Re: [patch 07/19] (NEW) add some sanity checks to get_scan_ratio

KAMEZAWA Hiroyuki
2008-01-09T04:14:19Z

On Tue, 08 Jan 2008 15:59:46 -0500
Rik van Riel <riel@redhat.com> wrote:

> The access ratio based scan rate determination in get_scan_ratio
> works ok in most situations, but needs to be corrected in some
> corner cases:
> - if we run out of swap space, do not bother scanning the anon LRUs
> - if we have already freed all of the page cache, we need to scan
> the anon LRUs
>
> Signed-off-by: Rik van Riel <riel@redhat.com>
>
> Index: linux-2.6.24-rc6-mm1/mm/vmscan.c
> ===================================================================
> --- linux-2.6.24-rc6-mm1.orig/mm/vmscan.c 2008-01-07 17:33:50.000000000 -0500
> +++ linux-2.6.24-rc6-mm1/mm/vmscan.c 2008-01-07 17:57:49.000000000 -0500
> @@ -1182,7 +1182,7 @@ static unsigned long shrink_list(enum lr
> static void get_scan_ratio(struct zone *zone, struct scan_control * sc,
> unsigned long *percent)
> {
> - unsigned long anon, file;
> + unsigned long anon, file, free;
> unsigned long anon_prio, file_prio;
> unsigned long rotate_sum;
> unsigned long ap, fp;
> @@ -1230,6 +1230,20 @@ static void get_scan_ratio(struct zone *
> else if (fp > 100)
> fp = 100;
> percent[1] = fp;
> +
> + free = zone_page_state(zone, NR_FREE_PAGES);
> +
> + /*
> + * If we have no swap space, do not bother scanning anon pages
> + */
> + if (nr_swap_pages <= 0)
> + percent[0] = 0;
Doesn't this mean that swap-cache in ACTIVE_ANON_LIST is not scanned ?
Or swap-cache is in File-Cache list ?

Thanks,
-Kame