/*
   * Macros for manipulating and testing flags related to a

   * pageblock_nr_pages number of pages.

   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation version 2 of the License
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   *
   * Copyright (C) IBM Corporation, 2006
   *
   * Original author, Mel Gorman
   * Major cleanups and reduction of bit operations, Andy Whitcroft
   */
  #ifndef PAGEBLOCK_FLAGS_H
  #define PAGEBLOCK_FLAGS_H
  
  #include <linux/types.h>

  /* Bit indices that affect a whole block of pages */
  enum pageblock_bits {

  	PB_migrate,
  	PB_migrate_end = PB_migrate + 3 - 1,
  			/* 3 bits required for migrate types */

  	PB_migrate_skip,/* If set the block is skipped by compaction */

  
  	/*
  	 * Assume the bits will always align on a word. If this assumption
  	 * changes then get/set pageblock needs updating.
  	 */

  	NR_PAGEBLOCK_BITS
  };

  #ifdef CONFIG_HUGETLB_PAGE
  
  #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
  
  /* Huge page sizes are variable */

  extern unsigned int pageblock_order;

  
  #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
  
  /* Huge pages are a constant size */
  #define pageblock_order		HUGETLB_PAGE_ORDER
  
  #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
  
  #else /* CONFIG_HUGETLB_PAGE */
  
  /* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
  #define pageblock_order		(MAX_ORDER-1)
  
  #endif /* CONFIG_HUGETLB_PAGE */
  
  #define pageblock_nr_pages	(1UL << pageblock_order)

  /* Forward declaration */
  struct page;

  unsigned long get_pfnblock_flags_mask(struct page *page,
  				unsigned long pfn,

  				unsigned long end_bitidx,
  				unsigned long mask);

  
  void set_pfnblock_flags_mask(struct page *page,

  				unsigned long flags,

  				unsigned long pfn,

  				unsigned long end_bitidx,
  				unsigned long mask);

  /* Declarations for getting and setting flags. See mm/page_alloc.c */

  #define get_pageblock_flags_group(page, start_bitidx, end_bitidx) \
  	get_pfnblock_flags_mask(page, page_to_pfn(page),		\
  			end_bitidx,					\
  			(1 << (end_bitidx - start_bitidx + 1)) - 1)
  #define set_pageblock_flags_group(page, flags, start_bitidx, end_bitidx) \
  	set_pfnblock_flags_mask(page, flags, page_to_pfn(page),		\
  			end_bitidx,					\
  			(1 << (end_bitidx - start_bitidx + 1)) - 1)

  #ifdef CONFIG_COMPACTION
  #define get_pageblock_skip(page) \
  			get_pageblock_flags_group(page, PB_migrate_skip,     \

  							PB_migrate_skip)

  #define clear_pageblock_skip(page) \
  			set_pageblock_flags_group(page, 0, PB_migrate_skip,  \

  							PB_migrate_skip)

  #define set_pageblock_skip(page) \
  			set_pageblock_flags_group(page, 1, PB_migrate_skip,  \

  							PB_migrate_skip)

  #endif /* CONFIG_COMPACTION */

  #endif	/* PAGEBLOCK_FLAGS_H */