| Message ID | 1442631959-10228-3-git-send-email-yangyingliang@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, 19 Sep 2015 11:05:57 +0800 Yang Yingliang <yangyingliang@huawei.com> wrote: > Add irq_migrate_all_off_this_cpu() into kernel/irq/migration.c. > So we can use it to migrate interrupts, when cpu is offline. > > Cc: Jiang Liu <jiang.liu@linux.intel.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Marc Zyngier <marc.zyngier@arm.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> > Cc: Hanjun Guo <hanjun.guo@linaro.org> > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> M.
On Sat, 19 Sep 2015, Yang Yingliang wrote:
> Add irq_migrate_all_off_this_cpu() into kernel/irq/migration.c.
This doesn't make any sense at all.
You just reuse the existing file to stick your new code into it
without reusing a single bit in that file. Aside of that it's
unconditionally compiled, which means all existing users of
CONFIG_GENERIC_PENDING_IRQ are burdened with pointless code.
The right thing to do is:
Add that code to a new file: kernel/irq/cpuhotplug.c and make that
depend on CONFIG_GENERIC_IRQ_MIGRATION.
Thanks,
tglx
On 2015/9/23 2:54, Thomas Gleixner wrote: > On Sat, 19 Sep 2015, Yang Yingliang wrote: > >> Add irq_migrate_all_off_this_cpu() into kernel/irq/migration.c. > > This doesn't make any sense at all. > > You just reuse the existing file to stick your new code into it > without reusing a single bit in that file. Aside of that it's > unconditionally compiled, which means all existing users of > CONFIG_GENERIC_PENDING_IRQ are burdened with pointless code. > > The right thing to do is: > > Add that code to a new file: kernel/irq/cpuhotplug.c and make that > depend on CONFIG_GENERIC_IRQ_MIGRATION. How about add #ifdef CONFIG_CPU_HOTPLUG around new code in kernel/irq/migration.c ? Thanks, Yang
On Wed, 23 Sep 2015, Yang Yingliang wrote: > On 2015/9/23 2:54, Thomas Gleixner wrote: > > On Sat, 19 Sep 2015, Yang Yingliang wrote: > > > > > Add irq_migrate_all_off_this_cpu() into kernel/irq/migration.c. > > > > This doesn't make any sense at all. > > > > You just reuse the existing file to stick your new code into it > > without reusing a single bit in that file. Aside of that it's > > unconditionally compiled, which means all existing users of > > CONFIG_GENERIC_PENDING_IRQ are burdened with pointless code. > > > > The right thing to do is: > > > > Add that code to a new file: kernel/irq/cpuhotplug.c and make that > > depend on CONFIG_GENERIC_IRQ_MIGRATION. > > How about add #ifdef CONFIG_CPU_HOTPLUG around new code > in kernel/irq/migration.c ? What's the point? Just to have useless churn and ifdeffery in that file for nothing? Thanks, tglx
diff --git a/include/linux/irq.h b/include/linux/irq.h index 6f8b340..c111fa1 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -438,6 +438,8 @@ extern int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *cpumask, bool force); extern int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info); +extern void irq_migrate_all_off_this_cpu(void); + #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_PENDING_IRQ) void irq_move_irq(struct irq_data *data); void irq_move_masked_irq(struct irq_data *data); diff --git a/kernel/irq/migration.c b/kernel/irq/migration.c index 1ff2b77..6e3e38d 100644 --- a/kernel/irq/migration.c +++ b/kernel/irq/migration.c @@ -1,6 +1,7 @@ #include <linux/irq.h> #include <linux/interrupt.h> +#include <linux/ratelimit.h> #include "internals.h" @@ -79,3 +80,66 @@ void irq_move_irq(struct irq_data *idata) idata->chip->irq_unmask(idata); } #endif + +static bool migrate_one_irq(struct irq_desc *desc) +{ + struct irq_data *d = irq_desc_get_irq_data(desc); + const struct cpumask *affinity = d->affinity; + struct irq_chip *c; + bool ret = false; + + /* + * If this is a per-CPU interrupt, or the affinity does not + * include this CPU, then we have nothing to do. + */ + if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity)) + return false; + + if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) { + affinity = cpu_online_mask; + ret = true; + } + + c = irq_data_get_irq_chip(d); + if (!c->irq_set_affinity) { + pr_warn_ratelimited("IRQ%u: unable to set affinity\n", d->irq); + } else { + int r = irq_do_set_affinity(d, affinity, false); + if (r) + pr_warn_ratelimited("IRQ%u: set affinity failed(%d).\n", d->irq, r); + } + + return ret; +} + +/* + * The current CPU has been marked offline. Migrate IRQs off this CPU. + * If the affinity settings do not allow other CPUs, force them onto any + * available CPU. + * + * Note: we must iterate over all IRQs, whether they have an attached + * action structure or not, as we need to get chained interrupts too. + */ +void irq_migrate_all_off_this_cpu(void) +{ + unsigned int irq; + struct irq_desc *desc; + unsigned long flags; + + local_irq_save(flags); + + for_each_active_irq(irq) { + bool affinity_broken; + + desc = irq_to_desc(irq); + raw_spin_lock(&desc->lock); + affinity_broken = migrate_one_irq(desc); + raw_spin_unlock(&desc->lock); + + if (affinity_broken) + pr_warn_ratelimited("IRQ%u no longer affine to CPU%u\n", + irq, smp_processor_id()); + } + + local_irq_restore(flags); +}
Add irq_migrate_all_off_this_cpu() into kernel/irq/migration.c. So we can use it to migrate interrupts, when cpu is offline. Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> Cc: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- include/linux/irq.h | 2 ++ kernel/irq/migration.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 66 insertions(+)