提交 0ba8f2d5 编写于 作者: L Li Haifeng 提交者: Linus Torvalds

mm/page_alloc: fix the page address of higher page's buddy calculation

The heuristic method for buddy has been introduced since commit
43506fad ("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: NHaifeng Li <omycle@gmail.com>
Signed-off-by: NGavin Shan <shangw@linux.vnet.ibm.com>
Reviewed-by: NMichal 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>
Cc: <stable@vger.kernel.org>	[2.6.38+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
上级 8dcebaa9
...@@ -584,7 +584,7 @@ static inline void __free_one_page(struct page *page, ...@@ -584,7 +584,7 @@ static inline void __free_one_page(struct page *page,
combined_idx = buddy_idx & page_idx; combined_idx = buddy_idx & page_idx;
higher_page = page + (combined_idx - page_idx); higher_page = page + (combined_idx - page_idx);
buddy_idx = __find_buddy_index(combined_idx, order + 1); 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)) { if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
list_add_tail(&page->lru, list_add_tail(&page->lru,
&zone->free_area[order].free_list[migratetype]); &zone->free_area[order].free_list[migratetype]);
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册