* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
+#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qemu/queue.h"
#include "qemu/thread.h"
-#include "qemu/osdep.h"
-#include "block/coroutine.h"
+#include "qemu/coroutine.h"
#include "trace.h"
-#include "block/block_int.h"
-#include "qemu/event_notifier.h"
#include "block/thread-pool.h"
-
-typedef struct ThreadPool ThreadPool;
+#include "qemu/main-loop.h"
static void do_spawn_thread(ThreadPool *pool);
THREAD_QUEUED,
THREAD_ACTIVE,
THREAD_DONE,
- THREAD_CANCELED,
};
struct ThreadPoolElement {
- BlockDriverAIOCB common;
+ BlockAIOCB common;
ThreadPool *pool;
ThreadPoolFunc *func;
void *arg;
};
struct ThreadPool {
- EventNotifier notifier;
+ AioContext *ctx;
+ QEMUBH *completion_bh;
QemuMutex lock;
- QemuCond check_cancel;
+ QemuCond worker_stopped;
QemuSemaphore sem;
int max_threads;
QEMUBH *new_thread_bh;
int idle_threads;
int new_threads; /* backlog of threads we need to create */
int pending_threads; /* threads created but not running yet */
- int pending_cancellations; /* whether we need a cond_broadcast */
+ bool stopping;
};
-/* Currently there is only one thread pool instance. */
-static ThreadPool global_pool;
-
static void *worker_thread(void *opaque)
{
ThreadPool *pool = opaque;
pool->pending_threads--;
do_spawn_thread(pool);
- while (1) {
+ while (!pool->stopping) {
ThreadPoolElement *req;
int ret;
qemu_mutex_lock(&pool->lock);
pool->idle_threads--;
} while (ret == -1 && !QTAILQ_EMPTY(&pool->request_list));
- if (ret == -1) {
+ if (ret == -1 || pool->stopping) {
break;
}
req->state = THREAD_DONE;
qemu_mutex_lock(&pool->lock);
- if (pool->pending_cancellations) {
- qemu_cond_broadcast(&pool->check_cancel);
- }
- event_notifier_set(&pool->notifier);
+ qemu_bh_schedule(pool->completion_bh);
}
pool->cur_threads--;
+ qemu_cond_signal(&pool->worker_stopped);
qemu_mutex_unlock(&pool->lock);
return NULL;
}
pool->new_threads--;
pool->pending_threads++;
- qemu_thread_create(&t, worker_thread, pool, QEMU_THREAD_DETACHED);
+ qemu_thread_create(&t, "worker", worker_thread, pool, QEMU_THREAD_DETACHED);
}
static void spawn_thread_bh_fn(void *opaque)
}
}
-static void event_notifier_ready(EventNotifier *notifier)
+static void thread_pool_completion_bh(void *opaque)
{
- ThreadPool *pool = container_of(notifier, ThreadPool, notifier);
+ ThreadPool *pool = opaque;
ThreadPoolElement *elem, *next;
- event_notifier_test_and_clear(notifier);
restart:
QLIST_FOREACH_SAFE(elem, &pool->head, all, next) {
- if (elem->state != THREAD_CANCELED && elem->state != THREAD_DONE) {
+ if (elem->state != THREAD_DONE) {
continue;
}
- if (elem->state == THREAD_DONE) {
- trace_thread_pool_complete(pool, elem, elem->common.opaque,
- elem->ret);
- }
- if (elem->state == THREAD_DONE && elem->common.cb) {
- QLIST_REMOVE(elem, all);
+
+ trace_thread_pool_complete(pool, elem, elem->common.opaque,
+ elem->ret);
+ QLIST_REMOVE(elem, all);
+
+ if (elem->common.cb) {
/* Read state before ret. */
smp_rmb();
+
+ /* Schedule ourselves in case elem->common.cb() calls aio_poll() to
+ * wait for another request that completed at the same time.
+ */
+ qemu_bh_schedule(pool->completion_bh);
+
elem->common.cb(elem->common.opaque, elem->ret);
- qemu_aio_release(elem);
+ qemu_aio_unref(elem);
goto restart;
} else {
- /* remove the request */
- QLIST_REMOVE(elem, all);
- qemu_aio_release(elem);
+ qemu_aio_unref(elem);
}
}
}
-static int thread_pool_active(EventNotifier *notifier)
-{
- ThreadPool *pool = container_of(notifier, ThreadPool, notifier);
- return !QLIST_EMPTY(&pool->head);
-}
-
-static void thread_pool_cancel(BlockDriverAIOCB *acb)
+static void thread_pool_cancel(BlockAIOCB *acb)
{
ThreadPoolElement *elem = (ThreadPoolElement *)acb;
ThreadPool *pool = elem->pool;
*/
qemu_sem_timedwait(&pool->sem, 0) == 0) {
QTAILQ_REMOVE(&pool->request_list, elem, reqs);
- elem->state = THREAD_CANCELED;
- event_notifier_set(&pool->notifier);
- } else {
- pool->pending_cancellations++;
- while (elem->state != THREAD_CANCELED && elem->state != THREAD_DONE) {
- qemu_cond_wait(&pool->check_cancel, &pool->lock);
- }
- pool->pending_cancellations--;
+ qemu_bh_schedule(pool->completion_bh);
+
+ elem->state = THREAD_DONE;
+ elem->ret = -ECANCELED;
}
+
qemu_mutex_unlock(&pool->lock);
}
+static AioContext *thread_pool_get_aio_context(BlockAIOCB *acb)
+{
+ ThreadPoolElement *elem = (ThreadPoolElement *)acb;
+ ThreadPool *pool = elem->pool;
+ return pool->ctx;
+}
+
static const AIOCBInfo thread_pool_aiocb_info = {
.aiocb_size = sizeof(ThreadPoolElement),
- .cancel = thread_pool_cancel,
+ .cancel_async = thread_pool_cancel,
+ .get_aio_context = thread_pool_get_aio_context,
};
-BlockDriverAIOCB *thread_pool_submit_aio(ThreadPoolFunc *func, void *arg,
- BlockDriverCompletionFunc *cb, void *opaque)
+BlockAIOCB *thread_pool_submit_aio(ThreadPool *pool,
+ ThreadPoolFunc *func, void *arg,
+ BlockCompletionFunc *cb, void *opaque)
{
- ThreadPool *pool = &global_pool;
ThreadPoolElement *req;
req = qemu_aio_get(&thread_pool_aiocb_info, NULL, cb, opaque);
ThreadPoolCo *co = opaque;
co->ret = ret;
- qemu_coroutine_enter(co->co, NULL);
+ qemu_coroutine_enter(co->co);
}
-int coroutine_fn thread_pool_submit_co(ThreadPoolFunc *func, void *arg)
+int coroutine_fn thread_pool_submit_co(ThreadPool *pool, ThreadPoolFunc *func,
+ void *arg)
{
ThreadPoolCo tpc = { .co = qemu_coroutine_self(), .ret = -EINPROGRESS };
assert(qemu_in_coroutine());
- thread_pool_submit_aio(func, arg, thread_pool_co_cb, &tpc);
+ thread_pool_submit_aio(pool, func, arg, thread_pool_co_cb, &tpc);
qemu_coroutine_yield();
return tpc.ret;
}
-void thread_pool_submit(ThreadPoolFunc *func, void *arg)
+void thread_pool_submit(ThreadPool *pool, ThreadPoolFunc *func, void *arg)
{
- thread_pool_submit_aio(func, arg, NULL, NULL);
+ thread_pool_submit_aio(pool, func, arg, NULL, NULL);
}
static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx)
}
memset(pool, 0, sizeof(*pool));
- event_notifier_init(&pool->notifier, false);
+ pool->ctx = ctx;
+ pool->completion_bh = aio_bh_new(ctx, thread_pool_completion_bh, pool);
qemu_mutex_init(&pool->lock);
- qemu_cond_init(&pool->check_cancel);
+ qemu_cond_init(&pool->worker_stopped);
qemu_sem_init(&pool->sem, 0);
pool->max_threads = 64;
pool->new_thread_bh = aio_bh_new(ctx, spawn_thread_bh_fn, pool);
QLIST_INIT(&pool->head);
QTAILQ_INIT(&pool->request_list);
-
- aio_set_event_notifier(ctx, &pool->notifier, event_notifier_ready,
- thread_pool_active);
}
-static void thread_pool_init(void)
+ThreadPool *thread_pool_new(AioContext *ctx)
{
- thread_pool_init_one(&global_pool, NULL);
+ ThreadPool *pool = g_new(ThreadPool, 1);
+ thread_pool_init_one(pool, ctx);
+ return pool;
}
-block_init(thread_pool_init)
+void thread_pool_free(ThreadPool *pool)
+{
+ if (!pool) {
+ return;
+ }
+
+ assert(QLIST_EMPTY(&pool->head));
+
+ qemu_mutex_lock(&pool->lock);
+
+ /* Stop new threads from spawning */
+ qemu_bh_delete(pool->new_thread_bh);
+ pool->cur_threads -= pool->new_threads;
+ pool->new_threads = 0;
+
+ /* Wait for worker threads to terminate */
+ pool->stopping = true;
+ while (pool->cur_threads > 0) {
+ qemu_sem_post(&pool->sem);
+ qemu_cond_wait(&pool->worker_stopped, &pool->lock);
+ }
+
+ qemu_mutex_unlock(&pool->lock);
+
+ qemu_bh_delete(pool->completion_bh);
+ qemu_sem_destroy(&pool->sem);
+ qemu_cond_destroy(&pool->worker_stopped);
+ qemu_mutex_destroy(&pool->lock);
+ g_free(pool);
+}
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