ksm: define MADV_MERGEABLE and MADV_UNMERGEABLE

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>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/alpha/include/asm/mman.h b/arch/alpha/include/asm/mman.h
index 90d7c35d286703a86a4f1c59061b2212b2de367d..c77c55756a7c41bb8bdd3a76c6dc08a46009c28f 100644 (file)
--- 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 e4d6f1fb1cf765c5ca8e23c3e8438f39ebcc0e2d..f15554d1518a067d544380758d47ca28b7753e6d 100644 (file)
--- 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 defe752cc996011164ee1600bd04e67441561fed..a12d9d43f50797b5a59938a0356f0ae89ab06584 100644 (file)
--- 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 9b92620c8a1ed262d3b10a9cb44dd0b746feacc8..6e55b4d1f9c5ef9a37aee57c6626fee81f3d6b1a 100644 (file)
--- 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 3b69ad34189a9d87e267e131daeb23557b7bfc7a..dd63bd38864b23627f36e57b53c8413af63cd238 100644 (file)
--- 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