[Intel-gfx] [PATCH 08/26] drm/i915/gem: Make eb_add_lut interruptible wait on object lock.

[Maarten Lankhorst]

Op 29-06-2020 om 17:14 schreef Tvrtko Ursulin:
>
> On 23/06/2020 15:28, Maarten Lankhorst wrote:
>> The lock here should be interruptible, so we can backoff if needed.
>
> I spied Chris posting "drm/i915/gem: Move obj->lut_list under its own lock" so maybe have a look at that.
>
> My question here is..
>
>>
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
>> ---
>>   drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 8 +++++++-
>>   1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
>> index 2636a130fb57..aa441af81431 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
>> @@ -774,7 +774,12 @@ static int __eb_add_lut(struct i915_execbuffer *eb,
>>           if (err == 0) { /* And nor has this handle */
>>               struct drm_i915_gem_object *obj = vma->obj;
>>   -            i915_gem_object_lock(obj, NULL);
>> +            err = i915_gem_object_lock_interruptible(obj, NULL);
>
> .. does this lock-unlock survive to the end of your series or gets completely subsumed by the ctx locking?
>
> Regards,
>
> Tvrtko
>
Yeah it survives, it's too early to use ww waiting. Separate lut lock is fine as well as re-using ww is a bit overkill.
>> +            if (err) {
>> +                radix_tree_delete(&ctx->handles_vma, handle);
>> +                goto unlock;
>> +            }
>> +
>>               if (idr_find(&eb->file->object_idr, handle) == obj) {
>>                   list_add(&lut->obj_link, &obj->lut_list);
>>               } else {
>> @@ -783,6 +788,7 @@ static int __eb_add_lut(struct i915_execbuffer *eb,
>>               }
>>               i915_gem_object_unlock(obj);
>>           }
>> +unlock:
>>           mutex_unlock(&ctx->mutex);
>>       }
>>       if (unlikely(err))
>>