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authorHugh Dickins <hugh.dickins@tiscali.co.uk>2009-09-21 17:02:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-22 07:17:31 -0700
commit9a840895147b12de5cdd633c600b38686840ee53 (patch)
treea266a69a39decb4ec0364ac331f0ab19b6f09f06 /mm/memory.c
parent21333b2b66b805a360641568588e5a0bb06d9d1f (diff)
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ksm: identify PageKsm pages
KSM will need to identify its kernel merged pages unambiguously, and /proc/kpageflags will probably like to do so too. Since KSM will only be substituting anonymous pages, statistics are best preserved by making a PageKsm page a special PageAnon page: one with no anon_vma. But KSM then needs its own page_add_ksm_rmap() - keep it in ksm.h near PageKsm; and do_wp_page() must COW them, unlike singly mapped PageAnons. 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: Wu Fengguang <fengguang.wu@intel.com> 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>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 7a61a11f186..1a435b81876 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -45,6 +45,7 @@
#include <linux/swap.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
+#include <linux/ksm.h>
#include <linux/rmap.h>
#include <linux/module.h>
#include <linux/delayacct.h>
@@ -1974,7 +1975,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
* Take out anonymous pages first, anonymous shared vmas are
* not dirty accountable.
*/
- if (PageAnon(old_page)) {
+ if (PageAnon(old_page) && !PageKsm(old_page)) {
if (!trylock_page(old_page)) {
page_cache_get(old_page);
pte_unmap_unlock(page_table, ptl);