[PATCH 3/6] pagemap: export KPF_THP

[Naoya Horiguchi]

This flag shows that a given pages is a subpage of transparent hugepage.
It helps us debug and test kernel by showing physical address of thp.

Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Reviewed-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>

Changes since v2:
  - replace if with else-if not to set KPF_THP for hugetlbfs page

Changes since v1:
  - remove unnecessary ifdefs
  - fix confusing patch description
---
 fs/proc/page.c                    |    2 ++
 include/linux/kernel-page-flags.h |    1 +
 2 files changed, 3 insertions(+), 0 deletions(-)

diff --git 3.3-rc2.orig/fs/proc/page.c 3.3-rc2/fs/proc/page.c
index 6d8e6a9..7fcd0d6 100644
--- 3.3-rc2.orig/fs/proc/page.c
+++ 3.3-rc2/fs/proc/page.c
@@ -115,6 +115,8 @@ u64 stable_page_flags(struct page *page)
 		u |= 1 << KPF_COMPOUND_TAIL;
 	if (PageHuge(page))
 		u |= 1 << KPF_HUGE;
+	else if (PageTransCompound(page))
+		u |= 1 << KPF_THP;
 
 	/*
 	 * Caveats on high order pages: page->_count will only be set
diff --git 3.3-rc2.orig/include/linux/kernel-page-flags.h 3.3-rc2/include/linux/kernel-page-flags.h
index bd92a89..26a6571 100644
--- 3.3-rc2.orig/include/linux/kernel-page-flags.h
+++ 3.3-rc2/include/linux/kernel-page-flags.h
@@ -30,6 +30,7 @@
 #define KPF_NOPAGE		20
 
 #define KPF_KSM			21
+#define KPF_THP			22
 
 /* kernel hacking assistances
  * WARNING: subject to change, never rely on them!
-- 
1.7.7.6

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/