On contiguous allocation, we round up the size to the *next* power of 2, implement a function to free the unused pages after the newly allocate block.
Signed-off-by: Arunpravin Arunpravin.PaneerSelvam@amd.com --- drivers/gpu/drm/drm_buddy.c | 103 ++++++++++++++++++++++++++++++++++++ include/drm/drm_buddy.h | 4 ++ 2 files changed, 107 insertions(+)
diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c index 9d3547bcc5da..0da8510736eb 100644 --- a/drivers/gpu/drm/drm_buddy.c +++ b/drivers/gpu/drm/drm_buddy.c @@ -284,6 +284,109 @@ static inline bool contains(u64 s1, u64 e1, u64 s2, u64 e2) return s1 <= s2 && e1 >= e2; }
+/** + * drm_buddy_free_unused_pages - free unused pages + * + * @mm: DRM buddy manager + * @actual_size: original size requested + * @blocks: output list head to add allocated blocks + * + * For contiguous allocation, we round up the size to the nearest + * power of two value, drivers consume *actual* size, so remaining + * portions are unused and it can be freed. + * + * Returns: + * 0 on success, error code on failure. + */ +int drm_buddy_free_unused_pages(struct drm_buddy_mm *mm, + u64 actual_size, + struct list_head *blocks) +{ + struct drm_buddy_block *block; + struct drm_buddy_block *buddy; + u64 actual_start; + u64 actual_end; + LIST_HEAD(dfs); + u64 count = 0; + int err; + + if (!list_is_singular(blocks)) + return -EINVAL; + + block = list_first_entry_or_null(blocks, + struct drm_buddy_block, + link); + + if (!block) + return -EINVAL; + + if (actual_size > drm_buddy_block_size(mm, block)) + return -EINVAL; + + if (actual_size == drm_buddy_block_size(mm, block)) + return 0; + + list_del(&block->link); + + actual_start = drm_buddy_block_offset(block); + actual_end = actual_start + actual_size - 1; + + if (drm_buddy_block_is_allocated(block)) + mark_free(mm, block); + + list_add(&block->tmp_link, &dfs); + + while (1) { + block = list_first_entry_or_null(&dfs, + struct drm_buddy_block, + tmp_link); + + if (!block) + break; + + list_del(&block->tmp_link); + + if (count == actual_size) + return 0; + + if (contains(actual_start, actual_end, drm_buddy_block_offset(block), + (drm_buddy_block_offset(block) + drm_buddy_block_size(mm, block) - 1))) { + BUG_ON(!drm_buddy_block_is_free(block)); + + /* Allocate only required blocks */ + mark_allocated(block); + mm->avail -= drm_buddy_block_size(mm, block); + list_add_tail(&block->link, blocks); + count += drm_buddy_block_size(mm, block); + continue; + } + + if (drm_buddy_block_order(block) == 0) + continue; + + if (!drm_buddy_block_is_split(block)) { + err = split_block(mm, block); + + if (unlikely(err)) + goto err_undo; + } + + list_add(&block->right->tmp_link, &dfs); + list_add(&block->left->tmp_link, &dfs); + } + + return -ENOSPC; + +err_undo: + buddy = get_buddy(block); + if (buddy && + (drm_buddy_block_is_free(block) && + drm_buddy_block_is_free(buddy))) + __drm_buddy_free(mm, block); + return err; +} +EXPORT_SYMBOL(drm_buddy_free_unused_pages); + static struct drm_buddy_block * alloc_range(struct drm_buddy_mm *mm, u64 start, u64 end, diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h index cd8021d2d6e7..1dfc80c88e1f 100644 --- a/include/drm/drm_buddy.h +++ b/include/drm/drm_buddy.h @@ -145,6 +145,10 @@ int drm_buddy_alloc(struct drm_buddy_mm *mm, struct list_head *blocks, unsigned long flags);
+int drm_buddy_free_unused_pages(struct drm_buddy_mm *mm, + u64 actual_size, + struct list_head *blocks); + void drm_buddy_free(struct drm_buddy_mm *mm, struct drm_buddy_block *block);
void drm_buddy_free_list(struct drm_buddy_mm *mm, struct list_head *objects);