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Date: Mon, 22 Apr 2013 16:05:30 -0400
From: Jiannan Ouyang <ouyang@cs.pitt.edu>
Subject: Re: Preemptable Ticket Spinlock
In-reply-to: <517595FA.800@redhat.com>
To: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>, LKML <linux-kernel@vger.kernel.org>,
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On Mon, Apr 22, 2013 at 3:56 PM, Rik van Riel <riel@redhat.com> wrote:
> On 04/22/2013 03:49 PM, Peter Zijlstra wrote:
>>
>> On Mon, 2013-04-22 at 08:52 -0400, Rik van Riel wrote:
>
>
>>> If the native spin_lock code has been called already at
>>> that time, the native code would still need to be modified
>>> to increment the ticket number by 2, so we end up with a
>>> compatible value in each spin lock's .tickets field, and
>>> prevent a deadlock after we switch over to the paravirt
>>> variant.
>>
>>
>> I thought the stuff already made it upstream, but apparently not; the
>> lastest posting I'm aware of is here:
>>
>>    https://lkml.org/lkml/2012/5/2/105
>>
>> That stuff changes the normal ticket increment as well..
>
>
> Jiannan,
>
> It looks like the patch above could make a good patch
> 1 (or 2) in your patch series :)
>
> --
> All rights reversed

Yes.
I'm going to move my code, updated with Rik's suggestions, to paravirt
ops based on Jeremy's patch.
I'll post a new patch series soon.

Thanks to everyone for the great feedback!
--Jiannan
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