include/linux/mman.h

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