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[109.81.31.109]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b725d86b9b1sm269126066b.25.2025.11.05.00.19.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Nov 2025 00:19:56 -0800 (PST) Date: Wed, 5 Nov 2025 09:19:55 +0100 From: Michal Hocko To: Leon Huang Fu Cc: linux-mm@kvack.org, hannes@cmpxchg.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, akpm@linux-foundation.org, joel.granados@kernel.org, jack@suse.cz, laoar.shao@gmail.com, mclapinski@google.com, kyle.meyer@hpe.com, corbet@lwn.net, lance.yang@linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [PATCH mm-new v2] mm/memcontrol: Flush stats when write stat file Message-ID: References: <20251105074917.94531-1-leon.huangfu@shopee.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251105074917.94531-1-leon.huangfu@shopee.com> X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: C2FAC14000C X-Stat-Signature: 3b1ny6audo3gbstjgxabgs3rf1qy5nz3 X-Rspam-User: X-HE-Tag: 1762330798-948010 X-HE-Meta: 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 mwjA/V6K jHEK5wHaHvvn+OobaoBy4NkkpC2kRTDHPwuQqVhLaCU5YLJFzrtGZ+hIZ/Jr+yDFvpeWhkmMnauFXWnMBSVCinyXwSGH2I/jNShf1O/gBiikGbAvuOFHssAzInWmQ9HttAeMaNFETHzdne/NWcUlKNnt2l4SyykOgdDQ2JF/SijXu+9oQWqpEXfGOeOhzetmkQLwoow0u3zUz8fkFEszS1WZ6ZZ557TeVOe1Qktj5wpB7iIQEfh03aHC4YNKaevi6peakSVIGWbnDECBWNKpMlBXKooR6sr3KpmCqLUVIc3RRNV+HczYjqxSYAUyEFm3HVodXuiy5XIVfcKdwt0udx4PXPKyIJOLc2P9PcsjufH5QlrftIvIAvqHyVDdPLsJ6BIB5R/WblnQ4Yfv0ktgr7V6Pjby+hwvIKy41m8DfyZJOYMo= 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 Wed 05-11-25 15:49:16, Leon Huang Fu wrote: > diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c > index 6eed14bff742..8cab6b52424b 100644 > --- a/mm/memcontrol-v1.c > +++ b/mm/memcontrol-v1.c > @@ -2040,6 +2040,7 @@ struct cftype mem_cgroup_legacy_files[] = { > { > .name = "stat", > .seq_show = memory_stat_show, > + .write_u64 = memory_stat_write, > }, > { > .name = "force_empty", > @@ -2078,6 +2079,7 @@ struct cftype mem_cgroup_legacy_files[] = { > { > .name = "numa_stat", > .seq_show = memcg_numa_stat_show, > + .write_u64 = memory_stat_write, > }, Any reason you are not using .write like others? Also is there any reason why a specific value is required. /proc/sys/vm/stat_refresh which does something similar ignores the value. Also memcg.peak write handler which resets the peak value ignores it. It is true that a specific value allows for future extensions but I guess it would be better to be consistent with others here. One last thing to consider is whether this should follow /proc/sys/vm/stat_refresh path and have a single file to flush them all or have a per file flushing. I do not have a strong preference but considering both are doing the same thing it makes sense to go stat_refresh path. In any case, thanks for considering the explicit flushing path which is IMHO much better than flushing tunning which would become really hard for admins to wrap their heads around. Especially when dealing with large fleets of machines to maintain. -- Michal Hocko SUSE Labs