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authorNick Piggin <nickpiggin@yahoo.com.au>2006-03-06 15:42:58 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-06 18:40:45 -0800
commitad820c5dd47dff9397ef1e94388bc6577983f68b (patch)
tree37c5386889669dd12899d28d2a38a25d1d9bcea2
parent5ddfae16bddb12104fff63c36fb5901f1a3729fc (diff)
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[PATCH] smaps: shared fix
The point of the smaps "shared" is to count the number of pages that are mapped by more than one process, according to Mauricio Lin. However, smaps uses page_count for this, so it will return a false positive for every page that is mapped by just that one process, which is also in pagecache or swapcache. There are false positive situations for anonymous pages not in swapcache as well: - page reclaim, migration - get_user_pages (eg. direct-io, ptrace) Use page_mapcount instead, to count the number of mappings to the page. Use vm_normal_page so that weird things like /dev/mem aren't counted either. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--fs/proc/task_mmu.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 35787f9..91b7c15 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -204,7 +204,6 @@ static void smaps_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
{
pte_t *pte, ptent;
spinlock_t *ptl;
- unsigned long pfn;
struct page *page;
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
@@ -214,12 +213,12 @@ static void smaps_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
continue;
mss->resident += PAGE_SIZE;
- pfn = pte_pfn(ptent);
- if (!pfn_valid(pfn))
+
+ page = vm_normal_page(vma, addr, ptent);
+ if (!page)
continue;
- page = pfn_to_page(pfn);
- if (page_count(page) >= 2) {
+ if (page_mapcount(page) >= 2) {
if (pte_dirty(ptent))
mss->shared_dirty += PAGE_SIZE;
else