From: Tao Ma Date: Fri, 21 Jan 2011 14:09:20 +0000 (+0800) Subject: ext3: speed up group trim with the right free block count. X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=bbac751dc85cbf0953a221171a746d69a0b1a85f;p=mv-sheeva.git 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 --- diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c index 5b8344fab79..db1906b4e39 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; }