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Annotation of coherent/f/etc/conf/streams/src/strmisc.c, revision 1.1

1.1     ! root        1: #define        _DDI_DKI        1
        !             2: #define        _SYSV4          1
        !             3: 
        !             4: /*
        !             5:  * This file contains various miscellaneous STREAMS library functions that
        !             6:  * have been moved into a file on their own. Mostly, this stuff deals with
        !             7:  * scheduling STREAMS service procedures, running STREAMS service procedures,
        !             8:  * invoking bufcall ()/esbbcall () events, and similar stuff.
        !             9:  */
        !            10: 
        !            11: #include <common/ccompat.h>
        !            12: #include <kernel/strmlib.h>
        !            13: #include <sys/debug.h>
        !            14: #include <sys/types.h>
        !            15: #include <sys/kmem.h>
        !            16: #include <sys/stream.h>
        !            17: 
        !            18: 
        !            19: /*
        !            20:  * Allocate and initialize a schedule.
        !            21:  *
        !            22:  * Callable only from base level. This function may sleep.
        !            23:  */
        !            24: 
        !            25: #if    __USE_PROTO__
        !            26: ssched_t * (QSCHED_ALLOC) (void)
        !            27: #else
        !            28: ssched_t *
        !            29: QSCHED_ALLOC __ARGS (())
        !            30: #endif
        !            31: {
        !            32:        ssched_t      * sched;
        !            33: 
        !            34:        if ((sched = (ssched_t *) kmem_alloc (sizeof (* sched), KM_SLEEP))
        !            35:            != NULL) {
        !            36: 
        !            37:                if (SCHLOCK_INIT (sched, KM_SLEEP) == 0) {
        !            38: 
        !            39:                        kmem_free (sched, sizeof (* sched));
        !            40:                        return NULL;
        !            41:                }
        !            42: 
        !            43:                sched->ss_head = sched->ss_tail = NULL;
        !            44:        }
        !            45: 
        !            46:        return sched;
        !            47: }
        !            48: 
        !            49: 
        !            50: /*
        !            51:  * Destroy a schedule.
        !            52:  *
        !            53:  * The schedule most not have any STREAMS queues threaded on it.
        !            54:  */
        !            55: 
        !            56: #if    __USE_PROTO__
        !            57: void (QSCHED_FREE) (ssched_t * sched)
        !            58: #else
        !            59: void
        !            60: QSCHED_FREE __ARGS ((sched))
        !            61: ssched_t      *        sched;
        !            62: #endif
        !            63: {
        !            64:        ASSERT (sched != NULL);
        !            65:        ASSERT (sched->ss_head == NULL && sched->ss_tail == NULL);
        !            66: 
        !            67:        SCHLOCK_DESTROY (sched);
        !            68: 
        !            69:        kmem_free (sched, sizeof (* sched));
        !            70: }
        !            71: 
        !            72: 
        !            73: /*
        !            74:  * Remove a queue from a schedule. This function is available for modules and
        !            75:  * drivers to call. Note that STREAMS itself will only call this function at
        !            76:  * queue destruction time.
        !            77:  */
        !            78: 
        !            79: #if    __USE_PROTO__
        !            80: void (QSCHED_UNSCHEDULE) (queue_t * q, ssched_t * sched)
        !            81: #else
        !            82: void
        !            83: QSCHED_UNSCHEDULE __ARGS ((q, sched))
        !            84: queue_t              * q;
        !            85: ssched_t      *        sched;
        !            86: #endif
        !            87: {
        !            88:        pl_t            lock_pl;
        !            89:        queue_t       * scan;
        !            90:        queue_t       * prev;
        !            91: 
        !            92:        ASSERT (sched != NULL);
        !            93:        QUEUE_TRACE (q, "QUEUE_UNSCHEDULE");
        !            94: 
        !            95:        lock_pl = SCHLOCK_LOCK (sched, "QUEUE_UNSCHEDULE");
        !            96: 
        !            97:        for (scan = sched->ss_head, prev = NULL ; scan != NULL ;
        !            98:             scan = (prev = scan)->q_link) {
        !            99: 
        !           100:                if (scan == q) {
        !           101: 
        !           102:                        if (prev == NULL)
        !           103:                                sched->ss_head = q->q_next;
        !           104:                        else
        !           105:                                prev->q_link = q->q_next;
        !           106: 
        !           107:                        if (sched->ss_tail == q)
        !           108:                                sched->ss_tail = prev;
        !           109:                        break;
        !           110:                }
        !           111:        }
        !           112: 
        !           113:        SCHLOCK_UNLOCK (str_mem->sm_sched, lock_pl);
        !           114: }
        !           115: 
        !           116: 
        !           117: /*
        !           118:  * Dequeue and return the first stream in the schedule.
        !           119:  */
        !           120: 
        !           121: #if    __USE_PROTO__
        !           122: queue_t * (QSCHED_GETFIRST) (ssched_t * sched)
        !           123: #else
        !           124: queue_t *
        !           125: QSCHED_GETFIRST __ARGS ((sched))
        !           126: ssched_t      *        sched;
        !           127: #endif
        !           128: {
        !           129:        pl_t            prev_pl;
        !           130:        queue_t       * q;
        !           131: 
        !           132:        ASSERT (sched != NULL);
        !           133: 
        !           134:        prev_pl = SCHLOCK_LOCK (sched, "QSCHED_GETFIRST");
        !           135: 
        !           136:        if ((q = sched->ss_head) != NULL) {
        !           137: 
        !           138:                if ((sched->ss_head = q->q_link) == NULL)
        !           139:                        sched->ss_tail = NULL;
        !           140:        }
        !           141: 
        !           142:        SCHLOCK_UNLOCK (sched, prev_pl);
        !           143: 
        !           144:        return q;
        !           145: }
        !           146: 
        !           147: 
        !           148: /*
        !           149:  * Add a queue to a schedule. This function is available for use by modules
        !           150:  * and drivers. It is callable from base or interrupt level and does not
        !           151:  * sleep.
        !           152:  *
        !           153:  * The return value is 0 for success, and -1 if it is unable to schedule the
        !           154:  * queue.
        !           155:  */
        !           156: 
        !           157: #if    __USE_PROTO__
        !           158: int (QSCHED_SCHEDULE) (queue_t * q, ssched_t * sched)
        !           159: #else
        !           160: int
        !           161: QSCHED_SCHEDULE __ARGS ((q, sched))
        !           162: queue_t              * q;
        !           163: ssched_t      * sched;
        !           164: #endif
        !           165: {
        !           166:        pl_t            lock_pl;
        !           167: 
        !           168:        QUEUE_TRACE (q, "QSCHED_SCHEDULE");
        !           169: 
        !           170:        /*
        !           171:         * Link this queue into the tail of the scheduling
        !           172:         * list after locking the scheduling list.
        !           173:         */
        !           174: 
        !           175:        lock_pl = SCHLOCK_LOCK (sched, "QSCHED_SCHEDULE");
        !           176: 
        !           177:        q->q_link = NULL;
        !           178: 
        !           179:        if (sched->ss_tail == NULL)
        !           180:                sched->ss_head = q;
        !           181:        else
        !           182:                sched->ss_tail->q_link = q;
        !           183: 
        !           184:        sched->ss_tail = q;
        !           185: 
        !           186:        SCHLOCK_UNLOCK (str_mem->sm_sched, lock_pl);
        !           187: 
        !           188: 
        !           189:        /*
        !           190:         * Under this implementation, it is not really possible for a request
        !           191:         * to fail, but because we are using STREAMS internal data here, we
        !           192:         * allow for a portable implementation that may fail.
        !           193:         */
        !           194: 
        !           195:        return 0;
        !           196: }
        !           197: 
        !           198: 
        !           199: /*
        !           200:  * Code for checking which bufcall events to call, in a function by itself to
        !           201:  * keep things clear and maintainable.
        !           202:  *
        !           203:  * We take a snapshot of the available memory, then loop over the bufcall ()/
        !           204:  * esbbcall () lists and give away memory until our notion of what the memory
        !           205:  * pool size ought to be drops to a level where there are cells we think we
        !           206:  * should hold off enabling... if we make that decision, we mark things so
        !           207:  * that next time through here we look again, then we exit.
        !           208:  */
        !           209: 
        !           210: #if    __USE_PROTO__
        !           211: void (RUN_BUFCALLS) (void)
        !           212: #else
        !           213: void
        !           214: RUN_BUFCALLS __ARGS (())
        !           215: #endif
        !           216: {
        !           217:        size_t          mem_level;
        !           218:        pl_t            prev_pl;
        !           219:        sevent_t      * runlist;
        !           220:        sevent_t      * seventp;
        !           221:        int             i;
        !           222: 
        !           223:        /*
        !           224:         * Take a snapshot of the amount of STREAMS memory that is in use, so
        !           225:         * we can parcel it out to the bufcall routines. We clear the bufcall
        !           226:         * defer flag now so that if STREAMS memory is made available after
        !           227:         * our snapshot we will be run again.
        !           228:         */
        !           229: 
        !           230:        ATOMIC_STORE_UCHAR (ddi_global_data ()->dg_run_bufcalls, 0);
        !           231: 
        !           232:        mem_level = str_mem->sm_used;
        !           233:        runlist = NULL;
        !           234: 
        !           235:        for (i = N_PRI_LEVELS ; i -- > 0 ; ) {
        !           236:                selist_t      * elistp;
        !           237:                unsigned long   max = str_mem->sm_max [i];
        !           238: 
        !           239:                elistp = & str_mem->sm_bcevents [i];
        !           240: 
        !           241:                prev_pl = SELIST_LOCK (elistp);
        !           242: 
        !           243:                while ((seventp = elistp->sl_head) != NULL) {
        !           244:                        /*
        !           245:                         * If the amount of memory requested in this cell is
        !           246:                         * enough to push the memory level over the top for
        !           247:                         * this allocation priority, then give up.
        !           248:                         */
        !           249: 
        !           250:                        if ((mem_level += seventp->se_size) > max)
        !           251:                                goto give_up;
        !           252: 
        !           253:                        /*
        !           254:                         * Dequeue the event from the event list and add it to
        !           255:                         * our work list.
        !           256:                         */
        !           257: 
        !           258:                        elistp->sl_head = seventp->se_next;
        !           259: 
        !           260:                        seventp->se_next = runlist;
        !           261:                        runlist = seventp;
        !           262:                }
        !           263: 
        !           264: #if    _FIFO_BUFCALL
        !           265:                /*
        !           266:                 * If we have drained all the events in this cell...
        !           267:                 */
        !           268: 
        !           269:                elistp->sl_tail = NULL;
        !           270: #endif
        !           271: 
        !           272: give_up:
        !           273:                SELIST_UNLOCK (elistp, prev_pl);
        !           274: 
        !           275:                if (seventp != NULL)
        !           276:                        break;
        !           277:        }
        !           278: 
        !           279: 
        !           280:        /*
        !           281:         * Now use 'i' as a boolean to remember whether we have any
        !           282:         * outstanding event cells we though it better not to run.
        !           283:         */
        !           284: 
        !           285:        i = seventp != NULL;
        !           286: 
        !           287: 
        !           288:        /*
        !           289:         * Now walk over our little work list...
        !           290:         */
        !           291: 
        !           292:        while (runlist != NULL) {
        !           293: 
        !           294:                seventp = runlist;
        !           295:                runlist = seventp->se_next;
        !           296: 
        !           297:                prev_pl = splstr ();
        !           298: 
        !           299:                (* seventp->se_func) (seventp->se_arg);
        !           300: 
        !           301:                (void) splx (prev_pl);
        !           302: 
        !           303:                kmem_free (seventp, sizeof (* seventp));
        !           304:        }
        !           305: 
        !           306: 
        !           307:        /*
        !           308:         * If we found anything worth running, try again after we have given
        !           309:         * the bufcall functions a chance to claim the memory that was free
        !           310:         * first time through. We queue another defer request so that we give
        !           311:         * a chance to other deferred routines.
        !           312:         */
        !           313: 
        !           314:        if (i)
        !           315:                SCHEDULE_BUFCALLS ();
        !           316: }
        !           317: 
        !           318: 
        !           319: /*
        !           320:  * Streams scheduling routine, invoked before return to user level. Runs any
        !           321:  * service procedures that have been enabled, calls bufcall ()/esbbcall ()
        !           322:  * events if memory is sitting around, and also wakes up processes sleeping
        !           323:  * in kmem_alloc ()/kmem_zalloc () for memory to become available.
        !           324:  */
        !           325: 
        !           326: #if    __USE_PROTO__
        !           327: void (RUN_STREAMS) (void)
        !           328: #else
        !           329: void
        !           330: RUN_STREAMS __ARGS (())
        !           331: #endif
        !           332: {
        !           333:        queue_t       * q;
        !           334: 
        !           335:        /*
        !           336:         * Before we start running through the queues that we need to service,
        !           337:         * turn off the "deferred" flag for this routine to avoid race
        !           338:          * conditions.
        !           339:         */
        !           340: 
        !           341:        ATOMIC_STORE_UCHAR (ddi_global_data ()->dg_run_strsched, 0);
        !           342: 
        !           343:        while ((q = QSCHED_GETFIRST (str_mem->sm_sched)) != NULL) {
        !           344:                pl_t            prev_pl;
        !           345: 
        !           346:                /*
        !           347:                 * Before we run the service procedure, we must ensure
        !           348:                 * that we are not going to re-enter the service
        !           349:                 * routine. After that, we can turn off the 'enabled'
        !           350:                 * flag.
        !           351:                 */
        !           352: 
        !           353:                prev_pl = QFREEZE_TRACE (q, "STREAMS_SCHEDULER");
        !           354: 
        !           355:                if ((q->q_flag & QSRVACTIVE) != 0) {
        !           356:                        /*
        !           357:                         * Put the queue back and look for something
        !           358:                         * else to do.
        !           359:                         */
        !           360: 
        !           361:                        QUNFREEZE_TRACE (q, prev_pl);
        !           362:                        QSCHED_SCHEDULE (q, str_mem->sm_sched);
        !           363: 
        !           364:                        continue;
        !           365:                }
        !           366: 
        !           367:                q->q_flag = (q->q_flag & ~ QENAB) | QSRVACTIVE;
        !           368: 
        !           369:                if ((q->q_flag & QPROCSOFF) != 0) {
        !           370:                        /*
        !           371:                         * The service procedure of this queue has
        !           372:                         * been disabled, so we leave things alone.
        !           373:                         */
        !           374: 
        !           375:                        goto srvdone;
        !           376:                }
        !           377: 
        !           378:                q->q_active ++;
        !           379: 
        !           380:                QUNFREEZE_TRACE (q, prev_pl);
        !           381: 
        !           382: 
        !           383:                (* q->q_qinfo->qi_srvp) (q);
        !           384: 
        !           385: 
        !           386:                prev_pl = QFREEZE_TRACE (q, "STREAMS_SCHEDULER");
        !           387: 
        !           388:                q->q_flag &= ~ QSRVACTIVE;
        !           389: 
        !           390:                if (-- q->q_active == 0 && (q->q_flag & QPROCSOFF) != 0) {
        !           391:                        /*
        !           392:                         * Wake up the qprocoffs () procedure waiting
        !           393:                         * for us to go exit.
        !           394:                         */
        !           395: 
        !           396:                        (void) LOCK (str_mem->sm_proc_lock, plstr);
        !           397:                        SV_BROADCAST (str_mem->sm_proc_sv, 0);
        !           398:                        UNLOCK (str_mem->sm_proc_lock, plstr);
        !           399:                }
        !           400: srvdone:
        !           401:                QUNFREEZE_TRACE (q, prev_pl);
        !           402:        }
        !           403: }

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