Messages in this thread Patch in this message | | | From | Thomas Gleixner <> | Subject | Re: [PATCH v3 3/3] genirq: Use the maple tree for IRQ descriptors management | Date | Mon, 08 May 2023 11:36:37 +0200 |
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Yujie!
On Sun, May 07 2023 at 16:05, Yujie Liu wrote: > Sorry for late reply as we were on public holiday earlier this week.
Holidays are more important and the problems do not run away :)
> On Fri, Apr 28, 2023 at 12:31:14PM +0200, Thomas Gleixner wrote: >> Under the assumption that the code is correct, then the effect of this >> patch is that it changes the timing. Sigh. >> >> 1) Does this happen with a 64-bit kernel too? > > It doesn't happen on a 64-bit kernel:
Ok. So one difference might be that a 64 bit kernel enables interrupt rempping. Can you add 'intremap=off' to the kernel command line please?
>> 2) Can you enable the irq_vector:vector_*.* tracepoints and provide >> the trace? > > I'm a beginner of kernel and not sure if I'm doing this correctly. Here > are my test steps:
They are perfectly fine.
> # check the trace > # cat /sys/kernel/debug/tracing/trace > # tracer: nop > # > # entries-in-buffer/entries-written: 0/0 #P:4 > # > # _-----=> irqs-off/BH-disabled > # / _----=> need-resched > # | / _---=> hardirq/softirq > # || / _--=> preempt-depth > # ||| / _-=> migrate-disable > # |||| / delay > # TASK-PID CPU# ||||| TIMESTAMP FUNCTION > # | | | ||||| | | > > Nothing was written to trace buffer, seems like no irq_vector events > were captured during this test.
Stupid me. I completely forgot that this happens on the outgoing CPU at a point where the tracer for that CPU is already shut down.
Can you please apply the patch below? No need to enable the irq_vector events. It just dumps the information into dmesg.
Thanks,
tglx --- --- a/kernel/irq/cpuhotplug.c +++ b/kernel/irq/cpuhotplug.c @@ -57,7 +57,8 @@ static bool migrate_one_irq(struct irq_d bool maskchip = !irq_can_move_pcntxt(d) && !irqd_irq_masked(d); const struct cpumask *affinity; bool brokeaff = false; - int err; + int err, irq = d->irq; + bool move_pending; /* * IRQ chip might be already torn down, but the irq descriptor is @@ -101,10 +102,16 @@ static bool migrate_one_irq(struct irq_d * there is no move pending or the pending mask does not contain * any online CPU, use the current affinity mask. */ - if (irq_fixup_move_pending(desc, true)) + move_pending = irqd_is_setaffinity_pending(d); + if (irq_fixup_move_pending(desc, true)) { affinity = irq_desc_get_pending_mask(desc); - else + pr_info("IRQ %3d: move_pending=%d pending mask: %*pbl\n", + irq, move_pending, cpumask_pr_args(affinity)); + } else { affinity = irq_data_get_affinity_mask(d); + pr_info("IRQ %3d: move_pending=%d affinity mask: %*pbl\n", + irq, move_pending, cpumask_pr_args(affinity)); + } /* Mask the chip for interrupts which cannot move in process context */ if (maskchip && chip->irq_mask) @@ -136,6 +143,9 @@ static bool migrate_one_irq(struct irq_d brokeaff = false; } + affinity = irq_data_get_effective_affinity_mask(d); + pr_info("IRQ %3d: Done: %*pbl\n", irq, cpumask_pr_args(affinity)); + if (maskchip && chip->irq_unmask) chip->irq_unmask(d);
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