On Wednesday 11 October 2017 06:35:33 Sebastian Andrzej Siewior wrote: > Dear RT folks! > > I'm pleased to announce the v4.11.12-rt15 patch set. > > Changes since v4.11.12-rt14: > > - Programmed wake ups (nanosleep, clock_nanosleep, …) by a task with > RT priority will still be carried out in the hardirq context > (nothing changes). If it is programmed by task with a normal > priority then the wake up will be carried out in the softirq > context via the ktimersoftd thread. > The advantage is that multiple wake ups of non-RT tasks won't > disturb the RT task. Reported by Gratian Crisan. > > - Paul Gortmaker reported splat during boot when TSC (on x86) > becomes unstable and kernel switches to an alternative. This has been > fixed by cherry-picking a patch from upstream. > > - After the hrtimer rework, certain wake ups (like those programmed > in the past using the softirq context) won't fire. Reported by Mike > Galbraith, patched by Anna-Maria Gleixner. > > - After the hrtimer rework, wake ups using CLOCK_REALTIME and a > relative delay were affected by clock_settime() (they should have > not been). Reported by Mike Galbraith. > > Known issues > None > > The delta patch against v4.11.12-rt14 is appended below and can be > found here: > > > https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.11/incr/patch-4. >11.12-rt14-rt15.patch.xz > > You can get this release via the git tree at: > > > git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git > v4.11.12-rt15 > > The RT patch against v4.11.12 can be found here: > > > https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.11/older/patch-4 >.11.12-rt15.patch.xz > > The split quilt queue is available at: > > > https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.11/older/patches >-4.11.12-rt15.tar.xz > > Sebastian > diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c > --- a/kernel/sched/clock.c > +++ b/kernel/sched/clock.c > @@ -124,6 +124,12 @@ int sched_clock_stable(void) > return static_branch_likely(&__sched_clock_stable); > } > > +static void __scd_stamp(struct sched_clock_data *scd) > +{ > + scd->tick_gtod = ktime_get_ns(); > + scd->tick_raw = sched_clock(); > +} > + > static void __set_sched_clock_stable(void) > { > struct sched_clock_data *scd; > @@ -148,8 +154,37 @@ static void __set_sched_clock_stable(void) > tick_dep_clear(TICK_DEP_BIT_CLOCK_UNSTABLE); > } > > +/* > + * If we ever get here, we're screwed, because we found out -- > typically after + * the fact -- that TSC wasn't good. This means all > our clocksources (including + * ktime) could have reported wrong > values. > + * > + * What we do here is an attempt to fix up and continue sort of where > we left + * off in a coherent manner. > + * > + * The only way to fully avoid random clock jumps is to boot with: > + * "tsc=unstable". > + */ > static void __sched_clock_work(struct work_struct *work) > { > + struct sched_clock_data *scd; > + int cpu; > + > + /* take a current timestamp and set 'now' */ > + preempt_disable(); > + scd = this_scd(); > + __scd_stamp(scd); > + scd->clock = scd->tick_gtod + __gtod_offset; > + preempt_enable(); > + > + /* clone to all CPUs */ > + for_each_possible_cpu(cpu) > + per_cpu(sched_clock_data, cpu) = *scd; > + > + printk(KERN_INFO "sched_clock: Marking unstable (%lld, %lld)<-(%lld, > %lld)\n", + scd->tick_gtod, __gtod_offset, > + scd->tick_raw, __sched_clock_offset); > + > static_branch_disable(&__sched_clock_stable); > } > > @@ -157,27 +192,11 @@ static DECLARE_WORK(sched_clock_work, > __sched_clock_work); > > static void __clear_sched_clock_stable(void) > { > - struct sched_clock_data *scd = this_scd(); > - > - /* > - * Attempt to make the stable->unstable transition continuous. > - * > - * Trouble is, this is typically called from the TSC watchdog > - * timer, which is late per definition. This means the tick > - * values can already be screwy. > - * > - * Still do what we can. > - */ > - __gtod_offset = (scd->tick_raw + __sched_clock_offset) - > (scd->tick_gtod); - > - printk(KERN_INFO "sched_clock: Marking unstable (%lld, %lld)<-(%lld, > %lld)\n", - scd->tick_gtod, __gtod_offset, > - scd->tick_raw, __sched_clock_offset); > + if (!sched_clock_stable()) > + return; > > tick_dep_set(TICK_DEP_BIT_CLOCK_UNSTABLE); > - > - if (sched_clock_stable()) > - schedule_work(&sched_clock_work); > + schedule_work(&sched_clock_work); > } > > void clear_sched_clock_stable(void) > @@ -364,8 +383,7 @@ void sched_clock_tick(void) > * XXX arguably we can skip this if we expose > tsc_clocksource_reliable */ > scd = this_scd(); > - scd->tick_raw = sched_clock(); > - scd->tick_gtod = ktime_get_ns(); > + __scd_stamp(scd); > > if (!sched_clock_stable() && likely(sched_clock_running)) > sched_clock_local(scd); > diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c > --- a/kernel/time/hrtimer.c > +++ b/kernel/time/hrtimer.c > @@ -562,8 +562,14 @@ static inline ktime_t hrtimer_update_base(struct > hrtimer_cpu_base *base) ktime_t *offs_boot = > &base->clock_base[HRTIMER_BASE_BOOTTIME].offset; ktime_t *offs_tai = > &base->clock_base[HRTIMER_BASE_TAI].offset; > > - return ktime_get_update_offsets_now(&base->clock_was_set_seq, > + ktime_t now = ktime_get_update_offsets_now(&base->clock_was_set_seq, > offs_real, offs_boot, offs_tai); > + > + base->clock_base[HRTIMER_BASE_REALTIME_SOFT].offset = *offs_real; > + base->clock_base[HRTIMER_BASE_BOOTTIME_SOFT].offset = *offs_boot; > + base->clock_base[HRTIMER_BASE_TAI_SOFT].offset = *offs_tai; > + > + return now; > } > > /* > @@ -1252,6 +1258,8 @@ static void __hrtimer_init(struct hrtimer > *timer, clockid_t clock_id, clock_id = CLOCK_MONOTONIC; > else if (clock_id == CLOCK_REALTIME_SOFT) > clock_id = CLOCK_MONOTONIC_SOFT; > + else if (clock_id == CLOCK_REALTIME_HARD) > + clock_id = CLOCK_MONOTONIC_HARD; > } > > base = hrtimer_clockid_to_base(clock_id); > @@ -1622,14 +1630,31 @@ static enum hrtimer_restart > hrtimer_wakeup(struct hrtimer *timer) return HRTIMER_NORESTART; > } > > +#ifdef CONFIG_PREEMPT_RT_FULL > +static bool task_is_elevated(struct task_struct *tsk) > +{ > + int policy = tsk->policy; > + > + if (policy == SCHED_FIFO || policy == SCHED_RR) > + return true; > + if (policy == SCHED_DEADLINE) > + return true; > + return false; > +} > +#endif > + > static void __hrtimer_init_sleeper(struct hrtimer_sleeper *sl, > clockid_t clock_id, > enum hrtimer_mode mode, > struct task_struct *task) > { > #ifdef CONFIG_PREEMPT_RT_FULL > - if (!(clock_id & HRTIMER_BASE_SOFT_MASK)) > - clock_id |= HRTIMER_BASE_HARD_MASK; > + if (!(clock_id & (HRTIMER_BASE_HARD_MASK | HRTIMER_BASE_SOFT_MASK))) > { + if (task_is_elevated(current) || system_state != SYSTEM_RUNNING) > + clock_id |= HRTIMER_BASE_HARD_MASK; > + else > + clock_id |= HRTIMER_BASE_SOFT_MASK; > + } > #endif > __hrtimer_init(&sl->timer, clock_id, mode); > sl->timer.function = hrtimer_wakeup; > diff --git a/localversion-rt b/localversion-rt > --- a/localversion-rt > +++ b/localversion-rt > @@ -1 +1 @@ > --rt14 > +-rt15 > -- > To unsubscribe from this list: send the line "unsubscribe > linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html Neat, and newer than the kernel.org release by several steps, its 4.10-rc3, so where can I get the whole thing, ready for a make menu|x|g| config? I am trying to make linuxcnc run on a rock64, its so new you can still smell the paint. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
