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([2620:10d:c090:500::4:3465]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-220d536738csm124699655ad.68.2025.02.20.10.14.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 20 Feb 2025 10:14:47 -0800 (PST) Message-ID: <158ea157-3411-45e6-bca4-fb70d67fb1c5@gmail.com> Date: Thu, 20 Feb 2025 10:14:45 -0800 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 00/11] cgroup: separate rstat trees To: Yosry Ahmed , Shakeel Butt Cc: 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 References: <20250218031448.46951-1-inwardvessel@gmail.com> Content-Language: en-US From: JP Kobryn In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2/20/25 9:59 AM, Yosry Ahmed wrote: > On Thu, Feb 20, 2025 at 09:53:33AM -0800, Shakeel Butt wrote: >> On Thu, Feb 20, 2025 at 05:26:04PM +0000, Yosry Ahmed wrote: >>> >>> Another question is, does it make sense to keep BPF flushing in the >>> "self" css with base stats flushing for now? IIUC BPF flushing is not >>> very popular now anyway, and doing so will remove the need to support >>> flushing and updating things that are not css's. Just food for thought. >>> >> >> Oh if this simplifies the code, I would say go for it. > > I think we wouldn't need cgroup_rstat_ops and some of the refactoring > may not be needed. It will also reduce the memory overhead, and keep it > constant regardless of using BPF which is nice. Yes, this is true. cgroup_rstat_ops was only added to allow cgroup_bpf to make use of rstat. If the bpf flushing remains tied to cgroup_subsys_state::self, then the ops interface and supporting code 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?