On Thu, Jun 20, 2013 at 10:13:10AM -0400, Theodore Ts'o wrote:
> On Thu, Jun 20, 2013 at 11:08:58AM +0300, Dan Carpenter wrote:
> > "diff" is unsigned so this doesn't sort the LRU list correctly.
> >
> > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > ---
> > This was introduced in 6480bad916be "ext4: improve extent cache shrink
> > mechanism to avoid to burn CPU time"
>
> Thanks for pointing this out! The following patch is better I think
> because it uses the time_after() abstraction. I will be folding the
> following into Zheng's "ext4: improve extent cache shrink > mechanism
> to avoid to burn CPU time".
Thanks for fixing it. The patch looks good to me.
Reviewed-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
>
> I've desk checked this but we may want to do some explicit testing to
> make sure we are in fact ejecting the appropriate inode from the list.
I will check it tomorrow. If there still has a problem, I will try to
fix it.
- Zheng
>
> - Ted
>
> fs/ext4/extents_status.c | 12 +++++-------
> 1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
> index 80dcc59..ee018d5 100644
> --- a/fs/ext4/extents_status.c
> +++ b/fs/ext4/extents_status.c
> @@ -880,17 +880,15 @@ static int ext4_inode_touch_time_cmp(void *priv, struct list_head *a,
> struct list_head *b)
> {
> struct ext4_inode_info *eia, *eib;
> - unsigned long diff;
> -
> eia = list_entry(a, struct ext4_inode_info, i_es_lru);
> eib = list_entry(b, struct ext4_inode_info, i_es_lru);
>
> - diff = eia->i_touch_when - eib->i_touch_when;
> - if (diff < 0)
> - return -1;
> - if (diff > 0)
> + if (eia->i_touch_when == eib->i_touch_when)
> + return 0;
> + if (time_after(eia->i_touch_when, eib->i_touch_when))
> return 1;
> - return 0;
> + else
> + return -1;
> }
>
> static int ext4_es_shrink(struct shrinker *shrink, struct shrink_control *sc)
> --
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