Re: [PATCH] mutex: Report recursive ww_mutex locking early

From	Chris Wilson <chris@chris-wilson.co.uk>
Newsgroups	linux.kernel
Subject	Re: [PATCH] mutex: Report recursive ww_mutex locking early
Date	2016-05-30 12:50 +0200
Message-ID	<rEsVH-2ZZ-7@gated-at.bofh.it> (permalink)
References	(1 earlier) <rD9Lr-2oU-5@gated-at.bofh.it> <rEq7w-1cH-23@gated-at.bofh.it> <rErwC-2fk-21@gated-at.bofh.it> <rErZD-2oF-5@gated-at.bofh.it> <rEsCm-2SM-13@gated-at.bofh.it>
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On Mon, May 30, 2016 at 12:27:46PM +0200, Peter Zijlstra wrote:
> On Mon, May 30, 2016 at 11:43:31AM +0200, Maarten Lankhorst wrote:
> > Patch not applied, SCHED_RR:
> 
> ww_mutex isn't RT aware at all; its one of the things I still have on a
> todo list. Should I look harder at finding time for this?

The RT usage in the test is to just try and starve the kernel threads
that may be used behind the atomic modeset - a problem we have
encountered in the past. Afaik, no one is using ww_mutex from RT in the
wild, calling the atomic modeset from the RT was just a shortcut to
having the system fully populated with RT threads. To be more realistic
we should be using a couple of normal modesetting threads vs a set of RT
cpu hogs.

Otoh, i915.ko always draws the ire of rt-linux so ww_mutex is likely to
be in their sights in the near future (when i915.ko completes its
transition to full atomic modesetting).
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Thread

[PATCH] mutex: Do not spin/queue before performing ww_mutex deadlock avoidance Chris Wilson <chris@chris-wilson.co.uk> - 2016-05-26 10:40 +0200
  Re: [PATCH] mutex: Do not spin/queue before performing ww_mutex  deadlock avoidance Maarten Lankhorst <maarten.lankhorst@linux.intel.com> - 2016-05-26 12:40 +0200
    Re: [PATCH] mutex: Do not spin/queue before performing ww_mutex  deadlock avoidance Chris Wilson <chris@chris-wilson.co.uk> - 2016-05-26 12:50 +0200
      Re: [PATCH] mutex: Do not spin/queue before performing ww_mutex  deadlock avoidance Maarten Lankhorst <maarten.lankhorst@linux.intel.com> - 2016-05-26 13:10 +0200
  [PATCH] mutex: Report recursive ww_mutex locking early Chris Wilson <chris@chris-wilson.co.uk> - 2016-05-26 22:10 +0200
    Re: [PATCH] mutex: Report recursive ww_mutex locking early Maarten Lankhorst <maarten.lankhorst@linux.intel.com> - 2016-05-30 09:50 +0200
      Re: [PATCH] mutex: Report recursive ww_mutex locking early Peter Zijlstra <peterz@infradead.org> - 2016-05-30 11:20 +0200
        Re: [PATCH] mutex: Report recursive ww_mutex locking early Maarten Lankhorst <maarten.lankhorst@linux.intel.com> - 2016-05-30 11:50 +0200
          Re: [PATCH] mutex: Report recursive ww_mutex locking early Peter Zijlstra <peterz@infradead.org> - 2016-05-30 12:30 +0200
            Re: [PATCH] mutex: Report recursive ww_mutex locking early Chris Wilson <chris@chris-wilson.co.uk> - 2016-05-30 12:50 +0200
              Re: [PATCH] mutex: Report recursive ww_mutex locking early Maarten Lankhorst <maarten.lankhorst@linux.intel.com> - 2016-05-30 13:20 +0200

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