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thread-pool: Convert thread_pool_aiocb_info.cancel to cancel_async

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The .cancel_async shares the same the first half with .cancel: try to
steal the request if not submitted yet. In this case set the elem to
THREAD_DONE status and ret to -ECANCELED, which means
thread_pool_completion_bh will call the cb with -ECANCELED.

If the request is already submitted, do nothing, as we know the normal
completion will happen in the future.

Testing code update:

Before, done_cb is only called if the request is already submitted by
thread pool. Now done_cb is always called, even before it is submitted,
because we emulate bdrv_aio_cancel with bdrv_aio_cancel_async. So also
update the test criteria accordingly.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Fam Zheng 2014-09-11 13:41:12 +08:00 committed by Stefan Hajnoczi
parent f600ac1902
commit 3391f5e51c
2 changed files with 40 additions and 26 deletions
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34
tests/test-thread-pool.c
View file

@ -33,7 +33,7 @@ static int long_cb(void *opaque)
static void done_cb(void *opaque, int ret)
{
WorkerTestData *data = opaque;
g_assert_cmpint(data->ret, ==, -EINPROGRESS);
g_assert(data->ret == -EINPROGRESS || data->ret == -ECANCELED);
data->ret = ret;
data->aiocb = NULL;
@ -132,7 +132,7 @@ static void test_submit_many(void)
}
}
static void test_cancel(void)
static void do_test_cancel(bool sync)
{
WorkerTestData data[100];
int num_canceled;
@ -170,18 +170,25 @@ static void test_cancel(void)
for (i = 0; i < 100; i++) {
if (atomic_cmpxchg(&data[i].n, 0, 3) == 0) {
data[i].ret = -ECANCELED;
bdrv_aio_cancel(data[i].aiocb);
active--;
if (sync) {
bdrv_aio_cancel(data[i].aiocb);
} else {
bdrv_aio_cancel_async(data[i].aiocb);
}
num_canceled++;
}
}
g_assert_cmpint(active, >, 0);
g_assert_cmpint(num_canceled, <, 100);
/* Canceling the others will be a blocking operation. */
for (i = 0; i < 100; i++) {
if (data[i].aiocb && data[i].n != 3) {
bdrv_aio_cancel(data[i].aiocb);
if (sync) {
/* Canceling the others will be a blocking operation. */
bdrv_aio_cancel(data[i].aiocb);
} else {
bdrv_aio_cancel_async(data[i].aiocb);
}
}
}
@ -193,15 +200,25 @@ static void test_cancel(void)
for (i = 0; i < 100; i++) {
if (data[i].n == 3) {
g_assert_cmpint(data[i].ret, ==, -ECANCELED);
g_assert(data[i].aiocb != NULL);
g_assert(data[i].aiocb == NULL);
} else {
g_assert_cmpint(data[i].n, ==, 2);
g_assert_cmpint(data[i].ret, ==, 0);
g_assert(data[i].ret == 0 || data[i].ret == -ECANCELED);
g_assert(data[i].aiocb == NULL);
}
}
}
static void test_cancel(void)
{
do_test_cancel(true);
}
static void test_cancel_async(void)
{
do_test_cancel(false);
}
int main(int argc, char **argv)
{
int ret;
@ -217,6 +234,7 @@ int main(int argc, char **argv)
g_test_add_func("/thread-pool/submit-co", test_submit_co);
g_test_add_func("/thread-pool/submit-many", test_submit_many);
g_test_add_func("/thread-pool/cancel", test_cancel);
g_test_add_func("/thread-pool/cancel-async", test_cancel_async);
ret = g_test_run();

32
thread-pool.c
View file

@ -31,7 +31,6 @@ enum ThreadState {
THREAD_QUEUED,
THREAD_ACTIVE,
THREAD_DONE,
THREAD_CANCELED,
};
struct ThreadPoolElement {
@ -58,7 +57,6 @@ struct ThreadPool {
AioContext *ctx;
QEMUBH *completion_bh;
QemuMutex lock;
QemuCond check_cancel;
QemuCond worker_stopped;
QemuSemaphore sem;
int max_threads;
@ -73,7 +71,6 @@ struct ThreadPool {
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;
};
@ -113,9 +110,6 @@ static void *worker_thread(void *opaque)
req->state = THREAD_DONE;
qemu_mutex_lock(&pool->lock);
if (pool->pending_cancellations) {
qemu_cond_broadcast(&pool->check_cancel);
}
qemu_bh_schedule(pool->completion_bh);
}
@ -173,7 +167,7 @@ static void thread_pool_completion_bh(void *opaque)
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) {
@ -217,22 +211,26 @@ static void thread_pool_cancel(BlockDriverAIOCB *acb)
*/
qemu_sem_timedwait(&pool->sem, 0) == 0) {
QTAILQ_REMOVE(&pool->request_list, elem, reqs);
elem->state = THREAD_CANCELED;
qemu_bh_schedule(pool->completion_bh);
} else {
pool->pending_cancellations++;
while (elem->state != THREAD_CANCELED && elem->state != THREAD_DONE) {
qemu_cond_wait(&pool->check_cancel, &pool->lock);
}
pool->pending_cancellations--;
elem->state = THREAD_DONE;
elem->ret = -ECANCELED;
}
qemu_mutex_unlock(&pool->lock);
thread_pool_completion_bh(pool);
}
static AioContext *thread_pool_get_aio_context(BlockDriverAIOCB *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(ThreadPool *pool,
@ -299,7 +297,6 @@ static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx)
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;
@ -342,7 +339,6 @@ void thread_pool_free(ThreadPool *pool)
qemu_bh_delete(pool->completion_bh);
qemu_sem_destroy(&pool->sem);
qemu_cond_destroy(&pool->check_cancel);
qemu_cond_destroy(&pool->worker_stopped);
qemu_mutex_destroy(&pool->lock);
g_free(pool);