Re: [BUGFIX][PATCH] fix wrong lru rotate back at lumpty reclaim

KOSAKI Motohiro
2009-06-09T08:59:01Z

>
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>
> In lumpty reclaim, "cursor_page" is found just by pfn. Then, we don't know
^^^^^^
lumpy?

> from which LRU "cursor" page came from. Then, putback it to "src" list is BUG.
> Just leave it as it is.
> (And I think rotate here is overkilling even if "src" is correct.)
>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Yes, thanks great catch!

lumpy reclaimed neighbor pages doesn't need to ratate, it because
neighbor pages doesn't stay in head of lru list.

Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>

> ---
> mm/vmscan.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> Index: mmotm-2.6.30-Jun4/mm/vmscan.c
> ===================================================================
> --- mmotm-2.6.30-Jun4.orig/mm/vmscan.c
> +++ mmotm-2.6.30-Jun4/mm/vmscan.c
> @@ -940,10 +940,9 @@ static unsigned long isolate_lru_pages(u
> nr_taken++;
> scan++;
> break;
> -
> case -EBUSY:
> - /* else it is being freed elsewhere */
> - list_move(&cursor_page->lru, src);
> + /* Do nothing because we don't know where
> + cusrsor_page comes from */
> default:
> break; /* ! on LRU or wrong list */
> }
>
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