From bbac751dc85cbf0953a221171a746d69a0b1a85f Mon Sep 17 00:00:00 2001 From: Tao Ma Date: Fri, 21 Jan 2011 22:09:20 +0800 Subject: [PATCH] ext3: speed up group trim with the right free block count. When we trim some free blocks in a group of ext3, we should calculate the free blocks properly and check whether there are enough freed blocks left for us to trim. Current solution will only calculate free spaces if they are large for a trim which is wrong. Let us see a small example: a group has 1.5M free which are 300k, 300k, 300k, 300k, 300k. And minblocks is 1M. With current solution, we have to iterate the whole group since these 300k will never be subtracted from 1.5M. But actually we should exit after we find the first 2 free spaces since the left 3 chunks only sum up to 900K if we subtract the first 600K although they can't be trimed. Cc: Jan Kara Cc: Lukas Czerner Signed-off-by: Tao Ma Signed-off-by: Jan Kara --- fs/ext3/balloc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c index 5b8344fab79d..db1906b4e39c 100644 --- a/fs/ext3/balloc.c +++ b/fs/ext3/balloc.c @@ -1991,6 +1991,7 @@ ext3_grpblk_t ext3_trim_all_free(struct super_block *sb, unsigned int group, spin_unlock(sb_bgl_lock(sbi, group)); percpu_counter_sub(&sbi->s_freeblocks_counter, next - start); + free_blocks -= next - start; /* Do not issue a TRIM on extents smaller than minblocks */ if ((next - start) < minblocks) goto free_extent; @@ -2040,7 +2041,7 @@ free_extent: cond_resched(); /* No more suitable extents */ - if ((free_blocks - count) < minblocks) + if (free_blocks < minblocks) break; } -- 2.34.1