From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 533ADC433B4 for ; Wed, 7 Apr 2021 16:50:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 283616120E for ; Wed, 7 Apr 2021 16:50:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354358AbhDGQuv (ORCPT ); Wed, 7 Apr 2021 12:50:51 -0400 Received: from mx2.suse.de ([195.135.220.15]:52354 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235801AbhDGQuu (ORCPT ); Wed, 7 Apr 2021 12:50:50 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1617814239; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=qWU3Uw013phP+5Jyksq3HX90ifPFm5gLyXDiR5rUIrE=; b=m6+WRvmmH+g7124eFx4ypgiNd+KeikLc/4TeP/xIFh9qlKMQvI/h07HYU4F7kVqdsFeN9k UrUkxPzG1F3doXw1wk7a13/2O7S+uQzieczVyAQLft7ZOdBYFQ6N16odeET0llll72QfUG uGl/pqrFc5ZWRrFpYyHcQBnECOpsN40= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 8BFC5AD41; Wed, 7 Apr 2021 16:50:39 +0000 (UTC) Date: Wed, 7 Apr 2021 18:50:32 +0200 From: Michal =?iso-8859-1?Q?Koutn=FD?= To: Tejun Heo Cc: Peter Zijlstra , joel@joelfernandes.org, chris.hyser@oracle.com, joshdon@google.com, mingo@kernel.org, vincent.guittot@linaro.org, valentin.schneider@arm.com, mgorman@suse.de, linux-kernel@vger.kernel.org, tglx@linutronix.de, Christian Brauner , Zefan Li Subject: Re: [PATCH 0/9] sched: Core scheduling interfaces Message-ID: References: <20210401131012.395311786@infradead.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="ojP5lI8yh47avJ/L" Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --ojP5lI8yh47avJ/L Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hello. IIUC, the premise is that the tasks that have different cookies imply they would never share a core. On Thu, Apr 01, 2021 at 03:10:12PM +0200, Peter Zijlstra wrote: > The cgroup interface now uses a 'core_sched' file, which still takes 0,1. It is > however changed such that you can have nested tags. The for any given task, the > first parent with a cookie is the effective one. The rationale is that this way > you can delegate subtrees and still allow them some control over grouping. Given the existence of prctl and clone APIs, I don't see the reason to have a separate cgroup-bound interface too (as argued by Tejun). The potential speciality is the possibility to re-tag whole groups of processes at runtime (but the listed use cases [1] don't require that and it's not such a good idea given its asynchronicity). Also, I would find useful some more explanation how the hierarchical behavior is supposed to work. In my understanding the task is either allowed to request its own isolation or not. The cgroups could be used to restrict this privilege, however, that doesn't seem to be the case here. My two cents, Michal [1] https://lore.kernel.org/lkml/20200822030155.GA414063@google.com/ --ojP5lI8yh47avJ/L Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEEoQaUCWq8F2Id1tNia1+riC5qSgFAmBt4tQACgkQia1+riC5 qSjb0BAAgEKtpTvMmS8odId7gPyWX6Vkn1BI3HMu4pXWvekwXCiVXssyn2KMJkwx xEXytGkPohJzpPYr7mq7PdK11L6Nlt8Qi9lq+ggvHF/nxcWLyRuELjp1Ypv/WDJ9 mXc370PYJ+kUEe3kOb2JGpDX0X6oGN1cplQy/UBPIH+5GspUrWyqmC2vvAvIkjx1 Vj+Jsa5Ek1TY+6LGmKTuqJ7LbCHB24acCTMZXDSFuhR1abAUnV1RalNYws3Te73Y kStEMiaGrnTHn7p+ogLoLBidr8lZAdNwn3+o1uaRFtzF39+WlS2mxsxMfrekf9Td kRCtmuXjUDTEfDqoiBtG+OcUAaTBRIxbW8kNnRvTcaAi31A7i6/KLxAiRdm8hlU5 bhG4hqIRJk4iM6YYz0mkDa1UZetpYqq9SEhQGdtSJQvuUydgRTpLMkiu4EygMyeI 0J/3cTNeYzEflswnpxlOOQLL4xyL0FsXUUUtBkRjHM8t/uyIfiNFU3DWl8jKPkVK Y54gxtUdTJ5opE4r1ffSbeHsehnPgqM71yzDXnbknLuRc4MeMOGIdt83Hsz0qpi+ KeKCq3+JuDaoalOf+zEmqMWbiLAdz0FC8pGh4FVIOAkn9tJiyp7IyXwc9y71boxq zAPeWngpWdzoTaeJ8YPN3fxYVdzyjJ0G+e12fI/o6a9tZ2iBdVc= =9N/g -----END PGP SIGNATURE----- --ojP5lI8yh47avJ/L--