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/disk-io.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/disk-io.c')
| -rw-r--r-- | fs/btrfs/disk-io.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index ad526aa5312a..25889a2362e2 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2814,6 +2814,7 @@ void btrfs_init_fs_info(struct btrfs_fs_info *fs_info) /* Usable values until the real ones are cached from the superblock */ fs_info->nodesize = 4096; fs_info->sectorsize = 4096; + fs_info->sectorsize_bits = ilog2(4096); fs_info->stripesize = 4096; spin_lock_init(&fs_info->swapfile_pins_lock); @@ -3078,6 +3079,7 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device /* Cache block sizes */ fs_info->nodesize = nodesize; fs_info->sectorsize = sectorsize; + fs_info->sectorsize_bits = ilog2(sectorsize); fs_info->stripesize = stripesize; /* |