From patchwork Fri Nov 5 19:20:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 12605229 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4CB18C433F5 for ; Fri, 5 Nov 2021 19:21:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1BB1D61262 for ; Fri, 5 Nov 2021 19:21:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233155AbhKETYK (ORCPT ); Fri, 5 Nov 2021 15:24:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:37738 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232647AbhKETYJ (ORCPT ); Fri, 5 Nov 2021 15:24:09 -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 C280D61051; Fri, 5 Nov 2021 19:21:29 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mj4mF-003ig2-FT; Fri, 05 Nov 2021 19:21:27 +0000 From: Marc Zyngier To: kvm@vger.kernel.org, linux-mips@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linuxppc-dev@lists.ozlabs.org Cc: Huacai Chen , Aleksandar Markovic , Anup Patel , Atish Patra , Christian Borntraeger , Janosch Frank , David Hildenbrand , Claudio Imbrenda , Paolo Bonzini , Juergen Gross , Nicholas Piggin , Sean Christopherson , Paul Mackerras , Michael Ellerman , James Morse , Suzuki K Poulose , Alexandru Elisei , kernel-team@android.com Subject: [PATCH 0/5] KVM: Turn the vcpu array into an xarray Date: Fri, 5 Nov 2021 19:20:56 +0000 Message-Id: <20211105192101.3862492-1-maz@kernel.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvm@vger.kernel.org, linux-mips@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linuxppc-dev@lists.ozlabs.org, chenhuacai@kernel.org, aleksandar.qemu.devel@gmail.com, anup.patel@wdc.com, atish.patra@wdc.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, david@redhat.com, imbrenda@linux.ibm.com, pbonzini@redhat.com, jgross@suse.com, npiggin@gmail.com, seanjc@google.com, paulus@samba.org, mpe@ellerman.id.au, james.morse@arm.com, suzuki.poulose@arm.com, alexandru.elisei@arm.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org The kvm structure is pretty large. A large portion of it is the vcpu array, which is 4kB on x86_64 and arm64 as they deal with 512 vcpu VMs. Of course, hardly anyone runs VMs this big, so this is often a net waste of memory and cache locality. A possible approach is to turn the fixed-size array into an xarray, which results in a net code deletion after a bit of cleanup. This series is on top of the current linux/master as it touches the RISC-V implementation. Only tested on arm64. Marc Zyngier (5): KVM: Move wiping of the kvm->vcpus array to common code KVM: mips: Use kvm_get_vcpu() instead of open-coded access KVM: s390: Use kvm_get_vcpu() instead of open-coded access KVM: x86: Use kvm_get_vcpu() instead of open-coded access KVM: Convert the kvm->vcpus array to a xarray arch/arm64/kvm/arm.c | 10 +--------- arch/mips/kvm/loongson_ipi.c | 4 ++-- arch/mips/kvm/mips.c | 23 ++--------------------- arch/powerpc/kvm/powerpc.c | 10 +--------- arch/riscv/kvm/vm.c | 10 +--------- arch/s390/kvm/kvm-s390.c | 26 ++++++-------------------- arch/x86/kvm/vmx/posted_intr.c | 2 +- arch/x86/kvm/x86.c | 9 +-------- include/linux/kvm_host.h | 7 ++++--- virt/kvm/kvm_main.c | 33 ++++++++++++++++++++++++++------- 10 files changed, 45 insertions(+), 89 deletions(-) Tested-by: Juergen Gross