From mboxrd@z Thu Jan 1 00:00:00 1970 From: jiang.liu@linux.intel.com (Jiang Liu) Date: Sun, 6 Sep 2015 16:07:26 +0800 Subject: [RFC PATCH v1 0/4] arm/arm64: fix a migrating irq bug when hotplug cpu In-Reply-To: <1441513421-8092-1-git-send-email-yangyingliang@huawei.com> References: <1441513421-8092-1-git-send-email-yangyingliang@huawei.com> Message-ID: <55EBF43E.8070501@linux.intel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 2015/9/6 12:23, Yang Yingliang wrote: > 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 make it selected by CONFIG_SMP and > CONFIG_HOTPLUG_CPU and rename it to CONFIG_GENERIC_IRQ_MIGRATION for more general. > When CONFIG_GENERIC_IRQ_MIGRATION is enabled, an interrupt whose state_use_accessors > is not set with IRQD_MOVE_PCNTXT won't be migrated immediately in irq_set_affinity_locked(). > So introduce irq_settings_set_move_pcntxt() helper to set the state in gic_irq_domain_map(). > > With the above preparation, move the migrating interrupts code into kernel/irq/migration.c > and fix the bug by using irq_do_set_affinity(). Hi Yingliang, As we are going to move migrate_irqs() to generic kernel code, and powerpc, metag, xtensa, sh, ia64 mn10300 also defines migrate_irqs() too. It would be great if we could consolidate all these. And as we are going to refine these code, there's another issue need attention. On x86, we need to allocate a CPU vector if an irq is directed to a CPU. So there's possibility that we run out of CPU vectors after CPU hot-removal. So we have a mechanism to detect whether we will run out of CPU vector after removing a CPU, and reject CPU hot-removal if that will happen. So the key point is, if we a need to allocate some sort of resource on the target CPUs for an irq, we need two steps when removing a CPU 1) check whether resources are available after removing the CPU, and reject CPU removal request if we ran out of resource 2) fix irqs after hot-removing the CPU. Thanks! Gerry > > Cc: Jiang Liu > Cc: Thomas Gleixner > Cc: Marc Zyngier > Cc: Mark Rutland > Cc: Will Deacon > Cc: Russell King - ARM Linux > Cc: Hanjun Guo > > Yang Yingliang (4): > genirq: Introduce irq_settings_set_move_pcntxt() helper > irqchip: GICv3: set non-percpu irqs status with _IRQ_MOVE_PCNTXT > genirq: rename config GENERIC_PENDING_IRQ to GENERIC_IRQ_MIGRATION > arm/arm64: fix a migrating irq bug when hotplug cpu > > arch/arc/Kconfig | 2 +- > arch/arm/Kconfig | 1 + > arch/arm/include/asm/irq.h | 1 - > arch/arm/kernel/irq.c | 62 ------------------------------------------ > arch/arm64/Kconfig | 1 + > arch/arm64/include/asm/irq.h | 1 - > arch/arm64/kernel/irq.c | 62 ------------------------------------------ > arch/hexagon/Kconfig | 2 +- > arch/ia64/Kconfig | 2 +- > arch/tile/Kconfig | 2 +- > arch/x86/Kconfig | 2 +- > arch/x86/kernel/apic/io_apic.c | 2 +- > drivers/irqchip/irq-gic-v3.c | 2 ++ > include/linux/irq.h | 5 +++- > include/linux/irqdesc.h | 2 +- > kernel/irq/Kconfig | 4 +-- > kernel/irq/Makefile | 2 +- > kernel/irq/irqdesc.c | 18 ++++++++++-- > kernel/irq/manage.c | 2 +- > kernel/irq/migration.c | 62 ++++++++++++++++++++++++++++++++++++++++++ > kernel/irq/proc.c | 2 +- > kernel/irq/settings.h | 5 ++++ > 22 files changed, 102 insertions(+), 142 deletions(-) >