Messages in this thread | | | Date | Fri, 15 Mar 2019 12:06:43 +0100 | From | luca abeni <> | Subject | Re: WARN ON at kernel/sched/deadline.c task_non_contending |
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Hi,
On Fri, 15 Mar 2019 08:43:00 +0800 "chengjian (D)" <cj.chengjian@huawei.com> wrote: [...] > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > > index 6a73e41a2016..43901fa3f269 100644 > > --- a/kernel/sched/deadline.c > > +++ b/kernel/sched/deadline.c > > @@ -252,7 +252,6 @@ static void task_non_contending(struct > > task_struct *p) if (dl_entity_is_special(dl_se)) > > return; > > > > - WARN_ON(hrtimer_active(&dl_se->inactive_timer)); > > WARN_ON(dl_se->dl_non_contending); > > > > zerolag_time = dl_se->deadline - > > @@ -269,7 +268,7 @@ static void task_non_contending(struct > > task_struct *p) > > * If the "0-lag time" already passed, decrease the active > > * utilization now, instead of starting a timer > > */ > > - if (zerolag_time < 0) { > > + if ((zerolag_time < 0) || > > hrtimer_active(&dl_se->inactive_timer)) { if (dl_task(p)) > > sub_running_bw(dl_se, dl_rq); > > if (!dl_task(p) || p->state == TASK_DEAD) { > > > > > > The idea is that if the timer is active, we leave dl_non_contending > > set to 0 (so that the timer handler does nothing), and we > > immediately decrease the running bw. > > I think this is OK, because this situation can happen only if the > > task blocks, wakes up while the timer handler is running, and then > > immediately blocks again - while the timer handler is still > > running. So, the "zero lag time" cannot be too much in the future. > > > > > > Thanks, > > Luca > > > > . > > > Yeah, it looks good. > > I can do some experiments with it , > > Do you have some testcases to help me with the test ?
I just tried the test you provided... I also have some other SCHED_DEADLINE tests at https://github.com/lucabe72/ReclaimingTests but I did not try them with this patch yet.
Claudio Scordino also had some SCHED_DEADLINE tests here: https://github.com/evidence/test-sched-dl
Luca
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