2012/09/07 9:39, Minchan Kim wrote:
> The page allocator caches the pageblock information in page->private while
> it is in the PCP freelists but this is overwritten with the order of the
> page when freed to the buddy allocator. This patch stores the migratetype
> of the page in the page->index field so that it is available at all times
> when the page remain in free_list.
> 
> This patch adds a new call site in __free_pages_ok so it might be
> overhead a bit but it's for high order allocation.
> So I believe damage isn't hurt.
> 
> * from v2
>    * Add Acked-by of Kame
> 
> * from v1
>    * Fix move_freepages's migratetype - Mel
>    * Add more kind explanation in description - Mel
> 
> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hir...@jp.fujitsu.com>
> Signed-off-by: Minchan Kim <minc...@kernel.org>

Reviewed-by: Yasuaki Ishimatsu <isimatu.yasu...@jp.fujitsu.com>

Thanks,
Yasuaki Ishimatsu

> ---
>   include/linux/mm.h |    4 ++--
>   mm/page_alloc.c    |    7 +++++--
>   2 files changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 84d1663f..68f9e8d 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -240,13 +240,13 @@ struct inode;
>   /* It's valid only if the page is free path or free_list */
>   static inline void set_freepage_migratetype(struct page *page, int 
> migratetype)
>   {
> -     set_page_private(page, migratetype);
> +     page->index = migratetype;
>   }
>   
>   /* It's valid only if the page is free path or free_list */
>   static inline int get_freepage_migratetype(struct page *page)
>   {
> -     return page_private(page);
> +     return page->index;
>   }
>   
>   /*
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index f5ba236..8531fa3 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -723,6 +723,7 @@ static void __free_pages_ok(struct page *page, unsigned 
> int order)
>   {
>       unsigned long flags;
>       int wasMlocked = __TestClearPageMlocked(page);
> +     int migratetype;
>   
>       if (!free_pages_prepare(page, order))
>               return;
> @@ -731,8 +732,9 @@ static void __free_pages_ok(struct page *page, unsigned 
> int order)
>       if (unlikely(wasMlocked))
>               free_page_mlock(page);
>       __count_vm_events(PGFREE, 1 << order);
> -     free_one_page(page_zone(page), page, order,
> -                                     get_pageblock_migratetype(page));
> +     migratetype = get_pageblock_migratetype(page);
> +     set_freepage_migratetype(page, migratetype);
> +     free_one_page(page_zone(page), page, order, migratetype);
>       local_irq_restore(flags);
>   }
>   
> @@ -952,6 +954,7 @@ static int move_freepages(struct zone *zone,
>               order = page_order(page);
>               list_move(&page->lru,
>                         &zone->free_area[order].free_list[migratetype]);
> +             set_freepage_migratetype(page, migratetype);
>               page += 1 << order;
>               pages_moved += 1 << order;
>       }
> 


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