The try_harder contiguous fallback could return a range whose start
offset did not match the caller's min_block_size. When a candidate's
start is misaligned, realign it: free the misaligned run and reallocate
exactly @size at the next lower min_block_size boundary. This keeps the
returned size unchanged with no surplus to trim, and rejects the request
only when no aligned candidate fits.
v2: align misaligned candidates down to min_block_size instead of
bailing out, for both the RHS and LHS paths (Matthew).
Fixes: 0a1844bf0b53 ("drm/buddy: Improve contiguous memory allocation")
Suggested-by: Christian König <[email protected]>
Cc: Matthew Auld <[email protected]>
Cc: Christian König <[email protected]>
Cc: Timur Kristóf <[email protected]>
Cc: [email protected]
Reviewed-by: Matthew Auld <[email protected]>
Tested-by: John Olender <[email protected]>
Signed-off-by: Arunpravin Paneer Selvam <[email protected]>
---
drivers/gpu/buddy.c | 63 +++++++++++++++++++++++++++++++--------------
1 file changed, 44 insertions(+), 19 deletions(-)
diff --git a/drivers/gpu/buddy.c b/drivers/gpu/buddy.c
index dc81fe0301ce..3c73ae87f3c5 100644
--- a/drivers/gpu/buddy.c
+++ b/drivers/gpu/buddy.c
@@ -1118,22 +1118,30 @@ static int __gpu_buddy_alloc_range(struct gpu_buddy *mm,
blocks, total_allocated_on_err);
}
+static int __alloc_contig_aligned_retry(struct gpu_buddy *mm,
+ u64 unaligned_offset,
+ u64 size,
+ u64 min_block_size,
+ struct list_head *blocks)
+{
+ u64 aligned_offset = round_down(unaligned_offset, min_block_size);
+
+ return __gpu_buddy_alloc_range(mm, aligned_offset, size, NULL, blocks);
+}
+
static int __alloc_contig_try_harder(struct gpu_buddy *mm,
u64 size,
u64 min_block_size,
struct list_head *blocks)
{
- u64 rhs_offset, lhs_offset, lhs_size, filled;
+ u64 rhs_offset, lhs_offset, filled;
struct gpu_buddy_block *block;
unsigned int tree, order;
- LIST_HEAD(blocks_lhs);
- unsigned long pages;
u64 modify_size;
int err;
modify_size = rounddown_pow_of_two(size);
- pages = modify_size >> ilog2(mm->chunk_size);
- order = fls(pages) - 1;
+ order = ilog2(modify_size) - ilog2(mm->chunk_size);
if (order == 0)
return -ENOSPC;
@@ -1149,31 +1157,48 @@ static int __alloc_contig_try_harder(struct gpu_buddy
*mm,
while (iter) {
block = rbtree_get_free_block(iter);
- /* Allocate blocks traversing RHS */
rhs_offset = gpu_buddy_block_offset(block);
+
+ /* Allocate blocks traversing RHS */
err = __gpu_buddy_alloc_range(mm, rhs_offset, size,
&filled, blocks);
- if (!err || err != -ENOSPC)
+ if (err && err != -ENOSPC)
return err;
+ if (!err && IS_ALIGNED(rhs_offset, min_block_size))
+ return 0;
+ if (!err) {
+ /* Allocate the unaligned RHS offset using
round_down */
+ gpu_buddy_free_list_internal(mm, blocks);
+ err = __alloc_contig_aligned_retry(mm,
rhs_offset,
+ size,
+
min_block_size,
+ blocks);
+ if (!err)
+ return 0;
+ if (err != -ENOSPC) {
+ gpu_buddy_free_list_internal(mm,
blocks);
+ return err;
+ }
+ goto next;
+ }
- lhs_size = max((size - filled), min_block_size);
- if (!IS_ALIGNED(lhs_size, min_block_size))
- lhs_size = round_up(lhs_size, min_block_size);
+ if (size - filled > rhs_offset)
+ goto next;
- /* Allocate blocks traversing LHS */
- lhs_offset = gpu_buddy_block_offset(block) - lhs_size;
- err = __gpu_buddy_alloc_range(mm, lhs_offset, lhs_size,
- NULL, &blocks_lhs);
- if (!err) {
- list_splice(&blocks_lhs, blocks);
+ lhs_offset = rhs_offset - (size - filled);
+
+ /* Allocate the unaligned LHS offset using round_down */
+ gpu_buddy_free_list_internal(mm, blocks);
+ err = __alloc_contig_aligned_retry(mm, lhs_offset, size,
+ min_block_size,
blocks);
+ if (!err)
return 0;
- } else if (err != -ENOSPC) {
+ if (err != -ENOSPC) {
gpu_buddy_free_list_internal(mm, blocks);
return err;
}
- /* Free blocks for the next iteration */
+next:
gpu_buddy_free_list_internal(mm, blocks);
-
iter = rb_prev(iter);
}
}
base-commit: 104c00917264c5b9571072471e3a8689cd1a2c4d
--
2.34.1
