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

[Minchan Kim]

On Tue, Jun 9, 2009 at 6:15 PM, KAMEZAWA
Hiroyuki<kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
>
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
>
> In lumpty reclaim, "cursor_page" is found just by pfn. Then, we don't know
> 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@xxxxxxxxxxxxxx>
> ---
> Âmm/vmscan.c | Â Â5 ++---
> Â1 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
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Ânr_taken++;
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Âscan++;
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Âbreak;
> -
> Â Â Â Â Â Â Â Â Â Â Â Âcase -EBUSY:

We can remove case -EBUSY itself, too.
It is meaningless.

> - Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â /* else it is being freed elsewhere */
> - Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â list_move(&cursor_page->lru, src);
> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â /* Do nothing because we don't know where
> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Âcusrsor_page comes from */
> Â Â Â Â Â Â Â Â Â Â Â Âdefault:
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Âbreak; Â/* ! on LRU or wrong list */

Hmm.. what meaning of this break ?
We are in switch case.
This "break" can't go out of loop.
But comment said "abort this block scan".

If I understand it properly , don't we add goto phrase ?

> Â Â Â Â Â Â Â Â Â Â Â Â}
>
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-- 
Kinds regards,
Minchan Kim
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