On Tue, 23 Jul 2024, Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@xxxxxxx> wrote:
> - Add a new start parameter in trim function to specify exact
> address from where to start the trimming. This would help us
> in situations like if drivers would like to do address alignment
> for specific requirements.
>
> - Add a new flag DRM_BUDDY_TRIM_DISABLE. Drivers can use this
> flag to disable the allocator trimming part. This patch enables
> the drivers control trimming and they can do it themselves
> based on the application requirements.
>
> v1:(Matthew)
> - check new_start alignment with min chunk_size
> - use range_overflows()
>
> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@xxxxxxx>
> Acked-by: Alex Deucher <alexander.deucher@xxxxxxx>
> Acked-by: Christian König <christian.koenig@xxxxxxx>
> ---
> drivers/gpu/drm/drm_buddy.c | 25 +++++++++++++++++++++++--
> drivers/gpu/drm/xe/xe_ttm_vram_mgr.c | 2 +-
> include/drm/drm_buddy.h | 2 ++
> 3 files changed, 26 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
> index 6a8e45e9d0ec..103c185bb1c8 100644
> --- a/drivers/gpu/drm/drm_buddy.c
> +++ b/drivers/gpu/drm/drm_buddy.c
> @@ -851,6 +851,7 @@ static int __alloc_contig_try_harder(struct drm_buddy *mm,
> * drm_buddy_block_trim - free unused pages
> *
> * @mm: DRM buddy manager
> + * @start: start address to begin the trimming.
> * @new_size: original size requested
> * @blocks: Input and output list of allocated blocks.
> * MUST contain single block as input to be trimmed.
> @@ -866,11 +867,13 @@ static int __alloc_contig_try_harder(struct drm_buddy *mm,
> * 0 on success, error code on failure.
> */
> int drm_buddy_block_trim(struct drm_buddy *mm,
> + u64 *start,
Is this a pointer only to allow passing NULL as "don't specify"? It's
not used for returning anything in *start. Maybe it should be a const
pointer?
Not the prettiest of interfaces, and the kernel-doc does not reflect any
of this.
BR,
Jani.
> u64 new_size,
> struct list_head *blocks)
> {
> struct drm_buddy_block *parent;
> struct drm_buddy_block *block;
> + u64 block_start, block_end;
> LIST_HEAD(dfs);
> u64 new_start;
> int err;
> @@ -882,6 +885,9 @@ int drm_buddy_block_trim(struct drm_buddy *mm,
> struct drm_buddy_block,
> link);
>
> + block_start = drm_buddy_block_offset(block);
> + block_end = block_start + drm_buddy_block_size(mm, block);
> +
> if (WARN_ON(!drm_buddy_block_is_allocated(block)))
> return -EINVAL;
>
> @@ -894,6 +900,20 @@ int drm_buddy_block_trim(struct drm_buddy *mm,
> if (new_size == drm_buddy_block_size(mm, block))
> return 0;
>
> + new_start = block_start;
> + if (start) {
> + new_start = *start;
> +
> + if (new_start < block_start)
> + return -EINVAL;
> +
> + if (!IS_ALIGNED(new_start, mm->chunk_size))
> + return -EINVAL;
> +
> + if (range_overflows(new_start, new_size, block_end))
> + return -EINVAL;
> + }
> +
> list_del(&block->link);
> mark_free(mm, block);
> mm->avail += drm_buddy_block_size(mm, block);
> @@ -904,7 +924,6 @@ int drm_buddy_block_trim(struct drm_buddy *mm,
> parent = block->parent;
> block->parent = NULL;
>
> - new_start = drm_buddy_block_offset(block);
> list_add(&block->tmp_link, &dfs);
> err = __alloc_range(mm, &dfs, new_start, new_size, blocks, NULL);
> if (err) {
> @@ -1066,7 +1085,8 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm,
> } while (1);
>
> /* Trim the allocated block to the required size */
> - if (original_size != size) {
> + if (!(flags & DRM_BUDDY_TRIM_DISABLE) &&
> + original_size != size) {
> struct list_head *trim_list;
> LIST_HEAD(temp);
> u64 trim_size;
> @@ -1083,6 +1103,7 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm,
> }
>
> drm_buddy_block_trim(mm,
> + NULL,
> trim_size,
> trim_list);
>
> diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
> index fe3779fdba2c..423b261ea743 100644
> --- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
> +++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
> @@ -150,7 +150,7 @@ static int xe_ttm_vram_mgr_new(struct ttm_resource_manager *man,
> } while (remaining_size);
>
> if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
> - if (!drm_buddy_block_trim(mm, vres->base.size, &vres->blocks))
> + if (!drm_buddy_block_trim(mm, NULL, vres->base.size, &vres->blocks))
> size = vres->base.size;
> }
>
> diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h
> index 2a74fa9d0ce5..9689a7c5dd36 100644
> --- a/include/drm/drm_buddy.h
> +++ b/include/drm/drm_buddy.h
> @@ -27,6 +27,7 @@
> #define DRM_BUDDY_CONTIGUOUS_ALLOCATION BIT(2)
> #define DRM_BUDDY_CLEAR_ALLOCATION BIT(3)
> #define DRM_BUDDY_CLEARED BIT(4)
> +#define DRM_BUDDY_TRIM_DISABLE BIT(5)
>
> struct drm_buddy_block {
> #define DRM_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12)
> @@ -155,6 +156,7 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm,
> unsigned long flags);
>
> int drm_buddy_block_trim(struct drm_buddy *mm,
> + u64 *start,
> u64 new_size,
> struct list_head *blocks);
>
>
> base-commit: b27d70e1042bf6a31ba7e5acf58b61c9cd28f95b
--
Jani Nikula, Intel
