Implement minimal exec_ctx offloading

2 files changed, 11 insertions, 4 deletions

diff --git a/src/core/lib/iomgr/exec_ctx.c b/src/core/lib/iomgr/exec_ctx.c
index c44aafcddf..059133f879 100644
--- a/src/core/lib/iomgr/exec_ctx.c
+++ b/src/core/lib/iomgr/exec_ctx.c
@@ -85,14 +85,17 @@ void grpc_exec_ctx_finish(grpc_exec_ctx *exec_ctx) {
 void grpc_exec_ctx_sched(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
                          grpc_error *error,
                          grpc_workqueue *offload_target_or_null) {
-  GPR_ASSERT(offload_target_or_null == NULL);
-  grpc_closure_list_append(&exec_ctx->closure_list, closure, error);
+  if (offload_target_or_null == NULL) {
+    grpc_closure_list_append(&exec_ctx->closure_list, closure, error);
+  } else {
+    grpc_workqueue_enqueue(exec_ctx, offload_target_or_null, closure, error);
+    GRPC_WORKQUEUE_UNREF(exec_ctx, offload_target_or_null, "exec_ctx_sched");
+  }
 }
 
 void grpc_exec_ctx_enqueue_list(grpc_exec_ctx *exec_ctx,
                                 grpc_closure_list *list,
                                 grpc_workqueue *offload_target_or_null) {
-  GPR_ASSERT(offload_target_or_null == NULL);
   grpc_closure_list_move(list, &exec_ctx->closure_list);
 }
 
diff --git a/src/core/lib/iomgr/exec_ctx.h b/src/core/lib/iomgr/exec_ctx.h
index 38f27d9b13..917f332f03 100644
--- a/src/core/lib/iomgr/exec_ctx.h
+++ b/src/core/lib/iomgr/exec_ctx.h
@@ -93,7 +93,11 @@ bool grpc_exec_ctx_flush(grpc_exec_ctx *exec_ctx);
 /** Finish any pending work for a grpc_exec_ctx. Must be called before
  *  the instance is destroyed, or work may be lost. */
 void grpc_exec_ctx_finish(grpc_exec_ctx *exec_ctx);
-/** Add a closure to be executed at the next flush/finish point */
+/** Add a closure to be executed in the future.
+    If \a offload_target_or_null is NULL, the closure will be executed at the
+    next exec_ctx.{finish,flush} point.
+    If \a offload_target_or_null is non-NULL, the closure will be scheduled
+    against the workqueue, and a reference to the workqueue will be consumed. */
 void grpc_exec_ctx_sched(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
                          grpc_error *error,
                          grpc_workqueue *offload_target_or_null);