Merge "mm/page_alloc: restrict max order of merging on isolated pageblock... (ac6c6499) · Commits · e / devices / android_kernel_sony_msm8994

mm/internal.h

+25 −0

Original line number	Diff line number	Diff line
		@@ -100,6 +100,31 @@ extern pmd_t mm_find_pmd(struct mm_struct mm, unsigned long address);
		/*
		* in mm/page_alloc.c
		*/

		/*
		* Locate the struct page for both the matching buddy in our
		* pair (buddy1) and the combined O(n+1) page they form (page).
		*
		* 1) Any buddy B1 will have an order O twin B2 which satisfies
		* the following equation:
		* B2 = B1 ^ (1 << O)
		* For example, if the starting buddy (buddy2) is #8 its order
		* 1 buddy is #10:
		* B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
		*
		* 2) Any buddy B will have an order O+1 parent P which
		* satisfies the following equation:
		* P = B & ~(1 << O)
		*
		* Assumption: *_mem_map is contiguous at least up to MAX_ORDER
		*/
		static inline unsigned long
		__find_buddy_index(unsigned long page_idx, unsigned int order)
		{
		return page_idx ^ (1 << order);
		}

		extern int __isolate_free_page(struct page *page, unsigned int order);
		extern void __free_pages_bootmem(struct page *page, unsigned int order);
		extern void prep_compound_page(struct page *page, unsigned long order);
		#ifdef CONFIG_MEMORY_FAILURE

mm/page_alloc.c

+14 −27

Original line number	Diff line number	Diff line
		@@ -478,29 +478,6 @@ static inline void rmv_page_order(struct page *page)
		set_page_private(page, 0);
		}

		/*
		* Locate the struct page for both the matching buddy in our
		* pair (buddy1) and the combined O(n+1) page they form (page).
		*
		* 1) Any buddy B1 will have an order O twin B2 which satisfies
		* the following equation:
		* B2 = B1 ^ (1 << O)
		* For example, if the starting buddy (buddy2) is #8 its order
		* 1 buddy is #10:
		* B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
		*
		* 2) Any buddy B will have an order O+1 parent P which
		* satisfies the following equation:
		* P = B & ~(1 << O)
		*
		* Assumption: *_mem_map is contiguous at least up to MAX_ORDER
		*/
		static inline unsigned long
		__find_buddy_index(unsigned long page_idx, unsigned int order)
		{
		return page_idx ^ (1 << order);
		}

		/*
		* This function checks whether a page is free && is the buddy
		* we can do coalesce a page and its buddy if
		@@ -567,6 +544,7 @@ static inline void __free_one_page(struct page *page,
		unsigned long combined_idx;
		unsigned long uninitialized_var(buddy_idx);
		struct page *buddy = NULL;
		int max_order = MAX_ORDER;

		VM_BUG_ON(!zone_is_initialized(zone));

		@@ -575,15 +553,24 @@ static inline void __free_one_page(struct page *page,
		return;

		VM_BUG_ON(migratetype == -1);
		if (!is_migrate_isolate(migratetype))
		if (is_migrate_isolate(migratetype)) {
		/*
		* We restrict max order of merging to prevent merge
		* between freepages on isolate pageblock and normal
		* pageblock. Without this, pageblock isolation
		* could cause incorrect freepage accounting.
		*/
		max_order = min(MAX_ORDER, pageblock_order + 1);
		} else {
		__mod_zone_freepage_state(zone, 1 << order, migratetype);
		}

		page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
		page_idx = page_to_pfn(page) & ((1 << max_order) - 1);

		VM_BUG_ON(page_idx & ((1 << order) - 1));
		VM_BUG_ON(bad_range(zone, page));

		while (order < MAX_ORDER-1) {
		while (order < max_order - 1) {
		buddy_idx = __find_buddy_index(page_idx, order);
		buddy = page + (buddy_idx - page_idx);
		if (!page_is_buddy(page, buddy, order))
		@@ -1481,7 +1468,7 @@ void split_page(struct page *page, unsigned int order)
		}
		EXPORT_SYMBOL_GPL(split_page);

		static int __isolate_free_page(struct page *page, unsigned int order)
		int __isolate_free_page(struct page *page, unsigned int order)
		{
		unsigned long watermark;
		struct zone *zone;

mm/page_isolation.c

+39 −2

Original line number	Diff line number	Diff line
		@@ -75,17 +75,54 @@ void unset_migratetype_isolate(struct page *page, unsigned migratetype)
		{
		struct zone *zone;
		unsigned long flags, nr_pages;
		struct page *isolated_page = NULL;
		unsigned int order;
		unsigned long page_idx, buddy_idx;
		struct page *buddy;

		zone = page_zone(page);
		spin_lock_irqsave(&zone->lock, flags);
		if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
		goto out;

		/*
		* Because freepage with more than pageblock_order on isolated
		* pageblock is restricted to merge due to freepage counting problem,
		* it is possible that there is free buddy page.
		* move_freepages_block() doesn't care of merge so we need other
		* approach in order to merge them. Isolation and free will make
		* these pages to be merged.
		*/
		if (PageBuddy(page)) {
		order = page_order(page);
		if (order >= pageblock_order) {
		page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
		buddy_idx = __find_buddy_index(page_idx, order);
		buddy = page + (buddy_idx - page_idx);

		if (!is_migrate_isolate_page(buddy)) {
		__isolate_free_page(page, order);
		set_page_refcounted(page);
		isolated_page = page;
		}
		}
		}

		/*
		* If we isolate freepage with more than pageblock_order, there
		* should be no freepage in the range, so we could avoid costly
		* pageblock scanning for freepage moving.
		*/
		if (!isolated_page) {
		nr_pages = move_freepages_block(zone, page, migratetype);
		__mod_zone_freepage_state(zone, nr_pages, migratetype);
		}
		set_pageblock_migratetype(page, migratetype);
		zone->nr_isolate_pageblock--;
		out:
		spin_unlock_irqrestore(&zone->lock, flags);
		if (isolated_page)
		__free_pages(isolated_page, order);
		}

		static inline struct page *