Re: [PATCH 1/3] mm: use get_page_migratetype instead of page_private

From: Kamezawa Hiroyuki
Date: Wed Sep 05 2012 - 22:03:25 EST


(2012/09/05 16:26), Minchan Kim wrote:
> page allocator uses set_page_private and page_private for handling
> migratetype when it frees page. Let's replace them with [set|get]
> _page_migratetype to make it more clear.
>
> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>

Hmm. one request from me.

> ---
> include/linux/mm.h | 10 ++++++++++
> mm/page_alloc.c | 11 +++++++----
> mm/page_isolation.c | 2 +-
> 3 files changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 5c76634..86d61d6 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -249,6 +249,16 @@ struct inode;
> #define page_private(page) ((page)->private)
> #define set_page_private(page, v) ((page)->private = (v))
>
> +static inline void set_page_migratetype(struct page *page, int migratetype)
> +{
> + set_page_private(page, migratetype);
> +}
> +
> +static inline int get_page_migratetype(struct page *page)
> +{
> + return page_private(page);
> +}
> +

Could you add comments to explain "when this function returns expected value" ?
These functions can work well only in very restricted area of codes.

By the way, does these functions should be static-inline ?

Thanks,
-Kame

> /*
> * FIXME: take this include out, include page-flags.h in
> * files which need it (119 of them)
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 710d91c..103ba66 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -671,8 +671,10 @@ static void free_pcppages_bulk(struct zone *zone, int count,
> /* must delete as __free_one_page list manipulates */
> list_del(&page->lru);
> /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
> - __free_one_page(page, zone, 0, page_private(page));
> - trace_mm_page_pcpu_drain(page, 0, page_private(page));
> + __free_one_page(page, zone, 0,
> + get_page_migratetype(page));
> + trace_mm_page_pcpu_drain(page, 0,
> + get_page_migratetype(page));
> } while (--to_free && --batch_free && !list_empty(list));
> }
> __mod_zone_page_state(zone, NR_FREE_PAGES, count);
> @@ -731,6 +733,7 @@ static void __free_pages_ok(struct page *page, unsigned int order)
> __count_vm_events(PGFREE, 1 << order);
> free_one_page(page_zone(page), page, order,
> get_pageblock_migratetype(page));
> +
> local_irq_restore(flags);
> }
>
> @@ -1134,7 +1137,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
> if (!is_migrate_cma(mt) && mt != MIGRATE_ISOLATE)
> mt = migratetype;
> }
> - set_page_private(page, mt);
> + set_page_migratetype(page, mt);
> list = &page->lru;
> }
> __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
> @@ -1301,7 +1304,7 @@ void free_hot_cold_page(struct page *page, int cold)
> return;
>
> migratetype = get_pageblock_migratetype(page);
> - set_page_private(page, migratetype);
> + set_page_migratetype(page, migratetype);
> local_irq_save(flags);
> if (unlikely(wasMlocked))
> free_page_mlock(page);
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index 64abb33..acf65a7 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -199,7 +199,7 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn)
> if (PageBuddy(page))
> pfn += 1 << page_order(page);
> else if (page_count(page) == 0 &&
> - page_private(page) == MIGRATE_ISOLATE)
> + get_page_migratetype(page) == MIGRATE_ISOLATE)
> pfn += 1;
> else
> break;
>


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