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