Commit ab130f91 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

mm: rename page_order() to buddy_order() 



The current page_order() can only be called on pages in the buddy
allocator.  For compound pages, you have to use compound_order().  This is
confusing and led to a bug, so rename page_order() to buddy_order().

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20201001152259.14932-2-willy@infradead.org


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1f0f8c0d

mm/compaction.c

+3 −3
Original line number Diff line number Diff line
@@ -625,7 +625,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, 
		}



		/* Found a free page, will break it into order-0 pages */

		order = page_order(page);

		order = buddy_order(page);

		isolated = __isolate_free_page(page, order);

		if (!isolated)

			break;
@@ -898,7 +898,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, 
		 * potential isolation targets.

		 */

		if (PageBuddy(page)) {

			unsigned long freepage_order = page_order_unsafe(page);

			unsigned long freepage_order = buddy_order_unsafe(page);



			/*

			 * Without lock, we cannot be sure that what we got is
@@ -1172,7 +1172,7 @@ static bool suitable_migration_target(struct compact_control *cc, 
		 * the only small danger is that we skip a potentially suitable

		 * pageblock, so it's not worth to check order for valid range.

		 */

		if (page_order_unsafe(page) >= pageblock_order)

		if (buddy_order_unsafe(page) >= pageblock_order)

			return false;

	}

mm/internal.h

+4 −4
Original line number Diff line number Diff line
@@ -270,16 +270,16 @@ int find_suitable_fallback(struct free_area *area, unsigned int order, 
 * page from being allocated in parallel and returning garbage as the order.

 * If a caller does not hold page_zone(page)->lock, it must guarantee that the

 * page cannot be allocated or merged in parallel. Alternatively, it must

 * handle invalid values gracefully, and use page_order_unsafe() below.

 * handle invalid values gracefully, and use buddy_order_unsafe() below.

 */

static inline unsigned int page_order(struct page *page)

static inline unsigned int buddy_order(struct page *page)

{

	/* PageBuddy() must be checked by the caller */

	return page_private(page);

}



/*

 * Like page_order(), but for callers who cannot afford to hold the zone lock.

 * Like buddy_order(), but for callers who cannot afford to hold the zone lock.

 * PageBuddy() should be checked first by the caller to minimize race window,

 * and invalid values must be handled gracefully.

 *
@@ -289,7 +289,7 @@ static inline unsigned int page_order(struct page *page) 
 * times, potentially observing different values in the tests and the actual

 * use of the result.

 */

#define page_order_unsafe(page)		READ_ONCE(page_private(page))

#define buddy_order_unsafe(page)	READ_ONCE(page_private(page))



static inline bool is_cow_mapping(vm_flags_t flags)

{

mm/page_alloc.c

+15 −15
Original line number Diff line number Diff line
@@ -792,7 +792,7 @@ 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_buddy_order(struct page *page, unsigned int order)

{

	set_page_private(page, order);

	__SetPageBuddy(page);
@@ -817,7 +817,7 @@ static inline bool page_is_buddy(struct page *page, struct page *buddy, 
	if (!page_is_guard(buddy) && !PageBuddy(buddy))

		return false;



	if (page_order(buddy) != order)

	if (buddy_order(buddy) != order)

		return false;



	/*
@@ -1059,7 +1059,7 @@ continue_merging: 
	}



done_merging:

	set_page_order(page, order);

	set_buddy_order(page, order);



	if (fpi_flags & FPI_TO_TAIL)

		to_tail = true;
@@ -2178,7 +2178,7 @@ static inline void expand(struct zone *zone, struct page *page, 
			continue;



		add_to_free_list(&page[size], zone, high, migratetype);

		set_page_order(&page[size], high);

		set_buddy_order(&page[size], high);

	}

}
@@ -2392,7 +2392,7 @@ static int move_freepages(struct zone *zone, 
		VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);

		VM_BUG_ON_PAGE(page_zone(page) != zone, page);



		order = page_order(page);

		order = buddy_order(page);

		move_to_free_list(page, zone, order, migratetype);

		page += 1 << order;

		pages_moved += 1 << order;
@@ -2516,7 +2516,7 @@ static inline void boost_watermark(struct zone *zone) 
static void steal_suitable_fallback(struct zone *zone, struct page *page,

		unsigned int alloc_flags, int start_type, bool whole_block)

{

	unsigned int current_order = page_order(page);

	unsigned int current_order = buddy_order(page);

	int free_pages, movable_pages, alike_pages;

	int old_block_type;
@@ -8344,7 +8344,7 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page, 
		 */

		if (!page_ref_count(page)) {

			if (PageBuddy(page))

				iter += (1 << page_order(page)) - 1;

				iter += (1 << buddy_order(page)) - 1;

			continue;

		}
@@ -8557,7 +8557,7 @@ int alloc_contig_range(unsigned long start, unsigned long end, 
	}



	if (outer_start != start) {

		order = page_order(pfn_to_page(outer_start));

		order = buddy_order(pfn_to_page(outer_start));



		/*

		 * outer_start page could be small order buddy page and
@@ -8782,7 +8782,7 @@ void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 


		BUG_ON(page_count(page));

		BUG_ON(!PageBuddy(page));

		order = page_order(page);

		order = buddy_order(page);

		del_page_from_free_list(page, zone, order);

		pfn += (1 << order);

	}
@@ -8801,7 +8801,7 @@ bool is_free_buddy_page(struct page *page) 
	for (order = 0; order < MAX_ORDER; order++) {

		struct page *page_head = page - (pfn & ((1 << order) - 1));



		if (PageBuddy(page_head) && page_order(page_head) >= order)

		if (PageBuddy(page_head) && buddy_order(page_head) >= order)

			break;

	}

	spin_unlock_irqrestore(&zone->lock, flags);
@@ -8838,7 +8838,7 @@ static void break_down_buddy_pages(struct zone *zone, struct page *page, 


		if (current_buddy != target) {

			add_to_free_list(current_buddy, zone, high, migratetype);

			set_page_order(current_buddy, high);

			set_buddy_order(current_buddy, high);

			page = next_page;

		}

	}
@@ -8858,16 +8858,16 @@ bool take_page_off_buddy(struct page *page) 
	spin_lock_irqsave(&zone->lock, flags);

	for (order = 0; order < MAX_ORDER; order++) {

		struct page *page_head = page - (pfn & ((1 << order) - 1));

		int buddy_order = page_order(page_head);

		int page_order = buddy_order(page_head);



		if (PageBuddy(page_head) && buddy_order >= order) {

		if (PageBuddy(page_head) && page_order >= order) {

			unsigned long pfn_head = page_to_pfn(page_head);

			int migratetype = get_pfnblock_migratetype(page_head,

								   pfn_head);



			del_page_from_free_list(page_head, zone, buddy_order);

			del_page_from_free_list(page_head, zone, page_order);

			break_down_buddy_pages(zone, page_head, page, 0,

						buddy_order, migratetype);

						page_order, migratetype);

			ret = true;

			break;

		}

mm/page_isolation.c

+2 −2
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype) 
	 * these pages to be merged.

	 */

	if (PageBuddy(page)) {

		order = page_order(page);

		order = buddy_order(page);

		if (order >= pageblock_order) {

			pfn = page_to_pfn(page);

			buddy_pfn = __find_buddy_pfn(pfn, order);
@@ -261,7 +261,7 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn, 
			 * the correct MIGRATE_ISOLATE freelist. There is no

			 * simple way to verify that as VM_BUG_ON(), though.

			 */

			pfn += 1 << page_order(page);

			pfn += 1 << buddy_order(page);

		else if ((flags & MEMORY_OFFLINE) && PageHWPoison(page))

			/* A HWPoisoned page cannot be also PageBuddy */

			pfn++;

mm/page_owner.c

+3 −3
Original line number Diff line number Diff line
@@ -295,7 +295,7 @@ void pagetypeinfo_showmixedcount_print(struct seq_file *m, 
			if (PageBuddy(page)) {

				unsigned long freepage_order;



				freepage_order = page_order_unsafe(page);

				freepage_order = buddy_order_unsafe(page);

				if (freepage_order < MAX_ORDER)

					pfn += (1UL << freepage_order) - 1;

				continue;
@@ -490,7 +490,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) 


		page = pfn_to_page(pfn);

		if (PageBuddy(page)) {

			unsigned long freepage_order = page_order_unsafe(page);

			unsigned long freepage_order = buddy_order_unsafe(page);



			if (freepage_order < MAX_ORDER)

				pfn += (1UL << freepage_order) - 1;
@@ -584,7 +584,7 @@ static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone) 
			 * heavy lock contention.

			 */

			if (PageBuddy(page)) {

				unsigned long order = page_order_unsafe(page);

				unsigned long order = buddy_order_unsafe(page);



				if (order > 0 && order < MAX_ORDER)

					pfn += (1UL << order) - 1;

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