From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDAE2C2BA19 for ; Thu, 16 Apr 2020 03:28:30 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A97F820771 for ; Thu, 16 Apr 2020 03:28:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="cQB1Rcxo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A97F820771 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=/zTr6xwd3Gb3TTAvJ62QIZKfUjEXELRIKsW4XH9Q8oI=; b=cQB1RcxomBW/y9 HptmXNxtzXI9qcvDK8C9c4wzNL7oBv+gVCTThvTNpMHI/5W/Bedjf/mEVO73e59A/Xb9cAsoE2WaY s8Kb/ud9yiFxuusk4SbxdopgM2Kq/m5rq5HSrp2jClHTH88ZgXZucpVs+O4L6tDuZigi7wXn1dHb6 sVv03PUi37LHOI1OI1H9UwjEPlgsft7/MbBuKyqEh70/ncj09/jXvlP2ZeGCjkJeda3xmN9/sdCfk IlsNw7yBpe6x31b+12rnv42I6VJPwpdakYrw+C17sw4LaJDR9inWDdaew1n+4iNTXIAUf4eXbwycx pI7erC3gM6bye2A4EOaQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jOvCU-0007bH-Re; Thu, 16 Apr 2020 03:28:26 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191] helo=huawei.com) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jOvCR-0007a3-LK for linux-arm-kernel@lists.infradead.org; Thu, 16 Apr 2020 03:28:25 +0000 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 0020A7D09D55C0CCF71F; Thu, 16 Apr 2020 11:28:09 +0800 (CST) Received: from [127.0.0.1] (10.173.221.230) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.487.0; Thu, 16 Apr 2020 11:27:59 +0800 Subject: Re: [PATCH v2] KVM/arm64: Support enabling dirty log gradually in small chunks To: , , , References: <20200413122023.52583-1-zhukeqian1@huawei.com> From: zhukeqian Message-ID: Date: Thu, 16 Apr 2020 11:27:57 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <20200413122023.52583-1-zhukeqian1@huawei.com> X-Originating-IP: [10.173.221.230] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200415_202823_864952_D970DFDE X-CRM114-Status: GOOD ( 22.01 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Suzuki K Poulose , Marc Zyngier , Sean Christopherson , James Morse , wanghaibin.wang@huawei.com, Jay Zhou , Paolo Bonzini , Will Deacon , Julien Thierry Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Marc, In RFC patch, I still write protect huge pages when DIRTY_LOG_INITIALLY_ALL_SET is enabled by userspace. I find that both huge pages and normal pages can be write protected during log clear. So this formal patch is pretty simple now. Thanks, Keqian On 2020/4/13 20:20, Keqian Zhu wrote: > There is already support of enabling dirty log graually in small chunks > for x86 in commit 3c9bd4006bfc ("KVM: x86: enable dirty log gradually in > small chunks"). This adds support for arm64. > > x86 still writes protect all huge pages when DIRTY_LOG_INITIALLY_ALL_SET > is eanbled. However, for arm64, both huge pages and normal pages can be > write protected gradually by userspace. > > Under the Huawei Kunpeng 920 2.6GHz platform, I did some tests on 128G > Linux VMs with different page size. The memory pressure is 127G in each > case. The time taken of memory_global_dirty_log_start in QEMU is listed > below: > > Page Size Before After Optimization > 4K 650ms 1.8ms > 2M 4ms 1.8ms > 1G 2ms 1.8ms > > Besides the time reduction, the biggest income is that we will minimize > the performance side effect (because of dissloving huge pages and marking > memslots dirty) on guest after enabling dirty log. > > Signed-off-by: Keqian Zhu > --- > Documentation/virt/kvm/api.rst | 2 +- > arch/arm64/include/asm/kvm_host.h | 3 +++ > virt/kvm/arm/mmu.c | 12 ++++++++++-- > 3 files changed, 14 insertions(+), 3 deletions(-) > > diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst > index efbbe570aa9b..0017f63fa44f 100644 > --- a/Documentation/virt/kvm/api.rst > +++ b/Documentation/virt/kvm/api.rst > @@ -5777,7 +5777,7 @@ will be initialized to 1 when created. This also improves performance because > dirty logging can be enabled gradually in small chunks on the first call > to KVM_CLEAR_DIRTY_LOG. KVM_DIRTY_LOG_INITIALLY_SET depends on > KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (it is also only available on > -x86 for now). > +x86 and arm64 for now). > > KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 was previously available under the name > KVM_CAP_MANUAL_DIRTY_LOG_PROTECT, but the implementation had bugs that make > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 32c8a675e5a4..a723f84fab83 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -46,6 +46,9 @@ > #define KVM_REQ_RECORD_STEAL KVM_ARCH_REQ(3) > #define KVM_REQ_RELOAD_GICv4 KVM_ARCH_REQ(4) > > +#define KVM_DIRTY_LOG_MANUAL_CAPS (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE | \ > + KVM_DIRTY_LOG_INITIALLY_SET) > + > DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use); > > extern unsigned int kvm_sve_max_vl; > diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c > index e3b9ee268823..1077f653a611 100644 > --- a/virt/kvm/arm/mmu.c > +++ b/virt/kvm/arm/mmu.c > @@ -2265,8 +2265,16 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, > * allocated dirty_bitmap[], dirty pages will be be tracked while the > * memory slot is write protected. > */ > - if (change != KVM_MR_DELETE && mem->flags & KVM_MEM_LOG_DIRTY_PAGES) > - kvm_mmu_wp_memory_region(kvm, mem->slot); > + if (change != KVM_MR_DELETE && mem->flags & KVM_MEM_LOG_DIRTY_PAGES) { > + /* > + * If we're with initial-all-set, we don't need to write > + * protect any pages because they're all reported as dirty. > + * Huge pages and normal pages will be write protect gradually. > + */ > + if (!kvm_dirty_log_manual_protect_and_init_set(kvm)) { > + kvm_mmu_wp_memory_region(kvm, mem->slot); > + } > + } > } > > int kvm_arch_prepare_memory_region(struct kvm *kvm, > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel