[Intel-gfx] [PATCH] drm/i915: Do not set cache_dirty for DGFX

[Das, Nirmoy]

On 11/2/2022 11:36 AM, Matthew Auld wrote:
> On 02/11/2022 07:39, Das, Nirmoy wrote:
>>
>> On 11/2/2022 6:14 AM, Niranjana Vishwanathapura wrote:
>>> Currently on DG1, which do not have LLC, we hit the below
>>> warning while rebinding an userptr invalidated object.
>>>
>>> WARNING: CPU: 4 PID: 13008 at 
>>> drivers/gpu/drm/i915/gem/i915_gem_pages.c:34 
>>> __i915_gem_object_set_pages+0x296/0x2d0 [i915]
>>> ...
>>> RIP: 0010:__i915_gem_object_set_pages+0x296/0x2d0 [i915]
>>> ...
>>> Call Trace:
>>>   <TASK>
>>>   i915_gem_userptr_get_pages+0x175/0x1a0 [i915]
>>>   ____i915_gem_object_get_pages+0x32/0xb0 [i915]
>>>   i915_gem_object_userptr_submit_init+0x286/0x470 [i915]
>>>   eb_lookup_vmas+0x2ff/0xcf0 [i915]
>>>   ? __intel_wakeref_get_first+0x55/0xb0 [i915]
>>>   i915_gem_do_execbuffer+0x785/0x21d0 [i915]
>>>   i915_gem_execbuffer2_ioctl+0xe7/0x3d0 [i915]
>>>
>>> We shouldn't be setting the obj->cache_dirty for DGFX,
>>> fix it.
>>
>> With Fixes: |d70af57944 |("drm/i915/shmem: ensure flush during 
>> swap-in on non-LLC")
>>
>> Acked-by: Nirmoy Das <nirmoy.das at intel.com>
>
> Any idea why this escaped our testing in CI? Perhaps something to 
> improve.


I ran some userptr related igt tests none hit 
__i915_gem_object_release_shmem . So I think we are missing

coverage here or I/CI isn't running such test.

Niranjana, what test did you ran to hit this case WARN ?


Regards,

Nirmoy


>
> Reviewed-by: Matthew Auld <matthew.auld at intel.com>
>
>>
>>> Suggested-by: Matthew Auld<matthew.auld at intel.com>
>>> Reported-by: Niranjana 
>>> Vishwanathapura<niranjana.vishwanathapura at intel.com>
>>> Signed-off-by: Niranjana 
>>> Vishwanathapura<niranjana.vishwanathapura at intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 4 ++--
>>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c 
>>> b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
>>> index 11125c32dd35..2f7804492cd5 100644
>>> --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
>>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
>>> @@ -369,14 +369,14 @@ __i915_gem_object_release_shmem(struct 
>>> drm_i915_gem_object *obj,
>>>         __start_cpu_write(obj);
>>>       /*
>>> -     * On non-LLC platforms, force the flush-on-acquire if this is 
>>> ever
>>> +     * On non-LLC igfx platforms, force the flush-on-acquire if 
>>> this is ever
>>>        * swapped-in. Our async flush path is not trust worthy enough 
>>> yet(and
>>>        * happens in the wrong order), and with some tricks it's 
>>> conceivable
>>>        * for userspace to change the cache-level to I915_CACHE_NONE 
>>> after the
>>>        * pages are swapped-in, and since execbuf binds the object 
>>> before doing
>>>        * the async flush, we have a race window.
>>>        */
>>> -    if (!HAS_LLC(i915))
>>> +    if (!HAS_LLC(i915) && !IS_DGFX(i915))
>>>           obj->cache_dirty = true;
>>>   }