Messages in this thread Patch in this message | | | Date | Wed, 9 Mar 2022 10:20:57 +0000 | Subject | Re: [PATCH] genirq/msi: Shutdown managed interrupts with unsatifiable affinities | From | John Garry <> |
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On 07/03/2022 19:06, Marc Zyngier wrote: > When booting with maxcpus=<small number>, interrupt controllers > such as the GICv3 ITS may not be able to satisfy the affinity of > some managed interrupts, as some of the HW resources are simply > not available. > > In order to deal with this, do not try to activate such interrupt > if there is no online CPU capable of handling it. Instead, place > it in shutdown state. Once a capable CPU shows up, it will be > activated. > > Reported-by: John Garry <john.garry@huawei.com> > Reported-by: David Decotigny <ddecotig@google.com> > Signed-off-by: Marc Zyngier <maz@kernel.org>
Tested-by: John Garry <john.garry@huawei.com>
> ---
JFYI, I could not recreate the same crash reported in the original thread for "nohz_full=5-127 isolcpus=nohz,domain,managed_irq,5-127 maxcpus=1". Here's just showing what I set via cmdline:
estuary:/$ dmesg | grep -i hz [ 0.000000] Kernel command line: BOOT_IMAGE=/john/Image rdinit=/init console=ttyS0,115200 no_console_suspend nvme.use_threaded_interrupts=0 iommu.strict=0 acpi=force earlycon=pl011,mmio32,0x602b0000 nohz_full=5-127 isolcpus=nohz,domain,managed_irq,5-127 maxcpus=1 [ 0.000000] NO_HZ: Full dynticks CPUs: 5-127. [ 0.000000] arch_timer: cp15 timer(s) running at 100.00MHz (phys). [ 0.000000] sched_clock: 57 bits at 100MHz, resolution 10ns, wraps every 4398046511100ns [ 15.314258] sbsa-gwdt sbsa-gwdt.0: Initialized with 10s timeout @ 100000000 Hz, action=0
And for the kernel build: $ more .config | grep NO_HZ CONFIG_NO_HZ_COMMON=y # CONFIG_NO_HZ_IDLE is not set CONFIG_NO_HZ_FULL=y # CONFIG_NO_HZ is not set $
Thanks, John > kernel/irq/msi.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c > index 2bdfce5edafd..aa84ce84c2ec 100644 > --- a/kernel/irq/msi.c > +++ b/kernel/irq/msi.c > @@ -818,6 +818,18 @@ static int msi_init_virq(struct irq_domain *domain, int virq, unsigned int vflag > irqd_clr_can_reserve(irqd); > if (vflags & VIRQ_NOMASK_QUIRK) > irqd_set_msi_nomask_quirk(irqd); > + > + /* > + * If the interrupt is managed but no CPU is available > + * to service it, shut it down until better times. > + */ > + if ((vflags & VIRQ_ACTIVATE) && > + irqd_affinity_is_managed(irqd) && > + !cpumask_intersects(irq_data_get_affinity_mask(irqd), > + cpu_online_mask)) { > + irqd_set_managed_shutdown(irqd); > + return 0; > + } > } > > if (!(vflags & VIRQ_ACTIVATE))
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