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From: "Yosry Ahmed" Message-ID: <07c9e4355ad4e3982d288306dddf18b391082b14@linux.dev> TLS-Required: No Subject: Re: [PATCH 00/11] cgroup: separate rstat trees To: "JP Kobryn" Cc: "Shakeel Butt" , tj@kernel.org, mhocko@kernel.org, hannes@cmpxchg.org, akpm@linux-foundation.org, linux-mm@kvack.org, cgroups@vger.kernel.org, kernel-team@meta.com In-Reply-To: References: <20250218031448.46951-1-inwardvessel@gmail.com> <158ea157-3411-45e6-bca4-fb70d67fb1c5@gmail.com> X-Migadu-Flow: FLOW_OUT X-Stat-Signature: nbxhtc6zxyeu35c1f31zbpiw5dhnc86p X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: D454B8000F X-Rspam-User: X-HE-Tag: 1740082941-609000 X-HE-Meta: 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 eX/zitCB 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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: > > Yes, this is true. cgroup_rstat_ops was only added to allow cgroup_b= pf > > to make use of rstat. If the bpf flushing remains tied to > > cgroup_subsys_state::self, then the ops interface and supporting cod= e > > can be removed. Probably stating the obvious but the trade-off would= be > > that if bpf cgroups are in use, they would account for some extra > > overhead while flushing the base stats. Is Google making use of bpf- > > based cgroups? > >=20 >=20 > Ironically I don't know, but I don't expect the BPF flushing to be > expensive enough to affect this. If someone has the use case that loads > enough BPF programs to cause a noticeable impact, we can address it > then. >=20 >=20This series will still be an improvement anyway. I actually just remembered. Using BPF programs to collect stats using rst= at is currently independent of the CGROUP_BPF stuff. So I think this appr= oach breaks that anyway.