Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757353Ab1BAOzM (ORCPT ); Tue, 1 Feb 2011 09:55:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35090 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757266Ab1BAOyM (ORCPT ); Tue, 1 Feb 2011 09:54:12 -0500 Date: Tue, 1 Feb 2011 09:52:41 -0500 From: Rik van Riel To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Avi Kiviti , Srivatsa Vaddagiri , Peter Zijlstra , Mike Galbraith , Chris Wright , "Nakajima, Jun" Subject: [PATCH -v8a 6/7] kvm: keep track of which task is running a KVM vcpu Message-ID: <20110201095241.2bdccb8e@annuminas.surriel.com> In-Reply-To: <20110201094433.72829892@annuminas.surriel.com> References: <20110201094433.72829892@annuminas.surriel.com> Organization: Red Hat, Inc. Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1994 Lines: 62 Keep track of which task is running a KVM vcpu. This helps us figure out later what task to wake up if we want to boost a vcpu that got preempted. Unfortunately there are no guarantees that the same task always keeps the same vcpu, so we can only track the task across a single "run" of the vcpu. Signed-off-by: Rik van Riel diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index a055742..9d56ed5 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -81,6 +81,7 @@ struct kvm_vcpu { #endif int vcpu_id; struct mutex mutex; + struct pid *pid; int cpu; atomic_t guest_mode; struct kvm_run *run; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 5225052..0fa9a48 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -117,6 +117,14 @@ void vcpu_load(struct kvm_vcpu *vcpu) int cpu; mutex_lock(&vcpu->mutex); + if (unlikely(vcpu->pid != current->pids[PIDTYPE_PID].pid)) { + /* The thread running this VCPU changed. */ + struct pid *oldpid = vcpu->pid; + struct pid *newpid = get_task_pid(current, PIDTYPE_PID); + rcu_assign_pointer(vcpu->pid, newpid); + synchronize_rcu(); + put_pid(oldpid); + } cpu = get_cpu(); preempt_notifier_register(&vcpu->preempt_notifier); kvm_arch_vcpu_load(vcpu, cpu); @@ -185,6 +193,7 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) vcpu->cpu = -1; vcpu->kvm = kvm; vcpu->vcpu_id = id; + vcpu->pid = NULL; init_waitqueue_head(&vcpu->wq); page = alloc_page(GFP_KERNEL | __GFP_ZERO); @@ -208,6 +217,7 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_init); void kvm_vcpu_uninit(struct kvm_vcpu *vcpu) { + put_pid(vcpu->pid); kvm_arch_vcpu_uninit(vcpu); free_page((unsigned long)vcpu->run); } -- 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/