| /SPARTAN/trunk/src/synch/rwlock.c |
|---|
| 0,0 → 1,310 |
| /* |
| * Reader/Writer locks |
| */ |
| /* |
| * Copyright (C) 2001-2004 Jakub Jermar |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| /* |
| * These locks are not recursive. |
| * Neither readers nor writers will suffer starvation. |
| * |
| * If there is a writer followed by a reader waiting for the rwlock |
| * and the writer times out, all leading readers are automatically woken up |
| * and allowed in. |
| */ |
| /* |
| * NOTE ON rwlock_holder_type |
| * This field is set on an attempt to acquire the exclusive mutex |
| * to the respective value depending whether the caller is a reader |
| * or a writer. The field is examined only if the thread had been |
| * previously blocked on the exclusive mutex. Thus it is save |
| * to store the rwlock type in the thread structure, because |
| * each thread can block on only one rwlock at a time. |
| */ |
| #include <synch/synch.h> |
| #include <synch/rwlock.h> |
| #include <synch/spinlock.h> |
| #include <synch/mutex.h> |
| #include <synch/waitq.h> |
| #include <list.h> |
| #include <typedefs.h> |
| #include <arch/asm.h> |
| #include <arch.h> |
| #include <proc/thread.h> |
| #include <panic.h> |
| #define ALLOW_ALL 0 |
| #define ALLOW_READERS_ONLY 1 |
| static void let_others_in(rwlock_t *rwl, int readers_only); |
| static void release_spinlock(void *arg); |
| void rwlock_initialize(rwlock_t *rwl) { |
| spinlock_initialize(&rwl->lock); |
| mutex_initialize(&rwl->exclusive); |
| rwl->readers_in = 0; |
| } |
| int _rwlock_write_lock_timeout(rwlock_t *rwl, __u32 usec, int trylock) |
| { |
| pri_t pri; |
| int rc; |
| pri = cpu_priority_high(); |
| spinlock_lock(&the->thread->lock); |
| the->thread->rwlock_holder_type = RWLOCK_WRITER; |
| spinlock_unlock(&the->thread->lock); |
| cpu_priority_restore(pri); |
| /* |
| * Writers take the easy part. |
| * They just need to acquire the exclusive mutex. |
| */ |
| rc = _mutex_lock_timeout(&rwl->exclusive, usec, trylock); |
| if (SYNCH_FAILED(rc)) { |
| /* |
| * Lock operation timed out. |
| * The state of rwl is UNKNOWN at this point. |
| * No claims about its holder can be made. |
| */ |
| pri = cpu_priority_high(); |
| spinlock_lock(&rwl->lock); |
| /* |
| * Now when rwl is locked, we can inspect it again. |
| * If it is held by some readers already, we can let |
| * readers from the head of the wait queue in. |
| */ |
| if (rwl->readers_in) |
| let_others_in(rwl, ALLOW_READERS_ONLY); |
| spinlock_unlock(&rwl->lock); |
| cpu_priority_restore(pri); |
| } |
| return rc; |
| } |
| int _rwlock_read_lock_timeout(rwlock_t *rwl, __u32 usec, int trylock) |
| { |
| int rc; |
| pri_t pri; |
| pri = cpu_priority_high(); |
| spinlock_lock(&the->thread->lock); |
| the->thread->rwlock_holder_type = RWLOCK_READER; |
| spinlock_unlock(&the->thread->lock); |
| spinlock_lock(&rwl->lock); |
| /* |
| * Find out whether we can get what we want without blocking. |
| */ |
| rc = mutex_trylock(&rwl->exclusive); |
| if (SYNCH_FAILED(rc)) { |
| /* |
| * 'exclusive' mutex is being held by someone else. |
| * If the holder is a reader and there is no one |
| * else waiting for it, we can enter the critical |
| * section. |
| */ |
| if (rwl->readers_in) { |
| spinlock_lock(&rwl->exclusive.sem.wq.lock); |
| if (list_empty(&rwl->exclusive.sem.wq.head)) { |
| /* |
| * We can enter. |
| */ |
| spinlock_unlock(&rwl->exclusive.sem.wq.lock); |
| goto shortcut; |
| } |
| spinlock_unlock(&rwl->exclusive.sem.wq.lock); |
| } |
| /* |
| * In order to prevent a race condition when a reader |
| * could block another reader at the head of the waitq, |
| * we register a function to unlock rwl->lock |
| * after this thread is put asleep. |
| */ |
| thread_register_call_me(release_spinlock, &rwl->lock); |
| rc = _mutex_lock_timeout(&rwl->exclusive, usec, trylock); |
| switch (rc) { |
| case ESYNCH_WOULD_BLOCK: |
| /* |
| * release_spinlock() wasn't called |
| */ |
| thread_register_call_me(NULL, NULL); |
| spinlock_unlock(&rwl->lock); |
| case ESYNCH_TIMEOUT: |
| /* |
| * The sleep timeouted. |
| * We just restore the cpu priority. |
| */ |
| case ESYNCH_OK_BLOCKED: |
| /* |
| * We were woken with rwl->readers_in already incremented. |
| * Note that this arrangement avoids race condition between |
| * two concurrent readers. (Race is avoided if 'exclusive' is |
| * locked at the same time as 'readers_in' is incremented. |
| * Same time means both events happen atomically when |
| * rwl->lock is held.) |
| */ |
| cpu_priority_restore(pri); |
| break; |
| case ESYNCH_OK_ATOMIC: |
| panic(PANIC "_mutex_lock_timeout()==ESYNCH_OK_ATOMIC"); |
| break; |
| dafault: |
| panic(PANIC "invalid ESYNCH"); |
| break; |
| } |
| return rc; |
| } |
| shortcut: |
| /* |
| * We can increment readers_in only if we didn't go to sleep. |
| * For sleepers, rwlock_let_others_in() will do the job. |
| */ |
| rwl->readers_in++; |
| spinlock_unlock(&rwl->lock); |
| cpu_priority_restore(pri); |
| return ESYNCH_OK_ATOMIC; |
| } |
| void rwlock_write_unlock(rwlock_t *rwl) |
| { |
| pri_t pri; |
| pri = cpu_priority_high(); |
| spinlock_lock(&rwl->lock); |
| let_others_in(rwl, ALLOW_ALL); |
| spinlock_unlock(&rwl->lock); |
| cpu_priority_restore(pri); |
| } |
| void rwlock_read_unlock(rwlock_t *rwl) |
| { |
| pri_t pri; |
| pri = cpu_priority_high(); |
| spinlock_lock(&rwl->lock); |
| if (!--rwl->readers_in) |
| let_others_in(rwl, ALLOW_ALL); |
| spinlock_unlock(&rwl->lock); |
| cpu_priority_restore(pri); |
| } |
| /* |
| * Must be called with rwl->lock locked. |
| * Must be called with cpu_priority_high'ed. |
| */ |
| /* |
| * If readers_only is false: (unlock scenario) |
| * Let the first sleeper on 'exclusive' mutex in, no matter |
| * whether it is a reader or a writer. If there are more leading |
| * readers in line, let each of them in. |
| * |
| * Otherwise: (timeout scenario) |
| * Let all leading readers in. |
| */ |
| void let_others_in(rwlock_t *rwl, int readers_only) |
| { |
| rwlock_type_t type = RWLOCK_NONE; |
| thread_t *t = NULL; |
| int one_more = 1; |
| spinlock_lock(&rwl->exclusive.sem.wq.lock); |
| if (!list_empty(&rwl->exclusive.sem.wq.head)) |
| t = list_get_instance(rwl->exclusive.sem.wq.head.next, thread_t, wq_link); |
| do { |
| if (t) { |
| spinlock_lock(&t->lock); |
| type = t->rwlock_holder_type; |
| spinlock_unlock(&t->lock); |
| } |
| /* |
| * If readers_only is true, we wake all leading readers |
| * if and only if rwl is locked by another reader. |
| * Assumption: readers_only ==> rwl->readers_in |
| */ |
| if (readers_only && (type != RWLOCK_READER)) |
| break; |
| if (type == RWLOCK_READER) { |
| /* |
| * Waking up a reader. |
| * We are responsible for incrementing rwl->readers_in for it. |
| */ |
| rwl->readers_in++; |
| } |
| /* |
| * Only the last iteration through this loop can increment |
| * rwl->exclusive.sem.wq.missed_wakeup's. All preceeding |
| * iterations will wake up a thread. |
| */ |
| /* We call the internal version of waitq_wakeup, which |
| * relies on the fact that the waitq is already locked. |
| */ |
| _waitq_wakeup_unsafe(&rwl->exclusive.sem.wq, WAKEUP_FIRST); |
| t = NULL; |
| if (!list_empty(&rwl->exclusive.sem.wq.head)) { |
| t = list_get_instance(rwl->exclusive.sem.wq.head.next, thread_t, wq_link); |
| if (t) { |
| spinlock_lock(&t->lock); |
| if (t->rwlock_holder_type != RWLOCK_READER) |
| one_more = 0; |
| spinlock_unlock(&t->lock); |
| } |
| } |
| } while ((type == RWLOCK_READER) && t && one_more); |
| spinlock_unlock(&rwl->exclusive.sem.wq.lock); |
| } |
| void release_spinlock(void *arg) |
| { |
| spinlock_unlock((spinlock_t *) arg); |
| } |
| /SPARTAN/trunk/src/synch/mutex.c |
|---|
| 0,0 → 1,46 |
| /* |
| * Copyright (C) 2001-2004 Jakub Jermar |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| #include <synch/synch.h> |
| #include <synch/mutex.h> |
| #include <synch/semaphore.h> |
| void mutex_initialize(mutex_t *mtx) |
| { |
| semaphore_initialize(&mtx->sem, 1); |
| } |
| int _mutex_lock_timeout(mutex_t *mtx, __u32 usec, int trylock) |
| { |
| return _semaphore_down_timeout(&mtx->sem, usec, trylock); |
| } |
| void mutex_unlock(mutex_t *mtx) |
| { |
| semaphore_up(&mtx->sem); |
| } |
| /SPARTAN/trunk/src/synch/spinlock.c |
|---|
| 0,0 → 1,79 |
| /* |
| * Copyright (C) 2001-2004 Jakub Jermar |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| #include <arch.h> |
| #ifdef __SMP__ |
| #include <arch/atomic.h> |
| #endif |
| #include <synch/spinlock.h> |
| #ifdef __SMP__ |
| void spinlock_initialize(spinlock_t *sl) |
| { |
| sl->val = 0; |
| } |
| #ifdef DEBUG_SPINLOCK |
| void spinlock_lock(spinlock_t *sl) |
| { |
| int i = 0; |
| __address caller = ((__u32 *) &sl)[-1]; |
| while (test_and_set(&sl->val)) { |
| if (i++ > 300000) { |
| printf("cpu%d: looping on spinlock %X, caller=%X\n", the->cpu->id, sl, caller); |
| i = 0; |
| } |
| } |
| } |
| #else |
| void spinlock_lock(spinlock_t *sl) |
| { |
| /* |
| * Each architecture has its own efficient/recommended |
| * implementation of spinlock. |
| */ |
| spinlock_arch(&sl->val); |
| } |
| #endif |
| int spinlock_trylock(spinlock_t *sl) |
| { |
| return !test_and_set(&sl->val); |
| } |
| void spinlock_unlock(spinlock_t *sl) |
| { |
| sl->val = 0; |
| } |
| #endif |
| /SPARTAN/trunk/src/synch/semaphore.c |
|---|
| 0,0 → 1,57 |
| /* |
| * Copyright (C) 2001-2004 Jakub Jermar |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| #include <synch/synch.h> |
| #include <synch/semaphore.h> |
| #include <synch/waitq.h> |
| #include <synch/spinlock.h> |
| void semaphore_initialize(semaphore_t *s, int val) |
| { |
| pri_t pri; |
| waitq_initialize(&s->wq); |
| pri = cpu_priority_high(); |
| spinlock_lock(&s->wq.lock); |
| s->wq.missed_wakeups = val; |
| spinlock_unlock(&s->wq.lock); |
| cpu_priority_restore(pri); |
| } |
| int _semaphore_down_timeout(semaphore_t *s, __u32 usec, int trydown) |
| { |
| return waitq_sleep_timeout(&s->wq, usec, trydown); |
| } |
| void semaphore_up(semaphore_t *s) |
| { |
| waitq_wakeup(&s->wq, WAKEUP_FIRST); |
| } |
| /SPARTAN/trunk/src/synch/waitq.c |
|---|
| 0,0 → 1,240 |
| /* |
| * Copyright (C) 2001-2004 Jakub Jermar |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| #include <context.h> |
| #include <proc/thread.h> |
| #include <synch/synch.h> |
| #include <synch/waitq.h> |
| #include <synch/spinlock.h> |
| #include <arch/asm.h> |
| #include <arch/types.h> |
| #include <arch.h> |
| #include <list.h> |
| #include <time/timeout.h> |
| void waitq_initialize(waitq_t *wq) |
| { |
| spinlock_initialize(&wq->lock); |
| list_initialize(&wq->head); |
| wq->missed_wakeups = 0; |
| } |
| /* |
| * Called with interrupts disabled from clock() when sleep_timeout |
| * timeouts. This function is not allowed to enable interrupts. |
| * |
| * It is supposed to try to remove 'its' thread from the waitqueue; it |
| * can eventually fail to achieve this goal when these two events |
| * overlap; in that case it behaves just as though there was no |
| * timeout at all |
| */ |
| void waitq_interrupted_sleep(void *data) |
| { |
| thread_t *t = (thread_t *) data; |
| waitq_t *wq; |
| int do_wakeup = 0; |
| spinlock_lock(&threads_lock); |
| if (!list_member(&t->threads_link, &threads_head)) |
| goto out; |
| grab_locks: |
| spinlock_lock(&t->lock); |
| if (wq = t->sleep_queue) { |
| if (!spinlock_trylock(&wq->lock)) { |
| spinlock_unlock(&t->lock); |
| goto grab_locks; /* avoid deadlock */ |
| } |
| list_remove(&t->wq_link); |
| t->saved_context = t->sleep_timeout_context; |
| do_wakeup = 1; |
| spinlock_unlock(&wq->lock); |
| t->sleep_queue = NULL; |
| } |
| t->timeout_pending = 0; |
| spinlock_unlock(&t->lock); |
| if (do_wakeup) thread_ready(t); |
| out: |
| spinlock_unlock(&threads_lock); |
| } |
| /* |
| * This is a sleep implementation which allows itself to be |
| * interrupted from the sleep, restoring a failover context. |
| * |
| * This function is really basic in that other functions as waitq_sleep() |
| * and all the *_timeout() functions use it. |
| * |
| * The third argument controls whether only a conditional sleep |
| * (non-blocking sleep) is called for when the second argument is 0. |
| * |
| * usec | nonblocking | what happens if there is no missed_wakeup |
| * -----+-------------+-------------------------------------------- |
| * 0 | 0 | blocks without timeout until wakeup |
| * 0 | <> 0 | immediately returns ESYNCH_WOULD_BLOCK |
| * > 0 | x | blocks with timeout until timeout or wakeup |
| * |
| * return values: |
| * ESYNCH_WOULD_BLOCK |
| * ESYNCH_TIMEOUT |
| * ESYNCH_OK_ATOMIC |
| * ESYNCH_OK_BLOCKED |
| */ |
| int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int nonblocking) |
| { |
| volatile pri_t pri; /* must be live after context_restore() */ |
| restart: |
| pri = cpu_priority_high(); |
| /* |
| * Busy waiting for a delayed timeout. |
| * This is an important fix for the race condition between |
| * a delayed timeout and a next call to waitq_sleep_timeout(). |
| * Simply, the thread is not allowed to go to sleep if |
| * there are timeouts in progress. |
| */ |
| spinlock_lock(&the->thread->lock); |
| if (the->thread->timeout_pending) { |
| spinlock_unlock(&the->thread->lock); |
| cpu_priority_restore(pri); |
| goto restart; |
| } |
| spinlock_unlock(&the->thread->lock); |
| spinlock_lock(&wq->lock); |
| /* checks whether to go to sleep at all */ |
| if (wq->missed_wakeups) { |
| wq->missed_wakeups--; |
| spinlock_unlock(&wq->lock); |
| cpu_priority_restore(pri); |
| return ESYNCH_OK_ATOMIC; |
| } |
| else { |
| if (nonblocking && (usec == 0)) { |
| /* return immediatelly instead of going to sleep */ |
| spinlock_unlock(&wq->lock); |
| cpu_priority_restore(pri); |
| return ESYNCH_WOULD_BLOCK; |
| } |
| } |
| /* |
| * Now we are firmly decided to go to sleep. |
| */ |
| spinlock_lock(&the->thread->lock); |
| if (usec) { |
| /* We use the timeout variant. */ |
| if (!context_save(&the->thread->sleep_timeout_context)) { |
| /* |
| * Short emulation of scheduler() return code. |
| */ |
| spinlock_unlock(&the->thread->lock); |
| cpu_priority_restore(pri); |
| return ESYNCH_TIMEOUT; |
| } |
| the->thread->timeout_pending = 1; |
| timeout_register(&the->thread->sleep_timeout, (__u64) usec, waitq_interrupted_sleep, the->thread); |
| } |
| list_append(&the->thread->wq_link, &wq->head); |
| /* |
| * Suspend execution. |
| */ |
| the->thread->state = Sleeping; |
| the->thread->sleep_queue = wq; |
| spinlock_unlock(&the->thread->lock); |
| scheduler(); /* wq->lock is released in scheduler_separated_stack() */ |
| cpu_priority_restore(pri); |
| return ESYNCH_OK_BLOCKED; |
| } |
| /* |
| * This is the SMP- and IRQ-safe wrapper meant for general use. |
| */ |
| /* |
| * Besides its 'normal' wakeup operation, it attempts to unregister possible timeout. |
| */ |
| void waitq_wakeup(waitq_t *wq, int all) |
| { |
| pri_t pri; |
| pri = cpu_priority_high(); |
| spinlock_lock(&wq->lock); |
| _waitq_wakeup_unsafe(wq, all); |
| spinlock_unlock(&wq->lock); |
| cpu_priority_restore(pri); |
| } |
| /* |
| * This is the internal SMP- and IRQ-unsafe version of waitq_wakeup. |
| * It assumes wq->lock is already locked. |
| */ |
| void _waitq_wakeup_unsafe(waitq_t *wq, int all) |
| { |
| thread_t *t; |
| loop: |
| if (list_empty(&wq->head)) { |
| wq->missed_wakeups++; |
| if (all) wq->missed_wakeups = 0; |
| return; |
| } |
| t = list_get_instance(wq->head.next, thread_t, wq_link); |
| list_remove(&t->wq_link); |
| spinlock_lock(&t->lock); |
| if (t->timeout_pending && timeout_unregister(&t->sleep_timeout)) |
| t->timeout_pending = 0; |
| t->sleep_queue = NULL; |
| spinlock_unlock(&t->lock); |
| thread_ready(t); |
| if (all) goto loop; |
| } |
| /SPARTAN/trunk/src/synch/condvar.c |
|---|
| 0,0 → 1,57 |
| /* |
| * Copyright (C) 2001-2004 Jakub Jermar |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| #include <synch/synch.h> |
| #include <synch/condvar.h> |
| #include <synch/mutex.h> |
| #include <synch/waitq.h> |
| void condvar_initialize(condvar_t *cv) |
| { |
| waitq_initialize(&cv->wq); |
| } |
| void condvar_signal(condvar_t *cv) |
| { |
| waitq_wakeup(&cv->wq, WAKEUP_FIRST); |
| } |
| void condvar_broadcast(condvar_t *cv) |
| { |
| waitq_wakeup(&cv->wq, WAKEUP_ALL); |
| } |
| int _condvar_wait_timeout(condvar_t *cv, mutex_t *mtx, __u32 usec, int trywait) |
| { |
| int rc; |
| mutex_unlock(mtx); |
| rc = waitq_sleep_timeout(&cv->wq, usec, trywait); |
| mutex_lock(mtx); |
| return rc; |
| } |