mm: align struct page more aesthetically

Patch series "Restructure struct page", v2.

This series does not attempt any grand restructuring.  Instead, it cures
the worst of the indentitis, fixes the documentation and reduces the
ifdeffery.  The only layout change is compound_dtor and compound_order
are each reduced to one byte.

This patch (of 8):

Instead of an ifdef block at the end of the struct, which needed its own
comment, define _struct_page_alignment up at the top where it fits
nicely with the existing comment.

Link: http://lkml.kernel.org/r/20171220155552.15884-2-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index cfd0ac4e5e0e6260963d8854c2b085477f8c8a43..4509f0cfaf399c1bc4864588d12aeae971b5fed9 100644 (file)
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -39,6 +39,12 @@ struct hmm;
  * allows the use of atomic double word operations on the flags/mapping
  * and lru list pointers also.
  */
+#ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
+#define _struct_page_alignment __aligned(2 * sizeof(unsigned long))
+#else
+#define _struct_page_alignment
+#endif
+
 struct page {
        /* First double word block */
        unsigned long flags;            /* Atomic flags, some possibly
@@ -212,15 +218,7 @@ struct page {
 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
        int _last_cpupid;
 #endif
-}
-/*
- * The struct page can be forced to be double word aligned so that atomic ops
- * on double words work. The SLUB allocator can make use of such a feature.
- */
-#ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
-       __aligned(2 * sizeof(unsigned long))
-#endif
-;
+} _struct_page_alignment;
 
 #define PAGE_FRAG_CACHE_MAX_SIZE       __ALIGN_MASK(32768, ~PAGE_MASK)
 #define PAGE_FRAG_CACHE_MAX_ORDER      get_order(PAGE_FRAG_CACHE_MAX_SIZE)