From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juri Lelli Subject: [PATCH 0/6] sched/deadline: cpuset: Rework DEADLINE bandwidth restoration Date: Wed, 29 Mar 2023 14:55:52 +0200 Message-ID: <20230329125558.255239-1-juri.lelli@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680094578; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=Bfp+uWRbOwM8a2jDGBZKgrnhrhJwiLY7EtO8YbQJdLo=; b=SmrIqzSxRYXn+p3LnuhTdtMpFEpq3odXtWHwTCxMIeM7+72pj5Oq4CuI6c3rT5HUJ3+DSh 9WLcya6pZjfZx/yj2iia08BzMajcQNxhRp+C25FA4bSlBIDZtoab5YbJviE60OG5F2XIX6 c86oj7l4I0zUy8t6jTGVIEZnp4iu0Yw= List-ID: Content-Type: text/plain; charset="us-ascii" To: Peter Zijlstra , Ingo Molnar , Qais Yousef , Waiman Long , Tejun Heo , Zefan Li , Johannes Weiner , Hao Luo Cc: 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 , Juri Lelli 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 Best, Juri 1 - https://lore.kernel.org/lkml/20230206221428.2125324-1-qyousef-wp2msK0BRk8tq7phqP6ubQ@public.gmane.org/ 2 - https://lore.kernel.org/lkml/20230315121812.206079-1-juri.lelli-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org/ Dietmar Eggemann (2): sched/deadline: Create DL BW alloc, free & check overflow interface cgroup/cpuset: Free DL BW in case can_attach() fails Juri Lelli (4): cgroup/cpuset: Rename functions dealing with DEADLINE accounting sched/cpuset: Bring back cpuset_mutex sched/cpuset: Keep track of SCHED_DEADLINE task in cpusets cgroup/cpuset: Iterate only if DEADLINE tasks are present include/linux/cpuset.h | 12 ++- include/linux/sched.h | 4 +- kernel/cgroup/cgroup.c | 4 + kernel/cgroup/cpuset.c | 232 ++++++++++++++++++++++++++-------------- kernel/sched/core.c | 41 ++++--- kernel/sched/deadline.c | 67 +++++++++--- kernel/sched/sched.h | 2 +- 7 files changed, 240 insertions(+), 122 deletions(-) -- 2.39.2