[PATCH] drm/xe: Remove redundant rebind from preempt rebind worker

[Cavitt, Jonathan]

-----Original Message-----
From: Brost, Matthew <matthew.brost at intel.com> 
Sent: Tuesday, November 12, 2024 2:10 PM
To: Cavitt, Jonathan <jonathan.cavitt at intel.com>
Cc: intel-xe at lists.freedesktop.org
Subject: Re: [PATCH] drm/xe: Remove redundant rebind from preempt rebind worker
> 
> On Tue, Nov 12, 2024 at 02:47:39PM -0700, Cavitt, Jonathan wrote:
> > -----Original Message-----
> > From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of Matthew Brost
> > Sent: Tuesday, November 12, 2024 1:41 PM
> > To: intel-xe at lists.freedesktop.org
> > Subject: [PATCH] drm/xe: Remove redundant rebind from preempt rebind worker
> > > 
> > > We issue a rebind in xe_preempt_work_begin so no need to call
> > > xe_vm_rebind again in the preempt rebind worker.
> > 
> > The call to xe_vm_rebind in xe_preempt_work_begin passes a rebind_worker value of "false",
> > whereas the call in preempt_rebind_work_func passes a rebind_worker value of "true".
> > Ergo, I think the execution requirements are different enough to warrant two separate calls.
> > 
> 
> Hmm, this still doesn't look right but yea this patch also isn't right.
> Let mm follow up on way we doing it is this way. I think we should just
> call xe_vm_bind in xe_preempt_work_begin with a value of true unless I'm
> mistaken.

Okay, it sounds like the solution is as simple as changing the "false" to "true" in
xe_preempt_work_begin on top of what we're doing here.  It's probably more
complicated than that, but if it somehow isn't, then you can add my Reviewed-by
to the patch preemptively, as then the xe_vm_rebind in preempt_rebind_work_func
would irrefutably be redundant.
Reviewed-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
-Jonathan Cavitt

> 
> Matt
> 
> > I could be wrong, though, so I won't nack.
> > -Jonathan Cavitt
> > 
> > > 
> > > Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> > > ---
> > >  drivers/gpu/drm/xe/xe_vm.c | 4 ----
> > >  1 file changed, 4 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> > > index 624133fae5f5..756c72cd6048 100644
> > > --- a/drivers/gpu/drm/xe/xe_vm.c
> > > +++ b/drivers/gpu/drm/xe/xe_vm.c
> > > @@ -525,10 +525,6 @@ static void preempt_rebind_work_func(struct work_struct *w)
> > >  	if (err)
> > >  		goto out_unlock;
> > >  
> > > -	err = xe_vm_rebind(vm, true);
> > > -	if (err)
> > > -		goto out_unlock;
> > > -
> > >  	/* Wait on rebinds and munmap style VM unbinds */
> > >  	wait = dma_resv_wait_timeout(xe_vm_resv(vm),
> > >  				     DMA_RESV_USAGE_KERNEL,
> > > -- 
> > > 2.34.1
> > > 
> > > 
>