On Wednesday, 2021-03-17 at 13:16:40 +01, Paolo Bonzini wrote:
> Test that rwlock upgrade is fair, and readers go back to sleep if a writer
> is in line.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Reviewed-by: David Edmondson <david.edmond...@oracle.com>
> ---
> tests/unit/test-coroutine.c | 62 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 62 insertions(+)
>
> diff --git a/tests/unit/test-coroutine.c b/tests/unit/test-coroutine.c
> index e946d93a65..6e6f51d480 100644
> --- a/tests/unit/test-coroutine.c
> +++ b/tests/unit/test-coroutine.c
> @@ -264,6 +264,67 @@ static void test_co_mutex_lockable(void)
> g_assert(QEMU_MAKE_LOCKABLE(null_pointer) == NULL);
> }
>
> +static CoRwlock rwlock;
> +
> +/* Test that readers are properly sent back to the queue when upgrading,
> + * even if they are the sole readers. The test scenario is as follows:
> + *
> + *
> + * | c1 | c2 |
> + * |--------------+------------+
> + * | rdlock | |
> + * | yield | |
> + * | | wrlock |
> + * | | <queued> |
> + * | upgrade | |
> + * | <queued> | <dequeued> |
> + * | | unlock |
> + * | <dequeued> | |
> + * | unlock | |
> + */
> +
> +static void coroutine_fn rwlock_yield_upgrade(void *opaque)
> +{
> + qemu_co_rwlock_rdlock(&rwlock);
> + qemu_coroutine_yield();
> +
> + qemu_co_rwlock_upgrade(&rwlock);
> + qemu_co_rwlock_unlock(&rwlock);
> +
> + *(bool *)opaque = true;
> +}
> +
> +static void coroutine_fn rwlock_wrlock_yield(void *opaque)
> +{
> + qemu_co_rwlock_wrlock(&rwlock);
> + qemu_coroutine_yield();
> +
> + qemu_co_rwlock_unlock(&rwlock);
> + *(bool *)opaque = true;
> +}
> +
> +static void test_co_rwlock_upgrade(void)
> +{
> + bool c1_done = false;
> + bool c2_done = false;
> + Coroutine *c1, *c2;
> +
> + qemu_co_rwlock_init(&rwlock);
> + c1 = qemu_coroutine_create(rwlock_yield_upgrade, &c1_done);
> + c2 = qemu_coroutine_create(rwlock_wrlock_yield, &c2_done);
> +
> + qemu_coroutine_enter(c1);
> + qemu_coroutine_enter(c2);
> +
> + /* c1 now should go to sleep. */
> + qemu_coroutine_enter(c1);
> + g_assert(!c1_done);
> +
> + qemu_coroutine_enter(c2);
> + g_assert(c1_done);
> + g_assert(c2_done);
> +}
> +
> /*
> * Check that creation, enter, and return work
> */
> @@ -501,6 +562,7 @@ int main(int argc, char **argv)
> g_test_add_func("/basic/order", test_order);
> g_test_add_func("/locking/co-mutex", test_co_mutex);
> g_test_add_func("/locking/co-mutex/lockable", test_co_mutex_lockable);
> + g_test_add_func("/locking/co-rwlock/upgrade", test_co_rwlock_upgrade);
> if (g_test_perf()) {
> g_test_add_func("/perf/lifecycle", perf_lifecycle);
> g_test_add_func("/perf/nesting", perf_nesting);
> --
> 2.29.2
dme.
--
Oh by the way, which one's Pink?
