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=-23.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 14980C433E0 for ; Tue, 23 Feb 2021 15:19:01 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A3C3964E61 for ; Tue, 23 Feb 2021 15:19:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A3C3964E61 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 336066B0006; Tue, 23 Feb 2021 10:19:00 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2BCFB6B006E; Tue, 23 Feb 2021 10:19:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 138448D0001; Tue, 23 Feb 2021 10:19:00 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0004.hostedemail.com [216.40.44.4]) by kanga.kvack.org (Postfix) with ESMTP id EE7036B0006 for ; Tue, 23 Feb 2021 10:18:59 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id B59554DDA for ; Tue, 23 Feb 2021 15:18:59 +0000 (UTC) X-FDA: 77849890398.13.424C3AC Received: from mail-lj1-f181.google.com (mail-lj1-f181.google.com [209.85.208.181]) by imf28.hostedemail.com (Postfix) with ESMTP id EA71E2000385 for ; Tue, 23 Feb 2021 15:18:58 +0000 (UTC) Received: by mail-lj1-f181.google.com with SMTP id o16so58799940ljj.11 for ; Tue, 23 Feb 2021 07:18:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=gQTPFz0KpYE2dWkk3abN3T0OszgB57hAvGOE8ZYtgAA=; b=o+//MZFFfHtdHG0DGPb2hEKrGlrSgOgpcvlv8EkAotugJY4tPbXDcnXMc/VzRl1B3v 8Se2eEU44z6Q2HXZys/VPsHf2iTTAXagOhaMxbzKf/kYTJgl/71uLPYbBHMQVhMIiqf6 lXh+kxA8+09dEncWcHnEJKWScOXu2/9+AcCwK4jrjBqPzowQtoohRQyVHx7jfl3vv4Fs Fijdk/U3Vezsc6EkpisJM7UVqdp7xiKs5x6ThOTcy4dnDSq/zFQA67Frm2NFaB8YAD1Q Mclf3NnaduBtsQcwblXZrVEVZ3XJAYcht0XC3zb/ADdnOxPytBSC2EUz+zidmXWF86UY bhHQ== 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=gQTPFz0KpYE2dWkk3abN3T0OszgB57hAvGOE8ZYtgAA=; b=I30XtFKjyuQMFctbm76zIXXxo1cvq0faJ5XUTrKqplX2wqi7qWemiQVcpSl5y7PDQg vbiz/PtlMqD0GcjusQM+I7AF6phOaOS3bPfnjpE8WY2DJWaftVokgKejIc462LSSt5NJ Ms68JQCtH7/SYDZpmTZ+Z8ny6dqyLSpIqipxwlFL5NIey49W/0qzRpcAGTvpJ1oYE6xB 8OsbU1k2GGNe0EZ4nzKWfvfWpyO8M4X+HkVcjyY8U/ggkBr7jYI0qjY2QOKYIe9p4jxN qZs+P8/Ztyr7y1fvLcHVZJ5VKg1Pzx+O5Q36T3MB+sCHqBS4bzt16/cJAd4ZFTxzaoAX +mPQ== X-Gm-Message-State: AOAM532Kdqf6wCODUpAK1wXP2rdV0YpzagnvKuMGjSbxZQ2lt1a0iIBI mQbiEC5szTsL4FvIiDK1bWP+cVhBmEf8szxepOnqkA== X-Google-Smtp-Source: ABdhPJytWIbvd5HdX9yo4bjjPo/hvJHu1yFtuH+7/DLHUFKLmC0yaai2hO26aAUsmhtGLUPJJv5KQJLr6A7968Nlm1M= X-Received: by 2002:a2e:5c02:: with SMTP id q2mr15091026ljb.81.1614093537053; Tue, 23 Feb 2021 07:18:57 -0800 (PST) MIME-Version: 1.0 References: <20210223091101.42150-1-songmuchun@bytedance.com> In-Reply-To: <20210223091101.42150-1-songmuchun@bytedance.com> From: Shakeel Butt Date: Tue, 23 Feb 2021 07:18:46 -0800 Message-ID: Subject: Re: [PATCH] mm: memcontrol: fix get_active_memcg return value To: Muchun Song , stable@vger.kernel.org Cc: Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , Roman Gushchin , Cgroups , Linux MM , LKML Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: 9gns9rwxkz8sy5xwo6no8w813s5dp6cc X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: EA71E2000385 Received-SPF: none (google.com>: No applicable sender policy available) receiver=imf28; identity=mailfrom; envelope-from=""; helo=mail-lj1-f181.google.com; client-ip=209.85.208.181 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614093538-343465 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, Feb 23, 2021 at 1:14 AM Muchun Song wrote: > > We use a global percpu int_active_memcg variable to store the remote > memcg when we are in the interrupt context. But get_active_memcg always > return the current->active_memcg or root_mem_cgroup. The remote memcg > (set in the interrupt context) is ignored. This is not what we want. > So fix it. > > Fixes: 37d5985c003d ("mm: kmem: prepare remote memcg charging infra for interrupt contexts") > Signed-off-by: Muchun Song Good catch. Cc: stable@vger.kernel.org Reviewed-by: Shakeel Butt > --- > mm/memcontrol.c | 10 +++------- > 1 file changed, 3 insertions(+), 7 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index be6bc5044150..bbe25655f7eb 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1061,13 +1061,9 @@ static __always_inline struct mem_cgroup *get_active_memcg(void) > > rcu_read_lock(); > memcg = active_memcg(); > - if (memcg) { > - /* current->active_memcg must hold a ref. */ > - if (WARN_ON_ONCE(!css_tryget(&memcg->css))) > - memcg = root_mem_cgroup; > - else > - memcg = current->active_memcg; > - } > + /* remote memcg must hold a ref. */ > + if (memcg && WARN_ON_ONCE(!css_tryget(&memcg->css))) > + memcg = root_mem_cgroup; > rcu_read_unlock(); > > return memcg; > -- > 2.11.0 >