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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 | #ifndef _LINUX_SHM_H_ #define _LINUX_SHM_H_ #include <linux/ipc.h> struct shmid_ds { struct ipc_perm shm_perm; /* operation perms */ int shm_segsz; /* size of segment (bytes) */ time_t shm_atime; /* last attach time */ time_t shm_dtime; /* last detach time */ time_t shm_ctime; /* last change time */ unsigned short shm_cpid; /* pid of creator */ unsigned short shm_lpid; /* pid of last operator */ short shm_nattch; /* no. of current attaches */ /* the following are private */ unsigned short shm_npages; /* size of segment (pages) */ unsigned long *shm_pages; /* array of ptrs to frames -> SHMMAX */ struct shm_desc *attaches; /* descriptors for attaches */ }; /* 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 */ /* super user shmctl commands */ #define SHM_LOCK 11 #define SHM_UNLOCK 12 struct shminfo { int shmmax; int shmmin; int shmmni; int shmseg; int shmall; }; #define SHM_RANGE_START 0x40000000 #define SHM_RANGE_END 0x60000000 /* _SHM_ID_BITS is a variable you can adjust to */ /* tune the kernel. It determines the value of */ /* SHMMNI, which specifies the maximum no. of */ /* shared segments (system wide). SRB. */ #define _SHM_ID_BITS 7 /* keep as low as possible */ /* a static array is declared */ /* using SHMMNI */ #define __SHM_IDX_BITS (BITS_PER_PTR-2-SHM_IDX_SHIFT) /* !!!!!!!????? * Why reserve the two (2) high bits of the signature (shm_sgn) field? * Since, as far as I can see, only the high bit is used (SHM_READ_ONLY). * SRB. */ #define _SHM_IDX_BITS (__SHM_IDX_BITS+PAGE_SHIFT>=BITS_PER_PTR?\ BITS_PER_PTR-PAGE_SHIFT-1:__SHM_IDX_BITS) /* sanity check */ /* not present page table entry format bit 0 is 0, low byte defined in mm.h */ #define SHM_ID_SHIFT 8 #define SHM_ID_MASK ((1<<_SHM_ID_BITS)-1) #define SHM_IDX_SHIFT (SHM_ID_SHIFT+_SHM_ID_BITS) #define SHM_IDX_MASK ((1<<_SHM_IDX_BITS)-1) #define SHM_READ_ONLY (1<<(BITS_PER_PTR-1)) #define SHMMAX 0x3fa000 /* max shared seg size (bytes) */ #define SHMMIN 1 /* really PAGE_SIZE */ /* min shared seg size (bytes) */ #define SHMMNI (1<<_SHM_ID_BITS) /* max num of segs system wide */ #define SHMALL (1<<(_SHM_IDX_BITS+_SHM_ID_BITS))/* max shm system wide (pages) */ #define SHMLBA 0x1000 /* attach addr a multiple of this */ #define SHMSEG SHMMNI /* max shared segs per process */ #ifdef __KERNEL__ /* 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 */ /* ipcs ctl commands */ #define SHM_STAT 13 #define SHM_INFO 14 struct shm_info { int used_ids; ulong shm_tot; /* total allocated shm */ ulong shm_rss; /* total resident shm */ ulong shm_swp; /* total swapped shm */ ulong swap_attempts; ulong swap_successes; }; /* * Per process internal structure for managing segments. * A shmat will add to and shmdt will remove from the list. */ struct shm_desc { struct task_struct *task; /* attacher */ unsigned long shm_sgn; /* signature for this attach */ unsigned long start; /* virt addr of attach, multiple of SHMLBA */ unsigned long end; /* multiple of SHMLBA */ struct shm_desc *task_next; /* next attach for task */ struct shm_desc *seg_next; /* next attach for segment */ }; #endif /* __KERNEL__ */ #endif /* _LINUX_SHM_H_ */ |