nilfs2: optimize rec_len functions

This is a similar change to those in ext2/ext3 codebase (commit
40a063f669 and a4ae309486, respectively).

The addition of 64k block capability in the rec_len_from_disk and
rec_len_to_disk functions added a bit of math overhead which slows
down file create workloads needlessly when the architecture cannot
even support 64k blocks.  This will cut the corner.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This commit is contained in:
Ryusuke Konishi 2011-02-04 01:19:38 +09:00
commit ae191838b0
2 changed files with 5 additions and 0 deletions

View file

@ -326,17 +326,21 @@ static inline unsigned nilfs_rec_len_from_disk(__le16 dlen)
{
unsigned len = le16_to_cpu(dlen);
#if !defined(__KERNEL__) || (PAGE_CACHE_SIZE >= 65536)
if (len == NILFS_MAX_REC_LEN)
return 1 << 16;
#endif
return len;
}
static inline __le16 nilfs_rec_len_to_disk(unsigned len)
{
#if !defined(__KERNEL__) || (PAGE_CACHE_SIZE >= 65536)
if (len == (1 << 16))
return cpu_to_le16(NILFS_MAX_REC_LEN);
else if (len > (1 << 16))
BUG();
#endif
return cpu_to_le16(len);
}