[Intel-xe] [PATCH 2/3] drm/xe: Use spinlock in forcewake instead of mutex

[Dixit, Ashutosh]

On Wed, 30 Aug 2023 13:56:57 -0700, Rodrigo Vivi wrote:
>
> On Tue, Aug 29, 2023 at 10:33:02PM -0700, Dixit, Ashutosh wrote:
> > On Tue, 29 Aug 2023 22:15:43 -0700, Aravind Iddamsetty wrote:
> > >
> >
> > Hi Aravind,
> >
> > > @@ -162,7 +162,7 @@ int xe_force_wake_get(struct xe_force_wake *fw,
> > >				   domain->id, ret);
> > >	}
> > >	fw->awake_domains |= woken;
> > > -	mutex_unlock(&fw->lock);
> > > +	spin_unlock(&fw->lock);
> >
> > No need to change anything yet, but let's get some more opinion on this: is
> > it ok to (a) just replace the mutex with a spinlock in these force_wake
> > functions, or, (b) should we have a second set of functions to be called in
> > atomic context, say: xe_force_wake_get/put_atomic? So we should use (b) in
> > atomic contexts and everywhere else we just continue to use the previous
> > set of non-atomic functions? Or just converting the default set of
> > functions to use spin lock (as is done in this patch) is ok?
>
> It looks okay to me,
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>

Still thinking about this, maybe some time (not part of this series) we
should do a power measurement comparison between mutex and spinlock and see
if there's an appreciable difference (unless we already know?). But till we
do that, this is fine, so this is also:

Reviewed-by: Ashutosh Dixit <ashutosh.dixit at intel.com>