Re: [patch]THP: add split tail pages to shrink page list in page reclaim

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 1 Apr 2013 21:26:05 +0800 Shaohua Li <shli@kernel.org> wrote:

> In page reclaim, huge page is split. split_huge_page() adds tail pages to LRU
> list. Since we are reclaiming a huge page, it's better we reclaim all subpages
> of the huge page instead of just the head page. This patch adds split tail
> pages to shrink page list so the tail pages can be reclaimed soon.
> 
> Before this patch, run a swap workload:
> thp_fault_alloc 3492
> thp_fault_fallback 608
> thp_collapse_alloc 6
> thp_collapse_alloc_failed 0
> thp_split 916
> 
> With this patch:
> thp_fault_alloc 4085
> thp_fault_fallback 16
> thp_collapse_alloc 90
> thp_collapse_alloc_failed 0
> thp_split 1272
> 
> fallback allocation is reduced a lot.
> 
> ...
>
> -int split_huge_page(struct page *page)
> +int split_huge_page_to_list(struct page *page, struct list_head *list)

While it's fresh, could you please prepare a covering comment describing
this function?  The meaning of the return value is particularly
cryptic.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>