Messages in this thread |  | | Date | Mon, 29 Jul 2019 10:57:11 +0200 | From | Juri Lelli <> | Subject | Re: [RFC][PATCH 01/13] sched/deadline: Impose global limits on sched_attr::sched_period |
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Hi,
On 26/07/19 16:54, Peter Zijlstra wrote: > > Cc: Daniel Bristot de Oliveira <bristot@redhat.com> > Cc: Luca Abeni <luca.abeni@santannapisa.it> > Cc: Juri Lelli <juri.lelli@redhat.com> > Cc: Dmitry Vyukov <dvyukov@google.com> > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > --- > include/linux/sched/sysctl.h | 3 +++ > kernel/sched/deadline.c | 23 +++++++++++++++++++++-- > kernel/sysctl.c | 14 ++++++++++++++ > 3 files changed, 38 insertions(+), 2 deletions(-) > > --- a/include/linux/sched/sysctl.h > +++ b/include/linux/sched/sysctl.h > @@ -56,6 +56,9 @@ int sched_proc_update_handler(struct ctl > extern unsigned int sysctl_sched_rt_period; > extern int sysctl_sched_rt_runtime; > > +extern unsigned int sysctl_sched_dl_period_max; > +extern unsigned int sysctl_sched_dl_period_min; > + > #ifdef CONFIG_UCLAMP_TASK > extern unsigned int sysctl_sched_uclamp_util_min; > extern unsigned int sysctl_sched_uclamp_util_max; > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -2597,6 +2597,14 @@ void __getparam_dl(struct task_struct *p > } > > /* > + * Default limits for DL period; on the top end we guard against small util > + * tasks still getting rediculous long effective runtimes, on the bottom end we
s/rediculous/ridiculous/
> + * guard against timer DoS. > + */ > +unsigned int sysctl_sched_dl_period_max = 1 << 22; /* ~4 seconds */ > +unsigned int sysctl_sched_dl_period_min = 100; /* 100 us */
These limits look sane to me. I've actually been experimenting with 10us period tasks and throttling seemed to behave fine, but I guess 100us is a saner default.
So, (with a few lines of changelog :)
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Thanks for doing this.
Best,
Juri
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