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authorNick Piggin <npiggin@suse.de>2006-09-25 23:30:55 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-26 08:48:44 -0700
commit725d704ecaca4a43f067092c140d4f3271cf2856 (patch)
tree320cf8ab5457ac6c01c05da8c30d6026538ee259 /include
parenta6ca1b99ed434f3fb41bbed647ed36c0420501e5 (diff)
[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 <npiggin@suse.de> Cc: Hugh Dickins <hugh@veritas.com> Cc: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/mm.h10
1 files changed, 9 insertions, 1 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 <linux/page-flags.h>
+#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);
}