bug: completely remove code generated by disabled VM_BUG_ON()
Even if CONFIG_DEBUG_VM=n gcc genereates code for some VM_BUG_ON()
for example VM_BUG_ON(!PageCompound(page) || !PageHead(page)); in
do_huge_pmd_wp_page() generates 114 bytes of code.
But they mostly disappears when I split this VM_BUG_ON into two:
-VM_BUG_ON(!PageCompound(page) || !PageHead(page));
+VM_BUG_ON(!PageCompound(page));
+VM_BUG_ON(!PageHead(page));
weird... but anyway after this patch code disappears completely.
add/remove: 0/0 grow/shrink: 7/97 up/down: 135/-1784 (-1649)
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index c04ecfe..580bd58 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -4,7 +4,7 @@
#ifdef CONFIG_DEBUG_VM
#define VM_BUG_ON(cond) BUG_ON(cond)
#else
-#define VM_BUG_ON(cond) do { (void)(cond); } while (0)
+#define VM_BUG_ON(cond) BUILD_BUG_ON_INVALID(cond)
#endif
#ifdef CONFIG_DEBUG_VIRTUAL