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authorTao Ma <boyu.mt@taobao.com>2011-01-21 09:09:20 -0500
committerJan Kara <jack@suse.cz>2011-02-24 05:42:45 -0500
commitbbac751dc85cbf0953a221171a746d69a0b1a85f (patch)
tree61be9cadcda63dfc65781de57176eef938a70ae6 /fs/ext3
parent4b44dd300d5bfd500f170bae13f95f589de0b28f (diff)
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 <jack@suse.cz> Cc: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/ext3')
-rw-r--r--fs/ext3/balloc.c3
1 files changed, 2 insertions, 1 deletions
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,
1991 spin_unlock(sb_bgl_lock(sbi, group)); 1991 spin_unlock(sb_bgl_lock(sbi, group));
1992 percpu_counter_sub(&sbi->s_freeblocks_counter, next - start); 1992 percpu_counter_sub(&sbi->s_freeblocks_counter, next - start);
1993 1993
1994 free_blocks -= next - start;
1994 /* Do not issue a TRIM on extents smaller than minblocks */ 1995 /* Do not issue a TRIM on extents smaller than minblocks */
1995 if ((next - start) < minblocks) 1996 if ((next - start) < minblocks)
1996 goto free_extent; 1997 goto free_extent;
@@ -2040,7 +2041,7 @@ free_extent:
2040 cond_resched(); 2041 cond_resched();
2041 2042
2042 /* No more suitable extents */ 2043 /* No more suitable extents */
2043 if ((free_blocks - count) < minblocks) 2044 if (free_blocks < minblocks)
2044 break; 2045 break;
2045 } 2046 }
2046 2047