mm,thp: stats for file backed THP

In preparation for non-shmem THP, this patch adds a few stats and exposes
them in /proc/meminfo, /sys/bus/node/devices/<node>/meminfo, and
/proc/<pid>/task/<tid>/smaps.

This patch is mostly a rewrite of Kirill A.  Shutemov's earlier version:
https://lkml.kernel.org/r/20170126115819.58875-5-kirill.shutemov@linux.intel.com/

Link: http://lkml.kernel.org/r/20190801184244.3169074-5-songliubraving@fb.com
Signed-off-by: Song Liu <songliubraving@fb.com>
Acked-by: Rik van Riel <riel@surriel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 257449cf061f..296546ffed6c 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -427,6 +427,8 @@ static ssize_t node_read_meminfo(struct device *dev,
                        "Node %d AnonHugePages:  %8lu kB\n"
                        "Node %d ShmemHugePages: %8lu kB\n"
                        "Node %d ShmemPmdMapped: %8lu kB\n"
+                       "Node %d FileHugePages: %8lu kB\n"
+                       "Node %d FilePmdMapped: %8lu kB\n"
 #endif
                         ,
                        nid, K(node_page_state(pgdat, NR_FILE_DIRTY)),
@@ -452,6 +454,10 @@ static ssize_t node_read_meminfo(struct device *dev,
                        nid, K(node_page_state(pgdat, NR_SHMEM_THPS) *
                                        HPAGE_PMD_NR),
                        nid, K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED) *
+                                       HPAGE_PMD_NR),
+                       nid, K(node_page_state(pgdat, NR_FILE_THPS) *
+                                       HPAGE_PMD_NR),
+                       nid, K(node_page_state(pgdat, NR_FILE_PMDMAPPED) *
                                        HPAGE_PMD_NR)
 #endif
                        );