchg.org, vbabka@suse.cz, willy@infradead.org, vasily.averin@linux.dev, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 15, 2022 at 09:19:07AM +0000, Haifeng Xu wrote: > The memory events aren't supported on root cgroup, so there is no need > to account MEMCG_OOM_KILL on root memcg. > Can you explain the scenario where this is happening and causing issue for you? > Signed-off-by: Haifeng Xu > --- > include/linux/memcontrol.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index 567f12323f55..09f75161a3bc 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -1142,7 +1142,7 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm, > > rcu_read_lock(); > memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); > - if (likely(memcg)) > + if (likely(memcg && !mem_cgroup_is_root(memcg))) Even if we need this additional check, this is not the right place. > memcg_memory_event(memcg, event); > rcu_read_unlock(); > } > -- > 2.25.1 >