From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e5.ny.us.ibm.com (e5.ny.us.ibm.com [32.97.182.145]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e5.ny.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTP id 8A068DDE30 for ; Thu, 19 Apr 2007 21:52:42 +1000 (EST) Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e5.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id l3JBqdun008981 for ; Thu, 19 Apr 2007 07:52:39 -0400 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v8.3) with ESMTP id l3JBqdjg510408 for ; Thu, 19 Apr 2007 07:52:39 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l3JBqccM024596 for ; Thu, 19 Apr 2007 07:52:38 -0400 Date: Thu, 19 Apr 2007 17:22:33 +0530 From: Mohan Kumar M To: Michael Ellerman Subject: Re: [PATCH] Fix interrupt distribution in ppc970 Message-ID: <20070419115233.GA4172@in.ibm.com> References: <20070306135754.GB7476@in.ibm.com> <1173190615.4675.30.camel@concordia.ozlabs.ibm.com> <20070306165529.GD7476@in.ibm.com> <1173202634.4675.37.camel@concordia.ozlabs.ibm.com> <20070307045341.GG7476@in.ibm.com> <1173264752.5101.49.camel@concordia.ozlabs.ibm.com> <20070409085732.GC4281@in.ibm.com> <1176188763.9836.16.camel@concordia.ozlabs.ibm.com> <1176254201.4815.14.camel@concordia.ozlabs.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1176254201.4815.14.camel@concordia.ozlabs.ibm.com> Cc: ppcdev , Paul Mackerras , Anton Blanchard , Milton Miller , fastboot@lists.osdl.org Reply-To: mohan@in.ibm.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Apr 11, 2007 at 11:16:41AM +1000, Michael Ellerman wrote: > On Tue, 2007-04-10 at 11:59 -0500, Milton Miller wrote: > > > > This means we are doing population counts of two masks, when we really > > just care that they are the same. How about using > > cpus_equal(cpu_online_mask, cpu_present_mask)? > > Yep that's sensible. > > > This shows how close these two functions are. The difference is > > what happens when cpus_empty is true -- we default in one and > > ignore in the other. > > > > How about adding another arg to get_server, that says to fail > > or default for the empty case, with failure being -1? > > > > I'll try to code this up, but it might be a day or two until i get > > the time. I modified the patch based on suggestions given by Milton and Mike. Milton is this patch okay? Tested on 2.6.21-rc7. ===== It is observed that in some PPC970 based machines, When the kernel is booted with maxcpus=1, interrupts were distributed to non online cpus also. So a condition is included to check whether the cpu online map and cpu present map are equal or not. If they are equal default_distrib_server is used as the interrupt server otherwise default_server(ie boot cpu) is used as the interrupt server. In addition to this, if an interrupt is assigned to a specific cpu (ie smp affinity) and if that cpu is not online, the earlier code used to return the default_distrib_server as interrupt server. This patch introduces an additional parameter to the get_irq function ie strict_check, based on this parameter, if the cpu is not online either default_distrib_server or -1 is returned. Cc: Milton Miller , Michael Ellerman Signed-off-by: Mohan Kumar M --- arch/powerpc/platforms/pseries/xics.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) Index: linux-2.6.21-rc4/arch/powerpc/platforms/pseries/xics.c =================================================================== --- linux-2.6.21-rc4.orig/arch/powerpc/platforms/pseries/xics.c +++ linux-2.6.21-rc4/arch/powerpc/platforms/pseries/xics.c @@ -156,9 +156,9 @@ static inline void lpar_qirr_info(int n_ #ifdef CONFIG_SMP -static int get_irq_server(unsigned int virq) +static int get_irq_server(unsigned int virq, unsigned int strict_check) { - unsigned int server; + int server; /* For the moment only implement delivery to all cpus or one cpu */ cpumask_t cpumask = irq_desc[virq].affinity; cpumask_t tmp = CPU_MASK_NONE; @@ -167,21 +167,25 @@ static int get_irq_server(unsigned int v return default_server; if (cpus_equal(cpumask, CPU_MASK_ALL)) { - server = default_distrib_server; + if (cpus_equal(cpu_online_map, cpu_present_map)) + server = default_distrib_server; + else + server = default_server; } else { cpus_and(tmp, cpu_online_map, cpumask); - if (cpus_empty(tmp)) + if (cpus_empty(tmp) && !strict_check) server = default_distrib_server; + else if(cpus_empty(tmp) && strict_check) + server = -1; else server = get_hard_smp_processor_id(first_cpu(tmp)); } return server; - } #else -static int get_irq_server(unsigned int virq) +static int get_irq_server(unsigned int virq, unsigned int strict_check) { return default_server; } @@ -192,7 +196,7 @@ static void xics_unmask_irq(unsigned int { unsigned int irq; int call_status; - unsigned int server; + int server; pr_debug("xics: unmask virq %d\n", virq); @@ -201,7 +205,7 @@ static void xics_unmask_irq(unsigned int if (irq == XICS_IPI || irq == XICS_IRQ_SPURIOUS) return; - server = get_irq_server(virq); + server = get_irq_server(virq, 0); call_status = rtas_call(ibm_set_xive, 3, 1, NULL, irq, server, DEFAULT_PRIORITY); @@ -415,7 +419,10 @@ static void xics_set_affinity(unsigned i /* For the moment only implement delivery to all cpus or one cpu */ if (cpus_equal(cpumask, CPU_MASK_ALL)) { - newmask = default_distrib_server; + if (cpus_equal(cpu_online_map, cpu_present_map)) + newmask = default_distrib_server; + else + newmask = default_server; } else { cpus_and(tmp, cpu_online_map, cpumask); if (cpus_empty(tmp))