From mboxrd@z Thu Jan 1 00:00:00 1970 From: Waiman Long Subject: Re: [PATCH 0/6] sched/deadline: cpuset: Rework DEADLINE bandwidth restoration Date: Tue, 18 Apr 2023 10:31:27 -0400 Message-ID: References: <20230329125558.255239-1-juri.lelli@redhat.com> <20230418141127.zbvsf7lwk27zvipt@airbuntu> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681828297; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Obc8o7+Jc2/xwzIMnjHntcd92yYzpwyuQHbYi3m2V4g=; b=gBE/jNRMTBVX7TaIAmVeObUB6kaHr1z/bvgPE6Tq1ttFup8l5ZpJNVogf3dI/dafeQ9oY5 jZ9sJV5F5w2OXBdtxjaS00FA55+BLOqgPdsaqIyhWVjs+7WUibXQbO0YYLpdtNPdOADPS2 Njrt04Es7F+zotx7qwJ0VjmjbNHS8uE= Content-Language: en-US In-Reply-To: <20230418141127.zbvsf7lwk27zvipt@airbuntu> List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Qais Yousef , Juri Lelli Cc: Peter Zijlstra , Ingo Molnar , Tejun Heo , Zefan Li , Johannes Weiner , Hao Luo , Dietmar Eggemann , Steven Rostedt , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, luca.abeni-5rdYK369eBLQB0XuIGIEkQ@public.gmane.org, claudio-YOzL5CV4y4YG1A2ADO40+w@public.gmane.org, tommaso.cucinotta-5rdYK369eBLQB0XuIGIEkQ@public.gmane.org, bristot-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, mathieu.poirier-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Vincent Guittot , Wei Wang , Rick Yiu , Quentin Perret , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Sudeep Holla On 4/18/23 10:11, Qais Yousef wrote: > On 03/29/23 14:55, Juri Lelli wrote: >> Qais reported [1] that iterating over all tasks when rebuilding root >> domains for finding out which ones are DEADLINE and need their bandwidth >> correctly restored on such root domains can be a costly operation (10+ >> ms delays on suspend-resume). He proposed we skip rebuilding root >> domains for certain operations, but that approach seemed arch specific >> and possibly prone to errors, as paths that ultimately trigger a rebuild >> might be quite convoluted (thanks Qais for spending time on this!). >> >> To fix the problem >> >> 01/06 - Rename functions deadline with DEADLINE accounting (cleanup >> suggested by Qais) - no functional change >> 02/06 - Bring back cpuset_mutex (so that we have write access to cpusets >> from scheduler operations - and we also fix some problems >> associated to percpu_cpuset_rwsem) >> 03/06 - Keep track of the number of DEADLINE tasks belonging to each cpuset >> 04/06 - Create DL BW alloc, free & check overflow interface for bulk >> bandwidth allocation/removal - no functional change >> 05/06 - Fix bandwidth allocation handling for cgroup operation >> involving multiple tasks >> 06/06 - Use this information to only perform the costly iteration if >> DEADLINE tasks are actually present in the cpuset for which a >> corresponding root domain is being rebuilt >> >> With respect to the RFC posting [2] >> >> 1 - rename DEADLINE bandwidth accounting functions - Qais >> 2 - call inc/dec_dl_tasks_cs from switched_{to,from}_dl - Qais >> 3 - fix DEADLINE bandwidth allocation with multiple tasks - Waiman, >> contributed by Dietmar >> >> This set is also available from >> >> https://github.com/jlelli/linux.git deadline/rework-cpusets > Is this just waiting to be picked up or still there's something to be addressed > still? There are some changes to cpuset code recently and so I believe that this patch series may need to be refreshed to reconcile the changes. Thanks, Longman