Re: [PATCH 0/9] qspinlock stuff -v15

From: Waiman Long
Date: Mon Mar 30 2015 - 12:43:55 EST


On 03/30/2015 12:29 PM, Peter Zijlstra wrote:
On Mon, Mar 30, 2015 at 12:25:12PM -0400, Waiman Long wrote:
I did it differently in my PV portion of the qspinlock patch. Instead of
just waking up the CPU, the new lock holder will check if the new queue head
has been halted. If so, it will set the slowpath flag for the halted queue
head in the lock so as to wake it up at unlock time. This should eliminate
your concern of dong twice as many VMEXIT in an overcommitted scenario.
We can still do that on top of all this right? As you might have
realized I'm a fan of gradual complexity :-)

Of course. I am just saying that the concern can be addressed with some additional code change.

-Longman
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