Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758438AbcJYSRQ convert rfc822-to-8bit (ORCPT ); Tue, 25 Oct 2016 14:17:16 -0400 Received: from smtprelay.synopsys.com ([198.182.60.111]:45255 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756621AbcJYSRM (ORCPT ); Tue, 25 Oct 2016 14:17:12 -0400 From: Yuriy Kolerov To: Vineet Gupta , Yuriy Kolerov , "linux-snps-arc@lists.infradead.org" CC: "marc.zyngier@arm.com" , "Vineet.Gupta1@synopsys.com" , "Alexey.Brodkin@synopsys.com" , "linux-kernel@vger.kernel.org" , "tglx@linutronix.de" Subject: RE: [PATCH v2 5/5] ARC: MCIP: Use IDU_M_DISTRI_DEST mode if there is only 1 destination core Thread-Topic: [PATCH v2 5/5] ARC: MCIP: Use IDU_M_DISTRI_DEST mode if there is only 1 destination core Thread-Index: AQHSLfS5nWckJPLEOECFQ/XDE+5TE6C5U7oAgAAniJA= Date: Tue, 25 Oct 2016 18:16:58 +0000 Message-ID: <3ABF60118B9B784CA5BF7C841D2F00EC0101864E@de02wembxa.internal.synopsys.com> References: <1477313194-2310-1-git-send-email-yuriy.kolerov@synopsys.com> <1477313194-2310-5-git-send-email-yuriy.kolerov@synopsys.com> <57be0620-b1a4-d205-cc37-f3866884317b@synopsys.com> In-Reply-To: <57be0620-b1a4-d205-cc37-f3866884317b@synopsys.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.13.178.24] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2900 Lines: 75 > -----Original Message----- > From: Vineet Gupta [mailto:vgupta@synopsys.com] > Sent: Tuesday, October 25, 2016 8:53 PM > To: Yuriy Kolerov ; linux-snps- > arc@lists.infradead.org > Cc: marc.zyngier@arm.com; Vineet.Gupta1@synopsys.com; > Alexey.Brodkin@synopsys.com; linux-kernel@vger.kernel.org; > tglx@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 > > --- > > 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); > > > >