include/linux/mman.h

   1 #ifndef _LINUX_MMAN_H
   2 #define _LINUX_MMAN_H
   3
   4 #include <linux/config.h>
   5 #include <linux/mm.h>
   6
   7 #include <asm/atomic.h>
   8 #include <asm/mman.h>
   9
  10 #define MREMAP_MAYMOVE  1
  11 #define MREMAP_FIXED    2
  12
  13 #define OVERCOMMIT_GUESS                0
  14 #define OVERCOMMIT_ALWAYS               1
  15 #define OVERCOMMIT_NEVER                2
  16 extern int sysctl_overcommit_memory;
  17 extern int sysctl_overcommit_ratio;
  18 extern atomic_t vm_committed_space;
  19
  20 #ifdef CONFIG_SMP
  21 extern void vm_acct_memory(long pages);
  22 #else
  23 static inline void vm_acct_memory(long pages)
  24 {
  25         atomic_add(pages, &vm_committed_space);
  26 }
  27 #endif
  28
  29 static inline void vm_unacct_memory(long pages)
  30 {
  31         vm_acct_memory(-pages);
  32 }
  33
  34 /*
  35  * Optimisation macro.  It is equivalent to:
  36  *      (x & bit1) ? bit2 : 0
  37  * but this version is faster.
  38  * ("bit1" and "bit2" must be single bits)
  39  */
  40 #define _calc_vm_trans(x, bit1, bit2) \
  41   ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
  42    : ((x) & (bit1)) / ((bit1) / (bit2)))
  43
  44 /*
  45  * Combine the mmap "prot" argument into "vm_flags" used internally.
  46  */
  47 static inline unsigned long
  48 calc_vm_prot_bits(unsigned long prot)
  49 {
  50         return _calc_vm_trans(prot, PROT_READ,  VM_READ ) |
  51                _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
  52                _calc_vm_trans(prot, PROT_EXEC,  VM_EXEC );
  53 }
  54
  55 /*
  56  * Combine the mmap "flags" argument into "vm_flags" used internally.
  57  */
  58 static inline unsigned long
  59 calc_vm_flag_bits(unsigned long flags)
  60 {
  61         return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
  62                _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
  63                _calc_vm_trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE) |
  64                _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    );
  65 }
  66
  67 #endif /* _LINUX_MMAN_H */