mm/balloon_compaction: add vmstat counters and kpageflags bit

Always mark pages with PageBalloon even if balloon compaction is disabled
and expose this mark in /proc/kpageflags as KPF_BALLOON.

Also this patch adds three counters into /proc/vmstat: "balloon_inflate",
"balloon_deflate" and "balloon_migrate".  They accumulate balloon
activity.  Current size of balloon is (balloon_inflate - balloon_deflate)
pages.

All generic balloon code now gathered under option CONFIG_MEMORY_BALLOON.
It should be selected by ballooning driver which wants use this feature.
Currently virtio-balloon is the only user.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 1 deletions

diff --git a/mm/vmstat.c b/mm/vmstat.c
index e9ab104b956f..cce7c766da7a 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -735,7 +735,7 @@ static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
 
 const char * const vmstat_text[] = {
-        /* Zoned VM counters */
+        /* enum zone_stat_item countes */
         "nr_free_pages",
         "nr_alloc_batch",
         "nr_inactive_anon",
@@ -778,10 +778,13 @@ const char * const vmstat_text[] = {
         "workingset_nodereclaim",
         "nr_anon_transparent_hugepages",
         "nr_free_cma",
+
+        /* enum writeback_stat_item counters */
         "nr_dirty_threshold",
         "nr_dirty_background_threshold",
 
 #ifdef CONFIG_VM_EVENT_COUNTERS
+        /* enum vm_event_item counters */
         "pgpgin",
         "pgpgout",
         "pswpin",
@@ -860,6 +863,13 @@ const char * const vmstat_text[] = {
         "thp_zero_page_alloc",
         "thp_zero_page_alloc_failed",
 #endif
+#ifdef CONFIG_MEMORY_BALLOON
+        "balloon_inflate",
+        "balloon_deflate",
+#ifdef CONFIG_BALLOON_COMPACTION
+        "balloon_migrate",
+#endif
+#endif /* CONFIG_MEMORY_BALLOON */
 #ifdef CONFIG_DEBUG_TLBFLUSH
 #ifdef CONFIG_SMP
         "nr_tlb_remote_flush",