Re: [Intel-gfx] [PATCH v3 6/6] drm/ttm: Switch to using the new res callback

[Arunpravin Paneer Selvam <arunpravin.paneerselvam@amd.com>]

On 7/28/2022 9:07 PM, Matthew Auld wrote:
> On 28/07/2022 15:33, Arunpravin Paneer Selvam wrote:
>> Apply new intersect and compatible callback instead
>> of having a generic placement range verfications.
>>
>> v2: Added a separate callback for compatiblilty
>>      checks (Christian)
>>
>> Signed-off-by: Christian König <christian.koenig@amd.com>
>> Signed-off-by: Arunpravin Paneer Selvam 
>> <Arunpravin.PaneerSelvam@amd.com>
>
> There is also some code at the bottom of i915_ttm_buddy_man_alloc() 
> playing games with res->start, which I think can be safely deleted 
> with this series (now that we have proper ->compatible() hook).
>
> Also, is the plan to remove res->start completely, or does that still 
> have a use?
yes we should remove res->start completely, I am working on it, planning 
to send in a separate series as amdgpu uses it in many places, and in 
some places we set res->start to AMDGPU_BO_INVALID_OFFSET,
I should find an alternative to indicate the invalid offset BO. Also, 
res->start used in drm/drm_gem_vram_helper.c at drm_gem_vram_pg_offset() 
function. I am removing all the dependencies, I will send the
patches in a separate series. I think i915 doesn't use res->start in its 
own driver code.
>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 45 +++++++------------------
>>   drivers/gpu/drm/ttm/ttm_bo.c            |  9 +++--
>>   drivers/gpu/drm/ttm/ttm_resource.c      |  5 +--
>>   3 files changed, 20 insertions(+), 39 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> index 170935c294f5..7d25a10395c0 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> @@ -1328,11 +1328,12 @@ uint64_t amdgpu_ttm_tt_pte_flags(struct 
>> amdgpu_device *adev, struct ttm_tt *ttm,
>>   static bool amdgpu_ttm_bo_eviction_valuable(struct 
>> ttm_buffer_object *bo,
>>                           const struct ttm_place *place)
>>   {
>> -    unsigned long num_pages = bo->resource->num_pages;
>>       struct dma_resv_iter resv_cursor;
>> -    struct amdgpu_res_cursor cursor;
>>       struct dma_fence *f;
>>   +    if (!amdgpu_bo_is_amdgpu_bo(bo))
>> +        return ttm_bo_eviction_valuable(bo, place);
>> +
>>       /* Swapout? */
>>       if (bo->resource->mem_type == TTM_PL_SYSTEM)
>>           return true;
>> @@ -1351,40 +1352,20 @@ static bool 
>> amdgpu_ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
>>               return false;
>>       }
>>   -    switch (bo->resource->mem_type) {
>> -    case AMDGPU_PL_PREEMPT:
>> -        /* Preemptible BOs don't own system resources managed by the
>> -         * driver (pages, VRAM, GART space). They point to resources
>> -         * owned by someone else (e.g. pageable memory in user mode
>> -         * or a DMABuf). They are used in a preemptible context so we
>> -         * can guarantee no deadlocks and good QoS in case of MMU
>> -         * notifiers or DMABuf move notifiers from the resource owner.
>> -         */
>> +    /* Preemptible BOs don't own system resources managed by the
>> +     * driver (pages, VRAM, GART space). They point to resources
>> +     * owned by someone else (e.g. pageable memory in user mode
>> +     * or a DMABuf). They are used in a preemptible context so we
>> +     * can guarantee no deadlocks and good QoS in case of MMU
>> +     * notifiers or DMABuf move notifiers from the resource owner.
>> +     */
>> +    if (bo->resource->mem_type == AMDGPU_PL_PREEMPT)
>>           return false;
>> -    case TTM_PL_TT:
>> -        if (amdgpu_bo_is_amdgpu_bo(bo) &&
>> -            amdgpu_bo_encrypted(ttm_to_amdgpu_bo(bo)))
>> -            return false;
>> -        return true;
>>   -    case TTM_PL_VRAM:
>> -        /* Check each drm MM node individually */
>> -        amdgpu_res_first(bo->resource, 0, (u64)num_pages << PAGE_SHIFT,
>> -                 &cursor);
>> -        while (cursor.remaining) {
>> -            if (place->fpfn < PFN_DOWN(cursor.start + cursor.size)
>> -                && !(place->lpfn &&
>> -                 place->lpfn <= PFN_DOWN(cursor.start)))
>> -                return true;
>> -
>> -            amdgpu_res_next(&cursor, cursor.size);
>> -        }
>> +    if (bo->resource->mem_type == TTM_PL_TT &&
>> +        amdgpu_bo_encrypted(ttm_to_amdgpu_bo(bo)))
>>           return false;
>>   -    default:
>> -        break;
>> -    }
>> -
>>       return ttm_bo_eviction_valuable(bo, place);
>>   }
>>   diff --git a/drivers/gpu/drm/ttm/ttm_bo.c 
>> b/drivers/gpu/drm/ttm/ttm_bo.c
>> index c1bd006a5525..03409409e43e 100644
>> --- a/drivers/gpu/drm/ttm/ttm_bo.c
>> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
>> @@ -518,6 +518,9 @@ static int ttm_bo_evict(struct ttm_buffer_object 
>> *bo,
>>   bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
>>                     const struct ttm_place *place)
>>   {
>> +    struct ttm_resource *res = bo->resource;
>> +    struct ttm_device *bdev = bo->bdev;
>> +
>>       dma_resv_assert_held(bo->base.resv);
>>       if (bo->resource->mem_type == TTM_PL_SYSTEM)
>>           return true;
>> @@ -525,11 +528,7 @@ bool ttm_bo_eviction_valuable(struct 
>> ttm_buffer_object *bo,
>>       /* Don't evict this BO if it's outside of the
>>        * requested placement range
>>        */
>> -    if (place->fpfn >= (bo->resource->start + 
>> bo->resource->num_pages) ||
>> -        (place->lpfn && place->lpfn <= bo->resource->start))
>> -        return false;
>> -
>> -    return true;
>> +    return ttm_resource_intersect(bdev, res, place, bo->base.size);
>>   }
>>   EXPORT_SYMBOL(ttm_bo_eviction_valuable);
>>   diff --git a/drivers/gpu/drm/ttm/ttm_resource.c 
>> b/drivers/gpu/drm/ttm/ttm_resource.c
>> index 84a6fe9e976e..c745faf72b1a 100644
>> --- a/drivers/gpu/drm/ttm/ttm_resource.c
>> +++ b/drivers/gpu/drm/ttm/ttm_resource.c
>> @@ -316,6 +316,8 @@ static bool ttm_resource_places_compat(struct 
>> ttm_resource *res,
>>                          const struct ttm_place *places,
>>                          unsigned num_placement)
>>   {
>> +    struct ttm_buffer_object *bo = res->bo;
>> +    struct ttm_device *bdev = bo->bdev;
>>       unsigned i;
>>         if (res->placement & TTM_PL_FLAG_TEMPORARY)
>> @@ -324,8 +326,7 @@ static bool ttm_resource_places_compat(struct 
>> ttm_resource *res,
>>       for (i = 0; i < num_placement; i++) {
>>           const struct ttm_place *heap = &places[i];
>>   -        if (res->start < heap->fpfn || (heap->lpfn &&
>> -            (res->start + res->num_pages) > heap->lpfn))
>> +        if (!ttm_resource_compatible(bdev, res, heap, bo->base.size))
>>               continue;
>>             if ((res->mem_type == heap->mem_type) &&