root/include/linux/shm.h

INCLUDED FROM

DEFINITIONS

1. do_shmat
2. is_file_shm_hugepages

#ifndef _LINUX_SHM_H_
#define _LINUX_SHM_H_

#include <linux/ipc.h>
#include <linux/errno.h>
#ifdef __KERNEL__
#include <asm/page.h>
#else
#include <unistd.h>
#endif

/*
 * SHMMAX, SHMMNI and SHMALL are upper limits are defaults which can
 * be increased by sysctl
 */

#define SHMMAX 0x2000000                 /* max shared seg size (bytes) */
#define SHMMIN 1                         /* min shared seg size (bytes) */
#define SHMMNI 4096                      /* max num of segs system wide */
#ifdef __KERNEL__
#define SHMALL (SHMMAX/PAGE_SIZE*(SHMMNI/16)) /* max shm system wide (pages) */
#else
#define SHMALL (SHMMAX/getpagesize()*(SHMMNI/16))
#endif
#define SHMSEG SHMMNI                    /* max shared segs per process */

#ifdef __KERNEL__
#include <asm/shmparam.h>
#endif

/* Obsolete, used only for backwards compatibility and libc5 compiles */
struct shmid_ds {
        struct ipc_perm         shm_perm;       /* operation perms */
        int                     shm_segsz;      /* size of segment (bytes) */
        __kernel_time_t         shm_atime;      /* last attach time */
        __kernel_time_t         shm_dtime;      /* last detach time */
        __kernel_time_t         shm_ctime;      /* last change time */
        __kernel_ipc_pid_t      shm_cpid;       /* pid of creator */
        __kernel_ipc_pid_t      shm_lpid;       /* pid of last operator */
        unsigned short          shm_nattch;     /* no. of current attaches */
        unsigned short          shm_unused;     /* compatibility */
        void                    *shm_unused2;   /* ditto - used by DIPC */
        void                    *shm_unused3;   /* unused */
};

/* Include the definition of shmid64_ds and shminfo64 */
#include <asm/shmbuf.h>

/* permission flag for shmget */
#define SHM_R           0400    /* or S_IRUGO from <linux/stat.h> */
#define SHM_W           0200    /* or S_IWUGO from <linux/stat.h> */

/* mode for attach */
#define SHM_RDONLY      010000  /* read-only access */
#define SHM_RND         020000  /* round attach address to SHMLBA boundary */
#define SHM_REMAP       040000  /* take-over region on attach */
#define SHM_EXEC        0100000 /* execution access */

/* super user shmctl commands */
#define SHM_LOCK        11
#define SHM_UNLOCK      12

/* ipcs ctl commands */
#define SHM_STAT        13
#define SHM_INFO        14

/* Obsolete, used only for backwards compatibility */
struct  shminfo {
        int shmmax;
        int shmmin;
        int shmmni;
        int shmseg;
        int shmall;
};

struct shm_info {
        int used_ids;
        unsigned long shm_tot;  /* total allocated shm */
        unsigned long shm_rss;  /* total resident shm */
        unsigned long shm_swp;  /* total swapped shm */
        unsigned long swap_attempts;
        unsigned long swap_successes;
};

#ifdef __KERNEL__
struct shmid_kernel /* private to the kernel */
{       
        struct kern_ipc_perm    shm_perm;
        struct file *           shm_file;
        unsigned long           shm_nattch;
        unsigned long           shm_segsz;
        time_t                  shm_atim;
        time_t                  shm_dtim;
        time_t                  shm_ctim;
        pid_t                   shm_cprid;
        pid_t                   shm_lprid;
        struct user_struct      *mlock_user;
};

/* shm_mode upper byte flags */
#define SHM_DEST        01000   /* segment will be destroyed on last detach */
#define SHM_LOCKED      02000   /* segment will not be swapped */
#define SHM_HUGETLB     04000   /* segment will use huge TLB pages */
#define SHM_NORESERVE   010000  /* don't check for reservations */

#ifdef CONFIG_SYSVIPC
long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr);
extern int is_file_shm_hugepages(struct file *file);
#else
static inline long do_shmat(int shmid, char __user *shmaddr,
                                int shmflg, unsigned long *addr)
{
        return -ENOSYS;
}
static inline int is_file_shm_hugepages(struct file *file)
{
        return 0;
}
#endif

#endif /* __KERNEL__ */

#endif /* _LINUX_SHM_H_ */