Quoting Peter Zijlstra (2020-07-23 19:28:41) > On Wed, Jul 22, 2020 at 10:57:56AM +0100, Chris Wilson wrote: > > > Perhaps more damning is that I can replace WF_ON_CPU with p->on_cpu to > > suppress the warning: > > *argh*, I'm starting to go mad... > > Chris, could you please try the below patch?
ttwu-IPI-self: 1==1, p->on_cpu=0;0, task_cpu(p)=1;1 ttwu-IPI-self: 1==1, p->on_cpu=0;0, task_cpu(p)=1;1 ttwu-IPI-self: 0==0, p->on_cpu=0;0, task_cpu(p)=0;0 ttwu-IPI-self: 3==3, p->on_cpu=0;0, task_cpu(p)=3;3 ttwu-IPI-self: 2==2, p->on_cpu=0;0, task_cpu(p)=2;2 ttwu-IPI-self: 1==1, p->on_cpu=0;0, task_cpu(p)=1;1 ttwu-IPI-self: 2==2, p->on_cpu=0;0, task_cpu(p)=2;2 ttwu-IPI-self: 2==2, p->on_cpu=0;0, task_cpu(p)=2;2 ttwu-IPI-self: 2==2, p->on_cpu=0;0, task_cpu(p)=2;2 > Can you also confirm that if you do: > > $ echo NO_TTWU_QUEUE_ON_CPU > /debug/sched_features With, sched_feat_disable(10):TTWU_QUEUE_ON_CPU the pr_alert is still being hit ttwu-IPI-self: 3==3, p->on_cpu=0;0, task_cpu(p)=3;3 At which point, it darns on me. Mea culpa, stray bits being passed into default_wake_function. I am very sorry for the wild goose chase. -Chris