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| author | Andy Whitcroft <apw@shadowen.org> | 2007-05-07 01:49:14 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-07 23:12:52 +0400 |
| commit | 14e072984179d3d421bf9ab75cc67e0961742841 (patch) | |
| tree | 65a5a6f7d9756b8e7010278b58908d04da257a28 /mm/page_alloc.c | |
| parent | ac267728f13c55017ed5ee243c9c3166e27ab929 (diff) | |
| download | linux-14e072984179d3d421bf9ab75cc67e0961742841.tar.xz | |
add pfn_valid_within helper for sub-MAX_ORDER hole detection
Generally we work under the assumption that memory the mem_map array is
contigious and valid out to MAX_ORDER_NR_PAGES block of pages, ie. that if we
have validated any page within this MAX_ORDER_NR_PAGES block we need not check
any other. This is not true when CONFIG_HOLES_IN_ZONE is set and we must
check each and every reference we make from a pfn.
Add a pfn_valid_within() helper which should be used when scanning pages
within a MAX_ORDER_NR_PAGES block when we have already checked the validility
of the block normally with pfn_valid(). This can then be optimised away when
we do not have holes within a MAX_ORDER_NR_PAGES block of pages.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 019ceda6a8b6..f564717d22f3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -156,10 +156,8 @@ static int page_outside_zone_boundaries(struct zone *zone, struct page *page) static int page_is_consistent(struct zone *zone, struct page *page) { -#ifdef CONFIG_HOLES_IN_ZONE - if (!pfn_valid(page_to_pfn(page))) + if (!pfn_valid_within(page_to_pfn(page))) return 0; -#endif if (zone != page_zone(page)) return 0; @@ -346,10 +344,8 @@ __find_combined_index(unsigned long page_idx, unsigned int order) static inline int page_is_buddy(struct page *page, struct page *buddy, int order) { -#ifdef CONFIG_HOLES_IN_ZONE - if (!pfn_valid(page_to_pfn(buddy))) + if (!pfn_valid_within(page_to_pfn(buddy))) return 0; -#endif if (page_zone_id(page) != page_zone_id(buddy)) return 0; |