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/scrub.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/scrub.c')
| -rw-r--r-- | fs/btrfs/scrub.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 04351b55dd14..c307f25c4846 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -2300,7 +2300,7 @@ static inline void __scrub_mark_bitmap(struct scrub_parity *sparity, u64 offset; u64 nsectors64; u32 nsectors; - int sectorsize = sparity->sctx->fs_info->sectorsize; + u32 sectorsize_bits = sparity->sctx->fs_info->sectorsize_bits; if (len >= sparity->stripe_len) { bitmap_set(bitmap, 0, sparity->nsectors); @@ -2309,8 +2309,8 @@ static inline void __scrub_mark_bitmap(struct scrub_parity *sparity, start -= sparity->logic_start; start = div64_u64_rem(start, sparity->stripe_len, &offset); - offset = div_u64(offset, sectorsize); - nsectors64 = div_u64(len, sectorsize); + offset = offset >> sectorsize_bits; + nsectors64 = len >> sectorsize_bits; ASSERT(nsectors64 < UINT_MAX); nsectors = (u32)nsectors64; @@ -2386,10 +2386,10 @@ static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u8 *csum) if (!sum) return 0; - index = div_u64(logical - sum->bytenr, sctx->fs_info->sectorsize); + index = (logical - sum->bytenr) >> sctx->fs_info->sectorsize_bits; ASSERT(index < UINT_MAX); - num_sectors = sum->len / sctx->fs_info->sectorsize; + num_sectors = sum->len >> sctx->fs_info->sectorsize_bits; memcpy(csum, sum->sums + index * sctx->csum_size, sctx->csum_size); if (index == num_sectors - 1) { list_del(&sum->list); @@ -2776,7 +2776,7 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx, int extent_mirror_num; int stop_loop = 0; - nsectors = div_u64(map->stripe_len, fs_info->sectorsize); + nsectors = map->stripe_len >> fs_info->sectorsize_bits; bitmap_len = scrub_calc_parity_bitmap_len(nsectors); sparity = kzalloc(sizeof(struct scrub_parity) + 2 * bitmap_len, GFP_NOFS); |