Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759105Ab2FUJG2 (ORCPT ); Thu, 21 Jun 2012 05:06:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23004 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759076Ab2FUJG0 (ORCPT ); Thu, 21 Jun 2012 05:06:26 -0400 Date: Thu, 21 Jun 2012 11:04:51 +0200 From: Alexander Gordeev To: Suresh Siddha Cc: Ingo Molnar , yinghai@kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, gorcunov@openvz.org Subject: Re: [PATCH 2/2] x86, x2apic: limit the vector reservation to the user specified mask Message-ID: <20120621090451.GD2223@dhcp-26-207.brq.redhat.com> References: <1340067097.3696.6.camel@sbsiddha-desk.sc.intel.com> <1340149411-2972-1-git-send-email-suresh.b.siddha@intel.com> <1340149411-2972-2-git-send-email-suresh.b.siddha@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1340149411-2972-2-git-send-email-suresh.b.siddha@intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7181 Lines: 184 On Tue, Jun 19, 2012 at 04:43:31PM -0700, Suresh Siddha wrote: > For the x2apic cluster mode, vector for an interrupt is currently reserved on > all the cpu's that are part of the x2apic cluster. But the interrupts will > be routed only to the cluster (derived from the first cpu in the mask) members > specified in the mask. So there is no need to reserve the vector in the unused > cluster members. > > Modify __assign_irq_vector() to reserve the vectors based on the user > specified irq destination mask and the corresponding vector domain specified > by the apic driver. > > Signed-off-by: Suresh Siddha > --- > arch/x86/include/asm/apic.h | 14 +++++++++--- > arch/x86/kernel/apic/apic_noop.c | 5 +++- > arch/x86/kernel/apic/io_apic.c | 36 ++++++++++++++++++++++----------- > arch/x86/kernel/apic/x2apic_cluster.c | 8 ++++-- > 4 files changed, 43 insertions(+), 20 deletions(-) > > diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h > index b37fa12..7746acb 100644 > --- a/arch/x86/include/asm/apic.h > +++ b/arch/x86/include/asm/apic.h > @@ -306,7 +306,9 @@ struct apic { > unsigned long (*check_apicid_used)(physid_mask_t *map, int apicid); > unsigned long (*check_apicid_present)(int apicid); > > - void (*vector_allocation_domain)(int cpu, struct cpumask *retmask); > + void (*vector_allocation_domain)(const struct cpumask *mask, > + struct cpumask *retmask, > + const struct cpumask *prevmask); > void (*init_apic_ldr)(void); > > void (*ioapic_phys_id_map)(physid_mask_t *phys_map, physid_mask_t *retmap); > @@ -615,7 +617,9 @@ default_cpu_mask_to_apicid_and(const struct cpumask *cpumask, > unsigned int *apicid); > > static inline void > -flat_vector_allocation_domain(int cpu, struct cpumask *retmask) > +flat_vector_allocation_domain(const struct cpumask *mask, > + struct cpumask *retmask, > + const struct cpumask *prevmask) > { > /* Careful. Some cpus do not strictly honor the set of cpus > * specified in the interrupt destination when using lowest > @@ -630,9 +634,11 @@ flat_vector_allocation_domain(int cpu, struct cpumask *retmask) > } > > static inline void > -default_vector_allocation_domain(int cpu, struct cpumask *retmask) > +default_vector_allocation_domain(const struct cpumask *mask, > + struct cpumask *retmask, > + const struct cpumask *prevmask) > { > - cpumask_copy(retmask, cpumask_of(cpu)); > + cpumask_copy(retmask, cpumask_of(cpumask_first(retmask))); > } > > static inline unsigned long default_check_apicid_used(physid_mask_t *map, int apicid) > diff --git a/arch/x86/kernel/apic/apic_noop.c b/arch/x86/kernel/apic/apic_noop.c > index 08c337b..847ece1 100644 > --- a/arch/x86/kernel/apic/apic_noop.c > +++ b/arch/x86/kernel/apic/apic_noop.c > @@ -100,8 +100,11 @@ static unsigned long noop_check_apicid_present(int bit) > return physid_isset(bit, phys_cpu_present_map); > } > > -static void noop_vector_allocation_domain(int cpu, struct cpumask *retmask) > +static void noop_vector_allocation_domain(const struct cpumask *mask, > + struct cpumask *retmask, > + const struct cpumask *prevmask) > { > + int cpu = cpumask_first(retmask); > if (cpu != 0) > pr_warning("APIC: Vector allocated for non-BSP cpu\n"); > cpumask_copy(retmask, cpumask_of(cpu)); > diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c > index 7a945f8..0a55eb8 100644 > --- a/arch/x86/kernel/apic/io_apic.c > +++ b/arch/x86/kernel/apic/io_apic.c > @@ -1097,6 +1097,22 @@ void unlock_vector_lock(void) > raw_spin_unlock(&vector_lock); > } > > +/* > + * New cpu mask using the vector is a subset of the current in use mask. > + * So cleanup the vector allocation for the members that are not used anymore. > + */ > +static inline int > +cleanup_unused_subset(struct cpumask *mask, struct irq_cfg *cfg) > +{ > + if (!cpumask_equal(mask, cfg->domain)) { > + cpumask_andnot(cfg->old_domain, cfg->domain, mask); > + cfg->move_in_progress = 1; > + cpumask_and(cfg->domain, cfg->domain, mask); > + } > + free_cpumask_var(mask); > + return 0; > +} > + Adding to 1st Yinghai's comment, this function does not appear needed at all... > static int > __assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask) > { > @@ -1126,10 +1142,9 @@ __assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask) > old_vector = cfg->vector; > if (old_vector) { > cpumask_and(tmp_mask, mask, cpu_online_mask); > - if (cpumask_subset(tmp_mask, cfg->domain)) { > - free_cpumask_var(tmp_mask); > - return 0; > - } > + apic->vector_allocation_domain(mask, tmp_mask, cfg->domain); > + if (cpumask_subset(tmp_mask, cfg->domain)) > + return cleanup_unused_subset(tmp_mask, cfg); ...but if you decide to leave cleanup_unused_subset() then cpumask_subset() check is better to move inside the function while free_cpumask_var() move out. > } > > /* Only try and allocate irqs on cpus that are present */ > @@ -1137,15 +1152,12 @@ __assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask) > cpumask_clear(cfg->old_domain); > cpu = cpumask_first_and(mask, cpu_online_mask); > while (cpu < nr_cpu_ids) { > - int new_cpu; > - int vector, offset; > + int new_cpu, vector, offset; > > - apic->vector_allocation_domain(cpu, tmp_mask); > - > - if (cpumask_subset(tmp_mask, cfg->domain)) { > - free_cpumask_var(tmp_mask); > - return 0; > - } > + cpumask_copy(tmp_mask, cpumask_of(cpu)); > + apic->vector_allocation_domain(mask, tmp_mask, cfg->domain); I might be missing the point.. in the two lines above you copy a cpumask to tmp_mask, then scan it in vector_allocation_domain() just to find the cpu which you already know. Why not just pass cpu rather then cpumask_of(cpu)? > + if (cpumask_subset(tmp_mask, cfg->domain)) > + return cleanup_unused_subset(tmp_mask, cfg); > > vector = current_vector; > offset = current_offset; > diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c > index b5d889b..4d49512 100644 > --- a/arch/x86/kernel/apic/x2apic_cluster.c > +++ b/arch/x86/kernel/apic/x2apic_cluster.c > @@ -212,10 +212,12 @@ static int x2apic_cluster_probe(void) > /* > * Each x2apic cluster is an allocation domain. > */ > -static void cluster_vector_allocation_domain(int cpu, struct cpumask *retmask) > +static void cluster_vector_allocation_domain(const struct cpumask *mask, > + struct cpumask *retmask, > + const struct cpumask *prevmask) > { > - cpumask_clear(retmask); > - cpumask_copy(retmask, per_cpu(cpus_in_cluster, cpu)); > + int cpu = cpumask_first(retmask); > + cpumask_and(retmask, mask, per_cpu(cpus_in_cluster, cpu)); > } > > static struct apic apic_x2apic_cluster = { > -- > 1.7.6.5 > -- Regards, Alexander Gordeev agordeev@redhat.com -- 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/