> -----Original Message----- > From: Vineet Gupta [mailto:vgupta at synopsys.com] > Sent: Tuesday, October 25, 2016 8:53 PM > To: Yuriy Kolerov <yuriy.kolerov at synopsys.com>; linux-snps- > arc at lists.infradead.org > Cc: marc.zyngier at arm.com; Vineet.Gupta1 at synopsys.com; > Alexey.Brodkin at synopsys.com; linux-kernel at vger.kernel.org; > tglx at linutronix.de > Subject: Re: [PATCH v2 5/5] ARC: MCIP: Use IDU_M_DISTRI_DEST mode if > there is only 1 destination core > > On 10/24/2016 05:46 AM, Yuriy Kolerov wrote: > > ARC linux uses 2 distribution modes for common interrupts: round robin > > mode (IDU_M_DISTRI_RR) and a simple destination mode > (IDU_M_DISTRI_DEST). > > The first one is used when more than 1 cores may handle a common > > interrupt and the second one is used when only 1 core may handle a > common interrupt. > > > > However idu_irq_set_affinity always sets IDU_M_DISTRI_RR for all > > affinity values. But there is no sense in setting of such mode if only > > 1 core must handle a common interrupt. > > > > Signed-off-by: Yuriy Kolerov <yuriy.kolerov at synopsys.com> > > --- > > arch/arc/kernel/mcip.c | 11 +++++++++-- > > 1 file changed, 9 insertions(+), 2 deletions(-) > > > > diff --git a/arch/arc/kernel/mcip.c b/arch/arc/kernel/mcip.c index > > 090f0a1..75e6d73 100644 > > --- a/arch/arc/kernel/mcip.c > > +++ b/arch/arc/kernel/mcip.c > > @@ -197,6 +197,7 @@ idu_irq_set_affinity(struct irq_data *data, const > > struct cpumask *cpumask, { > > unsigned long flags; > > cpumask_t online; > > + unsigned long dest_bits; > > > > /* errout if no online cpu per @cpumask */ > > if (!cpumask_and(&online, cpumask, cpu_online_mask)) @@ -204,8 > > +205,14 @@ idu_irq_set_affinity(struct irq_data *data, const struct > > cpumask *cpumask, > > > > raw_spin_lock_irqsave(&mcip_lock, flags); > > > > - idu_set_dest(data->hwirq, cpumask_bits(&online)[0]); > > - idu_set_mode(data->hwirq, IDU_M_TRIG_LEVEL, > IDU_M_DISTRI_RR); > > + dest_bits = cpumask_bits(&online)[0]; > > + idu_set_dest(data->hwirq, dest_bits); > > + > > + if (ffs(dest_bits) == fls(dest_bits)) { > > + idu_set_mode(data->hwirq, IDU_M_TRIG_LEVEL, > IDU_M_DISTRI_DEST); > > + } else { > > + idu_set_mode(data->hwirq, IDU_M_TRIG_LEVEL, > IDU_M_DISTRI_RR); > > + } > > Better to use a local variable to assign IDU_M_xxx and then call > idu_set_mode() outside the if. I know the compiler would do that anyways, > but that looks simpler to read ! Yep. > But on the other hand, adding all of this here - isn't there some sort of > duplication of code now between here and in the idu_irq_xlate() ? > Do we need the same stuff in 2 places ? I tried to explain in in [PATCH v2 4/5]. In short I moved logic for setting affinity to idu_irq_set_affinity because xlate function is not the best place where it must be done (see commit message for that patch). > > > > raw_spin_unlock_irqrestore(&mcip_lock, flags); > > > >
