From 44a1aad8df43bef416ac91dfc4b9b5614c3d34fd Mon Sep 17 00:00:00 2001
From: sander2 <sanderbosma@gmail.com>
Date: Fri, 29 Oct 2021 17:34:25 +0200
Subject: [PATCH] task: allocate callback on heap immediately in debug mode
 (#4203)

---
 tokio/src/runtime/handle.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tokio/src/runtime/handle.rs b/tokio/src/runtime/handle.rs
index 3fa012eb0e8..dbd7f47ebee 100644
--- a/tokio/src/runtime/handle.rs
+++ b/tokio/src/runtime/handle.rs
@@ -193,7 +193,11 @@ impl Handle {
         F: FnOnce() -> R + Send + 'static,
         R: Send + 'static,
     {
-        self.spawn_blocking_inner(func, None)
+        if cfg!(debug_assertions) && std::mem::size_of::<F>() > 2048 {
+            self.spawn_blocking_inner(Box::new(func), None)
+        } else {
+            self.spawn_blocking_inner(func, None)
+        }
     }
 
     #[cfg_attr(tokio_track_caller, track_caller)]