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From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <waiman.long@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Jason Low <jason.low2@hpe.com>,
	Ding Tianhong <dingtianhong@huawei.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <Will.Deacon@arm.com>, Ingo Molnar <mingo@redhat.com>,
	Imre Deak <imre.deak@intel.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Terry Rudd <terry.rudd@hpe.com>,
	"Paul E. McKenney" <paulmck@us.ibm.com>,
	Jason Low <jason.low2@hp.com>,
	Chris Wilson <chris@chris-wilson.co.uk>,
	Daniel Vetter <daniel.vetter@ffwll.ch>
Subject: Re: [RFC][PATCH -v2 4/4] locking/mutex: Add lock handoff to avoid starvation
Date: Fri, 26 Aug 2016 17:18:18 +0200	[thread overview]
Message-ID: <20160826151818.GO10121@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <57C05287.8000708@hpe.com>

On Fri, Aug 26, 2016 at 10:30:31AM -0400, Waiman Long wrote:
> On 08/25/2016 06:23 PM, Peter Zijlstra wrote:

> >You're right.. I'll try again tomorrow.
> 
> Actually, it is also OK to handoff from NULL=>new, but nothing else is
> appropriate.

I pushed out new patches to git, could you have a peek?

 - killed another of that mutex abuse
 - fixed ATOMIC_FETCH_OP for SH4
 - split: rm arch/*/include/asm/mutex*.h include/asm-generic/mutex*.h
   into a separate patch to aid in review
 - fixed lockdep
 - added an uncontended unlock fast path, to mirror the unconteded lock
   fast path
 - reworked the handoff stuff (again)

I didn't try and be too clever, since its far too hot to think.

Still need to look at adding spinning to the handoff case.
Also need to look at writing (much) better changelogs, they stink.

  reply	other threads:[~2016-08-26 15:18 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-25 18:37 [RFC][PATCH -v2 0/4] locking/mutex: Rewrite basic mutex Peter Zijlstra
2016-08-25 18:37 ` [RFC][PATCH -v2 1/4] locking/drm/i915: Kill mutex trickery Peter Zijlstra
2016-08-25 19:36   ` Daniel Vetter
2016-08-25 19:59     ` Waiman Long
2016-08-25 18:37 ` [RFC][PATCH -v2 2/4] locking/mutex: Rework mutex::owner Peter Zijlstra
2016-08-25 18:37 ` [RFC][PATCH -v2 3/4] locking/mutex: Allow MUTEX_SPIN_ON_OWNER when DEBUG_MUTEXES Peter Zijlstra
2016-08-25 18:37 ` [RFC][PATCH -v2 4/4] locking/mutex: Add lock handoff to avoid starvation Peter Zijlstra
2016-08-25 22:00   ` Waiman Long
2016-08-25 22:23     ` Peter Zijlstra
2016-08-26 14:30       ` Waiman Long
2016-08-26 15:18         ` Peter Zijlstra [this message]
2016-08-26 23:40           ` Waiman Long
2016-08-29 15:41             ` Peter Zijlstra
2016-08-30 11:53               ` Peter Zijlstra
2016-08-30 22:32                 ` Waiman Long

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