Re: [patch 6/8] mm: vmscan: clean up get_scan_count()

From: Michal Hocko
Date: Thu Dec 13 2012 - 11:18:01 EST


On Wed 12-12-12 16:43:38, Johannes Weiner wrote:
> Reclaim pressure balance between anon and file pages is calculated
> through a tuple of numerators and a shared denominator.
>
> Exceptional cases that want to force-scan anon or file pages configure
> the numerators and denominator such that one list is preferred, which
> is not necessarily the most obvious way:
>
> fraction[0] = 1;
> fraction[1] = 0;
> denominator = 1;
> goto out;
>
> Make this easier by making the force-scan cases explicit and use the
> fractionals only in case they are calculated from reclaim history.
>
> And bring the variable declarations/definitions in order.
>
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>

I like this.
Reviewed-by: Michal Hocko <mhocko@xxxxxxx>

[...]
> @@ -1638,14 +1645,15 @@ static int vmscan_swappiness(struct scan_control *sc)
> static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
> unsigned long *nr)
> {
> - unsigned long anon, file, free;
> + struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
> + u64 fraction[2], uninitialized_var(denominator);
> + struct zone *zone = lruvec_zone(lruvec);
> unsigned long anon_prio, file_prio;
> + enum scan_balance scan_balance;
> + unsigned long anon, file, free;
> + bool force_scan = false;
> unsigned long ap, fp;
> - struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
> - u64 fraction[2], denominator;
> enum lru_list lru;
> - bool force_scan = false;
> - struct zone *zone = lruvec_zone(lruvec);

You really do love trees, don't you :P

[...]
--
Michal Hocko
SUSE Labs
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