From patchwork Mon Aug 7 08:44:24 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Longpeng(Mike)" X-Patchwork-Id: 9884731 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 71F7C60363 for ; Mon, 7 Aug 2017 08:48:52 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 63FB5285DB for ; Mon, 7 Aug 2017 08:48:52 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 583AD285E7; Mon, 7 Aug 2017 08:48:52 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C3F6E285DC for ; Mon, 7 Aug 2017 08:48:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752666AbdHGIr3 (ORCPT ); Mon, 7 Aug 2017 04:47:29 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:2554 "EHLO szxga05-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752676AbdHGIqv (ORCPT ); Mon, 7 Aug 2017 04:46:51 -0400 Received: from 172.30.72.59 (EHLO DGGEMS410-HUB.china.huawei.com) ([172.30.72.59]) by dggrg05-dlp.huawei.com (MOS 4.4.6-GA FastPath queued) with ESMTP id DES23872; Mon, 07 Aug 2017 16:46:49 +0800 (CST) Received: from localhost (10.177.246.209) by DGGEMS410-HUB.china.huawei.com (10.3.19.210) with Microsoft SMTP Server id 14.3.301.0; Mon, 7 Aug 2017 16:46:39 +0800 From: "Longpeng(Mike)" To: , CC: , , , , , , , , , , , , , "Longpeng(Mike)" Subject: [PATCH 1/3] KVM: add spinlock-exiting optimize framework Date: Mon, 7 Aug 2017 16:44:24 +0800 Message-ID: <1502095466-21312-2-git-send-email-longpeng2@huawei.com> X-Mailer: git-send-email 1.8.4.msysgit.0 In-Reply-To: <1502095466-21312-1-git-send-email-longpeng2@huawei.com> References: <1502095466-21312-1-git-send-email-longpeng2@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.177.246.209] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020206.598828FA.0040, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 713c45112c703db584480b6a2b9b6ee0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If the vcpu(me) exit due to request a usermode spinlock, then the spinlock-holder may be preempted in usermode or kernmode. But if the vcpu(me) is in kernmode, then the holder must be preempted in kernmode, so we should choose a vcpu in kernmode as the most eligible candidate. For some architecture(e.g. arm/s390), spin/preempt_in_kernel() are the same, but they are different for X86. Signed-off-by: Longpeng(Mike) --- arch/mips/kvm/mips.c | 10 ++++++++++ arch/powerpc/kvm/powerpc.c | 10 ++++++++++ arch/s390/kvm/kvm-s390.c | 10 ++++++++++ arch/x86/kvm/x86.c | 10 ++++++++++ include/linux/kvm_host.h | 2 ++ virt/kvm/arm/arm.c | 10 ++++++++++ virt/kvm/kvm_main.c | 4 ++++ 7 files changed, 56 insertions(+) diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index d4b2ad1..e04e6b3 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -98,6 +98,16 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) return !!(vcpu->arch.pending_exceptions); } +bool kvm_arch_vcpu_spin_in_kernel(struct kvm_vcpu *vcpu) +{ + return false; +} + +bool kvm_arch_vcpu_preempt_in_kernel(struct kvm_vcpu *vcpu) +{ + return false; +} + int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) { return 1; diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 1a75c0b..c573ddd 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -58,6 +58,16 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *v) return !!(v->arch.pending_exceptions) || kvm_request_pending(v); } +bool kvm_arch_vcpu_spin_in_kernel(struct kvm_vcpu *vcpu) +{ + return false; +} + +bool kvm_arch_vcpu_preempt_in_kernel(struct kvm_vcpu *vcpu) +{ + return false; +} + int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) { return 1; diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index af09d34..f78cdc2 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -2447,6 +2447,16 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) return kvm_s390_vcpu_has_irq(vcpu, 0); } +bool kvm_arch_vcpu_spin_in_kernel(struct kvm_vcpu *vcpu) +{ + return false; +} + +bool kvm_arch_vcpu_preempt_in_kernel(struct kvm_vcpu *vcpu) +{ + return false; +} + void kvm_s390_vcpu_block(struct kvm_vcpu *vcpu) { atomic_or(PROG_BLOCK_SIE, &vcpu->arch.sie_block->prog20); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6c97c82..04c6a1f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8435,6 +8435,16 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) return kvm_vcpu_running(vcpu) || kvm_vcpu_has_events(vcpu); } +bool kvm_arch_vcpu_spin_in_kernel(struct kvm_vcpu *vcpu) +{ + return false; +} + +bool kvm_arch_vcpu_preempt_in_kernel(struct kvm_vcpu *vcpu) +{ + return false; +} + int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) { return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 890b706..9613620 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -798,6 +798,8 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, void kvm_arch_hardware_unsetup(void); void kvm_arch_check_processor_compat(void *rtn); int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu); +bool kvm_arch_vcpu_spin_in_kernel(struct kvm_vcpu *vcpu); +bool kvm_arch_vcpu_preempt_in_kernel(struct kvm_vcpu *vcpu); int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu); #ifndef __KVM_HAVE_ARCH_VM_ALLOC diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c index a39a1e1..e45f780 100644 --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -416,6 +416,16 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *v) && !v->arch.power_off && !v->arch.pause); } +bool kvm_arch_vcpu_spin_in_kernel(struct kvm_vcpu *vcpu) +{ + return false; +} + +bool kvm_arch_vcpu_preempt_in_kernel(struct kvm_vcpu *vcpu) +{ + return false; +} + /* Just ensure a guest exit from a particular CPU */ static void exit_vm_noop(void *info) { diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index f3f7427..0d0527b 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2324,12 +2324,14 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me) { struct kvm *kvm = me->kvm; struct kvm_vcpu *vcpu; + bool in_kern; int last_boosted_vcpu = me->kvm->last_boosted_vcpu; int yielded = 0; int try = 3; int pass; int i; + in_kern = kvm_arch_vcpu_spin_in_kernel(me); kvm_vcpu_set_in_spin_loop(me, true); /* * We boost the priority of a VCPU that is runnable but not @@ -2351,6 +2353,8 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me) continue; if (swait_active(&vcpu->wq) && !kvm_arch_vcpu_runnable(vcpu)) continue; + if (in_kern && !kvm_arch_vcpu_preempt_in_kernel(vcpu)) + continue; if (!kvm_vcpu_eligible_for_directed_yield(vcpu)) continue;