From e8ced39d5e8911c662d4d69a342b9d053eaaac4e Mon Sep 17 00:00:00 2001 From: Mingming Cao Date: Fri, 11 Jul 2008 19:27:31 -0400 Subject: 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 Signed-off-by: "Theodore Ts'o" --- fs/ext4/balloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/ext4/balloc.c') 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; -- cgit v1.2.3