Re: [PATCH 06/13] x86/ticketlock: add slowpath logic

[Jeremy Fitzhardinge]

On 09/02/2011 11:46 AM, Eric Northup wrote:
> On Thu, Sep 1, 2011 at 5:54 PM, Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:
>> From: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
>>
>> Maintain a flag in both LSBs of the ticket lock which indicates whether
>> anyone is in the lock slowpath and may need kicking when the current
>> holder unlocks.  The flags are set when the first locker enters
>> the slowpath, and cleared when unlocking to an empty queue.
> Are there actually two flags maintained?  I only see the one in the
> ticket tail getting set/cleared/tested.

Yeah, there's only one flag, so there's a spare bit in the other half.

    j

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