[PATCH 07/10] mm/page_alloc: store migratetype of the buddy list into freepage correctly

[Joonsoo Kim]

Whenever page is splited or merged, we don't set migratetype to new page,
so there can be no accurate onbuddy_migratetype information. To maintain
it correctly, we should reset whenever page order is changed.
I think that set_page_order() is the best place to do, because it is
called whenever page is merged or splited. Hence, this patch adds
set_onbuddy_migratetype() to set_page_order().

And this patch makes set/get_onbuddy_migratetype() only enabled if
memory isolation is enabeld, because it doesn't needed in other case.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
---
 include/linux/mm.h |    6 ++++++
 mm/page_alloc.c    |    9 +++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 278ecfd..b35bd3b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -281,6 +281,7 @@ struct inode;
 #define page_private(page)		((page)->private)
 #define set_page_private(page, v)	((page)->private = (v))
 
+#if defined(CONFIG_MEMORY_ISOLATION)
 static inline void set_onbuddy_migratetype(struct page *page, int migratetype)
 {
 	page->index = migratetype;
@@ -294,6 +295,11 @@ static inline int get_onbuddy_migratetype(struct page *page)
 {
 	return page->index;
 }
+#else
+static inline void set_onbuddy_migratetype(struct page *page,
+						int migratetype) {}
+static inline int get_onbuddy_migratetype(struct page *page) { return 0; }
+#endif
 
 static inline void set_onpcp_migratetype(struct page *page, int migratetype)
 {
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9d8ba2d..e1c4c3e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -465,9 +465,11 @@ static inline void clear_page_guard(struct zone *zone, struct page *page,
 				unsigned int order, int migratetype) {}
 #endif
 
-static inline void set_page_order(struct page *page, unsigned int order)
+static inline void set_page_order(struct page *page, unsigned int order,
+							int migratetype)
 {
 	set_page_private(page, order);
+	set_onbuddy_migratetype(page, migratetype);
 	__SetPageBuddy(page);
 }
 
@@ -633,7 +635,7 @@ static inline void __free_one_page(struct page *page,
 		page_idx = combined_idx;
 		order++;
 	}
-	set_page_order(page, order);
+	set_page_order(page, order, migratetype);
 
 	/*
 	 * If this is not the largest possible page, check if the buddy
@@ -797,7 +799,6 @@ static void __free_pages_ok(struct page *page, unsigned int order)
 	migratetype = get_pfnblock_migratetype(page, pfn);
 	local_irq_save(flags);
 	__count_vm_events(PGFREE, 1 << order);
-	set_onbuddy_migratetype(page, migratetype);
 	free_one_page(page_zone(page), page, pfn, order, migratetype);
 	local_irq_restore(flags);
 }
@@ -943,7 +944,7 @@ static inline void expand(struct zone *zone, struct page *page,
 #endif
 		list_add(&page[size].lru, &area->free_list[migratetype]);
 		area->nr_free++;
-		set_page_order(&page[size], high);
+		set_page_order(&page[size], high, migratetype);
 	}
 }
 
-- 
1.7.9.5

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