From 725d704ecaca4a43f067092c140d4f3271cf2856 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Mon, 25 Sep 2006 23:30:55 -0700 Subject: [PATCH] [PATCH] mm: VM_BUG_ON Introduce a VM_BUG_ON, which is turned on with CONFIG_DEBUG_VM. Use this in the lightweight, inline refcounting functions; PageLRU and PageActive checks in vmscan, because they're pretty well confined to vmscan. And in page allocate/free fastpaths which can be the hottest parts of the kernel for kbuilds. Unlike BUG_ON, VM_BUG_ON must not be used to execute statements with side-effects, and should not be used outside core mm code. Signed-off-by: Nick Piggin Cc: Hugh Dickins Cc: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 10 +++++++++- mm/internal.h | 4 ++-- mm/page_alloc.c | 23 +++++++++++------------ mm/swap.c | 12 ++++++------ mm/vmscan.c | 16 ++++++++-------- 5 files changed, 36 insertions(+), 29 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 224178a000d2..7d20b25c58fc 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -278,6 +278,12 @@ struct page { */ #include +#ifdef CONFIG_DEBUG_VM +#define VM_BUG_ON(cond) BUG_ON(cond) +#else +#define VM_BUG_ON(condition) do { } while(0) +#endif + /* * Methods to modify the page usage count. * @@ -297,7 +303,7 @@ struct page { */ static inline int put_page_testzero(struct page *page) { - BUG_ON(atomic_read(&page->_count) == 0); + VM_BUG_ON(atomic_read(&page->_count) == 0); return atomic_dec_and_test(&page->_count); } @@ -307,6 +313,7 @@ static inline int put_page_testzero(struct page *page) */ static inline int get_page_unless_zero(struct page *page) { + VM_BUG_ON(PageCompound(page)); return atomic_inc_not_zero(&page->_count); } @@ -323,6 +330,7 @@ static inline void get_page(struct page *page) { if (unlikely(PageCompound(page))) page = (struct page *)page_private(page); + VM_BUG_ON(atomic_read(&page->_count) == 0); atomic_inc(&page->_count); } diff --git a/mm/internal.h b/mm/internal.h index d20e3cc4aef0..d527b80b292f 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -24,8 +24,8 @@ static inline void set_page_count(struct page *page, int v) */ static inline void set_page_refcounted(struct page *page) { - BUG_ON(PageCompound(page) && page_private(page) != (unsigned long)page); - BUG_ON(atomic_read(&page->_count)); + VM_BUG_ON(PageCompound(page) && page_private(page) != (unsigned long)page); + VM_BUG_ON(atomic_read(&page->_count)); set_page_count(page, 1); } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 8a52ba9fe693..4b33878e9488 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -127,7 +127,6 @@ static int bad_range(struct zone *zone, struct page *page) return 0; } - #else static inline int bad_range(struct zone *zone, struct page *page) { @@ -218,12 +217,12 @@ static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags) { int i; - BUG_ON((gfp_flags & (__GFP_WAIT | __GFP_HIGHMEM)) == __GFP_HIGHMEM); + VM_BUG_ON((gfp_flags & (__GFP_WAIT | __GFP_HIGHMEM)) == __GFP_HIGHMEM); /* * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO * and __GFP_HIGHMEM from hard or soft interrupt context. */ - BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt()); + VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt()); for (i = 0; i < (1 << order); i++) clear_highpage(page + i); } @@ -347,8 +346,8 @@ static inline void __free_one_page(struct page *page, page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1); - BUG_ON(page_idx & (order_size - 1)); - BUG_ON(bad_range(zone, page)); + VM_BUG_ON(page_idx & (order_size - 1)); + VM_BUG_ON(bad_range(zone, page)); zone->free_pages += order_size; while (order < MAX_ORDER-1) { @@ -421,7 +420,7 @@ static void free_pages_bulk(struct zone *zone, int count, while (count--) { struct page *page; - BUG_ON(list_empty(list)); + VM_BUG_ON(list_empty(list)); page = list_entry(list->prev, struct page, lru); /* have to delete it as __free_one_page list manipulates */ list_del(&page->lru); @@ -512,7 +511,7 @@ static inline void expand(struct zone *zone, struct page *page, area--; high--; size >>= 1; - BUG_ON(bad_range(zone, &page[size])); + VM_BUG_ON(bad_range(zone, &page[size])); list_add(&page[size].lru, &area->free_list); area->nr_free++; set_page_order(&page[size], high); @@ -761,8 +760,8 @@ void split_page(struct page *page, unsigned int order) { int i; - BUG_ON(PageCompound(page)); - BUG_ON(!page_count(page)); + VM_BUG_ON(PageCompound(page)); + VM_BUG_ON(!page_count(page)); for (i = 1; i < (1 << order); i++) set_page_refcounted(page + i); } @@ -809,7 +808,7 @@ again: local_irq_restore(flags); put_cpu(); - BUG_ON(bad_range(zone, page)); + VM_BUG_ON(bad_range(zone, page)); if (prep_new_page(page, order, gfp_flags)) goto again; return page; @@ -1083,7 +1082,7 @@ fastcall unsigned long get_zeroed_page(gfp_t gfp_mask) * get_zeroed_page() returns a 32-bit address, which cannot represent * a highmem page */ - BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0); + VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0); page = alloc_pages(gfp_mask | __GFP_ZERO, 0); if (page) @@ -1116,7 +1115,7 @@ EXPORT_SYMBOL(__free_pages); fastcall void free_pages(unsigned long addr, unsigned int order) { if (addr != 0) { - BUG_ON(!virt_addr_valid((void *)addr)); + VM_BUG_ON(!virt_addr_valid((void *)addr)); __free_pages(virt_to_page((void *)addr), order); } } diff --git a/mm/swap.c b/mm/swap.c index 687686a61f7c..600235e43704 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -233,7 +233,7 @@ void fastcall __page_cache_release(struct page *page) struct zone *zone = page_zone(page); spin_lock_irqsave(&zone->lru_lock, flags); - BUG_ON(!PageLRU(page)); + VM_BUG_ON(!PageLRU(page)); __ClearPageLRU(page); del_page_from_lru(zone, page); spin_unlock_irqrestore(&zone->lru_lock, flags); @@ -284,7 +284,7 @@ void release_pages(struct page **pages, int nr, int cold) zone = pagezone; spin_lock_irq(&zone->lru_lock); } - BUG_ON(!PageLRU(page)); + VM_BUG_ON(!PageLRU(page)); __ClearPageLRU(page); del_page_from_lru(zone, page); } @@ -337,7 +337,7 @@ void __pagevec_release_nonlru(struct pagevec *pvec) for (i = 0; i < pagevec_count(pvec); i++) { struct page *page = pvec->pages[i]; - BUG_ON(PageLRU(page)); + VM_BUG_ON(PageLRU(page)); if (put_page_testzero(page)) pagevec_add(&pages_to_free, page); } @@ -364,7 +364,7 @@ void __pagevec_lru_add(struct pagevec *pvec) zone = pagezone; spin_lock_irq(&zone->lru_lock); } - BUG_ON(PageLRU(page)); + VM_BUG_ON(PageLRU(page)); SetPageLRU(page); add_page_to_inactive_list(zone, page); } @@ -391,9 +391,9 @@ void __pagevec_lru_add_active(struct pagevec *pvec) zone = pagezone; spin_lock_irq(&zone->lru_lock); } - BUG_ON(PageLRU(page)); + VM_BUG_ON(PageLRU(page)); SetPageLRU(page); - BUG_ON(PageActive(page)); + VM_BUG_ON(PageActive(page)); SetPageActive(page); add_page_to_active_list(zone, page); } diff --git a/mm/vmscan.c b/mm/vmscan.c index 5d4c4d02254d..41a3da3d6ccc 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -440,7 +440,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, if (TestSetPageLocked(page)) goto keep; - BUG_ON(PageActive(page)); + VM_BUG_ON(PageActive(page)); sc->nr_scanned++; @@ -564,7 +564,7 @@ keep_locked: unlock_page(page); keep: list_add(&page->lru, &ret_pages); - BUG_ON(PageLRU(page)); + VM_BUG_ON(PageLRU(page)); } list_splice(&ret_pages, page_list); if (pagevec_count(&freed_pvec)) @@ -603,7 +603,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, page = lru_to_page(src); prefetchw_prev_lru_page(page, src, flags); - BUG_ON(!PageLRU(page)); + VM_BUG_ON(!PageLRU(page)); list_del(&page->lru); target = src; @@ -674,7 +674,7 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, */ while (!list_empty(&page_list)) { page = lru_to_page(&page_list); - BUG_ON(PageLRU(page)); + VM_BUG_ON(PageLRU(page)); SetPageLRU(page); list_del(&page->lru); if (PageActive(page)) @@ -797,9 +797,9 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, while (!list_empty(&l_inactive)) { page = lru_to_page(&l_inactive); prefetchw_prev_lru_page(page, &l_inactive, flags); - BUG_ON(PageLRU(page)); + VM_BUG_ON(PageLRU(page)); SetPageLRU(page); - BUG_ON(!PageActive(page)); + VM_BUG_ON(!PageActive(page)); ClearPageActive(page); list_move(&page->lru, &zone->inactive_list); @@ -827,9 +827,9 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, while (!list_empty(&l_active)) { page = lru_to_page(&l_active); prefetchw_prev_lru_page(page, &l_active, flags); - BUG_ON(PageLRU(page)); + VM_BUG_ON(PageLRU(page)); SetPageLRU(page); - BUG_ON(!PageActive(page)); + VM_BUG_ON(!PageActive(page)); list_move(&page->lru, &zone->active_list); pgmoved++; if (!pagevec_add(&pvec, page)) { -- 2.30.2