From 6e9f0d582dde095d971a3c6ce4685a218a0eac8e Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 11 Feb 2015 15:25:50 -0800 Subject: [PATCH] mm/page_alloc.c: drop dead destroy_compound_page() The only caller is __free_one_page(). By the time we should have page->flags to be cleared already: - for 0-order pages though PCP list: free_hot_cold_page() free_pages_prepare() free_pages_check() page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; free_pcppages_bulk() page = __free_one_page(page) - for non-0-order pages: __free_pages_ok() free_pages_prepare() free_pages_check() page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; free_one_page() __free_one_page() So there's no way PageCompound() will return true in __free_one_page(). Let's remove dead destroy_compound_page() and put assert for page->flags there instead. Signed-off-by: Kirill A. Shutemov Cc: Vlastimil Babka Cc: Andrea Arcangeli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 35 +---------------------------------- 1 file changed, 1 insertion(+), 34 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d664eb922a7d..12d55b859d3f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -381,36 +381,6 @@ void prep_compound_page(struct page *page, unsigned long order) } } -/* update __split_huge_page_refcount if you change this function */ -static int destroy_compound_page(struct page *page, unsigned long order) -{ - int i; - int nr_pages = 1 << order; - int bad = 0; - - if (unlikely(compound_order(page) != order)) { - bad_page(page, "wrong compound order", 0); - bad++; - } - - __ClearPageHead(page); - - for (i = 1; i < nr_pages; i++) { - struct page *p = page + i; - - if (unlikely(!PageTail(p))) { - bad_page(page, "PageTail not set", 0); - bad++; - } else if (unlikely(p->first_page != page)) { - bad_page(page, "first_page not consistent", 0); - bad++; - } - __ClearPageTail(p); - } - - return bad; -} - static inline void prep_zero_page(struct page *page, unsigned int order, gfp_t gfp_flags) { @@ -613,10 +583,7 @@ static inline void __free_one_page(struct page *page, int max_order = MAX_ORDER; VM_BUG_ON(!zone_is_initialized(zone)); - - if (unlikely(PageCompound(page))) - if (unlikely(destroy_compound_page(page, order))) - return; + VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page); VM_BUG_ON(migratetype == -1); if (is_migrate_isolate(migratetype)) { -- 2.20.1