[lkml]   [2011]   [Dec]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] Set the initial TRIM information as TRIMMED
On 12/1/11 1:00 AM, Kyungmin Park wrote:
> From: Kyungmin Park <>
> Now trim information doesn't stored at disk so every boot time. it's cleared.
> and do the trim all disk groups.
> But assume that it's already trimmed at previous time so don't need to trim it again. So set the intial state as trimmed.
> Signed-off-by: Kyungmin Park <>
> ---
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index e2d8be8..97ef342 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -1098,6 +1098,12 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group)
> goto err;
> }
> mark_page_accessed(page);
> +
> + /*
> + * TRIM information is not stored at disk so set the initial
> + * state as trimmed. Since previous time it's already trimmed all
> + */
> + EXT4_MB_GRP_SET_TRIMMED(this_grp);

Hm, so if there were freed but un-trimmed blocks at this point, we will
never trim them until we free _another_ block in the group, right? That
might be a reasonable tradeoff, but it is somewhat surprising behavior.

i.e. say we do:

mount /mnt
rm -rf /mnt/very_big_file
umount /mnt

mount /mnt
fitrim /mnt

then we won't trim anything at all, right, despite there being many
new free blocks? Which would be rather unexpected.

If we don't store the trimmed state on disk, I think we should
probably stick with the slower first-time trim, and the more obvious
behavior (all free blocks are always trimmed whenever a trim
command is issued).


> err:
> ext4_mb_put_buddy_page_lock(&e4b);
> return ret;
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to
> More majordomo info at

 \ /
  Last update: 2011-12-01 23:09    [W:0.088 / U:0.220 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site