Re: [GIT PULL] workqueue fixes for v4.3-rc5

From	Mike Galbraith <umgwanakikbuti@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [GIT PULL] workqueue fixes for v4.3-rc5
Date	2015-10-19 06:00 +0200
Message-ID	<ql9M5-10B-9@gated-at.bofh.it> (permalink)
References	(4 earlier) <qjzB0-7Ge-9@gated-at.bofh.it> <qjzKF-7SB-1@gated-at.bofh.it> <qjA41-8f4-3@gated-at.bofh.it> <qjAGK-O8-5@gated-at.bofh.it> <qjAQq-10K-7@gated-at.bofh.it>
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On Wed, 2015-10-14 at 16:24 -0400, Tejun Heo wrote:

> But in terms of API consistency, it sucks to have queue_work()
> guarantee local queueing but not queue_delayed_work().  The ideal
> situation would be updating both so that neither guarantees.

You don't have to change anything to have neither guarantee local
queueing.  Called from a preemptible context, local means any CPU in
->cpus_allowed... which makes WORK_CPU_UNBOUND mean what one would
imagine WORK_CPU_UNBOUND to mean, not bound to any particular cpu.

      sh-16017   3.N.. 1510500545us : queue_work_on: golly, migrated cpu7 -> cpu3 -- target cpu8
      sh-16017   3.N.. 1510500550us : <stack trace>
 => tty_flip_buffer_push
 => pty_write
 => n_tty_write
 => tty_write
 => __vfs_write
 => vfs_write
 => SyS_write
 => entry_SYSCALL_64_fastpath

That was with a udelay(100) prior to disabling interrupts, but that just
makes it easier.

	-Mike

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Thread

[GIT PULL] workqueue fixes for v4.3-rc5 Tejun Heo <tj@kernel.org> - 2015-10-14 00:00 +0200
  Re: [GIT PULL] workqueue fixes for v4.3-rc5 Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-14 18:40 +0200
    Re: [GIT PULL] workqueue fixes for v4.3-rc5 Tejun Heo <tj@kernel.org> - 2015-10-14 19:00 +0200
      Re: [GIT PULL] workqueue fixes for v4.3-rc5 Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-14 19:40 +0200
        Re: [GIT PULL] workqueue fixes for v4.3-rc5 Christoph Lameter <cl@linux.com> - 2015-10-14 20:00 +0200
          Re: [GIT PULL] workqueue fixes for v4.3-rc5 Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-14 20:40 +0200
            Re: [GIT PULL] workqueue fixes for v4.3-rc5 Christoph Lameter <cl@linux.com> - 2015-10-14 21:00 +0200
            Re: [GIT PULL] workqueue fixes for v4.3-rc5 Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-14 21:10 +0200
        Re: [GIT PULL] workqueue fixes for v4.3-rc5 Tejun Heo <tj@kernel.org> - 2015-10-14 21:10 +0200
          Re: [GIT PULL] workqueue fixes for v4.3-rc5 Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-14 21:20 +0200
            Re: [GIT PULL] workqueue fixes for v4.3-rc5 Tejun Heo <tj@kernel.org> - 2015-10-14 21:40 +0200
              Re: [GIT PULL] workqueue fixes for v4.3-rc5 Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-14 22:20 +0200
                Re: [GIT PULL] workqueue fixes for v4.3-rc5 Tejun Heo <tj@kernel.org> - 2015-10-14 22:30 +0200
                Re: [GIT PULL] workqueue fixes for v4.3-rc5 Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-19 06:00 +0200
                Re: [PATCH] vmstat_update: ensure work remains on the same core Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-16 22:00 +0200
    Re: [GIT PULL] workqueue fixes for v4.3-rc5 Christoph Lameter <cl@linux.com> - 2015-10-14 20:10 +0200
      Re: [GIT PULL] workqueue fixes for v4.3-rc5 Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-14 20:50 +0200
        Re: [GIT PULL] workqueue fixes for v4.3-rc5 Christoph Lameter <cl@linux.com> - 2015-10-14 21:00 +0200
          Re: [GIT PULL] workqueue fixes for v4.3-rc5 Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-14 21:20 +0200

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