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| author | Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> | 2013-07-04 21:04:01 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-04 22:22:46 +0400 |
| commit | 275f495dbe34300d793466a7d96c70f83fbae1bc (patch) | |
| tree | 75785e0623188c52360f845419354b3b7cd67051 /fs/hpfs/map.c | |
| parent | a0c1b7596323a2323d5f5c7d2404af7b58a1ef4e (diff) | |
| download | linux-275f495dbe34300d793466a7d96c70f83fbae1bc.tar.xz | |
hpfs: implement prefetch to improve performance
This patch implements prefetch to improve performance. It helps mostly
when scanning the bitmaps to calculate free space.
Signed-off-by: Mikulas Patocka <mpatocka@artax.karlin.mff.cuni.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/hpfs/map.c')
| -rw-r--r-- | fs/hpfs/map.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/fs/hpfs/map.c b/fs/hpfs/map.c index 803d3da3a0fe..3aa66ae1031e 100644 --- a/fs/hpfs/map.c +++ b/fs/hpfs/map.c @@ -17,6 +17,7 @@ __le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block, struct quad_buffer_head *qbh, char *id) { secno sec; + __le32 *ret; unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14; if (hpfs_sb(s)->sb_chk) if (bmp_block >= n_bands) { hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id); @@ -27,7 +28,23 @@ __le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block, hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id); return NULL; } - return hpfs_map_4sectors(s, sec, qbh, 4); + ret = hpfs_map_4sectors(s, sec, qbh, 4); + if (ret) hpfs_prefetch_bitmap(s, bmp_block + 1); + return ret; +} + +void hpfs_prefetch_bitmap(struct super_block *s, unsigned bmp_block) +{ + unsigned to_prefetch, next_prefetch; + unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14; + if (unlikely(bmp_block >= n_bands)) + return; + to_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]); + if (unlikely(bmp_block + 1 >= n_bands)) + next_prefetch = 0; + else + next_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block + 1]); + hpfs_prefetch_sectors(s, to_prefetch, 4 + 4 * (to_prefetch + 4 == next_prefetch)); } /* |