pagemap: export KPF_THP
This flag shows that a given page is a subpage of a transparent hugepage.
It helps us debug and test the kernel by showing physical address of thp.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/proc/page.c b/fs/proc/page.c
index 6d8e6a9..7fcd0d6 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -115,6 +115,8 @@
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 a/include/linux/kernel-page-flags.h b/include/linux/kernel-page-flags.h
index bd92a89..26a6571 100644
--- a/include/linux/kernel-page-flags.h
+++ b/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!