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Subject: Re: [PATCH] locking/osq: Drop the overload of osq lock
From: panxinhui <xinhui@linux.vnet.ibm.com>
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Date: Sun, 26 Jun 2016 12:59:01 +0800
Cc: panxinhui <xinhui@linux.vnet.ibm.com>, Boqun Feng <boqun.feng@gmail.com>,
        Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>,
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To: Peter Zijlstra <peterz@infradead.org>
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> 在 2016年6月26日，03:12，Peter Zijlstra <peterz@infradead.org> 写道：
> 
> On Sun, Jun 26, 2016 at 01:27:51AM +0800, panxinhui wrote:
> 
>> by the way I still think mutex_unlock has a big overload too. 
> 
> Do you mean overhead?
> 
oh, maybe you are right. 
mutex_unlock ’s implementation uses inc_return variant on  ppc, and that’s expensive. I am thinking of using  cmpxchg instead.