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Commit bbeae5b0 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Linus Torvalds
Browse files

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: default avatarMel 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3c0ff468

include/linux/mm.h

+0 −40
Original line number Diff line number Diff line
@@ -581,51 +581,11 @@ 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

include/linux/mm_types.h

+1 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/cpumask.h>

#include <linux/page-debug-flags.h>

#include <linux/uprobes.h>

#include <linux/page-flags-layout.h>

#include <asm/page.h>

#include <asm/mmu.h>

include/linux/mmzone.h

+1 −21
Original line number Diff line number Diff line
@@ -15,7 +15,7 @@ 
#include <linux/seqlock.h>

#include <linux/nodemask.h>

#include <linux/pageblock-flags.h>

#include <generated/bounds.h>

#include <linux/page-flags-layout.h>

#include <linux/atomic.h>

#include <asm/page.h>
@@ -310,24 +310,6 @@ enum zone_type { 


#ifndef __GENERATING_BOUNDS_H



/*

 * When a memory allocation must conform to specific limitations (such

 * as being suitable for DMA) the caller will pass in hints to the

 * allocator in the gfp_mask, in the zone modifier bits.  These bits

 * are used to select a priority ordered list of memory zones which

 * match the requested limits. See gfp_zone() in include/linux/gfp.h

 */



#if MAX_NR_ZONES < 2

#define ZONES_SHIFT 0

#elif MAX_NR_ZONES <= 2

#define ZONES_SHIFT 1

#elif MAX_NR_ZONES <= 4

#define ZONES_SHIFT 2

#else

#error ZONES_SHIFT -- too many zones configured adjust calculation

#endif



struct zone {

	/* Fields commonly accessed by the page allocator */
@@ -1055,8 +1037,6 @@ static inline unsigned long early_pfn_to_nid(unsigned long pfn) 
 * PA_SECTION_SHIFT		physical address to/from section number

 * PFN_SECTION_SHIFT		pfn to/from section number

 */

#define SECTIONS_SHIFT		(MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)



#define PA_SECTION_SHIFT	(SECTION_SIZE_BITS)

#define PFN_SECTION_SHIFT	(SECTION_SIZE_BITS - PAGE_SHIFT)

include/linux/page-flags-layout.h

0 → 100644
+71 −0
Original line number Diff line number Diff line 
#ifndef PAGE_FLAGS_LAYOUT_H

#define PAGE_FLAGS_LAYOUT_H



#include <linux/numa.h>

#include <generated/bounds.h>



/*

 * When a memory allocation must conform to specific limitations (such

 * as being suitable for DMA) the caller will pass in hints to the

 * allocator in the gfp_mask, in the zone modifier bits.  These bits

 * are used to select a priority ordered list of memory zones which

 * match the requested limits. See gfp_zone() in include/linux/gfp.h

 */

#if MAX_NR_ZONES < 2

#define ZONES_SHIFT 0

#elif MAX_NR_ZONES <= 2

#define ZONES_SHIFT 1

#elif MAX_NR_ZONES <= 4

#define ZONES_SHIFT 2

#else

#error ZONES_SHIFT -- too many zones configured adjust calculation

#endif



#ifdef CONFIG_SPARSEMEM

#include <asm/sparsemem.h>



/* SECTION_SHIFT	#bits space required to store a section # */

#define SECTIONS_SHIFT	(MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)



#endif /* CONFIG_SPARSEMEM */



/*

 * 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



/*

 * 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



#endif /* _LINUX_PAGE_FLAGS_LAYOUT */