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authorHugh Dickins <hugh.dickins@tiscali.co.uk>2009-12-14 17:59:22 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-15 08:53:19 -0800
commit73848b4684e84a84cfd1555af78d41158f31e16b (patch)
treeb71ba30e2b20cbc45740a38e9b5aa51b8c2ea60e /mm
parentksm: stable_node point to page and back (diff)
downloadlinux-dev-73848b4684e84a84cfd1555af78d41158f31e16b.tar.xz
linux-dev-73848b4684e84a84cfd1555af78d41158f31e16b.zip
ksm: fix mlockfreed to munlocked
When KSM merges an mlocked page, it has been forgetting to munlock it: that's been left to free_page_mlock(), which reports it in /proc/vmstat as unevictable_pgs_mlockfreed instead of unevictable_pgs_munlocked (and whinges "Page flag mlocked set for process" in mmotm, whereas mainline is silently forgiving). Call munlock_vma_page() to fix that. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Izik Eidus <ieidus@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Chris Wright <chrisw@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r--mm/internal.h3
-rw-r--r--mm/ksm.c4
-rw-r--r--mm/mlock.c4
3 files changed, 8 insertions, 3 deletions
diff --git a/mm/internal.h b/mm/internal.h
index cb7d92d0a46d..a4b927cdca09 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -105,9 +105,10 @@ static inline int is_mlocked_vma(struct vm_area_struct *vma, struct page *page)
}
/*
- * must be called with vma's mmap_sem held for read, and page locked.
+ * must be called with vma's mmap_sem held for read or write, and page locked.
*/
extern void mlock_vma_page(struct page *page);
+extern void munlock_vma_page(struct page *page);
/*
* Clear the page's PageMlocked(). This can be useful in a situation where
diff --git a/mm/ksm.c b/mm/ksm.c
index 748785683399..af5f571185d5 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -34,6 +34,7 @@
#include <linux/ksm.h>
#include <asm/tlbflush.h>
+#include "internal.h"
/*
* A few notes about the KSM scanning process,
@@ -762,6 +763,9 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
pages_identical(page, kpage))
err = replace_page(vma, page, kpage, orig_pte);
+ if ((vma->vm_flags & VM_LOCKED) && !err)
+ munlock_vma_page(page);
+
unlock_page(page);
out:
return err;
diff --git a/mm/mlock.c b/mm/mlock.c
index 48691fb08514..adcbe9032b58 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -99,14 +99,14 @@ void mlock_vma_page(struct page *page)
* not get another chance to clear PageMlocked. If we successfully
* isolate the page and try_to_munlock() detects other VM_LOCKED vmas
* mapping the page, it will restore the PageMlocked state, unless the page
- * is mapped in a non-linear vma. So, we go ahead and SetPageMlocked(),
+ * is mapped in a non-linear vma. So, we go ahead and ClearPageMlocked(),
* perhaps redundantly.
* If we lose the isolation race, and the page is mapped by other VM_LOCKED
* vmas, we'll detect this in vmscan--via try_to_munlock() or try_to_unmap()
* either of which will restore the PageMlocked state by calling
* mlock_vma_page() above, if it can grab the vma's mmap sem.
*/
-static void munlock_vma_page(struct page *page)
+void munlock_vma_page(struct page *page)
{
BUG_ON(!PageLocked(page));