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authorLi Haifeng <omycle@gmail.com>2012-09-17 14:09:21 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-02 09:47:25 -0700
commit54fd21ca117a5dd36a1bf7e0b92bef2c89c2201e (patch)
treef222d8ac8f160d6188e7d6d655da436e48c0e37a
parentf2657804a840a7c5ed60b9a96c8e81e845579a25 (diff)
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mm/page_alloc: fix the page address of higher page's buddy calculation
commit 0ba8f2d59304dfe69b59c034de723ad80f7ab9ac upstream. The heuristic method for buddy has been introduced since commit 43506fad21ca ("mm/page_alloc.c: simplify calculation of combined index of adjacent buddy lists"). But the page address of higher page's buddy was wrongly calculated, which will lead page_is_buddy to fail for ever. IOW, the heuristic method would be disabled with the wrong page address of higher page's buddy. Calculating the page address of higher page's buddy should be based higher_page with the offset between index of higher page and index of higher page's buddy. Signed-off-by: Haifeng Li <omycle@gmail.com> Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: KyongHo Cho <pullip.cho@samsung.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--mm/page_alloc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9177aa35ae7..eb6b3fd3ba8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -540,7 +540,7 @@ static inline void __free_one_page(struct page *page,
combined_idx = buddy_idx & page_idx;
higher_page = page + (combined_idx - page_idx);
buddy_idx = __find_buddy_index(combined_idx, order + 1);
- higher_buddy = page + (buddy_idx - combined_idx);
+ higher_buddy = higher_page + (buddy_idx - combined_idx);
if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
list_add_tail(&page->lru,
&zone->free_area[order].free_list[migratetype]);