From 55c76eaac12af4e93f8de11bb25c835e8b65c623 Mon Sep 17 00:00:00 2001
From: Damien George
Date: Thu, 20 Aug 2020 23:13:25 +1000
Subject: extmod/uasyncio: Truncate negative sleeps to 0.

Otherwise a task that continuously awaits on a large negative sleep can
monopolise the scheduler (because its wake time is always less than
everything else in the pairing heap).

Signed-off-by: Damien George <damien@micropython.org>
---
 extmod/uasyncio/core.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'extmod')

diff --git a/extmod/uasyncio/core.py b/extmod/uasyncio/core.py
index 689487d36..045b4cd13 100644
--- a/extmod/uasyncio/core.py
+++ b/extmod/uasyncio/core.py
@@ -53,7 +53,7 @@ class SingletonGenerator:
 # Use a SingletonGenerator to do it without allocating on the heap
 def sleep_ms(t, sgen=SingletonGenerator()):
     assert sgen.state is None
-    sgen.state = ticks_add(ticks(), t)
+    sgen.state = ticks_add(ticks(), max(0, t))
     return sgen
 
 
-- 
cgit v1.2.3