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>

3 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h
index bc3d2985cc9a..9b0a15d06a4f 100644
--- a/include/linux/balloon_compaction.h
+++ b/include/linux/balloon_compaction.h
@@ -166,11 +166,13 @@ static inline gfp_t balloon_mapping_gfp_mask(void)
 static inline void balloon_page_insert(struct balloon_dev_info *balloon,
                                        struct page *page)
 {
+        __SetPageBalloon(page);
         list_add(&page->lru, &balloon->pages);
 }
 
 static inline void balloon_page_delete(struct page *page)
 {
+        __ClearPageBalloon(page);
         list_del(&page->lru);
 }
 
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index ced92345c963..730334cdf037 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -72,6 +72,13 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
                 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
 #ifdef CONFIG_DEBUG_TLBFLUSH
 #ifdef CONFIG_SMP
                 NR_TLB_REMOTE_FLUSH,    /* cpu tried to flush others' tlbs */
diff --git a/include/uapi/linux/kernel-page-flags.h b/include/uapi/linux/kernel-page-flags.h
index 5116a0e48172..2f96d233c980 100644
--- a/include/uapi/linux/kernel-page-flags.h
+++ b/include/uapi/linux/kernel-page-flags.h
@@ -31,6 +31,7 @@
 
 #define KPF_KSM                 21
 #define KPF_THP                 22
+#define KPF_BALLOON             23
 
 
 #endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */