Re: [PATCH 08/10] mm/page_alloc: use get_onbuddy_migratetype() to get buddy list type

[Vlastimil Babka]

On 07/04/2014 09:57 AM, Joonsoo Kim wrote:
> When isolating free page, what we want to know is which list
> the page is linked. If it is linked in isolate migratetype buddy list,
> we can skip watermark check and freepage counting. And if it is linked
> in CMA migratetype buddy list, we need to fixup freepage counting. For
> this purpose, get_onbuddy_migratetype() is more fit and cheap than
> get_pageblock_migratetype(). So use it.

Hm but you made get_onbuddy_migratetype() work only with 
CONFIG_MEMORY_ISOLATION. And __isolate_free_page is (despite the name) 
not at all limited to CONFIG_MEMORY_ISOLATION.

> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> ---
>   mm/page_alloc.c |    2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index e1c4c3e..d9fb8bb 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1597,7 +1597,7 @@ static int __isolate_free_page(struct page *page, unsigned int order)
>   	BUG_ON(!PageBuddy(page));
>
>   	zone = page_zone(page);
> -	mt = get_pageblock_migratetype(page);
> +	mt = get_onbuddy_migratetype(page);
>
>   	if (!is_migrate_isolate(mt)) {
>   		/* Obey watermarks as if the page was being allocated */

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