RE: [PATCH v4 1/7] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL

[Long, Wai Man]

Davidlohr,

I am sorry that I forgot to put in your tag.

Cheers,
Longman

-----Original Message-----
From: linux-kernel-owner@xxxxxxxxxxxxxxx [mailto:linux-kernel-owner@xxxxxxxxxxxxxxx] On Behalf Of Davidlohr Bueso
Sent: Saturday, August 01, 2015 2:01 PM
To: Long, Wai Man
Cc: Peter Zijlstra; Ingo Molnar; Thomas Gleixner; H. Peter Anvin; x86@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Norton, Scott J; Hatch, Douglas B (HPS Linux PM)
Subject: Re: [PATCH v4 1/7] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL

On Fri, 2015-07-31 at 22:21 -0400, Waiman Long wrote:
> The smp_store_release() is not a full barrier. In order to avoid 
> missed wakeup, we may need to add memory barrier around locked and cpu 
> state variables adding to complexity. As the chance of spurious wakeup 
> is very low, it is easier and safer to just do an unconditional kick 
> at unlock time.
> 
> Signed-off-by: Waiman Long <Waiman.Long@xxxxxx>

Please keep tags from previous versions ;)

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/