/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: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed