Re: [PATCH v4 13/30] drm/xe: Move ufence add to vm_bind_ioctl_ops_install_fences

[Matthew Brost <matthew.brost@intel.com>]

On Mon, Mar 25, 2024 at 02:54:44PM -0600, Zeng, Oak wrote:
> This patch makes sense to me. See two nit-pick inline
> 
> > -----Original Message-----
> > From: Intel-xe <intel-xe-bounces@lists.freedesktop.org> On Behalf Of Matthew
> > Brost
> > Sent: Friday, March 8, 2024 12:08 AM
> > To: intel-xe@lists.freedesktop.org
> > Cc: Brost, Matthew <matthew.brost@intel.com>
> > Subject: [PATCH v4 13/30] drm/xe: Move ufence add to
> > vm_bind_ioctl_ops_install_fences
> > 
> > Rather than adding a ufence to a VMA in the bind function, add the
> > ufence to all VMAs in the IOCTL that require binds in
> > vm_bind_ioctl_ops_install_fences. This will help with the transition to
> > job 1 per VM bind IOCTL.
> > 
> > Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> > ---
> >  drivers/gpu/drm/xe/xe_sync.c | 15 ++++++++++++
> >  drivers/gpu/drm/xe/xe_sync.h |  1 +
> >  drivers/gpu/drm/xe/xe_vm.c   | 44 ++++++++++++++++++++++++++++++------
> >  3 files changed, 53 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/xe/xe_sync.c b/drivers/gpu/drm/xe/xe_sync.c
> > index 02c9577fe418..07aa65d9bcab 100644
> > --- a/drivers/gpu/drm/xe/xe_sync.c
> > +++ b/drivers/gpu/drm/xe/xe_sync.c
> > @@ -343,6 +343,21 @@ xe_sync_in_fence_get(struct xe_sync_entry *sync, int
> > num_sync,
> >  	return ERR_PTR(-ENOMEM);
> >  }
> > 
> > +/**
> > + * __xe_sync_ufence_get() - Get user fence from user fence
> > + * @ufence: input user fence
> > + *
> > + * Get a user fence reference from user fence
> > + *
> > + * Return: xe_user_fence pointer with reference
> > + */
> > +struct xe_user_fence *__xe_sync_ufence_get(struct xe_user_fence *ufence)
> > +{
> > +	user_fence_get(ufence);
> > +
> > +	return ufence;
> > +}
> 
> I wonder why this is made part of xe_sync. Isn't just a ufence get function? Can we drop _sync_ from the function name?
> 
> 

Typically exported functions should have a prefix matching the header
file name.

e.g.

xe_sync.h -> all functions should start with xe_sync_*

In this case struct xe_user_fence is private date member to xe_sync.c
(only define in that C file) and just an opaque pointer to the rest of
the driver.

> > +
> >  /**
> >   * xe_sync_ufence_get() - Get user fence from sync
> >   * @sync: input sync
> > diff --git a/drivers/gpu/drm/xe/xe_sync.h b/drivers/gpu/drm/xe/xe_sync.h
> > index 0fd0d51208e6..26e9ec9de1a8 100644
> > --- a/drivers/gpu/drm/xe/xe_sync.h
> > +++ b/drivers/gpu/drm/xe/xe_sync.h
> > @@ -38,6 +38,7 @@ static inline bool xe_sync_is_ufence(struct xe_sync_entry
> > *sync)
> >  	return !!sync->ufence;
> >  }
> > 
> > +struct xe_user_fence *__xe_sync_ufence_get(struct xe_user_fence *ufence);
> >  struct xe_user_fence *xe_sync_ufence_get(struct xe_sync_entry *sync);
> >  void xe_sync_ufence_put(struct xe_user_fence *ufence);
> >  int xe_sync_ufence_get_status(struct xe_user_fence *ufence);
> > diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> > index 5767955529dd..5b93c71fc5e9 100644
> > --- a/drivers/gpu/drm/xe/xe_vm.c
> > +++ b/drivers/gpu/drm/xe/xe_vm.c
> > @@ -1810,17 +1810,10 @@ xe_vm_bind(struct xe_vm *vm, struct xe_vma *vma,
> > struct xe_exec_queue *q,
> >  {
> >  	struct dma_fence *fence;
> >  	struct xe_exec_queue *wait_exec_queue = to_wait_exec_queue(vm,
> > q);
> > -	struct xe_user_fence *ufence;
> > 
> >  	xe_vm_assert_held(vm);
> >  	xe_bo_assert_held(bo);
> > 
> > -	ufence = find_ufence_get(syncs, num_syncs);
> > -	if (vma->ufence && ufence)
> > -		xe_sync_ufence_put(vma->ufence);
> > -
> > -	vma->ufence = ufence ?: vma->ufence;
> > -
> >  	if (immediate) {
> >  		fence = xe_vm_bind_vma(vma, q, syncs, num_syncs, tile_mask,
> >  				       first_op, last_op);
> > @@ -2822,21 +2815,58 @@ struct dma_fence *xe_vm_ops_execute(struct
> > xe_vm *vm, struct xe_vma_ops *vops)
> >  	return fence;
> >  }
> > 
> > +static void vma_add_ufence(struct xe_vma *vma, struct xe_user_fence
> > *ufence)
> > +{
> > +	if (vma->ufence)
> > +		xe_sync_ufence_put(vma->ufence);
> 
> Not sure where/when we introduced xe_sync_ufence_put, for me this can be renamed to xe_ufence_put
> 

See above, I think the naming is correct. All of this is a matter of
opinion, we don't have any offical style guidelines for Xe but we might
want to think about writing some up / fixing Xe to conform while the
driver is still relatively small.

Matt

> Oak
> 
> > +	vma->ufence = __xe_sync_ufence_get(ufence);
> > +}
> > +
> > +static void op_add_ufence(struct xe_vm *vm, struct xe_vma_op *op,
> > +			  struct xe_user_fence *ufence)
> > +{
> > +	switch (op->base.op) {
> > +	case DRM_GPUVA_OP_MAP:
> > +		vma_add_ufence(op->map.vma, ufence);
> > +		break;
> > +	case DRM_GPUVA_OP_REMAP:
> > +		if (op->remap.prev)
> > +			vma_add_ufence(op->remap.prev, ufence);
> > +		if (op->remap.next)
> > +			vma_add_ufence(op->remap.next, ufence);
> > +		break;
> > +	case DRM_GPUVA_OP_UNMAP:
> > +		break;
> > +	case DRM_GPUVA_OP_PREFETCH:
> > +		vma_add_ufence(gpuva_to_vma(op->base.prefetch.va),
> > ufence);
> > +		break;
> > +	default:
> > +		drm_warn(&vm->xe->drm, "NOT POSSIBLE");
> > +	}
> > +}
> > +
> >  static void vm_bind_ioctl_ops_install_fences(struct xe_vm *vm,
> >  					     struct xe_vma_ops *vops,
> >  					     struct dma_fence *fence)
> >  {
> >  	struct xe_exec_queue *wait_exec_queue = to_wait_exec_queue(vm,
> > vops->q);
> > +	struct xe_user_fence *ufence;
> >  	struct xe_vma_op *op;
> >  	int i;
> > 
> > +	ufence = find_ufence_get(vops->syncs, vops->num_syncs);
> >  	list_for_each_entry(op, &vops->list, link) {
> > +		if (ufence)
> > +			op_add_ufence(vm, op, ufence);
> > +
> >  		if (op->base.op == DRM_GPUVA_OP_UNMAP)
> >  			xe_vma_destroy(gpuva_to_vma(op->base.unmap.va),
> > fence);
> >  		else if (op->base.op == DRM_GPUVA_OP_REMAP)
> >  			xe_vma_destroy(gpuva_to_vma(op-
> > >base.remap.unmap->va),
> >  				       fence);
> >  	}
> > +	if (ufence)
> > +		xe_sync_ufence_put(ufence);
> >  	for (i = 0; i < vops->num_syncs; i++)
> >  		xe_sync_entry_signal(vops->syncs + i, NULL, fence);
> >  	xe_exec_queue_last_fence_set(wait_exec_queue, vm, fence);
> > --
> > 2.34.1
>