coroutine-lock: convert CoQueue to use QemuLockable
There are cases in which a queued coroutine must be restarted from
non-coroutine context (with qemu_co_enter_next). In this cases,
qemu_co_enter_next also needs to be thread-safe, but it cannot use
a CoMutex and so cannot qemu_co_queue_wait. Use QemuLockable so
that the CoQueue can interchangeably use CoMutex or QemuMutex.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20180203153935.8056-4-pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index 846ff91..2a66fc1 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -40,13 +40,13 @@
QSIMPLEQ_INIT(&queue->entries);
}
-void coroutine_fn qemu_co_queue_wait(CoQueue *queue, CoMutex *mutex)
+void coroutine_fn qemu_co_queue_wait_impl(CoQueue *queue, QemuLockable *lock)
{
Coroutine *self = qemu_coroutine_self();
QSIMPLEQ_INSERT_TAIL(&queue->entries, self, co_queue_next);
- if (mutex) {
- qemu_co_mutex_unlock(mutex);
+ if (lock) {
+ qemu_lockable_unlock(lock);
}
/* There is no race condition here. Other threads will call
@@ -60,9 +60,11 @@
/* TODO: OSv implements wait morphing here, where the wakeup
* primitive automatically places the woken coroutine on the
* mutex's queue. This avoids the thundering herd effect.
+ * This could be implemented for CoMutexes, but not really for
+ * other cases of QemuLockable.
*/
- if (mutex) {
- qemu_co_mutex_lock(mutex);
+ if (lock) {
+ qemu_lockable_lock(lock);
}
}
