Re: [PATCH] vmscan: recalculate lru_pages on each priority

From: KOSAKI Motohiro
Date: Sun Jun 27 2010 - 21:39:48 EST


> On Fri, Jun 25, 2010 at 06:13:20PM +0900, KOSAKI Motohiro wrote:
> > shrink_zones() need relatively long time. and lru_pages can be
> > changed dramatically while shrink_zones().
> > then, lru_pages need recalculate on each priority.
>
> In the direct reclaim path, we bail out of that loop after
> SWAP_CLUSTER_MAX reclaimed pages, so in this case, decreasing priority
> levels actually mean we do _not_ make any progress and the total
> number of lru pages should not change (much). The possible distortion
> in shrink_slab() is small.

Oh, you seems forgot the case when much thread enter try_to_free_pages()
concurrently.

>
> However, for the suspend-to-disk case the reclaim target can be a lot
> higher and we inevitably end up at higher priorities even though we
> make progress, but fail to increase pressure on the shrinkers as well
> without your patch.
>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>



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