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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 E6C8FC352BE for ; Thu, 16 Apr 2020 15:09:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C2EB62222D for ; Thu, 16 Apr 2020 15:09:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587049792; bh=d+jYBOjHEQ4IMdmHevIiKoXNQP6Ha/WDzfGTquft15M=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=aG72Lh3YFaYkRrtEhkT2CDFZ8UchOiZ/G2v6H4mF7sAgA4hDpKKKqgbS14v6zIhJE uFcCcEGkSM3DN+vaSyIFO8JHVRRgrCtzSSxEPYnkyLBjjpwPlUJa92Z8t6Qug4eOSp 0u3PH3asGKgrVI+61vsmv/dGF3rGklNCB/Frzjvg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2395026AbgDPPJu (ORCPT ); Thu, 16 Apr 2020 11:09:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:55102 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394926AbgDPPJo (ORCPT ); Thu, 16 Apr 2020 11:09:44 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1A6402222D; Thu, 16 Apr 2020 15:09:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587049783; bh=d+jYBOjHEQ4IMdmHevIiKoXNQP6Ha/WDzfGTquft15M=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=bFE2oQgRFyl5eaViJHVH9ihqsKwAXnffRCx/4FIv9b/eQpX0cXb0JtebE9VyGHY8F 2qqE0D4ZFAaox2vHfmelWtQU26dZNF2xSH9tDN2NT4lS/ZjTMW3LLDfNEfcXFtgt3Z q1NupWDClMckGzO1vqmx6W0goEQlzp9XBYBQt93o= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why) by disco-boy.misterjones.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jP697-003tq8-E7; Thu, 16 Apr 2020 16:09:41 +0100 Date: Thu, 16 Apr 2020 16:09:39 +0100 From: Marc Zyngier To: Paolo Bonzini Cc: Keqian Zhu , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, James Morse , Julien Thierry , Will Deacon , Suzuki K Poulose , Sean Christopherson , Jay Zhou , wanghaibin.wang@huawei.com Subject: Re: [PATCH v2] KVM/arm64: Support enabling dirty log gradually in small chunks Message-ID: <20200416160939.7e9c1621@why> In-Reply-To: References: <20200413122023.52583-1-zhukeqian1@huawei.com> Organization: Approximate X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: pbonzini@redhat.com, zhukeqian1@huawei.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, james.morse@arm.com, julien.thierry.kdev@gmail.com, will@kernel.org, suzuki.poulose@arm.com, sean.j.christopherson@intel.com, jianjay.zhou@huawei.com, wanghaibin.wang@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, 15 Apr 2020 18:13:56 +0200 Paolo Bonzini wrote: > On 13/04/20 14:20, 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, > > > > Marc, what is the status of this patch? I just had a look at it. Is there any urgency for merging it? Thanks, M. -- Jazz is not dead. It just smells funny...