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Subject[PATCH 03/10] ksm: define MADV_MERGEABLE and MADV_UNMERGEABLE
Date
From: Hugh Dickins <hugh.dickins@tiscali.co.uk>

The out-of-tree KSM used ioctls on fds cloned from /dev/ksm to register
a memory area for merging: we prefer now to use an madvise(2) interface.

This patch just defines MADV_MERGEABLE (to tell KSM it may merge pages
in this area found identical to pages in other mergeable areas) and
MADV_UNMERGEABLE (to undo that).

Most architectures use asm-generic, but alpha, mips, parisc, xtensa
need their own definitions: included here for mmotm convenience, but
we'll probably want to split this and feed pieces to arch maintainers.

Based upon earlier patches by Chris Wright and Izik Eidus.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Chris Wright <chrisw@redhat.com>
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Helge Deller <deller@gmx.de>
Cc: Chris Zankel <chris@zankel.net>
---
arch/alpha/include/asm/mman.h | 3 +++
arch/mips/include/asm/mman.h | 3 +++
arch/parisc/include/asm/mman.h | 3 +++
arch/xtensa/include/asm/mman.h | 3 +++
include/asm-generic/mman-common.h | 3 +++
5 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/arch/alpha/include/asm/mman.h b/arch/alpha/include/asm/mman.h
index 90d7c35..c77c557 100644
--- a/arch/alpha/include/asm/mman.h
+++ b/arch/alpha/include/asm/mman.h
@@ -48,6 +48,9 @@
#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 */
+
/* compatibility flags */
#define MAP_FILE 0

diff --git a/arch/mips/include/asm/mman.h b/arch/mips/include/asm/mman.h
index e4d6f1f..f15554d 100644
--- a/arch/mips/include/asm/mman.h
+++ b/arch/mips/include/asm/mman.h
@@ -71,6 +71,9 @@
#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 */
+
/* compatibility flags */
#define MAP_FILE 0

diff --git a/arch/parisc/include/asm/mman.h b/arch/parisc/include/asm/mman.h
index defe752..a12d9d4 100644
--- a/arch/parisc/include/asm/mman.h
+++ b/arch/parisc/include/asm/mman.h
@@ -54,6 +54,9 @@
#define MADV_16M_PAGES 24 /* Use 16 Megabyte pages */
#define MADV_64M_PAGES 26 /* Use 64 Megabyte pages */

+#define MADV_MERGEABLE 65 /* KSM may merge identical pages */
+#define MADV_UNMERGEABLE 66 /* KSM may not merge identical pages */
+
/* compatibility flags */
#define MAP_FILE 0
#define MAP_VARIABLE 0
diff --git a/arch/xtensa/include/asm/mman.h b/arch/xtensa/include/asm/mman.h
index 9b92620..6e55b4d 100644
--- a/arch/xtensa/include/asm/mman.h
+++ b/arch/xtensa/include/asm/mman.h
@@ -78,6 +78,9 @@
#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 */
+
/* compatibility flags */
#define MAP_FILE 0

diff --git a/include/asm-generic/mman-common.h b/include/asm-generic/mman-common.h
index 3b69ad3..dd63bd3 100644
--- a/include/asm-generic/mman-common.h
+++ b/include/asm-generic/mman-common.h
@@ -35,6 +35,9 @@
#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 */
+
/* compatibility flags */
#define MAP_FILE 0

--
1.5.6.5


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