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[141.239.159.203]) by smtp.gmail.com with ESMTPSA id kn14-20020a170903078e00b001e27557050dsm1678564plb.178.2024.05.02.12.20.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 May 2024 12:20:17 -0700 (PDT) Sender: Tejun Heo Date: Thu, 2 May 2024 09:20:15 -1000 From: Tejun Heo To: Peter Zijlstra Cc: torvalds@linux-foundation.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org, joshdon@google.com, brho@google.com, pjt@google.com, derkling@google.com, haoluo@google.com, dvernet@meta.com, dschatzberg@meta.com, dskarlat@cs.cmu.edu, riel@surriel.com, changwoo@igalia.com, himadrics@inria.fr, memxor@gmail.com, andrea.righi@canonical.com, joel@joelfernandes.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCHSET v6] sched: Implement BPF extensible scheduler class Message-ID: References: <20240501151312.635565-1-tj@kernel.org> <20240502084800.GY30852@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240502084800.GY30852@noisy.programming.kicks-ass.net> Hello, Peter. On Thu, May 02, 2024 at 10:48:00AM +0200, Peter Zijlstra wrote: > Can you please put your efforts and the touted Google collaboration in > fixing the existing cgroup mess? I suppose you're referring to Rik's flattened hierarchy patchset. https://lore.kernel.org/all/20190822021740.15554-1-riel@surriel.com Rik spent a lot of time and energy on it and IIRC one of the reasons why it didn't get pushed further was the lack of any enthusiasm or support from the upstream community. We can resurrect the discussion on that patchset but how is that connected to sched_ext? One of the example schedulers, scx_flatcg, does employ the same approach with a twist (instead of flattening completely, it builds two-level hierarchy so that a leaf cgroup can be treated as a single entity) to demonstrate the idea but the two projects don't really have much in common otherwise. Are you saying that Meta and Google working on the flattened hierarchy is a prerequisite for landing sched_ext? Thanks. -- tejun