Messages in this thread | | | Date | Fri, 18 Sep 2020 13:27:59 -0400 | From | Tejun Heo <> | Subject | sched: rq->nr_iowait transiently going negative after the recent p->on_cpu optimization |
| |
Hello,
Peter, I noticed /proc/stat::procs_blocked going U64_MAX transiently once in the blue moon without any other persistent issues. After looking at the code with Rik for a bit, the culprit seems to be c6e7bd7afaeb ("sched/core: Optimize ttwu() spinning on p->on_cpu") - it changed where ttwu dec's nr_iowait and it looks like that can happen before the target task gets to inc.
Thanks.
-- tejun
| |