| Message ID | alpine.DEB.2.02.1404151711250.22697@ionos.tec.linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On wto, 2014-04-15 at 17:20 +0200, Thomas Gleixner wrote: > On Tue, 15 Apr 2014, Krzysztof Kozlowski wrote: > > > On wto, 2014-04-15 at 14:28 +0200, Daniel Lezcano wrote: > > > On 04/15/2014 11:34 AM, Krzysztof Kozlowski wrote: > > > > On pi?, 2014-03-28 at 14:06 +0100, Krzysztof Kozlowski wrote: > > > >> Fix stall after hotplugging CPU1. Affected are SoCs where Multi Core Timer > > > >> interrupts are shared (SPI), e.g. Exynos 4210. The stall was a result of > > > >> starting the CPU1 local timer not in L1 timer but in L0 (which is used > > > >> by CPU0). > > > > > > > > Hi, > > > > > > > > Do you have any comments on these 3 patches? They fix the CPU stall on > > > > Exynos4210 and also on Exynos3250 (Chanwoo Choi sent patches for it > > > > recently). > > > > > > You describe this issue as impacting different SoC not only the exynos, > > > right ? > > > > > > Do you know what other SoCs are impacted by this ? > > > > No, affected are only Exynos SoC-s. It was confirmed on Exynos4210 > > (Trats board) and Exynos3250 (new SoC, patches for it were recently > > posted by Chanwoo). > > > > Other Exynos SoC-s where MCT local timers use shared interrupts (SPI) > > can also be affected. Candidates are Exynos 5250 and 5420 but I haven't > > tested them. > > > > > I guess this issue is not reproducible just with the line below, we need > > > a timer to expire right at the moment CPU1 is hotplugged, right ? > > > > Right. The timer must fire in short time between enabling local timer > > for CPU1 and setting the affinity for IRQ. > > Why do you set the affinity in the CPU_ONLINE hotplug callback and not > right away when the interrupt is requested? Hi, I think the problem in such code is in GIC. The gic_set_affinity() uses cpu_online_mask: unsigned int cpu = cpumask_any_and(mask_val, cpu_online_mask); In that time this CPU is not present in that mask so -EINVAL would be returned. The stall occurred also on 3.10 where the IRQ affinity is set just after setup_irq(): if (cpu == 0) { mct_tick0_event_irq.dev_id = mevt; evt->irq = mct_irqs[MCT_L0_IRQ]; setup_irq(evt->irq, &mct_tick0_event_irq); } else { mct_tick1_event_irq.dev_id = mevt; evt->irq = mct_irqs[MCT_L1_IRQ]; setup_irq(evt->irq, &mct_tick1_event_irq); irq_set_affinity(evt->irq, cpumask_of(1)); } Best regards, Krzysztof > Thanks, > > tglx > > > Index: linux-2.6/drivers/clocksource/exynos_mct.c > =================================================================== > --- linux-2.6.orig/drivers/clocksource/exynos_mct.c > +++ linux-2.6/drivers/clocksource/exynos_mct.c > @@ -430,6 +430,7 @@ static int exynos4_local_timer_setup(str > evt->irq); > return -EIO; > } > + irq_set_affinity(mct_irqs[MCT_L0_IRQ + cpu], cpumask_of(cpu)); > } else { > enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); > } > @@ -461,12 +462,6 @@ static int exynos4_mct_cpu_notify(struct > mevt = this_cpu_ptr(&percpu_mct_tick); > exynos4_local_timer_setup(&mevt->evt); > break; > - case CPU_ONLINE: > - cpu = (unsigned long)hcpu; > - if (mct_int_type == MCT_INT_SPI) > - irq_set_affinity(mct_irqs[MCT_L0_IRQ + cpu], > - cpumask_of(cpu)); > - break; > case CPU_DYING: > mevt = this_cpu_ptr(&percpu_mct_tick); > exynos4_local_timer_stop(&mevt->evt); > > >
Index: linux-2.6/drivers/clocksource/exynos_mct.c =================================================================== --- linux-2.6.orig/drivers/clocksource/exynos_mct.c +++ linux-2.6/drivers/clocksource/exynos_mct.c @@ -430,6 +430,7 @@ static int exynos4_local_timer_setup(str evt->irq); return -EIO; } + irq_set_affinity(mct_irqs[MCT_L0_IRQ + cpu], cpumask_of(cpu)); } else { enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); } @@ -461,12 +462,6 @@ static int exynos4_mct_cpu_notify(struct mevt = this_cpu_ptr(&percpu_mct_tick); exynos4_local_timer_setup(&mevt->evt); break; - case CPU_ONLINE: - cpu = (unsigned long)hcpu; - if (mct_int_type == MCT_INT_SPI) - irq_set_affinity(mct_irqs[MCT_L0_IRQ + cpu], - cpumask_of(cpu)); - break; case CPU_DYING: mevt = this_cpu_ptr(&percpu_mct_tick); exynos4_local_timer_stop(&mevt->evt);