diff options
| author | David Sterba <dsterba@suse.com> | 2020-07-01 20:45:04 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-12-08 15:53:57 +0100 |
| commit | ab108d992b1248adfb7c13c1136cab59c944a98c (patch) | |
| tree | 3632b276548fe4abb15b73d675bfcf2c27805b2c /fs/btrfs/free-space-tree.c | |
| parent | e940e9a7c793e3fffe6cdef4f849d696c57ed3f7 (diff) | |
btrfs: use precalculated sectorsize_bits from fs_info
We do a lot of calculations where we divide or multiply by sectorsize.
We also know and make sure that sectorsize is a power of two, so this
means all divisions can be turned to shifts and avoid eg. expensive
u64/u32 divisions.
The type is u32 as it's more register friendly on x86_64 compared to u8
and the resulting assembly is smaller (movzbl vs movl).
There's also superblock s_blocksize_bits but it's usually one more
pointer dereference farther than fs_info.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/free-space-tree.c')
| -rw-r--r-- | fs/btrfs/free-space-tree.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c index 6b9faf3b0e96..84eb1a3ffaca 100644 --- a/fs/btrfs/free-space-tree.c +++ b/fs/btrfs/free-space-tree.c @@ -416,7 +416,7 @@ int convert_free_space_to_extents(struct btrfs_trans_handle *trans, btrfs_mark_buffer_dirty(leaf); btrfs_release_path(path); - nrbits = div_u64(block_group->length, block_group->fs_info->sectorsize); + nrbits = block_group->length >> block_group->fs_info->sectorsize_bits; start_bit = find_next_bit_le(bitmap, nrbits, 0); while (start_bit < nrbits) { @@ -540,8 +540,8 @@ static void free_space_set_bits(struct btrfs_block_group *block_group, end = found_end; ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); - first = div_u64(*start - found_start, fs_info->sectorsize); - last = div_u64(end - found_start, fs_info->sectorsize); + first = (*start - found_start) >> fs_info->sectorsize_bits; + last = (end - found_start) >> fs_info->sectorsize_bits; if (bit) extent_buffer_bitmap_set(leaf, ptr, first, last - first); else |