/*
   * 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 */

  	NR_PAGEBLOCK_BITS
  };

  #ifdef CONFIG_HUGETLB_PAGE
  
  #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
  
  /* Huge page sizes are variable */
  extern 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;
  
  /* Declarations for getting and setting flags. See mm/page_alloc.c */
  unsigned long get_pageblock_flags_group(struct page *page,
  					int start_bitidx, int end_bitidx);
  void set_pageblock_flags_group(struct page *page, unsigned long flags,
  					int start_bitidx, int end_bitidx);
  
  #define get_pageblock_flags(page) \
  			get_pageblock_flags_group(page, 0, NR_PAGEBLOCK_BITS-1)

  #define set_pageblock_flags(page, flags) \
  			set_pageblock_flags_group(page, flags,	\
  						  0, NR_PAGEBLOCK_BITS-1)

  
  #endif	/* PAGEBLOCK_FLAGS_H */