Re: [PATCH v4] locking/mutex: Prevent lock starvation when spinning is disabled

From	Peter Zijlstra <peterz@infradead.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v4] locking/mutex: Prevent lock starvation when spinning is disabled
Date	2016-08-23 14:50 +0200
Message-ID	<s9jjr-45B-9@gated-at.bofh.it> (permalink)
References	<s7HpU-7RC-31@gated-at.bofh.it> <s7XO1-1lr-5@gated-at.bofh.it> <s7XO1-1lr-3@gated-at.bofh.it> <s7XXI-1oQ-23@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Fri, Aug 19, 2016 at 12:45:27PM -0700, Linus Torvalds wrote:
> On Fri, Aug 19, 2016 at 12:33 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > That seems more messy to me..
> 
> Can't we just say that we always spin? Are there any really valid
> cases where spinning isn't ok?
> 
> We've historically disabled spinning when mutex debugging is enabled,
> but since the spinning is limited anyway, couldn't we just spin even
> with debugging enabled?
> 
> I hate how these patches are trying to solve a problem that doesn't
> even happen under normal circumstances, and add special-case code for
> something that is already a special-case condition. So rather than
> adding even more special cases, could we look at _removing_ the
> special cases that cause problems instead?

So I think I have a bunch of patches that solves the fundamental issues,
_However_... they're quite invasive and would need some serious
benchmarking.

I'll post them in a separate thread as RFC..

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

Thread

[PATCH v4] locking/mutex: Prevent lock starvation when spinning is  disabled Jason Low <jason.low2@hpe.com> - 2016-08-19 04:10 +0200
  Re: [PATCH v4] locking/mutex: Prevent lock starvation when spinning  is disabled Jason Low <jason.low2@hpe.com> - 2016-08-19 06:30 +0200
    Re: [PATCH v4] locking/mutex: Prevent lock starvation when spinning  is disabled Peter Zijlstra <peterz@infradead.org> - 2016-08-19 14:20 +0200
  Re: [PATCH v4] locking/mutex: Prevent lock starvation when spinning  is disabled Peter Zijlstra <peterz@infradead.org> - 2016-08-19 21:40 +0200
    Re: [PATCH v4] locking/mutex: Prevent lock starvation when spinning  is disabled Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-19 21:50 +0200
      Re: [PATCH v4] locking/mutex: Prevent lock starvation when spinning  is disabled Peter Zijlstra <peterz@infradead.org> - 2016-08-23 14:50 +0200

csiph-web