On Wed, 06 Jun 2018 03:40:24 +0100, Yang Yingliang wrote: [I'm travelling, so please do not expect any quick answer...]
> > When the kernel booted with maxcpus=x, 'x' is smaller > than actual cpu numbers, the TAs of offline cpus won't TA? Target Address? Target Affinity? Timing Advance? Terrible Acronym? > be set to its->collection. > > If LPI is bind to offline cpu, sync cmd will use zero TA, > it leads to ITS queue timeout. Fix this by choosing a > online cpu, if there is no online cpu in cpu_mask. So instead of fixing the emission of a sync command on a non-mapped collection, you hack set_affinity? It doesn't feel like the right thing to do. It is also worth noticing that mapping an LPI to a collection that is not mapped yet is perfectly legal. > Signed-off-by: Yang Yingliang <[email protected]> > --- > drivers/irqchip/irq-gic-v3-its.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/drivers/irqchip/irq-gic-v3-its.c > b/drivers/irqchip/irq-gic-v3-its.c > index 5416f2b..d8b9539 100644 > --- a/drivers/irqchip/irq-gic-v3-its.c > +++ b/drivers/irqchip/irq-gic-v3-its.c > @@ -2309,7 +2309,9 @@ static int its_irq_domain_activate(struct irq_domain > *domain, > cpu_mask = cpumask_of_node(its_dev->its->numa_node); > > /* Bind the LPI to the first possible CPU */ > - cpu = cpumask_first(cpu_mask); > + cpu = cpumask_first_and(cpu_mask, cpu_online_mask); > + if (cpu >= nr_cpu_ids) > + cpu = cpumask_first(cpu_online_mask); Now you're completely ignoring cpu_mask which constraints the NUMA affinity. On some systems, this ends up with a deadlock (Cavium TX1, if I remember well). Wouldn't it be better to just return that the affinity setting request is impossible to satisfy? And more to the point, how comes we end-up in such a case? Thanks, M. -- Jazz is not dead, it just smell funny.
