From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792456301; b=N3JbIUf0lgeiCnO2JdyYA3KXT26RzQnzhOeCgoq4eV9mkC+lOyZYiOUsk+VA4qhCINQG r/Gacp9ss5SzcL65RtoqTyEDVcSozdjciCaFlf6NRY77aKOwMQnSC5oLbUAV0Q4lpLG7v zPC4xDxgzlKFHbOq0iK9+MM2OIvquySqgeW9yqSOGw8heVtNsHNslfl+8uCNTibnGLuC8 U1z+M80HjkYre/z8YfLKhOKVaGjny3XiKEuvz6GUTOYWL5H76Rny2t6s+0Mh46Vpx5H33 6zGiNbteOJm9hFpC8T+cFpPrbuo2N4FHdNmSscoguhFNbd8aD5BNMAUPwy4Sa+Nv24Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792456301; h=Received:DKIM-Signature:Date:Message-ID:From:To:Cc:Subject: In-Reply-To:References; bh=751Y6zhqVlujoAmZVVL9yyvNp28mfGpF7nvRUspAqIc=; b=pCjoQzB5TioIGaMu3SapKm4AwodJKeWwHigLHb/pjzUZqi94UR5FvFZatshxqgzcm2CT LvUhelH4lJ45rC71b4AtpmbegGucUssUciqysnbTCz9jgrfCofXcno6CNyH4juguwms9w jjikm86Rr66SA1jihy1gpYrIYBI6hjd59C3Jy8jSM+QJYbRHk2uX9uKODYQfjSA0RtpH0 9nffeyADgVU0+mv/qDATsiErHBXxjYjOK4nZoQAE+y8g6ceqZZN6bcyZOITaHiE/oHnPw AWq2sKA/wMOYxP/1GYpNCvuQwhxKd/pXg54zPgEjouNctE1OfdwS+Txoadj1PrQMRpA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="GXixBEC/"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97BE3606A31A; Tue, 20 Oct 2026 00:31:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=GXixBEC/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id F00691F000C5; Tue, 20 Oct 2026 00:31:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792456301; bh=751Y6zhqVlujoAmZVVL9yyvNp28mfGpF7nvRUspAqIc=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=GXixBEC/r4jnwXB5/hHlBLU0pcxTo68MTZcS4HB1Blx3bHmcf0Q0eILL8DDNaEEkj rZZA8QMw9liBZ8jQhI1oT71WrqVqCq9LbrxdfQwaZsyRQHBAidJjkSCvcrKlAoQbFi uOKXSrhSE4hayvnQtDo66vKKmIwgad7z8XMBRDim8Ztt69xGMlCVjWQejLV1uRA4sy hltA0Oygv91LZuVni42dx2A7g+7ObIXHlC0TX0LqI+7Y7JszQ4mQsbIGUDIapiso2N wWbSlGUYjT6t4oZhonR0cn1f59wjbxhywq3srKoMECnkaqOjyJczZGZNbDN66NFWcx IJ0gE/mNoPy8Q== Date: Mon, 19 Oct 2026 14:31:40 -1000 Message-ID: <657547efeaea54276c50a0c106399366@kernel.org> From: Tejun Heo To: Kuba Piecuch Cc: Peter Zijlstra , David Vernet , Andrea Righi , Changwoo Min , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH sched_ext/for-7.4 0/5] sched_ext: Make ops.cpu_acquire/release() reliable In-Reply-To: <20261019144807.1207781-1-jpiecuch@google.com> References: <20261019144807.1207781-1-jpiecuch@google.com> X-Mailing-List: sched-ext@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Hello, Kuba. On Mon, Oct 19, 2026 at 02:48:05PM +0000, Kuba Piecuch wrote: > Tejun, Peter, would a hook like this be acceptable? The core.c > footprint is one line, it's a static branch when SCX isn't enabled, and > the out-of-line call only happens when the pick goes to a class above > SCX. If you're OK with it, I'd send the IMMED fix first, separately > (Fixes: 98d709cba319 ("sched_ext: Implement SCX_ENQ_IMMED")), and > rebase v2 of this series on top of it. I don't really see a lot of utility in ops.cpu_acquire/release(). As it currently stands, it doesn't add anything that can't be covered by IMMED, and given how asynchronous the events are, I'm not sure an edge-triggered view of CPU availability is particularly useful. IMMED works because it's something the kernel can check and enforce. If there are holes in it, let's plug them, but I don't think the holes justify keeping or updating ops.cpu_acquire/release(). Can you please send the IMMED fixes separately? Thanks. -- tejun