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Tue, 23 Apr 2024 21:19:08 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id qeOYDswlKGatcQAAD6G6ig (envelope-from ); Tue, 23 Apr 2024 21:19:08 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id E2E0BA082F; Tue, 23 Apr 2024 23:19:03 +0200 (CEST) Date: Tue, 23 Apr 2024 23:19:03 +0200 From: Jan Kara To: Tejun Heo Cc: Jan Kara , Xiu Jianfeng , viro@zeniv.linux.org.uk, brauner@kernel.org, lizefan.x@bytedance.com, hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH -next] cgroup: Introduce css_is_online() helper Message-ID: <20240423211903.aofflj5wanozhat7@quack3> References: <20240420094428.1028477-1-xiujianfeng@huawei.com> <20240423134923.osuljlalsd27awz3@quack3> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Action: no action X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 04185A0023 X-Stat-Signature: xmn3s6xy7389fa1c93u496fg5zfbbimp X-HE-Tag: 1713907149-74766 X-HE-Meta: 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 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: On Tue 23-04-24 05:56:38, Tejun Heo wrote: > Hello, > > On Tue, Apr 23, 2024 at 03:49:23PM +0200, Jan Kara wrote: > > On Sat 20-04-24 09:44:28, Xiu Jianfeng wrote: > > > Introduce css_is_online() helper to test if whether the specified > > > css is online, avoid testing css.flags with CSS_ONLINE directly > > > outside of cgroup.c. > > > > > > Signed-off-by: Xiu Jianfeng > > > > Looks good. Feel free to add: > > > > Reviewed-by: Jan Kara > > I'm a bit skeptical about these trivial helpers. If the test is something > more involved or has complications which need documentation (e.g. regarding > synchronization and what not), the helper would be useful even if it's just > as a place to centrally document what's going on. However, here, it's just > testing one flag and I'm not sure what benefits the helper brings. Yeah OK. I felt the motivation was so that writeback code doesn't have to peek into cgroup "internals" so I'm fine with the change from writeback POV. But if you don't see the point from cgroup side than sure I'm fine without this change as well. Honza -- Jan Kara SUSE Labs, CR