Thread (58 messages) 58 messages, 9 authors, 2013-09-06
STALE4673d

[PATCH 04/23] thp, mm: introduce mapping_can_have_hugepages() predicate

From: Kirill A. Shutemov <hidden>
Date: 2013-08-04 02:17:06
Also in: linux-fsdevel, lkml
Subsystem: page cache, the rest · Maintainers: Matthew Wilcox, Linus Torvalds

From: "Kirill A. Shutemov" <redacted>

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 <redacted>
---
 include/linux/pagemap.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index e8ca8cf..47b5082 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
-- 
1.8.3.2

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