| Message ID | 1409581297-29216-1-git-send-email-sudeep.holla@arm.com |
|---|---|
| State | Accepted |
| Commit | a040803a9d6b8c1876d3487a5cb69602ebcbb82c |
| Headers | show |
On Mon, Sep 01, 2014 at 03:21:37PM +0100, Sudeep Holla wrote: > From: Sudeep Holla <sudeep.holla@arm.com> > > Since commit 1dbfa187dad ("ARM: irq migration: force migration off CPU > going down") the ARM interrupt migration code on cpu offline calls > irqchip.irq_set_affinity() with the argument force=true. At the point > of this change the argument had no effect because it was not used by > any interrupt chip driver and there was no semantics defined. > > This changed with commit 01f8fa4f01d8 ("genirq: Allow forcing cpu > affinity of interrupts") which made the force argument useful to route > interrupts to not yet online cpus without checking the target cpu > against the cpu online mask. The following commit ffde1de64012 > ("irqchip: gic: Support forced affinity setting") implemented this for > the GIC interrupt controller. > > As a consequence the ARM cpu offline irq migration fails if CPU0 is > offlined, because CPU0 is still set in the affinity mask and the > validataion against cpu online mask is skipped to the force argument > being true. The following first_cpu(mask) selection always selects > CPU0 as the target. > > Solve the issue by calling irq_set_affinity() with force=false from > the CPU offline irq migration code so the GIC driver validates the > affinity mask against CPU online mask and therefore removes CPU0 from > the possible target candidates. > > Tested on TC2 hotpluging CPU0 in and out. Without this patch the system > locks up as the IRQs are not migrated away from CPU0. > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > Acked-by: Thomas Gleixner <tglx@linutronix.de> > Cc: Russell King <linux@arm.linux.org.uk> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: <stable@vger.kernel.org> # 3.10.x Acked-by: Mark Rutland <mark.rutland@arm.com> It's nice to finally know what we should be doing here. :) Would you be able to take a look at doing the same for arm64? The current solution (now in -stable) allows for hotplugging CPU0 but IIRC it would break the affinity mask unnecessarily. Cheers, Mark. > --- > arch/arm/kernel/irq.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Change v1->v2: > - Updated the changelog to reflect the actual history behind > this change as suggested by tglx and added his ack > > diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c > index 2c4257604513..5c4d38e32a51 100644 > --- a/arch/arm/kernel/irq.c > +++ b/arch/arm/kernel/irq.c > @@ -175,7 +175,7 @@ static bool migrate_one_irq(struct irq_desc *desc) > c = irq_data_get_irq_chip(d); > if (!c->irq_set_affinity) > pr_debug("IRQ%u: unable to set affinity\n", d->irq); > - else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret) > + else if (c->irq_set_affinity(d, affinity, false) == IRQ_SET_MASK_OK && ret) > cpumask_copy(d->affinity, affinity); > > return ret; > -- > 1.8.3.2 > -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c index 2c4257604513..5c4d38e32a51 100644 --- a/arch/arm/kernel/irq.c +++ b/arch/arm/kernel/irq.c @@ -175,7 +175,7 @@ static bool migrate_one_irq(struct irq_desc *desc) c = irq_data_get_irq_chip(d); if (!c->irq_set_affinity) pr_debug("IRQ%u: unable to set affinity\n", d->irq); - else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret) + else if (c->irq_set_affinity(d, affinity, false) == IRQ_SET_MASK_OK && ret) cpumask_copy(d->affinity, affinity); return ret;