include/linux/shm.h

   1 #ifndef _LINUX_SHM_H_
   2 #define _LINUX_SHM_H_
   3
   4 #include <linux/ipc.h>
   5 #include <asm/page.h>
   6
   7 /*
   8  * SHMMAX, SHMMNI and SHMALL are upper limits are defaults which can
   9  * be increased by sysctl
  10  */
  11
  12 #define SHMMAX 0x2000000                 /* max shared seg size (bytes) */
  13 #define SHMMIN 0                         /* min shared seg size (bytes) */
  14 #define SHMMNI 4096                      /* max num of segs system wide */
  15 #define SHMALL (SHMMAX/PAGE_SIZE*(SHMMNI/16)) /* max shm system wide (pages) */
  16 #define SHMSEG SHMMNI                    /* max shared segs per process */
  17
  18 #include <asm/shmparam.h>
  19
  20 /* Obsolete, used only for backwards compatibility and libc5 compiles */
  21 struct shmid_ds {
  22         struct ipc_perm         shm_perm;       /* operation perms */
  23         int                     shm_segsz;      /* size of segment (bytes) */
  24         __kernel_time_t         shm_atime;      /* last attach time */
  25         __kernel_time_t         shm_dtime;      /* last detach time */
  26         __kernel_time_t         shm_ctime;      /* last change time */
  27         __kernel_ipc_pid_t      shm_cpid;       /* pid of creator */
  28         __kernel_ipc_pid_t      shm_lpid;       /* pid of last operator */
  29         unsigned short          shm_nattch;     /* no. of current attaches */
  30         unsigned short          shm_unused;     /* compatibility */
  31         void                    *shm_unused2;   /* ditto - used by DIPC */
  32         void                    *shm_unused3;   /* unused */
  33 };
  34
  35 /* Include the definition of shmid64_ds and shminfo64 */
  36 #include <asm/shmbuf.h>
  37
  38 /* permission flag for shmget */
  39 #define SHM_R           0400    /* or S_IRUGO from <linux/stat.h> */
  40 #define SHM_W           0200    /* or S_IWUGO from <linux/stat.h> */
  41
  42 /* mode for attach */
  43 #define SHM_RDONLY      010000  /* read-only access */
  44 #define SHM_RND         020000  /* round attach address to SHMLBA boundary */
  45 #define SHM_REMAP       040000  /* take-over region on attach */
  46
  47 /* super user shmctl commands */
  48 #define SHM_LOCK        11
  49 #define SHM_UNLOCK      12
  50
  51 /* ipcs ctl commands */
  52 #define SHM_STAT        13
  53 #define SHM_INFO        14
  54
  55 /* Obsolete, used only for backwards compatibility */
  56 struct  shminfo {
  57         int shmmax;
  58         int shmmin;
  59         int shmmni;
  60         int shmseg;
  61         int shmall;
  62 };
  63
  64 struct shm_info {
  65         int used_ids;
  66         unsigned long shm_tot;  /* total allocated shm */
  67         unsigned long shm_rss;  /* total resident shm */
  68         unsigned long shm_swp;  /* total swapped shm */
  69         unsigned long swap_attempts;
  70         unsigned long swap_successes;
  71 };
  72
  73 #ifdef __KERNEL__
  74
  75 /* shm_mode upper byte flags */
  76 #define SHM_DEST        01000   /* segment will be destroyed on last detach */
  77 #define SHM_LOCKED      02000   /* segment will not be swapped */
  78
  79 asmlinkage long sys_shmget (key_t key, size_t size, int flag);
  80 asmlinkage long sys_shmat (int shmid, char *shmaddr, int shmflg, unsigned long *addr);
  81 asmlinkage long sys_shmdt (char *shmaddr);
  82 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds *buf);
  83 extern void shm_unuse(swp_entry_t entry, struct page *page);
  84
  85 #endif /* __KERNEL__ */
  86
  87 #endif /* _LINUX_SHM_H_ */