mm: move page flags layout to separate header

This is a preparation patch for moving page->_last_nid into page->flags
that moves page flag layout information to a separate header.  This
patch is necessary because otherwise there would be a circular
dependency between mm_types.h and mm.h.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Simon Jeons <simon.jeons@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 40 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index a114b8eb7676..c2d7d5993b14 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -581,52 +581,12 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
  * sets it, so none of the operations on it need to be atomic.
  */
 
-
-/*
- * page->flags layout:
- *
- * There are three possibilities for how page->flags get
- * laid out.  The first is for the normal case, without
- * sparsemem.  The second is for sparsemem when there is
- * plenty of space for node and section.  The last is when
- * we have run out of space and have to fall back to an
- * alternate (slower) way of determining the node.
- *
- * No sparsemem or sparsemem vmemmap: |       NODE     | ZONE | ... | FLAGS |
- * classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS |
- * classic sparse no space for node:  | SECTION |     ZONE    | ... | FLAGS |
- */
-#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
-#define SECTIONS_WIDTH          SECTIONS_SHIFT
-#else
-#define SECTIONS_WIDTH          0
-#endif
-
-#define ZONES_WIDTH             ZONES_SHIFT
-
-#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
-#define NODES_WIDTH             NODES_SHIFT
-#else
-#ifdef CONFIG_SPARSEMEM_VMEMMAP
-#error "Vmemmap: No space for nodes field in page flags"
-#endif
-#define NODES_WIDTH             0
-#endif
-
 /* Page flags: | [SECTION] | [NODE] | ZONE | ... | FLAGS | */
 #define SECTIONS_PGOFF          ((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
 #define NODES_PGOFF             (SECTIONS_PGOFF - NODES_WIDTH)
 #define ZONES_PGOFF             (NODES_PGOFF - ZONES_WIDTH)
 
 /*
- * We are going to use the flags for the page to node mapping if its in
- * there.  This includes the case where there is no node, so it is implicit.
- */
-#if !(NODES_WIDTH > 0 || NODES_SHIFT == 0)
-#define NODE_NOT_IN_PAGE_FLAGS
-#endif
-
-/*
  * Define the bit shifts to access each section.  For non-existent
  * sections we define the shift as 0; that plus a 0 mask ensures
  * the compiler will optimise away reference to them.