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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 59201CA9EA0 for ; Fri, 25 Oct 2019 13:28:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2B2A921D71 for ; Fri, 25 Oct 2019 13:28:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394628AbfJYN2D (ORCPT ); Fri, 25 Oct 2019 09:28:03 -0400 Received: from foss.arm.com ([217.140.110.172]:40616 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726393AbfJYN2D (ORCPT ); Fri, 25 Oct 2019 09:28:03 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B79EE28; Fri, 25 Oct 2019 06:28:02 -0700 (PDT) Received: from localhost (e113682-lin.copenhagen.arm.com [10.32.145.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 476EF3F718; Fri, 25 Oct 2019 06:28:02 -0700 (PDT) Date: Fri, 25 Oct 2019 15:28:01 +0200 From: Christoffer Dall To: Sean Christopherson Cc: James Hogan , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Marc Zyngier , David Hildenbrand , Cornelia Huck , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , James Morse , Julien Thierry , Suzuki K Poulose , linux-mips@vger.kernel.org, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 00/15] KVM: Dynamically size memslot arrays Message-ID: <20191025132801.GK2652@e113682-lin.lund.arm.com> References: <20191024230744.14543-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191024230744.14543-1-sean.j.christopherson@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Thu, Oct 24, 2019 at 04:07:29PM -0700, Sean Christopherson wrote: > The end goal of this series is to dynamically size the memslot array so > that KVM allocates memory based on the number of memslots in use, as > opposed to unconditionally allocating memory for the maximum number of > memslots. On x86, each memslot consumes 88 bytes, and so with 2 address > spaces of 512 memslots, each VM consumes ~90k bytes for the memslots. > E.g. given a VM that uses a total of 30 memslots, dynamic sizing reduces > the memory footprint from 90k to ~2.6k bytes. > > The changes required to support dynamic sizing are relatively small, > e.g. are essentially contained in patches 14/15 and 15/15. Patches 1-13 > clean up the memslot code, which has gotten quite crusty, especially > __kvm_set_memory_region(). The clean up is likely not strictly necessary > to switch to dynamic sizing, but I didn't have a remotely reasonable > level of confidence in the correctness of the dynamic sizing without first > doing the clean up. > > Christoffer, I added your Tested-by to the patches that I was confident > would be fully tested based on the desription of what you tested. Let me > know if you disagree with any of 'em. > The only testing I've done of patch 9 would be via the vm_free part of kvm selftest, so not sure how valid that is, but sure. Looks fine otherwise. Thanks, Christoffer