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authorAndrea Arcangeli <aarcange@redhat.com>2011-01-13 15:47:16 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 17:32:47 -0800
commit37c2ac7872a9387542616f658d20ac25f5bdb32e (patch)
treed115915db4a61e261012bf0f9c4cf14630243d71 /include
parent91600e9e592e48736e630851c83da2ad6bf0e91f (diff)
thp: compound_trans_order
Read compound_trans_order safe. Noop for CONFIG_TRANSPARENT_HUGEPAGE=n. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/mm.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9c2695beab86..ce97a2bb0b19 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -450,6 +450,20 @@ static inline int compound_order(struct page *page)
return (unsigned long)page[1].lru.prev;
}
+static inline int compound_trans_order(struct page *page)
+{
+ int order;
+ unsigned long flags;
+
+ if (!PageHead(page))
+ return 0;
+
+ flags = compound_lock_irqsave(page);
+ order = compound_order(page);
+ compound_unlock_irqrestore(page, flags);
+ return order;
+}
+
static inline void set_compound_order(struct page *page, unsigned long order)
{
page[1].lru.prev = (void *)order;