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From: Matthew Wilcox <willy@infradead.org>
Subject: [PATCH 5/8] mm: Introduce _slub_counter_t
Date: Wed, 20 Dec 2017 07:52:53 -0800
Message-Id: <20171220155256.9841-6-willy@infradead.org>
In-Reply-To: <20171220155256.9841-1-willy@infradead.org>
References: <20171220155256.9841-1-willy@infradead.org>
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To: linux-mm@kvack.org
Cc: akpm@linuxfoundation.org, Matthew Wilcox <mawilcox@microsoft.com>

From: Matthew Wilcox <mawilcox@microsoft.com>

Instead of putting the ifdef in the middle of the definition of struct
page, pull it forward to the rest of the ifdeffery around the SLUB
cmpxchg_double optimisation.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
---
 include/linux/mm_types.h | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 8c3b8cea22ee..5521c9799c50 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -41,9 +41,15 @@ struct hmm;
  */
 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
 #define _struct_page_alignment	__aligned(2 * sizeof(unsigned long))
+#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE)
+#define _slub_counter_t		unsigned long
 #else
-#define _struct_page_alignment
+#define _slub_counter_t		unsigned int
 #endif
+#else /* !CONFIG_HAVE_ALIGNED_STRUCT_PAGE */
+#define _struct_page_alignment
+#define _slub_counter_t		unsigned int
+#endif /* !CONFIG_HAVE_ALIGNED_STRUCT_PAGE */
 
 struct page {
 	/* First double word block */
@@ -66,18 +72,7 @@ struct page {
 	};
 
 	union {
-#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
-	defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
-		/* Used for cmpxchg_double in slub */
-		unsigned long counters;
-#else
-		/*
-		 * Keep _refcount separate from slub cmpxchg_double data.
-		 * As the rest of the double word is protected by slab_lock
-		 * but _refcount is not.
-		 */
-		unsigned counters;
-#endif
+		_slub_counter_t counters;
 		unsigned int active;		/* SLAB */
 		struct {			/* SLUB */
 			unsigned inuse:16;
-- 
2.15.1

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