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From: Peter Zijlstra <peterz@infradead.org>
To: tglx@linutronix.de, mingo@kernel.org
Cc: linux-kernel@vger.kernel.org, bigeasy@linutronix.de,
	qais.yousef@arm.com, swood@redhat.com, peterz@infradead.org,
	valentin.schneider@arm.com, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	bristot@redhat.com, vincent.donnefort@arm.com
Subject: [PATCH 0/9] sched: Migrate disable support
Date: Mon, 21 Sep 2020 18:35:57 +0200	[thread overview]
Message-ID: <20200921163557.234036895@infradead.org> (raw)

Hi,

Here's my take on migrate_disable(). It avoids growing a second means of
changing the affinity, documents how the things violates locking rules but
still mostly works.

It also avoids blocking completely, so no more futex band-aids required.

Also, no more atomics/locks on the fast path.

I also put in a comment that explains how the whole concept is fundamentally
flawed but a necessary evil to get PREEMPT_RT going -- for now.

Somewhat tested with PREEMPT_RT.

---
 include/linux/cpuhotplug.h    |    1 
 include/linux/preempt.h       |   60 +++
 include/linux/sched.h         |    4 
 include/linux/sched/hotplug.h |    2 
 include/linux/stop_machine.h  |    5 
 kernel/cpu.c                  |    9 
 kernel/sched/core.c           |  673 +++++++++++++++++++++++++++++++-----------
 kernel/sched/deadline.c       |    5 
 kernel/sched/sched.h          |   24 +
 kernel/stop_machine.c         |   23 +
 lib/dump_stack.c              |    2 
 lib/smp_processor_id.c        |    5 
 12 files changed, 635 insertions(+), 178 deletions(-)


             reply	other threads:[~2020-09-21 17:01 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-21 16:35 Peter Zijlstra [this message]
2020-09-21 16:35 ` [PATCH 1/9] stop_machine: Add function and caller debug info Peter Zijlstra
2020-09-21 16:35 ` [PATCH 2/9] sched: Fix balance_callback() Peter Zijlstra
2020-09-23 14:08   ` Thomas Gleixner
2020-09-21 16:36 ` [PATCH 3/9] sched/hotplug: Ensure only per-cpu kthreads run during hotplug Peter Zijlstra
2020-09-25 16:38   ` Dietmar Eggemann
2020-10-02 14:20     ` Peter Zijlstra
2020-09-21 16:36 ` [PATCH 4/9] sched/core: Wait for tasks being pushed away on hotplug Peter Zijlstra
2020-09-21 16:36 ` [PATCH 5/9] sched/hotplug: Consolidate task migration on CPU unplug Peter Zijlstra
2020-10-01 17:12   ` Vincent Donnefort
2020-10-02 14:17     ` Peter Zijlstra
2020-09-21 16:36 ` [PATCH 6/9] sched: Massage set_cpus_allowed Peter Zijlstra
2020-09-23 14:07   ` Thomas Gleixner
2020-09-21 16:36 ` [PATCH 7/9] sched: Add migrate_disable() Peter Zijlstra
2020-09-21 19:16   ` Thomas Gleixner
2020-09-21 20:42     ` Daniel Bristot de Oliveira
2020-09-23  8:31       ` Thomas Gleixner
2020-09-23 10:51         ` Daniel Bristot de Oliveira
2020-09-23 17:08         ` peterz
2020-09-23 17:54           ` Daniel Bristot de Oliveira
2020-09-23  7:48     ` peterz
2020-09-24 11:53   ` Valentin Schneider
2020-09-24 12:29     ` Peter Zijlstra
2020-09-24 12:33       ` Valentin Schneider
2020-09-24 12:35     ` Peter Zijlstra
2020-09-25 16:50   ` Sebastian Andrzej Siewior
2020-10-02 14:21     ` Peter Zijlstra
2020-10-02 14:36       ` Sebastian Andrzej Siewior
2020-09-21 16:36 ` [PATCH 8/9] sched: Fix migrate_disable() vs set_cpus_allowed_ptr() Peter Zijlstra
2020-09-24 19:59   ` Valentin Schneider
2020-09-25  8:43     ` Peter Zijlstra
2020-09-25 10:07       ` Valentin Schneider
2020-09-25  9:05     ` Peter Zijlstra
2020-09-25  9:56       ` Peter Zijlstra
2020-09-25 10:09         ` Valentin Schneider
2020-09-21 16:36 ` [PATCH 9/9] sched/core: Make migrate disable and CPU hotplug cooperative Peter Zijlstra
2020-09-25  9:12 ` [PATCH 0/9] sched: Migrate disable support Dietmar Eggemann
2020-09-25 10:10   ` Peter Zijlstra
2020-09-25 11:58     ` Dietmar Eggemann
2020-09-25 12:19       ` Valentin Schneider
2020-09-25 17:49         ` Valentin Schneider
2020-09-29  9:15           ` Dietmar Eggemann
2020-09-25 18:17 ` Sebastian Andrzej Siewior
2020-09-25 19:32   ` Valentin Schneider
2020-10-02 14:30     ` Peter Zijlstra

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