ref: 6756597802c0890d163f2b698eabebef13c1cc2e
parent: 99844f8e63ab750786ce25d3384444dd4b216318
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Mon Sep 17 20:53:05 EDT 2018
kernel: fix livelock in rebalance (thanks Richard Miller) Once a second rebalance() is called on cpu0 to adjust priorities, so cpu-bound processes won't lock others out. However it was only adjusting processes which were running on cpu0. This was observed to lead to livelock, eg when a higher-priority process spin-waits for a lock held by a lower priority one.
--- a/sys/src/9/port/proc.c
+++ b/sys/src/9/port/proc.c
@@ -478,8 +478,6 @@
p = rq->head;
if(p == nil)
continue;
- if(p->mp != MACHP(m->machno))
- continue;
if(pri == p->basepri)
continue;
updatecpu(p);
--
⑨