Messages in this thread | | | Date | Tue, 21 Sep 2010 13:41:04 -0700 | Subject | Re: [PATCH] x86 - irq vector assignment | From | Yinghai Lu <> |
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On Tue, Sep 21, 2010 at 1:05 PM, Jack Steiner <steiner@sgi.com> wrote: > Try to assign irq vectors to cpus on the correct node & fall back to global > assignment only if node-local fails. This reduces the chances of > using all of the interrupt vectors of a single cpu. > > Signed-off-by: Jack Steiner <steiner@sgi.com> > > > --- > Note: this is a fix for a problem we saw on systems with a large number of IOHs. > The IOHs are distributed across 10's of nodes. > > Early in boot, the IO infrastructure assigns interrupts for the DMA engines. > Currently, all interrupts are targeted to cpu 0. This uses all interrupt > vectors on cpu 0. Later, some drivers try to create irqs targeted to > cpu 0. The assignment fails because all vectors are assigned. > > This is a repost of a patch sent earlier. See > http://marc.info/?l=linux-kernel&m=127740806705617&w=2 > http://marc.info/?l=linux-kernel&m=127791052828867&w=2 > > > > arch/x86/kernel/apic/io_apic.c | 5 +++++ > 1 file changed, 5 insertions(+) > > Index: linux/arch/x86/kernel/apic/io_apic.c > =================================================================== > --- linux.orig/arch/x86/kernel/apic/io_apic.c 2010-09-17 13:00:19.164638447 -0500 > +++ linux/arch/x86/kernel/apic/io_apic.c 2010-09-17 13:00:23.448595373 -0500 > @@ -3253,6 +3253,11 @@ unsigned int create_irq_nr(unsigned int > desc_new = move_irq_desc(desc_new, node); > cfg_new = desc_new->chip_data; > > +#ifdef CONFIG_NUMA > + if (node >= 0 && __assign_irq_vector(new, cfg_new, node_to_cpumask_map[node]) == 0) > + irq = new; > + else > +#endif > if (__assign_irq_vector(new, cfg_new, apic->target_cpus()) == 0) > irq = new; > break;
target_cpus() for uv_x and x2apic phys mode all have cpu_online_mask()
so we should get the vector for other cpus. aka __assign_irq_vector() should not fail. unless you have so many irq > nr_irqs.
current code we only make sure irq_desc on device local node.
for the vectors, user can set irq smp_affinity move the device local cpus if needed.
Thanks
Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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