[RFC PATCH v5 0/4] arm/arm64: fix a migrating irq bug when hotplug cpu

From: Yang Yingliang
Date: Fri Sep 18 2015 - 23:08:29 EST


----
Changes in v5:
- remove the macro that guard move_irqs()
- use name irq_migrate_all_off_this_cpu instead of move_irqs

Changes in v4:
- select GENERIC_IRQ_MIGRATION when config GENERIC_IRQ_MIGRATION is enabled
- add move_irqs() into kerne/irq/migration.c for cpu hotplug
- use move_irqs() to migrate interrupts on arm/arm64 when cpu is going to down
- split bugfix patch into seperate patches for arm and arm64

Changes in v3:
- introduce config GENERIC_IRQ_MIGRATION for compiling migration.c
- rename migrate_irqs in arch/ia64/kernel/irq.c to avoid compiling error

Changes in v2:
- use the exiting helper to set IRQD_MOVE_PCNTXT flag
- use for_each_active_irq() instead of for_each_irq_desc()
- add some warn messages when affinity is null or do set affinity failed
----

Hi All,

There is a bug:

When cpu is disabled, all irqs will be migratged to another cpu.
In some cases, a new affinity is different, it needed to be coppied
to irq's affinity. But if the type of irq is LPI, it's affinity will
not be coppied because of irq_set_affinity's return value.



As Marc and Will suggested, I refactor the arm/arm64 migrating interrupts
code and fix the migrating irq bug while cpu is offline.

I'm trying let the core code do the migrating interrupts matter. kernel/irq/migration.c
depends on CONFIG_GENERIC_PENDING_IRQ, so I introduce config GENERIC_IRQ_MIGRATION for
compiling migration.c. Then add a generic function for migrating interrupts in migration.c.
And then use the function when cpu is going to down on arm and arm64.


Cc: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx>
Cc: Hanjun Guo <hanjun.guo@xxxxxxxxxx>

Yang Yingliang (4):
genirq: introduce CONFIG_GENERIC_IRQ_MIGRATION
genirq: add irq_migrate_all_off_this_cpu() for cpu hotplug
arm64: fix a migrating irq bug when hotplug cpu
arm: fix a migrating irq bug when hotplug cpu

arch/arm/Kconfig | 1 +
arch/arm/include/asm/irq.h | 1 -
arch/arm/kernel/irq.c | 62 -----------------------------------------
arch/arm/kernel/smp.c | 2 +-
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/irq.h | 1 -
arch/arm64/kernel/irq.c | 62 -----------------------------------------
arch/arm64/kernel/smp.c | 2 +-
include/linux/irq.h | 2 ++
kernel/irq/Kconfig | 5 ++++
kernel/irq/Makefile | 2 +-
kernel/irq/migration.c | 66 ++++++++++++++++++++++++++++++++++++++++++++
12 files changed, 78 insertions(+), 129 deletions(-)

--
2.5.0


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