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³»ºÎ ÀÚ·á ±¸Á¶ (Internal Data Structures)

¼¼¸¶ÆÛ ÁýÇÕÀ» À§ÇØ Ä¿³Î¿¡ ÀÇÇØ °ü¸®µÇ´Â ÀÚ·á ±¸Á¶¸¦ °£´ÜÈ÷ »ìÆ캸ÀÚ.



Ä¿³Î semid ds ±¸Á¶ (Kernel semid ds structure)

¸Þ¼¼Áö Å¥¿¡¼­ ó·³, Ä¿³ÎÀº ÁÖ¼Ò ¸Å°ÜÁø °ø°£(addressinf space)¿¡ ÀÖ´Â °¢°¢ÀÇ ¼¼¸¶ÆÛ ÁýÇÕÀ» À§ÇÑ Æ¯º°ÇÑ ³»ºÎ ÀÚ·á ±¸Á¶¸¦ °ü¸®ÇÑ´Ù. semid_ds ŸÀÔÀÇ ±¸Á¶´Â ´ÙÀ½°ú °°ÀÌ /linux/sem.h ¾È¿¡ Á¤ÀǵǾî ÀÖ´Ù.:


	/* ½Ã½ºÅÛ »ó¿¡¼­ÀÇ °¢°¢ÀÇ ¼¼¸¶ÆÛ ÁýÇÕ¿¡ ´ëÇÑ semid ÀÚ·á ±¸Á¶ */
        struct semid_ds {
                struct ipc_perm sem_perm;       /* permissions .. see ipc.h */
                time_t          sem_otime;      /* last semop time */
                time_t          sem_ctime;      /* last change time */
                struct sem      *sem_base;      /* ptr to first semaphore in array */
                struct wait_queue *eventn;
                struct wait_queue *eventz;
                struct sem_undo  *undo;         /* undo requests on this array */
                ushort          sem_nsems;      /* no. of semaphores in array */
        };

¸Þ¼¼Áö Å¥¿¡¼­ ó·³, ±¸Á¶ÀÇ µ¿ÀÛµéÀº Ưº°ÇÑ ½Ã½ºÅÛ È£Ãâ¿¡ ÀÇÇØ ¼öÇàµÇ°í Á÷Á¢ÀûÀ¸·Î ´Ù·ç¾î Áú ¼ö ¾ø´Ù. ¿©±â °¢ Çʵ忡 ´ëÇÑ º¸´Ù ÀûÀýÇÑ ¼³¸íÀÌ ÀÖ´Ù.:

sem_perm
ÀÌ°ÍÀº linux/ipc.h¿¡ Á¤ÀÇµÈ ipc_perm ±¸Á¶ÀÇ ÇÑ ¿¹ÀÌ´Ù. ÀÌ°ÍÀº ¼¼¸¶ÆÛ ÁýÇÕ¿¡ ´ëÇÑ Çã°¡»çÇ× Á¤º¸¸¦ Æ÷ÇÔÇÑ´Ù.
sem_otime
°¡Àå ¸¶Áö¸· semop() µ¿ÀÛÀÇ ¼öÇà½Ã°£
sem_ctime
ÀÌ ±¸Á¶ÀÇ °¡Àå ¸¶Áö¸· º¯°æ ½Ã°£ (mode º¯°æ µî)
sem_base
¹è¿­ÀÇ Ã¹¹ø° ¼¼¸¶ÆÛ¸¦ °¡¸®Å°´Â Æ÷ÀÎÅÍ
sem_undo
¹è¿­¾È¿¡ ÀÖ´Â undoÀÇ ¼ö
sem_nsems
¼¼¸¶ÆÛ ÁýÇվȿ¡ ÀÖ´Â ¼¼¸¶ÆÛÀÇ ¼ö

Ä¿³Î sem ±¸Á¶ (Kernel sem structure)

semid_ds ±¸Á¶¿¡´Â ¼¼¸¶ÆÛ ¹è¿­ ÀÚüÀÇ º£À̽º(base)¸¦ °¡¸®Å°´Â Æ÷ÀÎÅÍ°¡ ÀÖ´Ù. °¢°¢ÀÇ ¹è¿­ ¸â¹ö´Â sem ±¸Á¶ ŸÀÔÀÌ´Ù. ÀÌ°ÍÀº linux/sem.h¿¡ Á¤ÀǵǾîÀÖ´Ù.
	/* ½Ã½ºÅÛ¿¡¼­ÀÇ °¢ ¼¼¸¶ÆÛ¸¦ À§ÇÑ ¼¼¸¶ÆÛ ±¸Á¶ */
        struct sem {
                short   sempid;         /* pid of last operation */
                ushort  semval;         /* current value */
                ushort  semncnt;        /* num procs awaiting increase in semval */
                ushort  semzcnt;        /* num procs awaiting semval = 0 */
        };

sem_pid
¸¶Áö¸· µ¿ÀÛÀ» ¼öÇàÇÑ ÇÁ·Î¼¼½º ID(PID)
sem_semval
¼¼¸¶ÆÛÀÇ ÇöÀç °ª
sem_semcnt
ÀÚ¿øÀÌ »ç¿ëÇÒ ¼ö ÀÖ°Ô µÇ±â¸¦ ±â´Ù¸®´Â ÇÁ·Î¼¼½ºÀÇ ¼ö
sem_semzcnt
100% ÀÚ¿ø È°¿ëÀ» À§ÇØ ±â´Ù¸®´Â ÇÁ·Î¼¼½ºÀÇ ¼ö


ÀÌÀü:±âº» °³³ä (Basic Concepts) ´ÙÀ½:½Ã½ºÅÛ È£Ãâ:semget() (SYSTEM CALL:semget())

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LAST UPDATE Nov 24,1997
Created Nov 24,1997