Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1247062

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

From Linus Torvalds <torvalds@linux-foundation.org>
Newsgroups linux.kernel
Subject Re: [GIT PULL] workqueue fixes for v4.3-rc5
Date 2015-10-14 20:40 +0200
Message-ID <qjz7X-6RL-3@gated-at.bofh.it> (permalink)
References <qjfLY-2wy-17@gated-at.bofh.it> <qjxfR-493-33@gated-at.bofh.it> <qjxzd-4vK-23@gated-at.bofh.it> <qjybV-5uA-17@gated-at.bofh.it> <qjyvf-5SM-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


On Wed, Oct 14, 2015 at 10:57 AM, Christoph Lameter <cl@linux.com> wrote:
>
> Well yes the schedule_delayed_work_on() call is from another cpu and the
> schedule_delayed_work() from the same. No confusion there.

So "schedule_delayed_work()" does *not* guarantee that the work will
run on the same CPU.

Yes, yes, it so _happens_ that "add_timer()" preferentially uses the
current CPU etc, so in practice it may have happened to work. But
there's absolutely zero reason to think it should always work that
way.

If you want the scheduled work to happen on a particular CPU, then you
should use "schedule_delayed_work_on()"  It shouldn't matter which CPU
you call it from.

At least that's how I think the rules should be. Very simple, very
clear: if you require a specific CPU, say so. Don't silently depend on
"in practice, lots of times we tend to use the local cpu".

                  Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


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: [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

csiph-web