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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 7F974C2D0BF for ; Tue, 17 Dec 2019 22:24:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 536DA21775 for ; Tue, 17 Dec 2019 22:24:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="L6mniRuL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726551AbfLQWYx (ORCPT ); Tue, 17 Dec 2019 17:24:53 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:30199 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726296AbfLQWYw (ORCPT ); Tue, 17 Dec 2019 17:24:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576621491; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=n1zc/BAvLiuzmjBuBeyM8c5OGj4eP3sDEL7oyAZ0h/8=; b=L6mniRuLqkiHtIQ5cId5UnHm/phY6qnmT6e3j89rEyFXyvF5TcsGRMWglAQuSq4Ls/iLtu KuiOU20XwXm3XSeXn+BPNRQJ1nYbhdbTPKcWR78HBRvdO6CqqWBUgge/ju+ilYxLGrVSmZ gA3h1tu10Onkz9OTj+kUVmpBOhCQUeo= Received: from mail-qt1-f199.google.com (mail-qt1-f199.google.com [209.85.160.199]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-384-gXgbb0jiOYCyhCm5KD5P6w-1; Tue, 17 Dec 2019 17:24:49 -0500 X-MC-Unique: gXgbb0jiOYCyhCm5KD5P6w-1 Received: by mail-qt1-f199.google.com with SMTP id e8so172037qtg.9 for ; Tue, 17 Dec 2019 14:24:49 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=n1zc/BAvLiuzmjBuBeyM8c5OGj4eP3sDEL7oyAZ0h/8=; b=Nc3N2NujtHpr4h27kgEuQxiu1nEnt4FqKJb2r/Yjryu9hlz7vfdbqMt4fppdiH78zC BZZlSQ/7zMbGMNxVPT/AF5foPhhHAjqhkFTMB1/BIMoVxQRG6172tVC0v3ryF+131yY+ 2nuNG3GeoT0kH59H8A9J16dJ0v3YxtkRyMVyf8wUPnXMydZ6i0d4uN2EE4eXT+MzcF9W LVJ4pehY0fEB2/4JAUpG1X7YprXs+EunoWpVeiXX0ZvrdfHANFTaltt9z0+8kNsmHwAU 1pFGRQzxMGHfdzXy3u8FxJ2+LxmGABb5ySGEmiLo+cQ4NSm0rGYdlA5liosoQS6ZdD+4 p9tw== X-Gm-Message-State: APjAAAXicj1BgcYJ1M7/FdlJjoWS5vIJvuTs8+lfYZE65F2E1ok/hMaL ogJ85O0H1yWic12h1JV+y3CnrA2yjOnFTttYk1jAWeRZDsYO8/6K/wURjbQdCqZ76UmBd6Q0icU deCEq30jj39XD X-Received: by 2002:ac8:3177:: with SMTP id h52mr248052qtb.264.1576621488937; Tue, 17 Dec 2019 14:24:48 -0800 (PST) X-Google-Smtp-Source: APXvYqxa9aGwr5mHm2Cm0VxXNZlZXqTAo8dq2kd9eCG/gVR+l9nUybMoSUNtPMwlIhbLMlDgqBEiTQ== X-Received: by 2002:ac8:3177:: with SMTP id h52mr248020qtb.264.1576621488653; Tue, 17 Dec 2019 14:24:48 -0800 (PST) Received: from xz-x1 ([104.156.64.74]) by smtp.gmail.com with ESMTPSA id c84sm7565689qkg.78.2019.12.17.14.24.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Dec 2019 14:24:47 -0800 (PST) Date: Tue, 17 Dec 2019 17:24:46 -0500 From: Peter Xu To: Sean Christopherson Cc: James Hogan , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini , Marc Zyngier , linux-arm-kernel@lists.infradead.org, Wanpeng Li , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , kvm@vger.kernel.org, David Hildenbrand , Joerg Roedel , Cornelia Huck , linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org, Vitaly Kuznetsov , kvmarm@lists.cs.columbia.edu, Jim Mattson Subject: Re: [PATCH v4 07/19] KVM: Explicitly free allocated-but-unused dirty bitmap Message-ID: <20191217222446.GK7258@xz-x1> References: <20191217204041.10815-1-sean.j.christopherson@intel.com> <20191217204041.10815-8-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20191217204041.10815-8-sean.j.christopherson@intel.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Dec 17, 2019 at 12:40:29PM -0800, Sean Christopherson wrote: > Explicitly free an allocated-but-unused dirty bitmap instead of relying > on kvm_free_memslot() if an error occurs in __kvm_set_memory_region(). > There is no longer a need to abuse kvm_free_memslot() to free arch > specific resources as arch specific code is now called only after the > common flow is guaranteed to succeed. Arch code can still fail, but > it's responsible for its own cleanup in that case. > > Eliminating the error path's abuse of kvm_free_memslot() paves the way > for simplifying kvm_free_memslot(), i.e. dropping its @dont param. > > Signed-off-by: Sean Christopherson > --- > virt/kvm/kvm_main.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index d403e93e3028..6b2261a9e139 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -1096,7 +1096,7 @@ int __kvm_set_memory_region(struct kvm *kvm, > > slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT); > if (!slots) > - goto out_free; > + goto out_bitmap; > memcpy(slots, __kvm_memslots(kvm, as_id), sizeof(struct kvm_memslots)); > > if ((change == KVM_MR_DELETE) || (change == KVM_MR_MOVE)) { > @@ -1144,8 +1144,9 @@ int __kvm_set_memory_region(struct kvm *kvm, > if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) > slots = install_new_memslots(kvm, as_id, slots); > kvfree(slots); > -out_free: > - kvm_free_memslot(kvm, &new, &old); > +out_bitmap: > + if (new.dirty_bitmap && !old.dirty_bitmap) > + kvm_destroy_dirty_bitmap(&new); What if both the old and new have KVM_MEM_LOG_DIRTY_PAGES set? kvm_free_memslot() did cover that but I see that you explicitly dropped it. Could I ask why? Thanks, -- Peter Xu