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=-15.7 required=3.0 tests=BAYES_00,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 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 97D10C433DB for ; Wed, 24 Feb 2021 20:04:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2E30B64F28 for ; Wed, 24 Feb 2021 20:04:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E30B64F28 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BC0D88D0006; Wed, 24 Feb 2021 15:04:25 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B738C6B00A0; Wed, 24 Feb 2021 15:04:25 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AAC6E8D0006; Wed, 24 Feb 2021 15:04:25 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0203.hostedemail.com [216.40.44.203]) by kanga.kvack.org (Postfix) with ESMTP id 94AC06B009F for ; Wed, 24 Feb 2021 15:04:25 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 3F087FB45 for ; Wed, 24 Feb 2021 20:04:25 +0000 (UTC) X-FDA: 77854238490.29.EAAB2C7 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf06.hostedemail.com (Postfix) with ESMTP id 56EDFC0007DF for ; Wed, 24 Feb 2021 20:04:26 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 31F4764F11; Wed, 24 Feb 2021 20:04:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614197063; bh=G31EBYnGYWA+9ziOs13ui7hLFTA9Ds66VuzLUR1+Iv4=; h=Date:From:To:Subject:In-Reply-To:From; b=si5bUio5hFqsEjKRig7n4vmR60gzC42liNYSxQ6OQc3feQk003GyrD0TmiSURD3DK NqjymUnrfzPZHB1usvHOdEf13vscSZfoeV6hQINEKMuno0e5H0/KG4D1aFDvMsr/Te MmT+prNuBlA4QG+t3+FVRVtGntzQenx+rTuRsyWI= Date: Wed, 24 Feb 2021 12:04:22 -0800 From: Andrew Morton To: akpm@linux-foundation.org, guro@fb.com, hannes@cmpxchg.org, linux-mm@kvack.org, mhocko@kernel.org, mm-commits@vger.kernel.org, shakeelb@google.com, songmuchun@bytedance.com, stable@vger.kernel.org, torvalds@linux-foundation.org, vdavydov.dev@gmail.com Subject: [patch 074/173] mm: memcontrol: fix get_active_memcg return value Message-ID: <20210224200422.mMBuJs4L_%akpm@linux-foundation.org> In-Reply-To: <20210224115824.1e289a6895087f10c41dd8d6@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Stat-Signature: 77twxhejskxhpf6gfhda3p4jednb15go X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 56EDFC0007DF Received-SPF: none (linux-foundation.org>: No applicable sender policy available) receiver=imf06; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614197066-197917 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: From: Muchun Song Subject: mm: memcontrol: fix get_active_memcg return value 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. Link: https://lkml.kernel.org/r/20210223091101.42150-1-songmuchun@bytedance.com Fixes: 37d5985c003d ("mm: kmem: prepare remote memcg charging infra for interrupt contexts") Signed-off-by: Muchun Song Reviewed-by: Shakeel Butt Reviewed-by: Roman Gushchin Cc: Johannes Weiner Cc: Michal Hocko Cc: Vladimir Davydov Cc: Signed-off-by: Andrew Morton --- mm/memcontrol.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) --- a/mm/memcontrol.c~mm-memcontrol-fix-get_active_memcg-return-value +++ a/mm/memcontrol.c @@ -1061,13 +1061,9 @@ static __always_inline struct mem_cgroup 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; _