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>

5 files changed, 17 insertions, 1 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
                        );
diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index 4bd80e68eb03..ac9247371871 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -132,6 +132,10 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
                     global_node_page_state(NR_SHMEM_THPS) * HPAGE_PMD_NR);
         show_val_kb(m, "ShmemPmdMapped: ",
                     global_node_page_state(NR_SHMEM_PMDMAPPED) * HPAGE_PMD_NR);
+        show_val_kb(m, "FileHugePages: ",
+                    global_node_page_state(NR_FILE_THPS) * HPAGE_PMD_NR);
+        show_val_kb(m, "FilePmdMapped: ",
+                    global_node_page_state(NR_FILE_PMDMAPPED) * HPAGE_PMD_NR);
 #endif
 
 #ifdef CONFIG_CMA
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ea1630465474..9442631fd4af 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -417,6 +417,7 @@ struct mem_size_stats {
         unsigned long lazyfree;
         unsigned long anonymous_thp;
         unsigned long shmem_thp;
+        unsigned long file_thp;
         unsigned long swap;
         unsigned long shared_hugetlb;
         unsigned long private_hugetlb;
@@ -588,7 +589,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
         else if (is_zone_device_page(page))
                 /* pass */;
         else
-                VM_BUG_ON_PAGE(1, page);
+                mss->file_thp += HPAGE_PMD_SIZE;
         smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd), locked);
 }
 #else
@@ -809,6 +810,7 @@ static void __show_smap(struct seq_file *m, const struct mem_size_stats *mss,
         SEQ_PUT_DEC(" kB\nLazyFree:       ", mss->lazyfree);
         SEQ_PUT_DEC(" kB\nAnonHugePages:  ", mss->anonymous_thp);
         SEQ_PUT_DEC(" kB\nShmemPmdMapped: ", mss->shmem_thp);
+        SEQ_PUT_DEC(" kB\nFilePmdMapped: ", mss->file_thp);
         SEQ_PUT_DEC(" kB\nShared_Hugetlb: ", mss->shared_hugetlb);
         seq_put_decimal_ull_width(m, " kB\nPrivate_Hugetlb: ",
                                   mss->private_hugetlb >> 10, 7);
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 3f38c30d2f13..aafb7c38c627 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -235,6 +235,8 @@ enum node_stat_item {
         NR_SHMEM,               /* shmem pages (included tmpfs/GEM pages) */
         NR_SHMEM_THPS,
         NR_SHMEM_PMDMAPPED,
+        NR_FILE_THPS,
+        NR_FILE_PMDMAPPED,
         NR_ANON_THPS,
         NR_UNSTABLE_NFS,        /* NFS unstable pages */
         NR_VMSCAN_WRITE,
diff --git a/mm/vmstat.c b/mm/vmstat.c
index fd7e16ca6996..6afc892a148a 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1158,6 +1158,8 @@ const char * const vmstat_text[] = {
         "nr_shmem",
         "nr_shmem_hugepages",
         "nr_shmem_pmdmapped",
+        "nr_file_hugepages",
+        "nr_file_pmdmapped",
         "nr_anon_transparent_hugepages",
         "nr_unstable",
         "nr_vmscan_write",