Re: [PATCH 7/8] mm: vmscan: Immediately reclaim end-of-LRU dirty pages when writeback completes

Peter Zijlstra
2011-07-22T12:54:12Z

On Thu, 2011-07-21 at 17:28 +0100, Mel Gorman wrote:
> When direct reclaim encounters a dirty page, it gets recycled around
> the LRU for another cycle. This patch marks the page PageReclaim
> similar to deactivate_page() so that the page gets reclaimed almost
> immediately after the page gets cleaned. This is to avoid reclaiming
> clean pages that are younger than a dirty page encountered at the
> end of the LRU that might have been something like a use-once page.
>

> @@ -834,7 +834,15 @@ static unsigned long shrink_page_list(struct list_head *page_list,
> */
> if (page_is_file_cache(page) &&
> (!current_is_kswapd() || priority >= DEF_PRIORITY - 2)) {
> - inc_zone_page_state(page, NR_VMSCAN_WRITE_SKIP);
> + /*
> + * Immediately reclaim when written back.
> + * Similar in principal to deactivate_page()
> + * except we already have the page isolated
> + * and know it's dirty
> + */
> + inc_zone_page_state(page, NR_VMSCAN_INVALIDATE);
> + SetPageReclaim(page);
> +

I find the invalidate name somewhat confusing. It makes me think we'll
drop the page without writeback, like invalidatepage().