From mboxrd@z Thu Jan 1 00:00:00 1970 From: Srikar Dronamraju Date: Wed, 12 Nov 2014 10:29:41 +0000 Subject: Re: [RFC 02/11] powerpc: kvm: ensure vcpu-thread run only on primary hwthread Message-Id: <20141112101741.GB16566@linux.vnet.ibm.com> List-Id: References: <1413487800-7162-1-git-send-email-kernelfans@gmail.com> <1413487800-7162-3-git-send-email-kernelfans@gmail.com> In-Reply-To: <1413487800-7162-3-git-send-email-kernelfans@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kernelfans@gmail.com Cc: Paul Mackerras , linuxppc-dev@lists.ozlabs.org, Alexander Graf , kvm-ppc@vger.kernel.org * kernelfans@gmail.com [2014-10-16 15:29:51]: > When vcpu thread runs at the first time, it will ensure to stick > to the primary thread. > > Signed-off-by: Liu Ping Fan > --- > arch/powerpc/include/asm/kvm_host.h | 3 +++ > arch/powerpc/kvm/book3s_hv.c | 17 +++++++++++++++++ > 2 files changed, 20 insertions(+) > > diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h > index 98d9dd5..9a3355e 100644 > --- a/arch/powerpc/include/asm/kvm_host.h > +++ b/arch/powerpc/include/asm/kvm_host.h > @@ -666,6 +666,9 @@ struct kvm_vcpu_arch { > spinlock_t tbacct_lock; > u64 busy_stolen; > u64 busy_preempt; > +#ifdef CONFIG_KVMPPC_ENABLE_SECONDARY > + bool cpu_selected; > +#endif > #endif > }; > > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index 27cced9..ba258c8 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -1909,6 +1909,23 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu) > { > int r; > int srcu_idx; > +#ifdef CONFIG_KVMPPC_ENABLE_SECONDARY > + int cpu = smp_processor_id(); > + int target_cpu; > + unsigned int cpu; 2 variables with same name... cpu > + struct task_struct *p = current; > + > + if (unlikely(!vcpu->arch.cpu_selected)) { > + vcpu->arch.cpu_selected = true; Nit: something like cpumask_set seems to be better than cpu_selected > + for (cpu = 0; cpu < NR_CPUS; cpu+=threads_per_core) { > + cpumask_set_cpu(cpu, &p->sys_allowed); Dont we need to reset the cpumask first before we set the cpumask here? > + } > + if (cpu%threads_per_core != 0) { At this time, cpu should be NR_CPUS and most times it should be a multiple of threads_per_core. Unfortunately there wont be a cpu with cpu number NR_CPUS. > + target_cpu = cpu/threads_per_core*threads_per_core; Its probably better of to have parenthesis here. > + migrate_task_to(current, target_cpu); We are probably migrating to a non-existant cpu. Also dont you need to check if the target_cpu is part of the cpumask? > + } > + } > +#endif > > if (!vcpu->arch.sane) { > run->exit_reason = KVM_EXIT_INTERNAL_ERROR; > -- > 1.8.3.1 > > -- Thanks and Regards Srikar Dronamraju