Re: [PATCH 5/6] mm: page_alloc: Reduce cost of dirty zone balancing

[Andrew Morton]

On Wed, 25 Jun 2014 08:58:48 +0100 Mel Gorman <mgorman@xxxxxxx> wrote:

> @@ -325,7 +321,14 @@ static unsigned long zone_dirty_limit(struct zone *zone)
>   */
>  bool zone_dirty_ok(struct zone *zone)
>  {
> -	unsigned long limit = zone_dirty_limit(zone);
> +	unsigned long limit = zone->dirty_limit_cached;
> +	struct task_struct *tsk = current;
> +
> +	if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk)) {
> +		limit = zone_dirty_limit(zone);
> +		zone->dirty_limit_cached = limit;
> +		limit += limit / 4;
> +	}

Could we get a comment in here explaining what we're doing and why
PF_LESS_THROTTLE and rt_task control whether we do it?

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/