From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: 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(). Link: https://lkml.kernel.org/r/20201001152259.14932-2-willy@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/compaction.c | 6 +++--- mm/internal.h | 8 ++++---- mm/page_alloc.c | 30 +++++++++++++++--------------- mm/page_isolation.c | 4 ++-- mm/page_owner.c | 6 +++--- mm/page_reporting.c | 2 +- mm/shuffle.c | 2 +- 7 files changed, 29 insertions(+), 29 deletions(-) --- a/mm/compaction.c~mm-rename-page_order-to-buddy_order +++ a/mm/compaction.c @@ -625,7 +625,7 @@ static unsigned long isolate_freepages_b } /* 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 compac * 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(st * 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; } --- a/mm/internal.h~mm-rename-page_order-to-buddy_order +++ a/mm/internal.h @@ -270,16 +270,16 @@ int find_suitable_fallback(struct free_a * 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(st * 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) { --- a/mm/page_alloc.c~mm-rename-page_order-to-buddy_order +++ a/mm/page_alloc.c @@ -792,7 +792,7 @@ static inline void clear_page_guard(stru 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 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 *z 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 *z 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(struc 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 */ 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 sta } 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 l 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 *pag 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(struc 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 *pa 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; } --- a/mm/page_isolation.c~mm-rename-page_order-to-buddy_order +++ a/mm/page_isolation.c @@ -88,7 +88,7 @@ static void unset_migratetype_isolate(st * 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(unsign * 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++; --- a/mm/page_owner.c~mm-rename-page_order-to-buddy_order +++ a/mm/page_owner.c @@ -295,7 +295,7 @@ void pagetypeinfo_showmixedcount_print(s 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 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 * 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; --- a/mm/page_reporting.c~mm-rename-page_order-to-buddy_order +++ a/mm/page_reporting.c @@ -92,7 +92,7 @@ page_reporting_drain(struct page_reporti * report on the new larger page when we make our way * up to that higher order. */ - if (PageBuddy(page) && page_order(page) == order) + if (PageBuddy(page) && buddy_order(page) == order) __SetPageReported(page); } while ((sg = sg_next(sg))); --- a/mm/shuffle.c~mm-rename-page_order-to-buddy_order +++ a/mm/shuffle.c @@ -60,7 +60,7 @@ static struct page * __meminit shuffle_v * ...is the page on the same list as the page we will * shuffle it with? */ - if (page_order(page) != order) + if (buddy_order(page) != order) return NULL; return page; _
