mm, thp: fix mlock statistics
NR_MLOCK is only accounted in single page units: there's no logic to
handle transparent hugepages. This patch checks the appropriate number of
pages to adjust the statistics by so that the correct amount of memory is
reflected.
Currently:
$ grep Mlocked /proc/meminfo
Mlocked: 19636 kB
#define MAP_SIZE (4 << 30) /* 4GB */
void *ptr = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
mlock(ptr, MAP_SIZE);
$ grep Mlocked /proc/meminfo
Mlocked: 29844 kB
munlock(ptr, MAP_SIZE);
$ grep Mlocked /proc/meminfo
Mlocked: 19636 kB
And with this patch:
$ grep Mlock /proc/meminfo
Mlocked: 19636 kB
mlock(ptr, MAP_SIZE);
$ grep Mlock /proc/meminfo
Mlocked: 4213664 kB
munlock(ptr, MAP_SIZE);
$ grep Mlock /proc/meminfo
Mlocked: 19636 kB
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Hugh Dickens <hughd@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2 files changed