diff options
author | Zi Yan <ziy@nvidia.com> | 2022-04-28 23:16:01 -0700 |
---|---|---|
committer | akpm <akpm@linux-foundation.org> | 2022-04-28 23:16:01 -0700 |
commit | 8170ac4700d26f65a9a4ebc8ae488539158dc5f7 (patch) | |
tree | a85b7fc988ebc992de89502218d0905bbc61b7ec /mm/page_alloc.c | |
parent | bb0e28eb5bc2b3a22e47861ca59bccca566023e8 (diff) | |
download | linux-8170ac4700d26f65a9a4ebc8ae488539158dc5f7.tar.bz2 |
mm: wrap __find_buddy_pfn() with a necessary buddy page validation
Whenever the buddy of a page is found from __find_buddy_pfn(),
page_is_buddy() should be used to check its validity. Add a helper
function find_buddy_page_pfn() to find the buddy page and do the check
together.
[ziy@nvidia.com: updates per David]
Link: https://lkml.kernel.org/r/20220401230804.1658207-2-zi.yan@sent.com
Link: https://lore.kernel.org/linux-mm/CAHk-=wji_AmYygZMTsPMdJ7XksMt7kOur8oDfDdniBRMjm4VkQ@mail.gmail.com/
Link: https://lkml.kernel.org/r/7236E7CA-B5F1-4C04-AB85-E86FA3E9A54B@nvidia.com
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Zi Yan <ziy@nvidia.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r-- | mm/page_alloc.c | 52 |
1 files changed, 8 insertions, 44 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 26dea6cd3f53..8de8d7a5c3e3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -867,40 +867,6 @@ static inline void set_buddy_order(struct page *page, unsigned int order) __SetPageBuddy(page); } -/* - * This function checks whether a page is free && is the buddy - * we can coalesce a page and its buddy if - * (a) the buddy is not in a hole (check before calling!) && - * (b) the buddy is in the buddy system && - * (c) a page and its buddy have the same order && - * (d) a page and its buddy are in the same zone. - * - * For recording whether a page is in the buddy system, we set PageBuddy. - * Setting, clearing, and testing PageBuddy is serialized by zone->lock. - * - * For recording page's order, we use page_private(page). - */ -static inline bool page_is_buddy(struct page *page, struct page *buddy, - unsigned int order) -{ - if (!page_is_guard(buddy) && !PageBuddy(buddy)) - return false; - - if (buddy_order(buddy) != order) - return false; - - /* - * zone check is done late to avoid uselessly calculating - * zone/node ids for pages that could never merge. - */ - if (page_zone_id(page) != page_zone_id(buddy)) - return false; - - VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy); - - return true; -} - #ifdef CONFIG_COMPACTION static inline struct capture_control *task_capc(struct zone *zone) { @@ -1009,18 +975,17 @@ static inline bool buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn, struct page *page, unsigned int order) { - struct page *higher_page, *higher_buddy; - unsigned long combined_pfn; + unsigned long higher_page_pfn; + struct page *higher_page; if (order >= MAX_ORDER - 2) return false; - combined_pfn = buddy_pfn & pfn; - higher_page = page + (combined_pfn - pfn); - buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1); - higher_buddy = higher_page + (buddy_pfn - combined_pfn); + higher_page_pfn = buddy_pfn & pfn; + higher_page = page + (higher_page_pfn - pfn); - return page_is_buddy(higher_page, higher_buddy, order + 1); + return find_buddy_page_pfn(higher_page, higher_page_pfn, order + 1, + NULL) != NULL; } /* @@ -1074,10 +1039,9 @@ static inline void __free_one_page(struct page *page, migratetype); return; } - buddy_pfn = __find_buddy_pfn(pfn, order); - buddy = page + (buddy_pfn - pfn); - if (!page_is_buddy(page, buddy, order)) + buddy = find_buddy_page_pfn(page, pfn, order, &buddy_pfn); + if (!buddy) goto done_merging; if (unlikely(order >= pageblock_order)) { |