bf8f972d3a
Add SHM_NORESERVE functionality similar to MAP_NORESERVE for shared memory segments. This is mainly to avoid abuse of OVERCOMMIT_ALWAYS and this flag is ignored for OVERCOMMIT_NEVER. Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
109 lines
3.1 KiB
C
109 lines
3.1 KiB
C
#ifndef _LINUX_SHM_H_
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#define _LINUX_SHM_H_
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#include <linux/ipc.h>
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#include <linux/errno.h>
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#include <asm/page.h>
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/*
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* SHMMAX, SHMMNI and SHMALL are upper limits are defaults which can
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* be increased by sysctl
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*/
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#define SHMMAX 0x2000000 /* max shared seg size (bytes) */
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#define SHMMIN 1 /* min shared seg size (bytes) */
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#define SHMMNI 4096 /* max num of segs system wide */
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#define SHMALL (SHMMAX/PAGE_SIZE*(SHMMNI/16)) /* max shm system wide (pages) */
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#define SHMSEG SHMMNI /* max shared segs per process */
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#include <asm/shmparam.h>
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/* Obsolete, used only for backwards compatibility and libc5 compiles */
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struct shmid_ds {
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struct ipc_perm shm_perm; /* operation perms */
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int shm_segsz; /* size of segment (bytes) */
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__kernel_time_t shm_atime; /* last attach time */
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__kernel_time_t shm_dtime; /* last detach time */
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__kernel_time_t shm_ctime; /* last change time */
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__kernel_ipc_pid_t shm_cpid; /* pid of creator */
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__kernel_ipc_pid_t shm_lpid; /* pid of last operator */
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unsigned short shm_nattch; /* no. of current attaches */
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unsigned short shm_unused; /* compatibility */
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void *shm_unused2; /* ditto - used by DIPC */
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void *shm_unused3; /* unused */
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};
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/* Include the definition of shmid64_ds and shminfo64 */
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#include <asm/shmbuf.h>
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/* permission flag for shmget */
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#define SHM_R 0400 /* or S_IRUGO from <linux/stat.h> */
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#define SHM_W 0200 /* or S_IWUGO from <linux/stat.h> */
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/* mode for attach */
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#define SHM_RDONLY 010000 /* read-only access */
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#define SHM_RND 020000 /* round attach address to SHMLBA boundary */
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#define SHM_REMAP 040000 /* take-over region on attach */
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#define SHM_EXEC 0100000 /* execution access */
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/* super user shmctl commands */
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#define SHM_LOCK 11
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#define SHM_UNLOCK 12
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/* ipcs ctl commands */
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#define SHM_STAT 13
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#define SHM_INFO 14
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/* Obsolete, used only for backwards compatibility */
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struct shminfo {
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int shmmax;
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int shmmin;
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int shmmni;
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int shmseg;
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int shmall;
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};
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struct shm_info {
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int used_ids;
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unsigned long shm_tot; /* total allocated shm */
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unsigned long shm_rss; /* total resident shm */
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unsigned long shm_swp; /* total swapped shm */
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unsigned long swap_attempts;
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unsigned long swap_successes;
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};
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#ifdef __KERNEL__
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struct shmid_kernel /* private to the kernel */
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{
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struct kern_ipc_perm shm_perm;
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struct file * shm_file;
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int id;
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unsigned long shm_nattch;
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unsigned long shm_segsz;
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time_t shm_atim;
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time_t shm_dtim;
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time_t shm_ctim;
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pid_t shm_cprid;
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pid_t shm_lprid;
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struct user_struct *mlock_user;
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};
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/* shm_mode upper byte flags */
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#define SHM_DEST 01000 /* segment will be destroyed on last detach */
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#define SHM_LOCKED 02000 /* segment will not be swapped */
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#define SHM_HUGETLB 04000 /* segment will use huge TLB pages */
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#define SHM_NORESERVE 010000 /* don't check for reservations */
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#ifdef CONFIG_SYSVIPC
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long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr);
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#else
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static inline long do_shmat(int shmid, char __user *shmaddr,
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int shmflg, unsigned long *addr)
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{
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return -ENOSYS;
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}
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#endif
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#endif /* __KERNEL__ */
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#endif /* _LINUX_SHM_H_ */
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