Returns true if mapping can have huge pages. Just check for __GFP_COMP
in gfp mask of the mapping for now.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
include/linux/pagemap.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index e3dea75a07..ad60dcc50e 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -84,6 +84,20 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
(__force unsigned long)mask;
}
+static inline bool mapping_can_have_hugepages(struct address_space *m)
+{
+ gfp_t gfp_mask = mapping_gfp_mask(m);
+
+ if (!transparent_hugepage_pagecache())
+ return false;
+
+ /*
+ * It's up to filesystem what gfp mask to use.
+ * The only part of GFP_TRANSHUGE which matters for us is __GFP_COMP.
+ */
+ return !!(gfp_mask & __GFP_COMP);
+}
+
/*
* The page cache can done in larger chunks than
* one page, because it allows for more efficient
--
1.8.4.rc3
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