Re: [PATCH 07/11] qspinlock: Use a simple write to grab the lock, if applicable

2014-07-07 Thread Peter Zijlstra
On Wed, Jun 18, 2014 at 12:36:15PM -0400, Konrad Rzeszutek Wilk wrote: > On Sun, Jun 15, 2014 at 02:47:04PM +0200, Peter Zijlstra wrote: > > From: Waiman Long > > > > Currently, atomic_cmpxchg() is used to get the lock. However, this is > > not really necessary if there is more than one task in t

Re: [PATCH 07/11] qspinlock: Use a simple write to grab the lock, if applicable

2014-06-18 Thread Konrad Rzeszutek Wilk
On Sun, Jun 15, 2014 at 02:47:04PM +0200, Peter Zijlstra wrote: > From: Waiman Long > > Currently, atomic_cmpxchg() is used to get the lock. However, this is > not really necessary if there is more than one task in the queue and > the queue head don't need to reset the queue code word. For that c

[PATCH 07/11] qspinlock: Use a simple write to grab the lock, if applicable

2014-06-15 Thread Peter Zijlstra
From: Waiman Long Currently, atomic_cmpxchg() is used to get the lock. However, this is not really necessary if there is more than one task in the queue and the queue head don't need to reset the queue code word. For that case, a simple write to set the lock bit is enough as the queue head will b