On 5/20/20 8:38 PM, Juri Lelli wrote: > Hi Peter, > > On 26/07/19 16:54, Peter Zijlstra wrote: >> Cc: Daniel Bristot de Oliveira <[email protected]> >> Cc: Luca Abeni <[email protected]> >> Cc: Juri Lelli <[email protected]> >> Cc: Dmitry Vyukov <[email protected]> >> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> >> --- >> 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 >> + * 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 */ >> + >> +/* >> * This function validates the new parameters of a -deadline task. >> * We ask for the deadline not being zero, and greater or equal >> * than the runtime, as well as the period of being zero or >> @@ -2608,6 +2616,8 @@ void __getparam_dl(struct task_struct *p >> */ >> bool __checkparam_dl(const struct sched_attr *attr) >> { >> + u64 period, max, min; >> + >> /* special dl tasks don't actually use any parameter */ >> if (attr->sched_flags & SCHED_FLAG_SUGOV) >> return true; >> @@ -2631,12 +2641,21 @@ bool __checkparam_dl(const struct sched_ >> attr->sched_period & (1ULL << 63)) >> return false; >> >> + period = attr->sched_period; >> + if (!period) >> + period = attr->sched_deadline; >> + >> /* runtime <= deadline <= period (if period != 0) */ >> - if ((attr->sched_period != 0 && >> - attr->sched_period < attr->sched_deadline) || >> + if (period < attr->sched_deadline || >> attr->sched_deadline < attr->sched_runtime) >> return false; >> >> + max = (u64)READ_ONCE(sysctl_sched_dl_period_max) * NSEC_PER_USEC; >> + min = (u64)READ_ONCE(sysctl_sched_dl_period_min) * NSEC_PER_USEC; >> + >> + if (period < min || period > max) >> + return false; >> + >> return true; >> } >> >> --- a/kernel/sysctl.c >> +++ b/kernel/sysctl.c >> @@ -443,6 +443,20 @@ static struct ctl_table kern_table[] = { >> .proc_handler = sched_rt_handler, >> }, >> { >> + .procname = "sched_deadline_period_max_us", >> + .data = &sysctl_sched_dl_period_max, >> + .maxlen = sizeof(unsigned int), >> + .mode = 0644, >> + .proc_handler = proc_dointvec, >> + }, >> + { >> + .procname = "sched_deadline_period_min_us", >> + .data = &sysctl_sched_dl_period_min, >> + .maxlen = sizeof(unsigned int), >> + .mode = 0644, >> + .proc_handler = proc_dointvec, >> + }, >> + { >> .procname = "sched_rr_timeslice_ms", >> .data = &sysctl_sched_rr_timeslice, >> .maxlen = sizeof(int), > I think this never made it upstream. And I believe both me and Daniel > were OK with it. Do you recall if any additional change was needed?
Just to confirm, yes I am OK with it! -- Daniel
