[PATCH v4 2/6] drm: improve drm_buddy_alloc function
Arunpravin
Arunpravin.PaneerSelvam at amd.com
Wed Dec 1 16:39:34 UTC 2021
- Make drm_buddy_alloc a single function to handle
range allocation and non-range allocation demands
- Implemented a new function alloc_range() which allocates
the requested power-of-two block comply with range limitations
- Moved order computation and memory alignment logic from
i915 driver to drm buddy
v2:
merged below changes to keep the build unbroken
- drm_buddy_alloc_range() becomes obsolete and may be removed
- enable ttm range allocation (fpfn / lpfn) support in i915 driver
- apply enhanced drm_buddy_alloc() function to i915 driver
v3(Matthew Auld):
- Fix alignment issues and remove unnecessary list_empty check
- add more validation checks for input arguments
- make alloc_range() block allocations as bottom-up
- optimize order computation logic
- replace uint64_t with u64, which is preferred in the kernel
v4(Matthew Auld):
- keep drm_buddy_alloc_range() function implementation for generic
actual range allocations
- keep alloc_range() implementation for end bias allocations
Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam at amd.com>
---
drivers/gpu/drm/drm_buddy.c | 316 +++++++++++++-----
drivers/gpu/drm/i915/i915_ttm_buddy_manager.c | 67 ++--
drivers/gpu/drm/i915/i915_ttm_buddy_manager.h | 2 +
include/drm/drm_buddy.h | 22 +-
4 files changed, 285 insertions(+), 122 deletions(-)
diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
index 9340a4b61c5a..7f47632821f4 100644
--- a/drivers/gpu/drm/drm_buddy.c
+++ b/drivers/gpu/drm/drm_buddy.c
@@ -280,23 +280,97 @@ void drm_buddy_free_list(struct drm_buddy_mm *mm, struct list_head *objects)
}
EXPORT_SYMBOL(drm_buddy_free_list);
-/**
- * drm_buddy_alloc - allocate power-of-two blocks
- *
- * @mm: DRM buddy manager to allocate from
- * @order: size of the allocation
- *
- * The order value here translates to:
- *
- * 0 = 2^0 * mm->chunk_size
- * 1 = 2^1 * mm->chunk_size
- * 2 = 2^2 * mm->chunk_size
- *
- * Returns:
- * allocated ptr to the &drm_buddy_block on success
- */
-struct drm_buddy_block *
-drm_buddy_alloc(struct drm_buddy_mm *mm, unsigned int order)
+static inline bool overlaps(u64 s1, u64 e1, u64 s2, u64 e2)
+{
+ return s1 <= e2 && e1 >= s2;
+}
+
+static inline bool contains(u64 s1, u64 e1, u64 s2, u64 e2)
+{
+ return s1 <= s2 && e1 >= e2;
+}
+
+static struct drm_buddy_block *
+alloc_range_bias(struct drm_buddy_mm *mm,
+ u64 start, u64 end,
+ unsigned int order)
+{
+ struct drm_buddy_block *block;
+ struct drm_buddy_block *buddy;
+ LIST_HEAD(dfs);
+ int err;
+ int i;
+
+ end = end - 1;
+
+ for (i = 0; i < mm->n_roots; ++i)
+ list_add_tail(&mm->roots[i]->tmp_link, &dfs);
+
+ do {
+ u64 block_start;
+ u64 block_end;
+
+ block = list_first_entry_or_null(&dfs,
+ struct drm_buddy_block,
+ tmp_link);
+ if (!block)
+ break;
+
+ list_del(&block->tmp_link);
+
+ if (drm_buddy_block_order(block) < order)
+ continue;
+
+ block_start = drm_buddy_block_offset(block);
+ block_end = block_start + drm_buddy_block_size(mm, block) - 1;
+
+ if (!overlaps(start, end, block_start, block_end))
+ continue;
+
+ if (drm_buddy_block_is_allocated(block))
+ continue;
+
+ if (contains(start, end, block_start, block_end) &&
+ order == drm_buddy_block_order(block)) {
+ /*
+ * Find the free block within the range.
+ */
+ if (drm_buddy_block_is_free(block))
+ return block;
+
+ 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);
+ } while (1);
+
+ return ERR_PTR(-ENOSPC);
+
+err_undo:
+ /*
+ * We really don't want to leave around a bunch of split blocks, since
+ * bigger is better, so make sure we merge everything back before we
+ * free the allocated blocks.
+ */
+ 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_PTR(err);
+}
+
+static struct drm_buddy_block *
+alloc_from_freelist(struct drm_buddy_mm *mm,
+ unsigned int order,
+ unsigned long flags)
{
struct drm_buddy_block *block = NULL;
unsigned int i;
@@ -318,78 +392,28 @@ drm_buddy_alloc(struct drm_buddy_mm *mm, unsigned int order)
while (i != order) {
err = split_block(mm, block);
if (unlikely(err))
- goto out_free;
+ goto err_undo;
- /* Go low */
- block = block->left;
+ block = block->right;
i--;
}
-
- mark_allocated(block);
- mm->avail -= drm_buddy_block_size(mm, block);
- kmemleak_update_trace(block);
return block;
-out_free:
+err_undo:
if (i != order)
__drm_buddy_free(mm, block);
return ERR_PTR(err);
}
-EXPORT_SYMBOL(drm_buddy_alloc);
-
-static inline bool overlaps(u64 s1, u64 e1, u64 s2, u64 e2)
-{
- return s1 <= e2 && e1 >= s2;
-}
-static inline bool contains(u64 s1, u64 e1, u64 s2, u64 e2)
-{
- return s1 <= s2 && e1 >= e2;
-}
-
-/**
- * drm_buddy_alloc_range - allocate range
- *
- * @mm: DRM buddy manager to allocate from
- * @blocks: output list head to add allocated blocks
- * @start: start of the allowed range for this block
- * @size: size of the allocation
- *
- * Intended for pre-allocating portions of the address space, for example to
- * reserve a block for the initial framebuffer or similar, hence the expectation
- * here is that drm_buddy_alloc() is still the main vehicle for
- * allocations, so if that's not the case then the drm_mm range allocator is
- * probably a much better fit, and so you should probably go use that instead.
- *
- * Note that it's safe to chain together multiple alloc_ranges
- * with the same blocks list
- *
- * Returns:
- * 0 on success, error code on failure.
- */
-int drm_buddy_alloc_range(struct drm_buddy_mm *mm,
- struct list_head *blocks,
- u64 start, u64 size)
+static int __alloc_range(struct drm_buddy_mm *mm,
+ struct list_head *dfs,
+ u64 start, u64 size,
+ struct list_head *blocks)
{
struct drm_buddy_block *block;
struct drm_buddy_block *buddy;
- LIST_HEAD(allocated);
- LIST_HEAD(dfs);
u64 end;
int err;
- int i;
-
- if (size < mm->chunk_size)
- return -EINVAL;
-
- if (!IS_ALIGNED(size | start, mm->chunk_size))
- return -EINVAL;
-
- if (range_overflows(start, size, mm->size))
- return -EINVAL;
-
- for (i = 0; i < mm->n_roots; ++i)
- list_add_tail(&mm->roots[i]->tmp_link, &dfs);
end = start + size - 1;
@@ -397,7 +421,7 @@ int drm_buddy_alloc_range(struct drm_buddy_mm *mm,
u64 block_start;
u64 block_end;
- block = list_first_entry_or_null(&dfs,
+ block = list_first_entry_or_null(dfs,
struct drm_buddy_block,
tmp_link);
if (!block)
@@ -424,7 +448,7 @@ int drm_buddy_alloc_range(struct drm_buddy_mm *mm,
mark_allocated(block);
mm->avail -= drm_buddy_block_size(mm, block);
- list_add_tail(&block->link, &allocated);
+ list_add_tail(&block->link, blocks);
continue;
}
@@ -434,11 +458,10 @@ int drm_buddy_alloc_range(struct drm_buddy_mm *mm,
goto err_undo;
}
- list_add(&block->right->tmp_link, &dfs);
- list_add(&block->left->tmp_link, &dfs);
+ list_add(&block->right->tmp_link, dfs);
+ list_add(&block->left->tmp_link, dfs);
} while (1);
- list_splice_tail(&allocated, blocks);
return 0;
err_undo:
@@ -453,11 +476,144 @@ int drm_buddy_alloc_range(struct drm_buddy_mm *mm,
drm_buddy_block_is_free(buddy)))
__drm_buddy_free(mm, block);
+err_free:
+ drm_buddy_free_list(mm, blocks);
+ return err;
+}
+
+/**
+ * __drm_buddy_alloc_range - actual range allocation
+ *
+ * @mm: DRM buddy manager to allocate from
+ * @start: start of the allowed range for this block
+ * @size: size of the allocation
+ * @blocks: output list head to add allocated blocks
+ *
+ * Intended for pre-allocating portions of the address space, for example to
+ * reserve a block for the initial framebuffer or similar
+ *
+ * Note that it's safe to chain together multiple alloc_ranges
+ * with the same blocks list
+ *
+ * Returns:
+ * 0 on success, error code on failure.
+ */
+static int __drm_buddy_alloc_range(struct drm_buddy_mm *mm,
+ u64 start,
+ u64 size,
+ struct list_head *blocks)
+{
+ LIST_HEAD(dfs);
+ int i;
+
+ for (i = 0; i < mm->n_roots; ++i)
+ list_add_tail(&mm->roots[i]->tmp_link, &dfs);
+
+ return __alloc_range(mm, &dfs, start, size, blocks);
+}
+
+/**
+ * drm_buddy_alloc - allocate power-of-two blocks
+ *
+ * @mm: DRM buddy manager to allocate from
+ * @start: start of the allowed range for this block
+ * @end: end of the allowed range for this block
+ * @size: size of the allocation
+ * @min_page_size: alignment of the allocation
+ * @blocks: output list head to add allocated blocks
+ * @flags: DRM_BUDDY_*_ALLOCATION flags
+ *
+ * alloc_range_bias() called on range limitations, which traverses
+ * the tree and returns the desired block.
+ *
+ * alloc_from_freelist() called when *no* range restrictions
+ * are enforced, which picks the block from the freelist.
+ *
+ * blocks are allocated in order, the order value here translates to:
+ *
+ * 0 = 2^0 * mm->chunk_size
+ * 1 = 2^1 * mm->chunk_size
+ * 2 = 2^2 * mm->chunk_size
+ *
+ * Returns:
+ * 0 on success, error code on failure.
+ */
+int drm_buddy_alloc(struct drm_buddy_mm *mm,
+ u64 start, u64 end, u64 size,
+ u64 min_page_size,
+ struct list_head *blocks,
+ unsigned long flags)
+{
+ struct drm_buddy_block *block = NULL;
+ unsigned int min_order, order;
+ unsigned long pages;
+ LIST_HEAD(allocated);
+ int err;
+
+ if (size < mm->chunk_size)
+ return -EINVAL;
+
+ if (min_page_size < mm->chunk_size)
+ return -EINVAL;
+
+ if (!is_power_of_2(min_page_size))
+ return -EINVAL;
+
+ if (!IS_ALIGNED(start | end | size, mm->chunk_size))
+ return -EINVAL;
+
+ if (check_range_overflow(start, end, size, mm->size))
+ return -EINVAL;
+
+ /* Actual range allocation */
+ if (start + size == end)
+ return __drm_buddy_alloc_range(mm, start, size, blocks);
+
+ pages = size >> ilog2(mm->chunk_size);
+ order = fls(pages) - 1;
+ min_order = ilog2(min_page_size) - ilog2(mm->chunk_size);
+
+ do {
+ order = min(order, (unsigned int)fls(pages) - 1);
+ BUG_ON(order > mm->max_order);
+ BUG_ON(order < min_order);
+
+ do {
+ if (flags & DRM_BUDDY_RANGE_ALLOCATION)
+ /* Allocate traversing within the range */
+ block = alloc_range_bias(mm, start, end, order);
+ else
+ /* Allocate from freelist */
+ block = alloc_from_freelist(mm, order, flags);
+
+ if (!IS_ERR(block))
+ break;
+
+ if (order-- == min_order) {
+ err = -ENOSPC;
+ goto err_free;
+ }
+ } while (1);
+
+ mark_allocated(block);
+ mm->avail -= drm_buddy_block_size(mm, block);
+ kmemleak_update_trace(block);
+ list_add_tail(&block->link, &allocated);
+
+ pages -= BIT(order);
+
+ if (!pages)
+ break;
+ } while (1);
+
+ list_splice_tail(&allocated, blocks);
+ return 0;
+
err_free:
drm_buddy_free_list(mm, &allocated);
return err;
}
-EXPORT_SYMBOL(drm_buddy_alloc_range);
+EXPORT_SYMBOL(drm_buddy_alloc);
/**
* drm_buddy_block_print - print block information
diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
index c4b70cb8c248..7621d42155e6 100644
--- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
+++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
@@ -36,13 +36,14 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
struct i915_ttm_buddy_resource *bman_res;
struct drm_buddy_mm *mm = &bman->mm;
- unsigned long n_pages;
- unsigned int min_order;
+ unsigned long n_pages, lpfn;
u64 min_page_size;
u64 size;
int err;
- GEM_BUG_ON(place->fpfn || place->lpfn);
+ lpfn = place->lpfn;
+ if (!lpfn)
+ lpfn = man->size;
bman_res = kzalloc(sizeof(*bman_res), GFP_KERNEL);
if (!bman_res)
@@ -52,6 +53,9 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
INIT_LIST_HEAD(&bman_res->blocks);
bman_res->mm = mm;
+ if (place->fpfn || lpfn != man->size)
+ bman_res->flags |= DRM_BUDDY_RANGE_ALLOCATION;
+
GEM_BUG_ON(!bman_res->base.num_pages);
size = bman_res->base.num_pages << PAGE_SHIFT;
@@ -60,10 +64,16 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
min_page_size = bo->page_alignment << PAGE_SHIFT;
GEM_BUG_ON(min_page_size < mm->chunk_size);
- min_order = ilog2(min_page_size) - ilog2(mm->chunk_size);
+
if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
+ unsigned long pages;
+
size = roundup_pow_of_two(size);
- min_order = ilog2(size) - ilog2(mm->chunk_size);
+ min_page_size = size;
+
+ pages = size >> ilog2(mm->chunk_size);
+ if (pages > lpfn)
+ lpfn = pages;
}
if (size > mm->size) {
@@ -73,34 +83,16 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
n_pages = size >> ilog2(mm->chunk_size);
- do {
- struct drm_buddy_block *block;
- unsigned int order;
-
- order = fls(n_pages) - 1;
- GEM_BUG_ON(order > mm->max_order);
- GEM_BUG_ON(order < min_order);
-
- do {
- mutex_lock(&bman->lock);
- block = drm_buddy_alloc(mm, order);
- mutex_unlock(&bman->lock);
- if (!IS_ERR(block))
- break;
-
- if (order-- == min_order) {
- err = -ENOSPC;
- goto err_free_blocks;
- }
- } while (1);
-
- n_pages -= BIT(order);
-
- list_add_tail(&block->link, &bman_res->blocks);
-
- if (!n_pages)
- break;
- } while (1);
+ mutex_lock(&bman->lock);
+ err = drm_buddy_alloc(mm, (u64)place->fpfn << PAGE_SHIFT,
+ (u64)place->lpfn << PAGE_SHIFT,
+ (u64)n_pages << PAGE_SHIFT,
+ min_page_size,
+ &bman_res->blocks,
+ bman_res->flags);
+ mutex_unlock(&bman->lock);
+ if (unlikely(err))
+ goto err_free_blocks;
*res = &bman_res->base;
return 0;
@@ -266,10 +258,17 @@ int i915_ttm_buddy_man_reserve(struct ttm_resource_manager *man,
{
struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
struct drm_buddy_mm *mm = &bman->mm;
+ unsigned long flags = 0;
int ret;
+ flags |= DRM_BUDDY_RANGE_ALLOCATION;
+
mutex_lock(&bman->lock);
- ret = drm_buddy_alloc_range(mm, &bman->reserved, start, size);
+ ret = drm_buddy_alloc(mm, start,
+ start + size,
+ size, mm->chunk_size,
+ &bman->reserved,
+ flags);
mutex_unlock(&bman->lock);
return ret;
diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
index fa644b512c2e..5ba490875f66 100644
--- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
+++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
@@ -20,6 +20,7 @@ struct drm_buddy_mm;
*
* @base: struct ttm_resource base class we extend
* @blocks: the list of struct i915_buddy_block for this resource/allocation
+ * @flags: DRM_BUDDY_*_ALLOCATION flags
* @mm: the struct i915_buddy_mm for this resource
*
* Extends the struct ttm_resource to manage an address space allocation with
@@ -28,6 +29,7 @@ struct drm_buddy_mm;
struct i915_ttm_buddy_resource {
struct ttm_resource base;
struct list_head blocks;
+ unsigned long flags;
struct drm_buddy_mm *mm;
};
diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h
index f9ff48a3f3a6..221de702e909 100644
--- a/include/drm/drm_buddy.h
+++ b/include/drm/drm_buddy.h
@@ -13,15 +13,22 @@
#include <drm/drm_print.h>
-#define range_overflows(start, size, max) ({ \
+#define check_range_overflow(start, end, size, max) ({ \
typeof(start) start__ = (start); \
+ typeof(end) end__ = (end);\
typeof(size) size__ = (size); \
typeof(max) max__ = (max); \
(void)(&start__ == &size__); \
(void)(&start__ == &max__); \
- start__ >= max__ || size__ > max__ - start__; \
+ (void)(&start__ == &end__); \
+ (void)(&end__ == &size__); \
+ (void)(&end__ == &max__); \
+ start__ >= max__ || end__ > max__ || \
+ size__ > end__ - start__; \
})
+#define DRM_BUDDY_RANGE_ALLOCATION (1 << 0)
+
struct drm_buddy_block {
#define DRM_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12)
#define DRM_BUDDY_HEADER_STATE GENMASK_ULL(11, 10)
@@ -132,12 +139,11 @@ int drm_buddy_init(struct drm_buddy_mm *mm, u64 size, u64 chunk_size);
void drm_buddy_fini(struct drm_buddy_mm *mm);
-struct drm_buddy_block *
-drm_buddy_alloc(struct drm_buddy_mm *mm, unsigned int order);
-
-int drm_buddy_alloc_range(struct drm_buddy_mm *mm,
- struct list_head *blocks,
- u64 start, u64 size);
+int drm_buddy_alloc(struct drm_buddy_mm *mm,
+ u64 start, u64 end, u64 size,
+ u64 min_page_size,
+ struct list_head *blocks,
+ unsigned long flags);
void drm_buddy_free(struct drm_buddy_mm *mm, struct drm_buddy_block *block);
--
2.25.1
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