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b=c6zhY/03sYoUPxFSOAzcqpJZNdgcpIlguB8F8Ya6QtatTsdz1qTJrxroGNpHDCz+k 63siMOOcIga85eiVqw+IX/X812bDb4yBSEqrDk9+o5uVWH/9ctrNBM23BfhFgLPrsT I4nqhdNFK8iX8f1eHUSVJvzq8t9Do5uJJCXj7TPuI5lJpjHGDiiRrOhXElPMv17s9y 6KIy8W6mYttmVmJm3RacrZOIa2pvOM3aPhO1Zfjf3mfBReG/qxdPROL1ds0WTuQwEH KQTj/QzUOPlguiUi08443cGHf6c0PFubwpXdFlPzxWgELpwCX6rG5Gf394rdIFTzJJ xdbZJUcVlK+wA== Received: by mail-pg1-f174.google.com with SMTP id 41be03b00d2f7-5c21e185df5so2785003a12.1 for ; Mon, 04 Dec 2023 16:36:09 -0800 (PST) X-Gm-Message-State: AOJu0YwovgcWwHy43HHIpwZK/nIvLl5VDxREzB4w6LDlEfDZlXkvX9BN RccSAC+iTUNGF+6+AFn2DivhroABj6rQdmhyMGA6Aw== X-Google-Smtp-Source: AGHT+IFEGHhgC5vm9lb6tIiaRJZgs/RHNtib/ITvbq5Wlcj1rLMMGwqG+hEI5SF0R/fth38EIgqoS5P+F/X0FUD92DU= X-Received: by 2002:a05:6a21:6215:b0:18c:1248:bb17 with SMTP id wm21-20020a056a21621500b0018c1248bb17mr4976625pzb.21.1701736568967; Mon, 04 Dec 2023 16:36:08 -0800 (PST) MIME-Version: 1.0 References: <20231130194023.4102148-1-nphamcs@gmail.com> <20231130194023.4102148-3-nphamcs@gmail.com> In-Reply-To: <20231130194023.4102148-3-nphamcs@gmail.com> From: Chris Li Date: Mon, 4 Dec 2023 16:35:57 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v8 2/6] memcontrol: implement mem_cgroup_tryget_online() To: Nhat Pham Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, cerasuolodomenico@gmail.com, yosryahmed@google.com, sjenning@redhat.com, ddstreet@ieee.org, vitaly.wool@konsulko.com, mhocko@kernel.org, roman.gushchin@linux.dev, shakeelb@google.com, muchun.song@linux.dev, linux-mm@kvack.org, kernel-team@meta.com, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, shuah@kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 5E09640004 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: 1nb3rww61a97sn4gaje5isth95swdixs X-HE-Tag: 1701736571-816547 X-HE-Meta: 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 gnPzI5h5 BbZpLdE630VgZc9muksz1V5CFkrNuvwSNW7PqUahbDCP3ti9B8MYU7QJjQxCWoqgSM4S6hio3AfiRVF9ek88NfQY3E19KriayN5rTNrrxnei+yx0GZlVqSVuraF5bOsAnlX8O7p2yMJuvIkEwOtx45mlBJPwcSG5nz9DodIwPacOe4lbndGofX2oVST3+H3hktQhQI2u5vkmYNUQB1Lk55Poe3nquHvq/6hJIJaiMR1b1vgQmBkxLe41guJ7AUGuThtoQnSz5EHnnkqKyVg8ehBKKAYo3KcuGbhFa 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: List-Subscribe: List-Unsubscribe: Hi Nhat, Very minor nitpick. This patch can fold with the later patch that uses it. That makes the review easier, no need to cross reference different patches. It will also make it harder to introduce API that nobody uses. Chris On Thu, Nov 30, 2023 at 11:40=E2=80=AFAM Nhat Pham wrot= e: > > This patch implements a helper function that try to get a reference to > an memcg's css, as well as checking if it is online. This new function > is almost exactly the same as the existing mem_cgroup_tryget(), except > for the onlineness check. In the !CONFIG_MEMCG case, it always returns > true, analogous to mem_cgroup_tryget(). This is useful for e.g to the > new zswap writeback scheme, where we need to select the next online > memcg as a candidate for the global limit reclaim. Very minor nitpick. This patch can fold with the later patch that uses it. That makes the review easier, no need to cross reference different patches. It will also make it harder to introduce API that nobody uses. Chris > > Signed-off-by: Nhat Pham > --- > include/linux/memcontrol.h | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index 7bdcf3020d7a..2bd7d14ace78 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -821,6 +821,11 @@ static inline bool mem_cgroup_tryget(struct mem_cgro= up *memcg) > return !memcg || css_tryget(&memcg->css); > } > > +static inline bool mem_cgroup_tryget_online(struct mem_cgroup *memcg) > +{ > + return !memcg || css_tryget_online(&memcg->css); > +} > + > static inline void mem_cgroup_put(struct mem_cgroup *memcg) > { > if (memcg) > @@ -1349,6 +1354,11 @@ static inline bool mem_cgroup_tryget(struct mem_cg= roup *memcg) > return true; > } > > +static inline bool mem_cgroup_tryget_online(struct mem_cgroup *memcg) > +{ > + return true; > +} > + > static inline void mem_cgroup_put(struct mem_cgroup *memcg) > { > } > -- > 2.34.1 >