diff options
| author | David Sterba <dsterba@suse.com> | 2020-07-02 10:54:11 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-12-08 15:53:58 +0100 |
| commit | fe5ecbe818de38774895305e1f2d48972f1b745f (patch) | |
| tree | 098ab0742863dee92a57cc1dc3cf6bb6c624cb06 /fs/btrfs/disk-io.c | |
| parent | 22b6331d961712ac2735423e5a6c04e9d0fd7897 (diff) | |
btrfs: precalculate checksums per leaf once
btrfs_csum_bytes_to_leaves shows up in system profiles, which makes it a
candidate for optimizations. After the 64bit division has been replaced
by shift, there's still a calculation done each time the function is
called: checksums per leaf.
As this is a constant value for the entire filesystem lifetime, we
can calculate it once at mount time and reuse. This also allows to
reduce the division to 64bit/32bit as we know the constant will always
fit the 32bit type.
Replace the open-coded rounding up with a macro that internally handles
the 64bit division and as it's now a short function, make it static
inline (slight code increase, slight stack usage reduction).
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 | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 475bd197c482..0e540ddd7d99 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3081,6 +3081,7 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device fs_info->sectorsize = sectorsize; fs_info->sectorsize_bits = ilog2(sectorsize); fs_info->csum_size = btrfs_super_csum_size(disk_super); + fs_info->csums_per_leaf = BTRFS_MAX_ITEM_SIZE(fs_info) / fs_info->csum_size; fs_info->stripesize = stripesize; /* |