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Mon, 29 Mar 2021 13:59:50 -0700 (PDT) MIME-Version: 1.0 References: <20210329144829.1834347-1-schatzberg.dan@gmail.com> <20210329144829.1834347-3-schatzberg.dan@gmail.com> In-Reply-To: From: Shakeel Butt Date: Mon, 29 Mar 2021 13:59:39 -0700 Message-ID: Subject: Re: [External] [PATCH 2/3] mm: Charge active memcg when no mm is set To: Muchun Song Cc: Dan Schatzberg , Jens Axboe , Tejun Heo , Zefan Li , Johannes Weiner , Andrew Morton , Michal Hocko , Vladimir Davydov , Hugh Dickins , Roman Gushchin , Yang Shi , Alex Shi , Alexander Duyck , Yafang Shao , Wei Yang , "open list:BLOCK LAYER" , open list , "open list:CONTROL GROUP (CGROUP)" , "open list:MEMORY MANAGEMENT" , Chris Down Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 6B236200027A X-Stat-Signature: iokp7bng5ai74wzjg57ja3hb8fe9nhjw Received-SPF: none (google.com>: No applicable sender policy available) receiver=imf28; identity=mailfrom; envelope-from=""; helo=mail-lf1-f49.google.com; client-ip=209.85.167.49 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1617051592-157729 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 Mon, Mar 29, 2021 at 9:13 AM Muchun Song wrote: > > On Mon, Mar 29, 2021 at 10:49 PM Dan Schatzberg > wrote: [...] > > Since remote memcg must hold a reference, we do not > need to do something like get_active_memcg() does. > Just use css_get to obtain a ref, it is simpler. Just > Like below. > > + if (unlikely(!mm)) { > + memcg = active_memcg(); > + if (unlikely(memcg)) { > + /* remote memcg must hold a ref. */ > + css_get(memcg); > + return memcg; > + } > I second Muchun's suggestion.