tests: add thread pool unit tests

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

tests/Makefile

@@ -16,6 +16,7 @@ check-unit-y += tests/test-coroutine$(EXESUF)
 check-unit-y += tests/test-visitor-serialization$(EXESUF)
 check-unit-y += tests/test-iov$(EXESUF)
 check-unit-y += tests/test-aio$(EXESUF)
+check-unit-y += tests/test-thread-pool$(EXESUF)
 
 check-block-$(CONFIG_POSIX) += tests/qemu-iotests-quick.sh
 
@@ -51,6 +52,7 @@ tests/check-qfloat$(EXESUF): tests/check-qfloat.o qfloat.o
 tests/check-qjson$(EXESUF): tests/check-qjson.o $(qobject-obj-y) qemu-tool.o
 tests/test-coroutine$(EXESUF): tests/test-coroutine.o $(coroutine-obj-y) $(tools-obj-y) $(block-obj-y) iov.o libqemustub.a
 tests/test-aio$(EXESUF): tests/test-aio.o $(coroutine-obj-y) $(tools-obj-y) $(block-obj-y) libqemustub.a
+tests/test-thread-pool$(EXESUF): tests/test-thread-pool.o $(coroutine-obj-y) $(tools-obj-y) $(block-obj-y) libqemustub.a
 tests/test-iov$(EXESUF): tests/test-iov.o iov.o
 
 tests/test-qapi-types.c tests/test-qapi-types.h :\

tests/test-thread-pool.c

+#include <glib.h>
+#include "qemu-common.h"
+#include "qemu-aio.h"
+#include "thread-pool.h"
+#include "block.h"
+
+static int active;
+
+typedef struct {
+    BlockDriverAIOCB *aiocb;
+    int n;
+    int ret;
+} WorkerTestData;
+
+static int worker_cb(void *opaque)
+{
+    WorkerTestData *data = opaque;
+    return __sync_fetch_and_add(&data->n, 1);
+}
+
+static int long_cb(void *opaque)
+{
+    WorkerTestData *data = opaque;
+    __sync_fetch_and_add(&data->n, 1);
+    g_usleep(2000000);
+    __sync_fetch_and_add(&data->n, 1);
+    return 0;
+}
+
+static void done_cb(void *opaque, int ret)
+{
+    WorkerTestData *data = opaque;
+    g_assert_cmpint(data->ret, ==, -EINPROGRESS);
+    data->ret = ret;
+    data->aiocb = NULL;
+
+    /* Callbacks are serialized, so no need to use atomic ops.  */
+    active--;
+}
+
+/* A non-blocking poll of the main AIO context (we cannot use aio_poll
+ * because we do not know the AioContext).
+ */
+static void qemu_aio_wait_nonblocking(void)
+{
+    qemu_notify_event();
+    qemu_aio_wait();
+}
+
+static void test_submit(void)
+{
+    WorkerTestData data = { .n = 0 };
+    thread_pool_submit(worker_cb, &data);
+    qemu_aio_flush();
+    g_assert_cmpint(data.n, ==, 1);
+}
+
+static void test_submit_aio(void)
+{
+    WorkerTestData data = { .n = 0, .ret = -EINPROGRESS };
+    data.aiocb = thread_pool_submit_aio(worker_cb, &data, done_cb, &data);
+
+    /* The callbacks are not called until after the first wait.  */
+    active = 1;
+    g_assert_cmpint(data.ret, ==, -EINPROGRESS);
+    qemu_aio_flush();
+    g_assert_cmpint(active, ==, 0);
+    g_assert_cmpint(data.n, ==, 1);
+    g_assert_cmpint(data.ret, ==, 0);
+}
+
+static void co_test_cb(void *opaque)
+{
+    WorkerTestData *data = opaque;
+
+    active = 1;
+    data->n = 0;
+    data->ret = -EINPROGRESS;
+    thread_pool_submit_co(worker_cb, data);
+
+    /* The test continues in test_submit_co, after qemu_coroutine_enter... */
+
+    g_assert_cmpint(data->n, ==, 1);
+    data->ret = 0;
+    active--;
+
+    /* The test continues in test_submit_co, after qemu_aio_flush... */
+}
+
+static void test_submit_co(void)
+{
+    WorkerTestData data;
+    Coroutine *co = qemu_coroutine_create(co_test_cb);
+
+    qemu_coroutine_enter(co, &data);
+
+    /* Back here once the worker has started.  */
+
+    g_assert_cmpint(active, ==, 1);
+    g_assert_cmpint(data.ret, ==, -EINPROGRESS);
+
+    /* qemu_aio_flush will execute the rest of the coroutine.  */
+
+    qemu_aio_flush();
+
+    /* Back here after the coroutine has finished.  */
+
+    g_assert_cmpint(active, ==, 0);
+    g_assert_cmpint(data.ret, ==, 0);
+}
+
+static void test_submit_many(void)
+{
+    WorkerTestData data[100];
+    int i;
+
+    /* Start more work items than there will be threads.  */
+    for (i = 0; i < 100; i++) {
+        data[i].n = 0;
+        data[i].ret = -EINPROGRESS;
+        thread_pool_submit_aio(worker_cb, &data[i], done_cb, &data[i]);
+    }
+
+    active = 100;
+    while (active > 0) {
+        qemu_aio_wait();
+    }
+    for (i = 0; i < 100; i++) {
+        g_assert_cmpint(data[i].n, ==, 1);
+        g_assert_cmpint(data[i].ret, ==, 0);
+    }
+}
+
+static void test_cancel(void)
+{
+    WorkerTestData data[100];
+    int i;
+
+    /* Start more work items than there will be threads, to ensure
+     * the pool is full.
+     */
+    test_submit_many();
+
+    /* Start long running jobs, to ensure we can cancel some.  */
+    for (i = 0; i < 100; i++) {
+        data[i].n = 0;
+        data[i].ret = -EINPROGRESS;
+        data[i].aiocb = thread_pool_submit_aio(long_cb, &data[i],
+                                               done_cb, &data[i]);
+    }
+
+    /* Starting the threads may be left to a bottom half.  Let it
+     * run, but do not waste too much time...
+     */
+    active = 100;
+    qemu_aio_wait_nonblocking();
+
+    /* Wait some time for the threads to start, with some sanity
+     * testing on the behavior of the scheduler...
+     */
+    g_assert_cmpint(active, ==, 100);
+    g_usleep(1000000);
+    g_assert_cmpint(active, >, 50);
+
+    /* Cancel the jobs that haven't been started yet.  */
+    for (i = 0; i < 100; i++) {
+        if (__sync_val_compare_and_swap(&data[i].n, 0, 3) == 0) {
+            data[i].ret = -ECANCELED;
+            bdrv_aio_cancel(data[i].aiocb);
+            active--;
+        }
+    }
+    g_assert_cmpint(active, >, 5);
+    g_assert_cmpint(active, <, 95);
+
+    /* Canceling the others will be a blocking operation.  */
+    for (i = 0; i < 100; i++) {
+        if (data[i].n != 3) {
+            bdrv_aio_cancel(data[i].aiocb);
+        }
+    }
+
+    /* Finish execution and execute any remaining callbacks.  */
+    qemu_aio_flush();
+    g_assert_cmpint(active, ==, 0);
+    for (i = 0; i < 100; i++) {
+        if (data[i].n == 3) {
+            g_assert_cmpint(data[i].ret, ==, -ECANCELED);
+            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].aiocb == NULL);
+        }
+    }
+}
+
+int main(int argc, char **argv)
+{
+    /* These should be removed once each AioContext has its thread pool.
+     * The test should create its own AioContext.
+     */
+    qemu_init_main_loop();
+    bdrv_init();
+
+    g_test_init(&argc, &argv, NULL);
+    g_test_add_func("/thread-pool/submit", test_submit);
+    g_test_add_func("/thread-pool/submit-aio", test_submit_aio);
+    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);
+    return g_test_run();
+}