diff mbox series

[CI,2/2] drm/i915: limit the async bind to bind_async_flags

Message ID 20220304095934.925036-2-matthew.auld@intel.com (mailing list archive)
State New, archived
Headers show
Series [CI,1/2] drm/i915/fbdev: fixup setting screen_size | expand

Commit Message

Matthew Auld March 4, 2022, 9:59 a.m. UTC
If the vm doesn't request async binding, like for example with the dpt,
then we should be able to skip the async path and avoid calling
i915_vm_lock_objects() altogether. Currently if we have a moving fence
set for the BO(even though it might have signalled), we still take the
async patch regardless of the bind_async setting, and then later still
end up just doing i915_gem_object_wait_moving_fence() anyway.

Alternatively we would need to add dummy scratch object which can be
locked, just for the dpt.

Suggested-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
---
 drivers/gpu/drm/i915/i915_vma.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Thomas Hellstrom March 4, 2022, 4:41 p.m. UTC | #1
On Fri, 2022-03-04 at 09:59 +0000, Matthew Auld wrote:
> If the vm doesn't request async binding, like for example with the
> dpt,
> then we should be able to skip the async path and avoid calling
> i915_vm_lock_objects() altogether. Currently if we have a moving
> fence
> set for the BO(even though it might have signalled), we still take
> the
> async patch regardless of the bind_async setting, and then later
> still
> end up just doing i915_gem_object_wait_moving_fence() anyway.
> 
> Alternatively we would need to add dummy scratch object which can be
> locked, just for the dpt.
> 
> Suggested-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_vma.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_vma.c
> b/drivers/gpu/drm/i915/i915_vma.c
> index 94fcdb7bd21d..4d4d3659c938 100644
> --- a/drivers/gpu/drm/i915/i915_vma.c
> +++ b/drivers/gpu/drm/i915/i915_vma.c
> @@ -1360,8 +1360,7 @@ int i915_vma_pin_ww(struct i915_vma *vma,
> struct i915_gem_ww_ctx *ww,
>         if (flags & PIN_GLOBAL)
>                 wakeref = intel_runtime_pm_get(&vma->vm->i915-
> >runtime_pm);
>  
> -       moving = vma->obj ?

Is there a chance that "moving" will be used uninitialized later?


> i915_gem_object_get_moving_fence(vma->obj) : NULL;
> -       if (flags & vma->vm->bind_async_flags || moving) {
> +       if (flags & vma->vm->bind_async_flags) {
>                 /* lock VM */
>                 err = i915_vm_lock_objects(vma->vm, ww);
>                 if (err)
> @@ -1375,6 +1374,7 @@ int i915_vma_pin_ww(struct i915_vma *vma,
> struct i915_gem_ww_ctx *ww,
>  
>                 work->vm = i915_vm_get(vma->vm);
>  
> +               moving = vma->obj ?
> i915_gem_object_get_moving_fence(vma->obj) : NULL;

IIRC, with Maarten's recent changes, vma->obj is always non-NULL.

Otherwise LGTM.
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>


>                 dma_fence_work_chain(&work->base, moving);
>  
>                 /* Allocate enough page directories to used PTE */

/Thomas
Matthew Auld March 4, 2022, 5:28 p.m. UTC | #2
On 04/03/2022 16:41, Thomas Hellström wrote:
> On Fri, 2022-03-04 at 09:59 +0000, Matthew Auld wrote:
>> If the vm doesn't request async binding, like for example with the
>> dpt,
>> then we should be able to skip the async path and avoid calling
>> i915_vm_lock_objects() altogether. Currently if we have a moving
>> fence
>> set for the BO(even though it might have signalled), we still take
>> the
>> async patch regardless of the bind_async setting, and then later
>> still
>> end up just doing i915_gem_object_wait_moving_fence() anyway.
>>
>> Alternatively we would need to add dummy scratch object which can be
>> locked, just for the dpt.
>>
>> Suggested-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
>> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
>> Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_vma.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_vma.c
>> b/drivers/gpu/drm/i915/i915_vma.c
>> index 94fcdb7bd21d..4d4d3659c938 100644
>> --- a/drivers/gpu/drm/i915/i915_vma.c
>> +++ b/drivers/gpu/drm/i915/i915_vma.c
>> @@ -1360,8 +1360,7 @@ int i915_vma_pin_ww(struct i915_vma *vma,
>> struct i915_gem_ww_ctx *ww,
>>          if (flags & PIN_GLOBAL)
>>                  wakeref = intel_runtime_pm_get(&vma->vm->i915-
>>> runtime_pm);
>>   
>> -       moving = vma->obj ?
> 
> Is there a chance that "moving" will be used uninitialized later?

It looks to be initialised with NULL further up.

> 
> 
>> i915_gem_object_get_moving_fence(vma->obj) : NULL;
>> -       if (flags & vma->vm->bind_async_flags || moving) {
>> +       if (flags & vma->vm->bind_async_flags) {
>>                  /* lock VM */
>>                  err = i915_vm_lock_objects(vma->vm, ww);
>>                  if (err)
>> @@ -1375,6 +1374,7 @@ int i915_vma_pin_ww(struct i915_vma *vma,
>> struct i915_gem_ww_ctx *ww,
>>   
>>                  work->vm = i915_vm_get(vma->vm);
>>   
>> +               moving = vma->obj ?
>> i915_gem_object_get_moving_fence(vma->obj) : NULL;
> 
> IIRC, with Maarten's recent changes, vma->obj is always non-NULL.

Yup, a number of these seem to have crept back in. I was going to send a 
follow up patch to fix all of them at once.

> 
> Otherwise LGTM.
> Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>

Thanks.

> 
> 
>>                  dma_fence_work_chain(&work->base, moving);
>>   
>>                  /* Allocate enough page directories to used PTE */
> 
> /Thomas
> 
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 94fcdb7bd21d..4d4d3659c938 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -1360,8 +1360,7 @@  int i915_vma_pin_ww(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
 	if (flags & PIN_GLOBAL)
 		wakeref = intel_runtime_pm_get(&vma->vm->i915->runtime_pm);
 
-	moving = vma->obj ? i915_gem_object_get_moving_fence(vma->obj) : NULL;
-	if (flags & vma->vm->bind_async_flags || moving) {
+	if (flags & vma->vm->bind_async_flags) {
 		/* lock VM */
 		err = i915_vm_lock_objects(vma->vm, ww);
 		if (err)
@@ -1375,6 +1374,7 @@  int i915_vma_pin_ww(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
 
 		work->vm = i915_vm_get(vma->vm);
 
+		moving = vma->obj ? i915_gem_object_get_moving_fence(vma->obj) : NULL;
 		dma_fence_work_chain(&work->base, moving);
 
 		/* Allocate enough page directories to used PTE */