Commit 1c2499ae authored by KOSAKI Motohiro's avatar KOSAKI Motohiro Committed by Linus Torvalds

/proc/pid/smaps: fix dirty pages accounting

Currently, /proc/<pid>/smaps has wrong dirty pages accounting.
Shared_Dirty and Private_Dirty output only pte dirty pages and ignore
PG_dirty page flag.  It is difference against documentation, but also
inconsistent against Referenced field.  (Referenced checks both pte and
page flags)

This patch fixes it.

Test program:

 large-array.c
 ---------------------------------------------------
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>

 char array[1*1024*1024*1024L];

 int main(void)
 {
         memset(array, 1, sizeof(array));
         pause();

         return 0;
 }
 ---------------------------------------------------

Test case:
 1. run ./large-array
 2. cat /proc/`pidof large-array`/smaps
 3. swapoff -a
 4. cat /proc/`pidof large-array`/smaps again

Test result:
 <before patch>

00601000-40601000 rw-p 00000000 00:00 0
Size:            1048576 kB
Rss:             1048576 kB
Pss:             1048576 kB
Shared_Clean:          0 kB
Shared_Dirty:          0 kB
Private_Clean:    218992 kB   <-- showed pages as clean incorrectly
Private_Dirty:    829584 kB
Referenced:       388364 kB
Swap:                  0 kB
KernelPageSize:        4 kB
MMUPageSize:           4 kB

 <after patch>

00601000-40601000 rw-p 00000000 00:00 0
Size:            1048576 kB
Rss:             1048576 kB
Pss:             1048576 kB
Shared_Clean:          0 kB
Shared_Dirty:          0 kB
Private_Clean:         0 kB
Private_Dirty:   1048576 kB  <-- fixed
Referenced:       388480 kB
Swap:                  0 kB
KernelPageSize:        4 kB
MMUPageSize:           4 kB
Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: default avatarHugh Dickins <hughd@google.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 142092e5
...@@ -363,13 +363,13 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, ...@@ -363,13 +363,13 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
mss->referenced += PAGE_SIZE; mss->referenced += PAGE_SIZE;
mapcount = page_mapcount(page); mapcount = page_mapcount(page);
if (mapcount >= 2) { if (mapcount >= 2) {
if (pte_dirty(ptent)) if (pte_dirty(ptent) || PageDirty(page))
mss->shared_dirty += PAGE_SIZE; mss->shared_dirty += PAGE_SIZE;
else else
mss->shared_clean += PAGE_SIZE; mss->shared_clean += PAGE_SIZE;
mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount; mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount;
} else { } else {
if (pte_dirty(ptent)) if (pte_dirty(ptent) || PageDirty(page))
mss->private_dirty += PAGE_SIZE; mss->private_dirty += PAGE_SIZE;
else else
mss->private_clean += PAGE_SIZE; mss->private_clean += PAGE_SIZE;
......
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