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      1 #ifndef _LINUX_SHM_H_
      2 #define _LINUX_SHM_H_
      3 
      4 #include <linux/ipc.h>
      5 #include <linux/errno.h>
      6 #include <asm/page.h>
      7 
      8 /*
      9  * SHMMAX, SHMMNI and SHMALL are upper limits are defaults which can
     10  * be increased by sysctl
     11  */
     12 
     13 #define SHMMAX 0x2000000		 /* max shared seg size (bytes) */
     14 #define SHMMIN 1			 /* min shared seg size (bytes) */
     15 #define SHMMNI 4096			 /* max num of segs system wide */
     16 #define SHMALL (SHMMAX/PAGE_SIZE*(SHMMNI/16)) /* max shm system wide (pages) */
     17 #define SHMSEG SHMMNI			 /* max shared segs per process */
     18 
     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 #define	SHM_EXEC	0100000	/* execution access */
     47 
     48 /* super user shmctl commands */
     49 #define SHM_LOCK 	11
     50 #define SHM_UNLOCK 	12
     51 
     52 /* ipcs ctl commands */
     53 #define SHM_STAT 	13
     54 #define SHM_INFO 	14
     55 
     56 /* Obsolete, used only for backwards compatibility */
     57 struct	shminfo {
     58 	int shmmax;
     59 	int shmmin;
     60 	int shmmni;
     61 	int shmseg;
     62 	int shmall;
     63 };
     64 
     65 struct shm_info {
     66 	int used_ids;
     67 	unsigned long shm_tot;	/* total allocated shm */
     68 	unsigned long shm_rss;	/* total resident shm */
     69 	unsigned long shm_swp;	/* total swapped shm */
     70 	unsigned long swap_attempts;
     71 	unsigned long swap_successes;
     72 };
     73 
     74 
     75 #endif /* _LINUX_SHM_H_ */
     76