On Thu, 9 Dec 2010 11:18:19 +0000
Mel Gorman <mel@xxxxxxxxx> wrote:
> After DEF_PRIORITY, balance_pgdat() considers all_unreclaimable zones to
> be balanced but sleeping_prematurely does not. This can force kswapd to
> stay awake longer than it should. This patch fixes it.
>
> Signed-off-by: Mel Gorman <mel@xxxxxxxxx>
Hmm, maybe the logic works well but I don't like very much.
How about adding below instead of pgdat->node_present_pages ?
static unsigned long required_balanced_pages(pgdat, classzone_idx)
{
unsigned long present = 0;
for_each_zone_in_node(zone, pgdat) {
if (zone->all_unreclaimable) /* Ignore unreclaimable zone at checking balance */
continue;
if (zone_idx(zone) > classzone_idx)
continue;
present = zone->present_pages;
}
return present;
}
> ---
> mm/vmscan.c | 10 +++++++++-
> 1 files changed, 9 insertions(+), 1 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index bc233d8..d7b0a3c 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -2149,8 +2149,16 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
> if (!populated_zone(zone))
> continue;
>
> - if (zone->all_unreclaimable)
> + /*
> + * balance_pgdat() skips over all_unreclaimable after
> + * DEF_PRIORITY. Effectively, it considers them balanced so
> + * they must be considered balanced here as well if kswapd
> + * is to sleep
> + */
> + if (zone->all_unreclaimable) {
> + balanced += zone->present_pages;
> continue;
> + }
>
> if (!zone_watermark_ok(zone, order, high_wmark_pages(zone),
> 0, 0))
> --
> 1.7.1
>
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