[PATCH mmotm] ksm: antidote to MADV_MERGEABLE HWPOISON

[Hugh Dickins]

linux-next is now sporting MADV_HWPOISON at 12, which would have a very
nasty effect on KSM if you had CONFIG_MEMORY_FAILURE=y with CONFIG_KSM=y.
Shift MADV_MERGEABLE and MADV_UNMERGEABLE down two - two to reduce the
confusion if old and new userspace and kernel are mismatched.

Personally I'd prefer the MADV_HWPOISON testing feature to shift; but
linux-next comes first in the mmotm lineup, and I can't be sure that
madvise KSM already has more users than there are HWPOISON testers:
so unless Andi is happy to shift MADV_HWPOISON, mmotm needs this.
---
Fix to ksm-define-madv_mergeable-and-madv_unmergeable.patch
parisc unaffected because its MADVs are displaced.

 arch/alpha/include/asm/mman.h     |    4 ++--
 arch/mips/include/asm/mman.h      |    4 ++--
 arch/xtensa/include/asm/mman.h    |    4 ++--
 include/asm-generic/mman-common.h |    4 ++--
 4 files changed, 8 insertions(+), 8 deletions(-)

--- mmotm/arch/alpha/include/asm/mman.h	2009-08-21 12:08:18.000000000 +0100
+++ linux/arch/alpha/include/asm/mman.h	2009-08-21 18:28:14.000000000 +0100
@@ -48,8 +48,8 @@
 #define MADV_DONTFORK	10		/* don't inherit across fork */
 #define MADV_DOFORK	11		/* do inherit across fork */
 
-#define MADV_MERGEABLE   12		/* KSM may merge identical pages */
-#define MADV_UNMERGEABLE 13		/* KSM may not merge identical pages */
+#define MADV_MERGEABLE   14		/* KSM may merge identical pages */
+#define MADV_UNMERGEABLE 15		/* KSM may not merge identical pages */
 
 /* compatibility flags */
 #define MAP_FILE	0
--- mmotm/arch/mips/include/asm/mman.h	2009-08-21 12:08:18.000000000 +0100
+++ linux/arch/mips/include/asm/mman.h	2009-08-21 18:28:24.000000000 +0100
@@ -71,8 +71,8 @@
 #define MADV_DONTFORK	10		/* don't inherit across fork */
 #define MADV_DOFORK	11		/* do inherit across fork */
 
-#define MADV_MERGEABLE   12		/* KSM may merge identical pages */
-#define MADV_UNMERGEABLE 13		/* KSM may not merge identical pages */
+#define MADV_MERGEABLE   14		/* KSM may merge identical pages */
+#define MADV_UNMERGEABLE 15		/* KSM may not merge identical pages */
 
 /* compatibility flags */
 #define MAP_FILE	0
--- mmotm/arch/xtensa/include/asm/mman.h	2009-08-21 12:08:18.000000000 +0100
+++ linux/arch/xtensa/include/asm/mman.h	2009-08-21 18:28:52.000000000 +0100
@@ -78,8 +78,8 @@
 #define MADV_DONTFORK	10		/* don't inherit across fork */
 #define MADV_DOFORK	11		/* do inherit across fork */
 
-#define MADV_MERGEABLE   12		/* KSM may merge identical pages */
-#define MADV_UNMERGEABLE 13		/* KSM may not merge identical pages */
+#define MADV_MERGEABLE   14		/* KSM may merge identical pages */
+#define MADV_UNMERGEABLE 15		/* KSM may not merge identical pages */
 
 /* compatibility flags */
 #define MAP_FILE	0
--- mmotm/include/asm-generic/mman-common.h	2009-08-21 12:08:18.000000000 +0100
+++ linux/include/asm-generic/mman-common.h	2009-08-21 18:29:01.000000000 +0100
@@ -36,8 +36,8 @@
 #define MADV_DOFORK	11		/* do inherit across fork */
 #define MADV_HWPOISON	12		/* poison a page for testing */
 
-#define MADV_MERGEABLE   12		/* KSM may merge identical pages */
-#define MADV_UNMERGEABLE 13		/* KSM may not merge identical pages */
+#define MADV_MERGEABLE   14		/* KSM may merge identical pages */
+#define MADV_UNMERGEABLE 15		/* KSM may not merge identical pages */
 
 /* compatibility flags */
 #define MAP_FILE	0
--
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