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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2015-11-06 16:30:00 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-06 17:50:42 -0800
commit1965c8b7ac7dd147663faf77a66a693ac3ddcb85 (patch)
tree9f26e091a39be20625434a98e54b2fe395fc6498 /include
parentd00181b96eb86c914cb327d1de974a1b71366e1b (diff)
downloadlinux-stericsson-1965c8b7ac7dd147663faf77a66a693ac3ddcb85.tar.gz
mm: use 'unsigned int' for compound_dtor/compound_order on 64BIT
On 64 bit system we have enough space in struct page to encode compound_dtor and compound_order with unsigned int. On x86-64 it leads to slightly smaller code size due usesage of plain MOV instead of MOVZX (zero-extended move) or similar effect. allyesconfig: text data bss dec hex filename 159520446 48146736 72196096 279863278 10ae5fee vmlinux.pre 159520382 48146736 72196096 279863214 10ae5fae vmlinux.post On other architectures without native support of 16-bit data types the Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> 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_types.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index bb91658c603f..f8d1492a114f 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -143,8 +143,19 @@ struct page {
unsigned long compound_head; /* If bit zero is set */
/* First tail page only */
+#ifdef CONFIG_64BIT
+ /*
+ * On 64 bit system we have enough space in struct page
+ * to encode compound_dtor and compound_order with
+ * unsigned int. It can help compiler generate better or
+ * smaller code on some archtectures.
+ */
+ unsigned int compound_dtor;
+ unsigned int compound_order;
+#else
unsigned short int compound_dtor;
unsigned short int compound_order;
+#endif
};
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS