mirror of
https://gitlab.com/qemu-project/qemu
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e680cfa7e2
Now that AsyncContexts don't exist any more, we can use one global bottom half for restarting coroutines instead of allocating a new one every time (before removing AsyncContexts, the problem with having a global BH was that it had to belong to a single AsyncContexts and wouldn't be executed in a different one - which leads to deadlocks) Signed-off-by: Kevin Wolf <kwolf@redhat.com>
117 lines
3.3 KiB
C
117 lines
3.3 KiB
C
/*
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* coroutine queues and locks
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*
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* Copyright (c) 2011 Kevin Wolf <kwolf@redhat.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu-common.h"
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#include "qemu-coroutine.h"
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#include "qemu-coroutine-int.h"
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#include "qemu-queue.h"
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#include "trace.h"
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static QTAILQ_HEAD(, Coroutine) unlock_bh_queue =
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QTAILQ_HEAD_INITIALIZER(unlock_bh_queue);
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static QEMUBH* unlock_bh;
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static void qemu_co_queue_next_bh(void *opaque)
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{
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Coroutine *next;
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trace_qemu_co_queue_next_bh();
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while ((next = QTAILQ_FIRST(&unlock_bh_queue))) {
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QTAILQ_REMOVE(&unlock_bh_queue, next, co_queue_next);
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qemu_coroutine_enter(next, NULL);
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}
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}
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void qemu_co_queue_init(CoQueue *queue)
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{
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QTAILQ_INIT(&queue->entries);
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if (!unlock_bh) {
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unlock_bh = qemu_bh_new(qemu_co_queue_next_bh, NULL);
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}
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}
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void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
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{
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Coroutine *self = qemu_coroutine_self();
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QTAILQ_INSERT_TAIL(&queue->entries, self, co_queue_next);
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qemu_coroutine_yield();
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assert(qemu_in_coroutine());
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}
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bool qemu_co_queue_next(CoQueue *queue)
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{
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Coroutine *next;
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next = QTAILQ_FIRST(&queue->entries);
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if (next) {
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QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
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QTAILQ_INSERT_TAIL(&unlock_bh_queue, next, co_queue_next);
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trace_qemu_co_queue_next(next);
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qemu_bh_schedule(unlock_bh);
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}
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return (next != NULL);
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}
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bool qemu_co_queue_empty(CoQueue *queue)
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{
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return (QTAILQ_FIRST(&queue->entries) == NULL);
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}
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void qemu_co_mutex_init(CoMutex *mutex)
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{
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memset(mutex, 0, sizeof(*mutex));
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qemu_co_queue_init(&mutex->queue);
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}
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void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
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{
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Coroutine *self = qemu_coroutine_self();
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trace_qemu_co_mutex_lock_entry(mutex, self);
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while (mutex->locked) {
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qemu_co_queue_wait(&mutex->queue);
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}
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mutex->locked = true;
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trace_qemu_co_mutex_lock_return(mutex, self);
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}
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void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
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{
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Coroutine *self = qemu_coroutine_self();
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trace_qemu_co_mutex_unlock_entry(mutex, self);
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assert(mutex->locked == true);
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assert(qemu_in_coroutine());
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mutex->locked = false;
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qemu_co_queue_next(&mutex->queue);
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trace_qemu_co_mutex_unlock_return(mutex, self);
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}
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