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=-6.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 F3DFDC2BBC7 for ; Tue, 14 Apr 2020 00:36:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B5F8A2087E for ; Tue, 14 Apr 2020 00:36:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="lhDUuiON" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B5F8A2087E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4E6578E0003; Mon, 13 Apr 2020 20:36:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4969C8E0001; Mon, 13 Apr 2020 20:36:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 385218E0003; Mon, 13 Apr 2020 20:36:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0200.hostedemail.com [216.40.44.200]) by kanga.kvack.org (Postfix) with ESMTP id 245C88E0001 for ; Mon, 13 Apr 2020 20:36:03 -0400 (EDT) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id CD9208245578 for ; Tue, 14 Apr 2020 00:36:02 +0000 (UTC) X-FDA: 76704593364.19.shoe22_51da0d1e1e113 X-HE-Tag: shoe22_51da0d1e1e113 X-Filterd-Recvd-Size: 5741 Received: from mail-io1-f66.google.com (mail-io1-f66.google.com [209.85.166.66]) by imf48.hostedemail.com (Postfix) with ESMTP for ; Tue, 14 Apr 2020 00:36:02 +0000 (UTC) Received: by mail-io1-f66.google.com with SMTP id n10so11448025iom.3 for ; Mon, 13 Apr 2020 17:36:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=OEbRxfVNnC3F8F9BB/v68cNb4um6sbV0P/8UYr2B5QE=; b=lhDUuiONwPgVb0UFhv85NDZzitWYfs1GBStt89GKOEfGT/VCS/+FdcAEVLdpk27YJY Oo39lmKt0T7T0VoZU3mX5kiSdLhwPMVLgwnNf7+2RfO/0j8ecnPcun/spcosu3FjTEmS 13UstQmWHrsRrrj7/1iAU9wKGS/BHJSQ6JagoBU3znwq4rnC8f72K+bNOJ/VyvIt/wi2 8TuLiLLShhcjuJGMeyLW9CWFDk5APBmzoUdSiuxMf3qMuE+i5pejVhtKC1IsizybSS3l eySm/kMRdyNGG/UL63bmskX+JZKjrI6OoGZrW4ge5SDfnKj9ByFwpgZtgFTK6eNf6Ucc BuAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=OEbRxfVNnC3F8F9BB/v68cNb4um6sbV0P/8UYr2B5QE=; b=KIZj1L6GFIHZvkY65WR1ynNWWNn4IfR1b7WaOPgw9bIEjpv2aykOEBIXkhNFe0Hc36 8d9hsFlavbDTAKIEX6kgfVzVP6PpolOraZ5ZZxJ03r9vOsFBPNLKeCuuVNiM3Rx/7qnh OzVFMgK7rIZFWZdWbksz1bK4aNgQMmxOIT8oIZwmZ6A2zRpd6Sf2HEHUmgkpFt8GiqkF msPueFJ4uJZ1FQKckBo1NWmyNoxMZXPOqfOxaYXatdgD1scaBKtmw0+osJe213M/OqCK K4Qnvlubx7LOo3CMV3KYro5W3sM6Db3Uvt/EvuQAb7fVUN8sFI1p2661mkjhdtY1flKR k4vA== X-Gm-Message-State: AGi0PuaJhvrvEXs+lkVljMMj6X69Gk0weuZUAPML4KDleOOErv4U0hQA 5iPE0KJrR5gm06XjmIcbP9W0ce03iIvLiW4qTPI= X-Google-Smtp-Source: APiQypL3aRsV/4MioL76gsoXTg/IiONe1cFdzbKLhzD+sRH5wIsVSzxTNslaZSK1ezeG4Ek+lRwhKUqWzYBlWQoOmnM= X-Received: by 2002:a05:6602:199:: with SMTP id m25mr18921125ioo.13.1586824561716; Mon, 13 Apr 2020 17:36:01 -0700 (PDT) MIME-Version: 1.0 References: <20200412140427.6732-1-laoar.shao@gmail.com> In-Reply-To: From: Yafang Shao Date: Tue, 14 Apr 2020 08:35:25 +0800 Message-ID: Subject: Re: [PATCH] mm, memcg: fix inconsistent oom event behavior To: Shakeel Butt Cc: Chris Down , Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , Linux MM , stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" 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: On Tue, Apr 14, 2020 at 1:06 AM Shakeel Butt wrote: > > On Sun, Apr 12, 2020 at 7:04 AM Yafang Shao wrote: > > > > A recent commit 9852ae3fe529 ("mm, memcg: consider subtrees in > > memory.events") changes the behavior of memcg events, which will > > consider subtrees in memory.events. But oom_kill event is a special one > > as it is used in both cgroup1 and cgroup2. In cgroup1, it is displayed > > in memory.oom_control. The file memory.oom_control is in both root memcg > > and non root memcg, that is different with memory.event as it only in > > non-root memcg. That commit is okay for cgroup2, but it is not okay for > > cgroup1 as it will cause inconsistent behavior between root memcg and > > non-root memcg. > > I still couldn't understand the cgroup v1's root vs non_root behavior > change. The behavior change I see is the hierarchical one i.e. > MEMCG_OOM_KILL event in the descendant will cause the notification and > count increment in the ancestors even in the cgroup v1. For the non-root memcg, its memory.oom_control(oom_kill) includes its descendants' oom_kill, but for root memcg, it doesn't include its descendants' oom_kill. That means, memory.oom_control(oom_kill) has different meanings in different memcgs. That is inconsistent. [snip] > I suppose we > don't want that behavior change in v1. > That is another topic. I think this feature is welcomed to cgroup1, if we can fully support it, for example by adding memory.events.local into cgroup1 as well, but as far as I know the cgroup1 is frozen. > > Let's recover the original behavior for cgroup1. > > > > Fixes: 9852ae3fe529 ("mm, memcg: consider subtrees in memory.events") > > Cc: Chris Down > > Cc: Johannes Weiner > > Cc: Shakeel Butt > > Cc: stable@vger.kernel.org > > Signed-off-by: Yafang Shao > > --- > > include/linux/memcontrol.h | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > > index 8c340e6b347f..a0ae080a67d1 100644 > > --- a/include/linux/memcontrol.h > > +++ b/include/linux/memcontrol.h > > @@ -798,7 +798,8 @@ static inline void memcg_memory_event(struct mem_cgroup *memcg, > > atomic_long_inc(&memcg->memory_events[event]); > > cgroup_file_notify(&memcg->events_file); > > > > - if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS) > > + if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS || > > + !cgroup_subsys_on_dfl(memory_cgrp_subsys)) > > break; > > } while ((memcg = parent_mem_cgroup(memcg)) && > > !mem_cgroup_is_root(memcg)); > > -- > > 2.18.2 > > Thanks Yafang