[Qemu-devel] [PATCH RFC 01/14] qemu coroutine: support bypass mode

[Ming Lei <ming.lei@canonical.com>]

This patch introduces several APIs for supporting bypass qemu coroutine
in case of being not necessary and for performance's sake.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
 include/block/coroutine.h     |    7 +++++++
 include/block/coroutine_int.h |    5 +++++
 qemu-coroutine-lock.c         |    4 ++--
 qemu-coroutine.c              |   33 +++++++++++++++++++++++++++++++++
 4 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/include/block/coroutine.h b/include/block/coroutine.h
index b9b7f48..9bd64da 100644
--- a/include/block/coroutine.h
+++ b/include/block/coroutine.h
@@ -234,4 +234,11 @@ void coroutine_fn yield_until_fd_readable(int fd);
  */
 void qemu_coroutine_adjust_pool_size(int n);
 
+/* qemu coroutine bypass APIs */
+void qemu_coroutine_set_bypass(bool bypass);
+bool qemu_coroutine_bypassed(Coroutine *self);
+bool qemu_coroutine_self_bypassed(void);
+void qemu_coroutine_set_var(void *var);
+void *qemu_coroutine_get_var(void);
+
 #endif /* QEMU_COROUTINE_H */
diff --git a/include/block/coroutine_int.h b/include/block/coroutine_int.h
index f133d65..106d0b2 100644
--- a/include/block/coroutine_int.h
+++ b/include/block/coroutine_int.h
@@ -39,6 +39,11 @@ struct Coroutine {
     Coroutine *caller;
     QSLIST_ENTRY(Coroutine) pool_next;
 
+    bool bypass;
+
+    /* only used in bypass mode */
+    void *opaque;
+
     /* Coroutines that should be woken up when we yield or terminate */
     QTAILQ_HEAD(, Coroutine) co_queue_wakeup;
     QTAILQ_ENTRY(Coroutine) co_queue_next;
diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c
index e4860ae..7c69ff6 100644
--- a/qemu-coroutine-lock.c
+++ b/qemu-coroutine-lock.c
@@ -82,13 +82,13 @@ static bool qemu_co_queue_do_restart(CoQueue *queue, bool single)
 
 bool coroutine_fn qemu_co_queue_next(CoQueue *queue)
 {
-    assert(qemu_in_coroutine());
+    assert(qemu_in_coroutine() || qemu_coroutine_self_bypassed());
     return qemu_co_queue_do_restart(queue, true);
 }
 
 void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue)
 {
-    assert(qemu_in_coroutine());
+    assert(qemu_in_coroutine() || qemu_coroutine_self_bypassed());
     qemu_co_queue_do_restart(queue, false);
 }
 
diff --git a/qemu-coroutine.c b/qemu-coroutine.c
index bd574aa..324f5ad 100644
--- a/qemu-coroutine.c
+++ b/qemu-coroutine.c
@@ -157,3 +157,36 @@ void qemu_coroutine_adjust_pool_size(int n)
 
     qemu_mutex_unlock(&pool_lock);
 }
+
+void qemu_coroutine_set_bypass(bool bypass)
+{
+    Coroutine *self = qemu_coroutine_self();
+
+    self->bypass = bypass;
+}
+
+bool qemu_coroutine_bypassed(Coroutine *self)
+{
+    return self->bypass;
+}
+
+bool qemu_coroutine_self_bypassed(void)
+{
+    Coroutine *self = qemu_coroutine_self();
+
+    return qemu_coroutine_bypassed(self);
+}
+
+void qemu_coroutine_set_var(void *var)
+{
+    Coroutine *self = qemu_coroutine_self();
+
+    self->opaque = var;
+}
+
+void *qemu_coroutine_get_var(void)
+{
+    Coroutine *self = qemu_coroutine_self();
+
+    return self->opaque;
+}
-- 
1.7.9.5