On 2023-10-06 at 21:24:45 +0200, Peter Zijlstra wrote: > On Fri, Oct 06, 2023 at 05:55:01PM +0200, Peter Zijlstra wrote: > > > And yeah, min_deadline is hosed somehow. > > > > migration/28-185 [028] d..2. 70.264274: validate_cfs_rq: --- / > > migration/28-185 [028] d..2. 70.264277: __print_se: ffff88845cf48080 w: 1024 ve: -58857638 lag: 870381 vd: -55861854 vmd: -66302085 E (11372/tr) > > migration/28-185 [028] d..2. 70.264280: __print_se: ffff88810d165800 w: 25 ve: -80323686 lag: 22336429 vd: -41496434 vmd: -66302085 E (-1//autogroup-31) > > migration/28-185 [028] d..2. 70.264282: __print_se: ffff888108379000 w: 25 ve: 0 lag: -57987257 vd: 114632828 vmd: 114632828 N (-1//autogroup-33) > > migration/28-185 [028] d..2. 70.264283: validate_cfs_rq: min_deadline: -55861854 avg_vruntime: -62278313462 / 1074 = -57987256 > > > > I need to go make dinner (kids hungry), but I'll see if I can figure out > > how this happens... > > *sigh*, does the below help? > > --- > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 04fbcbda97d5..6a670f119efa 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -3632,6 +3747,7 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, > */ > deadline = div_s64(deadline * old_weight, weight); > se->deadline = se->vruntime + deadline; > + min_deadline_cb_propagate(&se->run_node, NULL); > } > > #ifdef CONFIG_SMP Is it because without this patch, the se->deadline is not always synced with se->min_deadline, then in pick_eevdf() the following condition could not be met, thus we get a NULL candidate and has to pick the leftmost one? if (se->deadline == se->min_deadline) Regarding the circular locking warning triggered by printk, does it mean we should not get a NULL candidate from __pick_eevdf() in theory? And besides, we should not use printk with rq lock hold? thanks, Chenyu
