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=-3.8 required=3.0 tests=BAYES_00, 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 E2E44C64E7C for ; Wed, 2 Dec 2020 11:35:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8196622203 for ; Wed, 2 Dec 2020 11:35:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729319AbgLBLfB (ORCPT ); Wed, 2 Dec 2020 06:35:01 -0500 Received: from foss.arm.com ([217.140.110.172]:36874 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726126AbgLBLfA (ORCPT ); Wed, 2 Dec 2020 06:35:00 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A9934101E; Wed, 2 Dec 2020 03:34:14 -0800 (PST) Received: from e107158-lin.cambridge.arm.com (e107158-lin.cambridge.arm.com [10.1.194.78]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 77F6D3F575; Wed, 2 Dec 2020 03:34:12 -0800 (PST) Date: Wed, 2 Dec 2020 11:34:10 +0000 From: Qais Yousef To: Will Deacon Cc: Quentin Perret , linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Suren Baghdasaryan , Tejun Heo , Li Zefan , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , kernel-team@android.com Subject: Re: [PATCH v4 09/14] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Message-ID: <20201202113410.dx4m2gb7zkyregys@e107158-lin.cambridge.arm.com> References: <20201124155039.13804-1-will@kernel.org> <20201124155039.13804-10-will@kernel.org> <20201127133245.4hbx65mo3zinawvo@e107158-lin.cambridge.arm.com> <20201130170531.qo67rai5lftskmk2@e107158-lin.cambridge.arm.com> <20201130173610.GA1715200@google.com> <20201201115842.t77abecneuesd5ih@e107158-lin.cambridge.arm.com> <20201201123748.GA1896574@google.com> <20201201141121.5w2wed3633slo6dw@e107158-lin.cambridge.arm.com> <20201201155649.GB1914005@google.com> <20201201223056.GB28496@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20201201223056.GB28496@willie-the-truck> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/01/20 22:30, Will Deacon wrote: > On Tue, Dec 01, 2020 at 03:56:49PM +0000, Quentin Perret wrote: > > On Tuesday 01 Dec 2020 at 14:11:21 (+0000), Qais Yousef wrote: > > > For cpusets, if hotunplug results in an empty cpuset, then all tasks are moved > > > to the nearest ancestor if I read the code correctly. In our case, only 32bit > > > tasks have to move out to retain this behavior. Since now for the first time we > > > have tasks that can't run on all cpus. > > > > > > Which by the way might be the right behavior for 64bit tasks execing 32bit > > > binary in a 64bit only cpuset. I suggested SIGKILL'ing them but maybe moving > > > them to the nearest ancestor too is more aligned with the behavior above. > > > > Hmm, I guess that means putting all 32-bit-execd-from-64-bit tasks in > > the root group in Android. I'll try and check the implications, but that > > might be just fine... Sounds like a sensible behaviour to me anyways. > > I'll look into this -- anything we can do to avoid forcefully resetting the > affinity mask to the arch_task_cpu_possible_mask() is worth considering. Happy to lend a hand, just let me know. Thanks -- Qais Yousef 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=-5.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A3F85C64E7C for ; Wed, 2 Dec 2020 11:35:29 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F2B8620575 for ; Wed, 2 Dec 2020 11:35:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F2B8620575 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=nyjIhTrVnIddQ43gspoGtIlFCHLm+3wGWvG2ofyUilo=; b=wSwW7sApntg3Q1w6ezRRDp0fF 7CvasEKcimW7yvaeuUVxLroBPiKDXDBr7XL1jtctL9YnhUgK6RDn9/584X2hACttHnzc4gAi/AnLs tFfBJgO6xOlzwHUXeCJJFlPDt2usDJctG2rEdBjlePJHV8RtgGG5Yanfw2RkdfiowJwuUqvcftEv2 ciabp3soc1e/7WnPRR+YNIAOmjQ1vqo+C9DRIqjtp2jpVFUuChPIK76aQM2fJ5kRgwAHZJme+eZLV qnyS5w2k+VdbwZs69OtpyhCajSslhAJqaOLC1t7u5aAsJ/XosTFtghqFGzAUUswSGuGFrRuFh3ij6 5evKxJGXQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kkQOr-00066c-7J; Wed, 02 Dec 2020 11:34:21 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kkQOo-000665-PO for linux-arm-kernel@lists.infradead.org; Wed, 02 Dec 2020 11:34:19 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A9934101E; Wed, 2 Dec 2020 03:34:14 -0800 (PST) Received: from e107158-lin.cambridge.arm.com (e107158-lin.cambridge.arm.com [10.1.194.78]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 77F6D3F575; Wed, 2 Dec 2020 03:34:12 -0800 (PST) Date: Wed, 2 Dec 2020 11:34:10 +0000 From: Qais Yousef To: Will Deacon Subject: Re: [PATCH v4 09/14] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Message-ID: <20201202113410.dx4m2gb7zkyregys@e107158-lin.cambridge.arm.com> References: <20201124155039.13804-1-will@kernel.org> <20201124155039.13804-10-will@kernel.org> <20201127133245.4hbx65mo3zinawvo@e107158-lin.cambridge.arm.com> <20201130170531.qo67rai5lftskmk2@e107158-lin.cambridge.arm.com> <20201130173610.GA1715200@google.com> <20201201115842.t77abecneuesd5ih@e107158-lin.cambridge.arm.com> <20201201123748.GA1896574@google.com> <20201201141121.5w2wed3633slo6dw@e107158-lin.cambridge.arm.com> <20201201155649.GB1914005@google.com> <20201201223056.GB28496@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201201223056.GB28496@willie-the-truck> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201202_063418_908634_71CE9538 X-CRM114-Status: GOOD ( 19.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, Juri Lelli , kernel-team@android.com, Vincent Guittot , Quentin Perret , Peter Zijlstra , Catalin Marinas , Johannes Weiner , linux-kernel@vger.kernel.org, Ingo Molnar , Li Zefan , Greg Kroah-Hartman , Marc Zyngier , Tejun Heo , Suren Baghdasaryan , Morten Rasmussen , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 12/01/20 22:30, Will Deacon wrote: > On Tue, Dec 01, 2020 at 03:56:49PM +0000, Quentin Perret wrote: > > On Tuesday 01 Dec 2020 at 14:11:21 (+0000), Qais Yousef wrote: > > > For cpusets, if hotunplug results in an empty cpuset, then all tasks are moved > > > to the nearest ancestor if I read the code correctly. In our case, only 32bit > > > tasks have to move out to retain this behavior. Since now for the first time we > > > have tasks that can't run on all cpus. > > > > > > Which by the way might be the right behavior for 64bit tasks execing 32bit > > > binary in a 64bit only cpuset. I suggested SIGKILL'ing them but maybe moving > > > them to the nearest ancestor too is more aligned with the behavior above. > > > > Hmm, I guess that means putting all 32-bit-execd-from-64-bit tasks in > > the root group in Android. I'll try and check the implications, but that > > might be just fine... Sounds like a sensible behaviour to me anyways. > > I'll look into this -- anything we can do to avoid forcefully resetting the > affinity mask to the arch_task_cpu_possible_mask() is worth considering. Happy to lend a hand, just let me know. Thanks -- Qais Yousef _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel