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[36.225.109.31]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-364ec027690sm14337636a91.13.2026.05.05.01.35.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 May 2026 01:35:56 -0700 (PDT) Date: Tue, 5 May 2026 16:35:52 +0800 From: Cheng-Yang Chou To: Andrea Righi Cc: Tejun Heo , Kuba Piecuch , David Vernet , Changwoo Min , Emil Tsalapatis , Christian Loehle , Daniel Hodges , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org, Ching-Chun Huang , Chia-Ping Tsai Subject: Re: [PATCH v2 sched_ext/for-7.1] sched_ext: Invalidate dispatch decisions on CPU affinity changes Message-ID: <20260505162907.G7f07@cchengyang.duckdns.org> References: <20260422142633.G7180@cchengyang.duckdns.org> <20260426093756.Gd781@cchengyang.duckdns.org> <20260502000039.Ga94c@cchengyang.duckdns.org> Precedence: bulk X-Mailing-List: linux-kernel@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: Hi Andrea, On Mon, May 04, 2026 at 11:58:21PM +0200, Andrea Righi wrote: > On Mon, May 04, 2026 at 11:24:57AM -1000, Tejun Heo wrote: > > On Mon, May 04, 2026 at 08:00:50AM +0000, Kuba Piecuch wrote: > > > Random thought: If exposing qseq values to BPF directly is undesirable, then > > > perhaps a less objectionable approach would be to expose them as opaque > > > cookie/token values? Same semantics, but fewer SCX internals leaking to BPF. > > > > Yeah, cookie sounds fine to me and let's clearly note that this is for > > schedulers that don't implement properly synchronized dequeue. > > I also like the idea of exposing cookies and extending scx_bpf_dispatch_cancel() > to support direct dispatches, it it doesn't introduce too much complexity (it > shouldn't be too painful). > > Cheng-Yang, just to make sure we're not doing the work twice, are you planning > to work on this? If you are already working on this, I can help with testing after your patches! Otherwise, I'm happy to help. FYI, I'm already working on deferring ext_server bandwidth to SCX enable and releasing it when disabled, but it still needs more testing! -- Cheers, Cheng-Yang