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=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 82536C433E0 for ; Fri, 5 Feb 2021 09:55:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B2A1064FC8 for ; Fri, 5 Feb 2021 09:55:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B2A1064FC8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=bytedance.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0D7A96B0005; Fri, 5 Feb 2021 04:55:50 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0617D6B006C; Fri, 5 Feb 2021 04:55:49 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E1C936B006E; Fri, 5 Feb 2021 04:55:49 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0128.hostedemail.com [216.40.44.128]) by kanga.kvack.org (Postfix) with ESMTP id C65D56B0005 for ; Fri, 5 Feb 2021 04:55:49 -0500 (EST) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 967ABAC17 for ; Fri, 5 Feb 2021 09:55:49 +0000 (UTC) X-FDA: 77783757618.21.legs30_470b87e275e3 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin21.hostedemail.com (Postfix) with ESMTP id 7681C1804D8AE for ; Fri, 5 Feb 2021 09:55:49 +0000 (UTC) X-HE-Tag: legs30_470b87e275e3 X-Filterd-Recvd-Size: 6130 Received: from mail-pj1-f41.google.com (mail-pj1-f41.google.com [209.85.216.41]) by imf14.hostedemail.com (Postfix) with ESMTP for ; Fri, 5 Feb 2021 09:55:48 +0000 (UTC) Received: by mail-pj1-f41.google.com with SMTP id my11so6437190pjb.1 for ; Fri, 05 Feb 2021 01:55:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ieUooMRLCXwYSeJ9XkKaTLtXyvbKzpUTDthbUyzSnHk=; b=n2VvabbtalXtuWpwbmHrFHJWDgt6VXAhGhwbdn3LLJHGWqrhuY1N1pvOqWjuurIqKV Wt3gfI4ENRh3m8WarXLdQHKsglwcB4jQsQTM1FI2RSigJffepY0Wy71+tM3V3y4RtSSB QTEvWtWx/bCX+wZeWnYBnFl6sOklG98bYXTY+nRt2JTdu7ep0btUjMsqM8vHPIE8xV2S zPjlJw9l0v6K132xILNn5kzQSUkq1lRERXtvOqA0aviqyozZSAcyU6EafIjtfPscn7Xj 1M1ol+Alt9uIyVWhKELcKRAaY4CmATJTQRaZlrqnPDYlaEZCc6SKLOiJF0BeWF3ngw3K kCEQ== 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=ieUooMRLCXwYSeJ9XkKaTLtXyvbKzpUTDthbUyzSnHk=; b=km/QQN2hXWqvCDy+id4qNYfugKZ30DZQJrfLkQ0TUopw8aMibdVqnb/j6FBKLrkorw eYHmcR+qoR7427om/aNVSjotUPtOFAEo2ALS35qfYEOm4lUhTIINSdHxSQOprP8kplWx qhf2HHGN2d+colEknw/QECDTMGb6EXCP9Qvr309g1UyMcb6TJGuPLyBlVOQmeGiiuM66 kA9Ov3qF12csutCrD9PwaiU/8mnL3mzBokqvIbOmT2f4Yd5f+/rgCjqehLAJMnPxTQau 7ehfVQ9+YR5cJsp9Yk9baX9BS4SLOKq8T/hZdJUJAfoBTYRz+yYK1N7ocpjhR0OXIEYT 0r8Q== X-Gm-Message-State: AOAM532HtvauFThperzG2fBPKtqR78+wCCjOCmhtKSQJLdiYZJLByNwy pxBXytd5I9nAgrDdhD9tGMe6QKmoLaJPhDDARWuVQg== X-Google-Smtp-Source: ABdhPJxK1r8J0nG6jTXmBfGsdJeNahQkfxe4JrZpdvLIp4t6/1mUBUVkIh/l3tNLmHc08ZQ1RyE72w6OxKnOVFPQonM= X-Received: by 2002:a17:902:9341:b029:e1:7b4e:57a8 with SMTP id g1-20020a1709029341b02900e17b4e57a8mr3346497plp.34.1612518947675; Fri, 05 Feb 2021 01:55:47 -0800 (PST) MIME-Version: 1.0 References: <20210205062310.74268-1-songmuchun@bytedance.com> In-Reply-To: From: Muchun Song Date: Fri, 5 Feb 2021 17:55:10 +0800 Message-ID: Subject: Re: [External] Re: [PATCH] mm: memcontrol: fix missing wakeup oom task To: Michal Hocko Cc: Johannes Weiner , Vladimir Davydov , Andrew Morton , Cgroups , Linux Memory Management List , LKML 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 Fri, Feb 5, 2021 at 4:24 PM Michal Hocko wrote: > > On Fri 05-02-21 14:23:10, Muchun Song wrote: > > We call memcg_oom_recover() in the uncharge_batch() to wakeup OOM task > > when page uncharged, but for the slab pages, we do not do this when page > > uncharged. > > How does the patch deal with this? When we uncharge a slab page via __memcg_kmem_uncharge, actually, this path forgets to do this for us compared to uncharge_batch(). Right? > > > When we drain per cpu stock, we also should do this. > > Can we have anything the per-cpu stock while entering the OOM path. IIRC > we do drain all cpus before entering oom path. You are right. I did not notice this. Thank you. > > > The memcg_oom_recover() is small, so make it inline. > > Does this lead to any code generation improvements? I would expect > compiler to be clever enough to inline static functions if that pays > off. If yes make this a patch on its own. I have disassembled the code, I see memcg_oom_recover is not inline. Maybe because memcg_oom_recover has a lot of callers. Just guess. (gdb) disassemble uncharge_batch [...] 0xffffffff81341c73 <+227>: callq 0xffffffff8133c420 0xffffffff81341c78 <+232>: jmpq 0xffffffff81341bc0 0xffffffff81341c7d <+237>: callq 0xffffffff8133e2c0 > > > And the parameter > > of memcg cannot be NULL, so remove the check. > > 2bd9bb206b338 has introduced the check without any explanation > whatsoever. I indeed do not see any potential path to provide a NULL > memcg here. This is an internal function so the check is unnecessary > indeed. Please make it a patch on its own. OK. Will do this. Thanks. > > > Signed-off-by: Muchun Song > > --- > > mm/memcontrol.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > index 8c035846c7a4..8569f4dbea2a 100644 > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -1925,7 +1925,7 @@ static int memcg_oom_wake_function(wait_queue_entry_t *wait, > > return autoremove_wake_function(wait, mode, sync, arg); > > } > > > > -static void memcg_oom_recover(struct mem_cgroup *memcg) > > +static inline void memcg_oom_recover(struct mem_cgroup *memcg) > > { > > /* > > * For the following lockless ->under_oom test, the only required > > @@ -1935,7 +1935,7 @@ static void memcg_oom_recover(struct mem_cgroup *memcg) > > * achieved by invoking mem_cgroup_mark_under_oom() before > > * triggering notification. > > */ > > - if (memcg && memcg->under_oom) > > + if (memcg->under_oom) > > __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); > > } > > > > @@ -2313,6 +2313,7 @@ static void drain_stock(struct memcg_stock_pcp *stock) > > page_counter_uncharge(&old->memory, stock->nr_pages); > > if (do_memsw_account()) > > page_counter_uncharge(&old->memsw, stock->nr_pages); > > + memcg_oom_recover(old); > > stock->nr_pages = 0; > > } > > > > -- > > 2.11.0 > > -- > Michal Hocko > SUSE Labs