Re: [PATCH 6/8] drm/i915: add free_unused_pages support to i915

[Matthew Auld <matthew.auld@intel.com>]

On 25/10/2021 14:00, Arunpravin wrote:
> add drm_buddy_free_unused_pages() support on
> contiguous allocation
> 
> Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam@amd.com>
> ---
>   drivers/gpu/drm/i915/i915_ttm_buddy_manager.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
> index 963468228392..162947af8e04 100644
> --- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
> +++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
> @@ -98,6 +98,14 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>   	if (unlikely(err))
>   		goto err_free_blocks;
>   
> +	if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
> +		err = drm_buddy_free_unused_pages(mm, (uint64_t)n_pages << PAGE_SHIFT,
> +						       &bman_res->blocks);
> +
> +		if (unlikely(err))
> +			goto err_free_blocks;

That needs some locking, mark_free/mark_split are all globally visible. 
Some concurrent user might steal the block, or worse.

> +	}
> +
>   	*res = &bman_res->base;
>   	return 0;
>   
>