linux-kernel - Re: [PATCH RFC] locking/mutexes: don't spin on owner when wait list is not NULL.

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Message-ID: <CAC=cRTNWnt3UUdN4bRiyGd+ySndu078gnhpAdNWcOwvXnv-s1g@mail.gmail.com>
Date:	Mon, 1 Feb 2016 11:29:13 +0800
From:	huang ying <huang.ying.caritas@...il.com>
To:	Ding Tianhong <dingtianhong@...wei.com>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Waiman Long <waiman.long@....com>,
	Jason Low <jason.low2@...com>, Ingo Molnar <mingo@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Davidlohr Bueso <dave@...olabs.net>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	"Paul E. McKenney" <paulmck@...ibm.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Will Deacon <Will.Deacon@....com>,
	Tim Chen <tim.c.chen@...ux.intel.com>,
	Waiman Long <Waiman.Long@...com>,
	Huang Ying <ying.huang@...el.com>
Subject: Re: [PATCH RFC] locking/mutexes: don't spin on owner when wait list
 is not NULL.

On Sat, Jan 30, 2016 at 9:18 AM, Ding Tianhong <dingtianhong@...wei.com> wrote:
> On 2016/1/29 17:53, Peter Zijlstra wrote:
>> On Sun, Jan 24, 2016 at 04:03:50PM +0800, Ding Tianhong wrote:
>>
>>> looks good to me, I will try this solution and report the result, thanks everyone.
>>
>> Did you get a change to run with this?
>>
>> .
>>
>
> I backport this patch to 3.10 lts kernel, and didn't change any logic, Till now, the patch works fine to me, and no need to change anything,
> So I think this patch is no problem, could you formal release this patch to the latest kernel? :)
>
> Thanks.
> Ding
>
>

The original patch from Tianhong triggered a performance regression
because the optimistic spinning is turned off in effect.  I tested
Peter's patch with same configuration and there show no regression.
So I think the patch keep the optimistic spinning.  Test result
details will be in the next email.

Best Regards,
Huang, YIng