Re: [Intel-gfx] [PATCH] drm/i915: Suppress oom warning for shmemfs object allocation failure

["Das, Nirmoy" <nirmoy.das@intel.com>]

On 7/21/2022 11:49 AM, Matthew Auld wrote:
> On 20/07/2022 13:23, Nirmoy Das wrote:
>> From: Chris Wilson <chris@chris-wilson.co.uk>
>>
>> We report object allocation failures to userspace with ENOMEM, yet we
>> still show the memory warning after failing to shrink device allocated
>> pages. While this warning is similar to other system page allocation
>> failures, it is superfluous to the ENOMEM provided directly to
>> userspace.
>>
>> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4936
>
> Is it not possible that this triggers OOM warning when calling 
> sg_alloc_table() or similar?


I haven't observed any after running the test for a while but I think it 
might be possible, Do you think I should add __GFP_NOWARN for that too ?


Nirmoy


> I guess shmem_read_mapping_page_gfp() is the most likely spot where 
> this triggers OOM, but that doesn't have to be the case?
>
>> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>> Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
>> ---
>>   drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c 
>> b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
>> index 4eed3dd90ba8..4466173e1bcc 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
>> @@ -137,7 +137,7 @@ int shmem_sg_alloc_table(struct drm_i915_private 
>> *i915, struct sg_table *st,
>>                    * trigger the out-of-memory killer and for
>>                    * this we want __GFP_RETRY_MAYFAIL.
>>                    */
>> -                gfp |= __GFP_RETRY_MAYFAIL;
>> +                gfp |= __GFP_RETRY_MAYFAIL | __GFP_NOWARN;
>>               }
>>           } while (1);