linux-kernel - [PATCH v3 0/8] Fix SCHED_DEADLINE bandwidth accounting during suspend

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Message-ID: <20250310092050.23052-1-juri.lelli@redhat.com>
Date: Mon, 10 Mar 2025 10:20:42 +0100
From: Juri Lelli <juri.lelli@...hat.com>
To: linux-kernel@...r.kernel.org,
	cgroups@...r.kernel.org
Cc: Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Juri Lelli <juri.lelli@...hat.com>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Ben Segall <bsegall@...gle.com>,
	Mel Gorman <mgorman@...e.de>,
	Valentin Schneider <vschneid@...hat.com>,
	Waiman Long <longman@...hat.com>,
	Tejun Heo <tj@...nel.org>,
	Johannes Weiner <hannes@...xchg.org>,
	Michal Koutný <mkoutny@...e.com>,
	Qais Yousef <qyousef@...alina.io>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Swapnil Sapkal <swapnil.sapkal@....com>,
	Shrikanth Hegde <sshegde@...ux.ibm.com>,
	Phil Auld <pauld@...hat.com>,
	luca.abeni@...tannapisa.it,
	tommaso.cucinotta@...tannapisa.it,
	Jon Hunter <jonathanh@...dia.com>
Subject: [PATCH v3 0/8] Fix SCHED_DEADLINE bandwidth accounting during suspend

Hello!

Jon reported [1] a suspend regression on a Tegra board configured to
boot with isolcpus and bisected it to commit 53916d5fd3c0
("sched/deadline: Check bandwidth overflow earlier for hotplug").

Root cause analysis pointed out that we are currently failing to
correctly clear and restore bandwidth accounting on root domains after
changes that initiate from partition_sched_domains(), as it is the case
for suspend operations on that board.

This is v3 [2] of the proposed approach to fix the issue. With respect
to v2, the following implements the approach by:

- 01: filter out DEADLINE special tasks
- 02: preparatory wrappers to be able to grab sched_domains_mutex on
      UP (added !SMP wrappers back as sched_rt_handler() needs them)
- 03: generalize unique visiting of root domains so that we can
      re-use the mechanism elsewhere
- 04: the bulk of the approach, clean and rebuild after changes
- 05: clean up a now redundant call
- 06: remove partition_and_rebuild_sched_domains()
- 07: stop exposing partition_sched_domains_locked

I kept Jon and Waiman's Tested-by tags from v2 as there are no
functional changes in v3.

Please test and review. The set is also available at

git@...hub.com:jlelli/linux.git upstream/deadline/domains-suspend

Best,
Juri

1 - https://lore.kernel.org/lkml/ba51a43f-796d-4b79-808a-b8185905638a@nvidia.com/
2 - v1 https://lore.kernel.org/lkml/20250304084045.62554-1-juri.lelli@redhat.com
    v2 https://lore.kernel.org/lkml/20250306141016.268313-1-juri.lelli@redhat.com/

Juri Lelli (8):
  sched/deadline: Ignore special tasks when rebuilding domains
  sched/topology: Wrappers for sched_domains_mutex
  sched/deadline: Generalize unique visiting of root domains
  sched/deadline: Rebuild root domain accounting after every update
  sched/topology: Remove redundant dl_clear_root_domain call
  cgroup/cpuset: Remove partition_and_rebuild_sched_domains
  sched/topology: Stop exposing partition_sched_domains_locked
  include/{topology,cpuset}: Move dl_rebuild_rd_accounting to cpuset.h

 include/linux/cpuset.h         |  5 +++++
 include/linux/sched.h          |  5 +++++
 include/linux/sched/deadline.h |  4 ++++
 include/linux/sched/topology.h | 10 ---------
 kernel/cgroup/cpuset.c         | 27 +++++++++----------------
 kernel/sched/core.c            |  4 ++--
 kernel/sched/deadline.c        | 37 ++++++++++++++++++++--------------
 kernel/sched/debug.c           |  8 ++++----
 kernel/sched/rt.c              |  2 ++
 kernel/sched/sched.h           |  2 +-
 kernel/sched/topology.c        | 32 +++++++++++++----------------
 11 files changed, 69 insertions(+), 67 deletions(-)


base-commit: 80e54e84911a923c40d7bee33a34c1b4be148d7a
-- 
2.48.1