Re: [Intel-gfx] [PATCH 1/2] drm/i915/ttm: limit where we apply TTM_PL_FLAG_CONTIGUOUS

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

On 3/24/22 18:21, Matthew Auld wrote:
> We only need this when allocating device local-memory, where this
> influences the drm_buddy. Currently there is some funny behaviour where
> an "in limbo" system memory object is lacking the relevant placement
> flags etc. before we first allocate the ttm_tt, leading to ttm
> performing a move when not needed, since the current placement is seen
> as not compatible.
>
> Suggested-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Fixes: 2ed38cec5606 ("drm/i915: opportunistically apply ALLOC_CONTIGIOUS")
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Nirmoy Das <nirmoy.das@linux.intel.com>
> ---
>   drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> index e4a06fcf741a..97e648fa76bd 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> @@ -133,6 +133,9 @@ i915_ttm_place_from_region(const struct intel_memory_region *mr,
>   	memset(place, 0, sizeof(*place));
>   	place->mem_type = intel_region_to_ttm_type(mr);
>   
> +	if (mr->type == INTEL_MEMORY_SYSTEM)
> +		return;
> +

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

>   	if (flags & I915_BO_ALLOC_CONTIGUOUS)
>   		place->flags |= TTM_PL_FLAG_CONTIGUOUS;
>   	if (offset != I915_BO_INVALID_OFFSET) {