include/asm-x86/sparsemem.h

   1 #ifndef _ASM_X86_SPARSEMEM_H
   2 #define _ASM_X86_SPARSEMEM_H
   3
   4 #ifdef CONFIG_SPARSEMEM
   5 /*
   6  * generic non-linear memory support:
   7  *
   8  * 1) we will not split memory into more chunks than will fit into the flags
   9  *    field of the struct page
  10  *
  11  * SECTION_SIZE_BITS            2^n: size of each section
  12  * MAX_PHYSADDR_BITS            2^n: max size of physical address space
  13  * MAX_PHYSMEM_BITS             2^n: how much memory we can have in that space
  14  *
  15  */
  16
  17 #ifdef CONFIG_X86_32
  18 # ifdef CONFIG_X86_PAE
  19 #  define SECTION_SIZE_BITS     30
  20 #  define MAX_PHYSADDR_BITS     36
  21 #  define MAX_PHYSMEM_BITS      36
  22 # else
  23 #  define SECTION_SIZE_BITS     26
  24 #  define MAX_PHYSADDR_BITS     32
  25 #  define MAX_PHYSMEM_BITS      32
  26 # endif
  27 #else /* CONFIG_X86_32 */
  28 # define SECTION_SIZE_BITS      27 /* matt - 128 is convenient right now */
  29 # define MAX_PHYSADDR_BITS      40
  30 # define MAX_PHYSMEM_BITS       40
  31 #endif
  32
  33 #endif /* CONFIG_SPARSEMEM */
  34 #endif