Messages in this thread Patch in this message | | | From | Dietmar Eggemann <> | Subject | [PATCH] ARM: irq: Add IRQ_SET_MASK_OK_DONE handling in migrate_one_irq() | Date | Tue, 8 Jan 2019 13:58:05 +0000 |
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Arm TC2 (multi_v7_defconfig plus CONFIG_ARM_BIG_LITTLE_CPUFREQ=y and CONFIG_ARM_VEXPRESS_SPC_CPUFREQ=y) fails hotplug stress tests.
This issue was tracked down to a missing copy of the new affinity cpumask of the vexpress-spc interrupt into struct irq_common_data.affinity when the interrupt is migrated in migrate_one_irq().
Commit 0407daceedfe ("irqchip/gic: Return IRQ_SET_MASK_OK_DONE in the set_affinity method") changed the return value of the irq_set_affinity() function of the GIC from IRQ_SET_MASK_OK to IRQ_SET_MASK_OK_DONE.
In migrate_one_irq() if the current irq affinity mask and the cpu online mask do not share any CPU, the affinity mask is set to the cpu online mask. In this case (ret == true) and when the irq chip function irq_set_affinity() returns successfully (IRQ_SET_MASK_OK), struct irq_common_data.affinity should also be updated.
Add IRQ_SET_MASK_OK_DONE next to IRQ_SET_MASK_OK when checking that the irq chip function irq_set_affinity() returns successfully.
Commit 2cb625478f8c ("genirq: Add IRQ_SET_MASK_OK_DONE to support stacked irqchip") only added IRQ_SET_MASK_OK_DONE handling to irq_do_set_affinity() in the irq core and not to the Arm32 irq code.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> ---
The hotplug issue on Arm TC2 happens because the vexpress-spc interrupt (irq=22) is affine to CPU0. This occurs since it is setup early when the cpu_online_mask is still 0. But the problem with the missing copy of the affinity mask should occur with every interrupt which is forced to migrate.
With additional debug in irq_setup_affinity():
[0.000619] irq_setup_affinity(): irq=17 mask=0 cpu_online_mask=0 set=0-4 [0.007065] irq_setup_affinity(): irq=22 mask=0 cpu_online_mask=0 set=0-4 [3.372907] irq_setup_affinity(): irq=47 mask=0-4 cpu_online_mask=0-4 set=0-4
cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 CPU4 22: 316 0 0 0 0 GIC-0 127 Level vexpress-spc
cat /proc/irq/22/smp_affinity_list 0
arch/arm/kernel/irq.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c index 9908dacf9229..ddb828b0235b 100644 --- a/arch/arm/kernel/irq.c +++ b/arch/arm/kernel/irq.c @@ -117,6 +117,7 @@ static bool migrate_one_irq(struct irq_desc *desc) const struct cpumask *affinity = irq_data_get_affinity_mask(d); struct irq_chip *c; bool ret = false; + int ret2; /* * If this is a per-CPU interrupt, or the affinity does not @@ -131,9 +132,14 @@ static bool migrate_one_irq(struct irq_desc *desc) } c = irq_data_get_irq_chip(d); - if (!c->irq_set_affinity) + if (!c->irq_set_affinity) { pr_debug("IRQ%u: unable to set affinity\n", d->irq); - else if (c->irq_set_affinity(d, affinity, false) == IRQ_SET_MASK_OK && ret) + return ret; + } + + ret2 = c->irq_set_affinity(d, affinity, false); + + if ((ret2 == IRQ_SET_MASK_OK || ret2 == IRQ_SET_MASK_OK_DONE) && ret) cpumask_copy(irq_data_get_affinity_mask(d), affinity); return ret; -- 2.11.0
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