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| author | Mingming Cao <cmm@us.ibm.com> | 2008-07-12 01:27:31 +0200 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2008-07-12 01:27:31 +0200 |
| commit | e8ced39d5e8911c662d4d69a342b9d053eaaac4e (patch) | |
| tree | cd4d643bfbd37c67ff9bd2feff2c0b477a56f117 /fs/ext4/balloc.c | |
| parent | ext4: Add delayed allocation support in data=writeback mode (diff) | |
| download | linux-e8ced39d5e8911c662d4d69a342b9d053eaaac4e.tar.xz linux-e8ced39d5e8911c662d4d69a342b9d053eaaac4e.zip | |
percpu_counter: new function percpu_counter_sum_and_set
Delayed allocation need to check free blocks at every write time.
percpu_counter_read_positive() is not quit accurate. delayed
allocation need a more accurate accounting, but using
percpu_counter_sum_positive() is frequently is quite expensive.
This patch added a new function to update center counter when sum
per-cpu counter, to increase the accurate rate for next
percpu_counter_read() and require less calling expensive
percpu_counter_sum().
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/balloc.c')
| -rw-r--r-- | fs/ext4/balloc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c index 25f63d8c1b3d..6369bacf0dcb 100644 --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -1621,7 +1621,7 @@ ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi, #ifdef CONFIG_SMP if (free_blocks - root_blocks < FBC_BATCH) free_blocks = - percpu_counter_sum_positive(&sbi->s_freeblocks_counter); + percpu_counter_sum_and_set(&sbi->s_freeblocks_counter); #endif if (free_blocks - root_blocks < nblocks) return free_blocks - root_blocks; |