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authorJoonsoo Kim <iamjoonsoo.kim@lge.com>2014-11-13 15:19:36 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-11-13 16:17:06 -0800
commit57cbc87e03c2f473d8f0579186c078ee06f48f2c (patch)
tree8aa1d1aca7250f09301a312155450fa623e71e15
parent8edc6e1688fc8f02c8c1f53a2ec4928cb1055f4d (diff)
mm/debug-pagealloc: correct freepage accounting and order resetting
One thing I did in this patch is fixing freepage accounting. If we clear guard page and link it onto isolate buddy list, we should not increase freepage count. This patch adds conditional branch to skip counting in this case. Without this patch, this overcounting happens frequently if guard order is set and CMA is used. Another thing fixed in this patch is the target to reset order. In __free_one_page(), we check the buddy page whether it is a guard page or not. And, if so, we should clear guard attribute on the buddy page and reset order of it to 0. But, current code resets original page's order rather than buddy one's. Maybe, this doesn't have any problem, because whole merged page's order will be re-assigned soon. But, it is better to correct code. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Gioh Kim <gioh.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/page_alloc.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 181dc593962b..616a2c956b4b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -583,9 +583,11 @@ static inline void __free_one_page(struct page *page,
*/
if (page_is_guard(buddy)) {
clear_page_guard_flag(buddy);
- set_page_private(page, 0);
- __mod_zone_freepage_state(zone, 1 << order,
- migratetype);
+ set_page_private(buddy, 0);
+ if (!is_migrate_isolate(migratetype)) {
+ __mod_zone_freepage_state(zone, 1 << order,
+ migratetype);
+ }
} else {
list_del(&buddy->lru);
zone->free_area[order].nr_free--;

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