From patchwork Tue Oct 30 10:02:22 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Graf X-Patchwork-Id: 195371 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 107852C007F for ; Tue, 30 Oct 2012 21:02:43 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758017Ab2J3KCj (ORCPT ); Tue, 30 Oct 2012 06:02:39 -0400 Received: from cantor2.suse.de ([195.135.220.15]:45752 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757507Ab2J3KCf (ORCPT ); Tue, 30 Oct 2012 06:02:35 -0400 Received: from relay2.suse.de (unknown [195.135.220.254]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id BBB79A3EBF; Tue, 30 Oct 2012 11:02:34 +0100 (CET) From: Alexander Graf To: KVM list Cc: kvm-ppc , Avi Kivity , Marcelo Tosatti , Paul Mackerras Subject: [PATCH 09/12] KVM: PPC: Book3S HV: Run virtual core whenever any vcpus in it can run Date: Tue, 30 Oct 2012 11:02:22 +0100 Message-Id: <1351591345-23071-10-git-send-email-agraf@suse.de> X-Mailer: git-send-email 1.6.0.2 In-Reply-To: <1351591345-23071-1-git-send-email-agraf@suse.de> References: <1351591345-23071-1-git-send-email-agraf@suse.de> Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org From: Paul Mackerras Currently the Book3S HV code implements a policy on multi-threaded processors (i.e. POWER7) that requires all of the active vcpus in a virtual core to be ready to run before we run the virtual core. However, that causes problems on reset, because reset stops all vcpus except vcpu 0, and can also reduce throughput since all four threads in a virtual core have to wait whenever any one of them hits a hypervisor page fault. This relaxes the policy, allowing the virtual core to run as soon as any vcpu in it is runnable. With this, the KVMPPC_VCPU_STOPPED state and the KVMPPC_VCPU_BUSY_IN_HOST state have been combined into a single KVMPPC_VCPU_NOTREADY state, since we no longer need to distinguish between them. Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf --- arch/powerpc/include/asm/kvm_host.h | 5 +- arch/powerpc/kvm/book3s_hv.c | 74 ++++++++++++++++++----------------- 2 files changed, 40 insertions(+), 39 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 218534d..1e8cbd1 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -563,9 +563,8 @@ struct kvm_vcpu_arch { }; /* Values for vcpu->arch.state */ -#define KVMPPC_VCPU_STOPPED 0 -#define KVMPPC_VCPU_BUSY_IN_HOST 1 -#define KVMPPC_VCPU_RUNNABLE 2 +#define KVMPPC_VCPU_NOTREADY 0 +#define KVMPPC_VCPU_RUNNABLE 1 /* Values for vcpu->arch.io_gpr */ #define KVM_MMIO_REG_MASK 0x001f diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 89995fa..61d2934 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -776,10 +776,7 @@ struct kvm_vcpu *kvmppc_core_vcpu_create(struct kvm *kvm, unsigned int id) kvmppc_mmu_book3s_hv_init(vcpu); - /* - * We consider the vcpu stopped until we see the first run ioctl for it. - */ - vcpu->arch.state = KVMPPC_VCPU_STOPPED; + vcpu->arch.state = KVMPPC_VCPU_NOTREADY; init_waitqueue_head(&vcpu->arch.cpu_run); @@ -866,9 +863,8 @@ static void kvmppc_remove_runnable(struct kvmppc_vcore *vc, { if (vcpu->arch.state != KVMPPC_VCPU_RUNNABLE) return; - vcpu->arch.state = KVMPPC_VCPU_BUSY_IN_HOST; + vcpu->arch.state = KVMPPC_VCPU_NOTREADY; --vc->n_runnable; - ++vc->n_busy; list_del(&vcpu->arch.run_list); } @@ -1169,7 +1165,6 @@ static void kvmppc_vcore_blocked(struct kvmppc_vcore *vc) static int kvmppc_run_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) { int n_ceded; - int prev_state; struct kvmppc_vcore *vc; struct kvm_vcpu *v, *vn; @@ -1186,7 +1181,6 @@ static int kvmppc_run_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) vcpu->arch.ceded = 0; vcpu->arch.run_task = current; vcpu->arch.kvm_run = kvm_run; - prev_state = vcpu->arch.state; vcpu->arch.state = KVMPPC_VCPU_RUNNABLE; list_add_tail(&vcpu->arch.run_list, &vc->runnable_threads); ++vc->n_runnable; @@ -1196,35 +1190,26 @@ static int kvmppc_run_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) * If the vcore is already running, we may be able to start * this thread straight away and have it join in. */ - if (prev_state == KVMPPC_VCPU_STOPPED) { + if (!signal_pending(current)) { if (vc->vcore_state == VCORE_RUNNING && VCORE_EXIT_COUNT(vc) == 0) { vcpu->arch.ptid = vc->n_runnable - 1; kvmppc_create_dtl_entry(vcpu, vc); kvmppc_start_thread(vcpu); + } else if (vc->vcore_state == VCORE_SLEEPING) { + wake_up(&vc->wq); } - } else if (prev_state == KVMPPC_VCPU_BUSY_IN_HOST) - --vc->n_busy; + } while (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE && !signal_pending(current)) { - if (vc->n_busy || vc->vcore_state != VCORE_INACTIVE) { + if (vc->vcore_state != VCORE_INACTIVE) { spin_unlock(&vc->lock); kvmppc_wait_for_exec(vcpu, TASK_INTERRUPTIBLE); spin_lock(&vc->lock); continue; } - vc->runner = vcpu; - n_ceded = 0; - list_for_each_entry(v, &vc->runnable_threads, arch.run_list) - if (!v->arch.pending_exceptions) - n_ceded += v->arch.ceded; - if (n_ceded == vc->n_runnable) - kvmppc_vcore_blocked(vc); - else - kvmppc_run_core(vc); - list_for_each_entry_safe(v, vn, &vc->runnable_threads, arch.run_list) { kvmppc_core_prepare_to_enter(v); @@ -1236,23 +1221,40 @@ static int kvmppc_run_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) wake_up(&v->arch.cpu_run); } } + if (!vc->n_runnable || vcpu->arch.state != KVMPPC_VCPU_RUNNABLE) + break; + vc->runner = vcpu; + n_ceded = 0; + list_for_each_entry(v, &vc->runnable_threads, arch.run_list) + if (!v->arch.pending_exceptions) + n_ceded += v->arch.ceded; + if (n_ceded == vc->n_runnable) + kvmppc_vcore_blocked(vc); + else + kvmppc_run_core(vc); vc->runner = NULL; } - if (signal_pending(current)) { - while (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE && - (vc->vcore_state == VCORE_RUNNING || - vc->vcore_state == VCORE_EXITING)) { - spin_unlock(&vc->lock); - kvmppc_wait_for_exec(vcpu, TASK_UNINTERRUPTIBLE); - spin_lock(&vc->lock); - } - if (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE) { - kvmppc_remove_runnable(vc, vcpu); - vcpu->stat.signal_exits++; - kvm_run->exit_reason = KVM_EXIT_INTR; - vcpu->arch.ret = -EINTR; - } + while (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE && + (vc->vcore_state == VCORE_RUNNING || + vc->vcore_state == VCORE_EXITING)) { + spin_unlock(&vc->lock); + kvmppc_wait_for_exec(vcpu, TASK_UNINTERRUPTIBLE); + spin_lock(&vc->lock); + } + + if (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE) { + kvmppc_remove_runnable(vc, vcpu); + vcpu->stat.signal_exits++; + kvm_run->exit_reason = KVM_EXIT_INTR; + vcpu->arch.ret = -EINTR; + } + + if (vc->n_runnable && vc->vcore_state == VCORE_INACTIVE) { + /* Wake up some vcpu to run the core */ + v = list_first_entry(&vc->runnable_threads, + struct kvm_vcpu, arch.run_list); + wake_up(&v->arch.cpu_run); } spin_unlock(&vc->lock);