diff options
| author | David Sterba <dsterba@suse.com> | 2025-07-01 19:23:51 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2025-07-22 00:09:21 +0200 |
| commit | 58383c6866a76acb719b1f22caaba64fa4dd3f6e (patch) | |
| tree | a1beb8bbde94f7df24043531328e21c761d9af16 | |
| parent | d5a87dbd958398c1926dd35a328ccf89a410cbd2 (diff) | |
btrfs: accessors: compile-time fast path for u8
Reading/writing 1 byte (u8) is a special case compared to the others as
it's always contained in the folio we find, so the split memcpy will
never be needed. Turn it to a compile-time check that the memcpy part
can be optimized out.
The stack usage is reduced:
btrfs_set_8 -16 (32 -> 16)
btrfs_get_8 -16 (24 -> 8)
Code size reduction:
text data bss dec hex filename
1454951 115665 16088 1586704 183610 pre/btrfs.ko
1454691 115665 16088 1586444 18350c post/btrfs.ko
DELTA: -260
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/accessors.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/btrfs/accessors.c b/fs/btrfs/accessors.c index a7b6b2d7bde2..547e9f8fb87d 100644 --- a/fs/btrfs/accessors.c +++ b/fs/btrfs/accessors.c @@ -55,7 +55,8 @@ u##bits btrfs_get_##bits(const struct extent_buffer *eb, \ report_setget_bounds(eb, ptr, off, sizeof(u##bits)); \ return 0; \ } \ - if (INLINE_EXTENT_BUFFER_PAGES == 1 || likely(sizeof(u##bits) <= part)) \ + if (INLINE_EXTENT_BUFFER_PAGES == 1 || sizeof(u##bits) == 1 || \ + likely(sizeof(u##bits) <= part)) \ return get_unaligned_le##bits(kaddr + oil); \ \ memcpy(lebytes, kaddr + oil, part); \ @@ -78,7 +79,7 @@ void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr, \ report_setget_bounds(eb, ptr, off, sizeof(u##bits)); \ return; \ } \ - if (INLINE_EXTENT_BUFFER_PAGES == 1 || \ + if (INLINE_EXTENT_BUFFER_PAGES == 1 || sizeof(u##bits) == 1 || \ likely(sizeof(u##bits) <= part)) { \ put_unaligned_le##bits(val, kaddr + oil); \ return; \ |