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authorNick Piggin <nickpiggin@yahoo.com.au>2006-03-06 18:42:58 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-06 21:40:45 -0500
commitad820c5dd47dff9397ef1e94388bc6577983f68b (patch)
tree37c5386889669dd12899d28d2a38a25d1d9bcea2 /fs/proc
parent5ddfae16bddb12104fff63c36fb5901f1a3729fc (diff)
[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>
Diffstat (limited to 'fs/proc')
-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 35787f907f12..91b7c15ab373 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,
204{ 204{
205 pte_t *pte, ptent; 205 pte_t *pte, ptent;
206 spinlock_t *ptl; 206 spinlock_t *ptl;
207 unsigned long pfn;
208 struct page *page; 207 struct page *page;
209 208
210 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 209 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,
214 continue; 213 continue;
215 214
216 mss->resident += PAGE_SIZE; 215 mss->resident += PAGE_SIZE;
217 pfn = pte_pfn(ptent); 216
218 if (!pfn_valid(pfn)) 217 page = vm_normal_page(vma, addr, ptent);
218 if (!page)
219 continue; 219 continue;
220 220
221 page = pfn_to_page(pfn); 221 if (page_mapcount(page) >= 2) {
222 if (page_count(page) >= 2) {
223 if (pte_dirty(ptent)) 222 if (pte_dirty(ptent))
224 mss->shared_dirty += PAGE_SIZE; 223 mss->shared_dirty += PAGE_SIZE;
225 else 224 else