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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 5C842C2D0CD for ; Tue, 17 Dec 2019 16:42:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 328B621D7D for ; Tue, 17 Dec 2019 16:42:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SHRvw6AZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727727AbfLQQmu (ORCPT ); Tue, 17 Dec 2019 11:42:50 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:45666 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726402AbfLQQmt (ORCPT ); Tue, 17 Dec 2019 11:42:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576600968; 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=CrCf/NwWYpCGoTQAsLWIUU7mZVErqP3JdIsj9e1SaPg=; b=SHRvw6AZ4IdvuqPcD6JfuTAuBoE7mWJuOyeo/5aF9o0gx1RHv4J3uWfLEKnSaqOjyqxhPF fmVAl6xbChYvOKBB3nYfybDqNjTkYztq5424LHpHIfjsnAXV1qHXL1v0zkmoRZK9DKh1VG y8sD51SGUg5K8BuG6Z4LT53FI4205I0= Received: from mail-qk1-f200.google.com (mail-qk1-f200.google.com [209.85.222.200]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-76-qzGUAUeKNZ2sinHN9CJh5g-1; Tue, 17 Dec 2019 11:42:47 -0500 X-MC-Unique: qzGUAUeKNZ2sinHN9CJh5g-1 Received: by mail-qk1-f200.google.com with SMTP id 12so7196171qkf.20 for ; Tue, 17 Dec 2019 08:42:47 -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=CrCf/NwWYpCGoTQAsLWIUU7mZVErqP3JdIsj9e1SaPg=; b=EynGE/Do5ZNEtipruqkUeP8cl8fAs63cAvtjP6xOJMeMQT4r9bsh7cbcb0mwO5Imfo yuMMiYCRhzxZvfV4jwmKnMlymgyGPTuXn50lTUF1XG7qXGsBnWWiJTKJ7cIUKUwrUtlf AB85JR0/hkzm4KdVHA0Ia+r20swCPOOUoGDX4jpTVHPt094q8oMo92/9P0Sk+tchPy3m LIIMbn07I7OWbWVXkbTjLntBciqYA49pjYqT+8JFJRtZfROruOgAjch9EFMlEyXAxmwX boPSRt4fBCwRQ7Y2SoUGy5XV7qmmatDYHRvszm4LFPpAr9J2LZkv61/CSmiiq84/cA3b EsMQ== X-Gm-Message-State: APjAAAUAYoy/V7v8/KRrHp6L+F0B7RO46ZBfFoKO5VptzDbN0JKkbnhk oJ5kggU/ub9ng16naEHlDaT63O2b2XrlYtvXyJrhloBBy80NUYBKVsJcb8iYMcuyhUA5Mxid5WJ ZQJFyoGPCV9erOp/nG20XvWaM X-Received: by 2002:ac8:21ec:: with SMTP id 41mr5448845qtz.242.1576600966836; Tue, 17 Dec 2019 08:42:46 -0800 (PST) X-Google-Smtp-Source: APXvYqwDiMxFU/n4dbLE4zkIZGOqGfipV+5VvUOqIWv7WdbeVIwoUMjJm6HdqztecpahePvpe+tBww== X-Received: by 2002:ac8:21ec:: with SMTP id 41mr5448824qtz.242.1576600966557; Tue, 17 Dec 2019 08:42:46 -0800 (PST) Received: from xz-x1 ([104.156.64.74]) by smtp.gmail.com with ESMTPSA id t73sm7262985qke.71.2019.12.17.08.42.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Dec 2019 08:42:45 -0800 (PST) Date: Tue, 17 Dec 2019 11:42:44 -0500 From: Peter Xu To: Paolo Bonzini Cc: Christophe de Dinechin , Christophe de Dinechin , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Sean Christopherson , "Dr . David Alan Gilbert" , Vitaly Kuznetsov Subject: Re: [PATCH RFC 04/15] KVM: Implement ring-based dirty memory tracking Message-ID: <20191217164244.GE7258@xz-x1> References: <20191129213505.18472-1-peterx@redhat.com> <20191129213505.18472-5-peterx@redhat.com> <20191213202324.GI16429@xz-x1> <20191217153837.GC7258@xz-x1> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 17, 2019 at 05:31:48PM +0100, Paolo Bonzini wrote: > On 17/12/19 16:38, Peter Xu wrote: > > There's still time to persuade me to going back to it. :) > > > > (Though, yes I still like current solution... if we can get rid of the > > only kvmgt ugliness, we can even throw away the per-vm ring with its > > "extra" 4k page. Then I suppose it'll be even harder to persuade me :) > > Actually that's what convinced me in the first place, so let's > absolutely get rid of both the per-VM ring and the union. Kevin and > Alex have answered and everybody seems to agree. Yeah that'd be perfect. However I just noticed something... Note that we still didn't read into non-x86 archs, I think it's the same question as when I asked whether we can unify the kvm[_vcpu]_write() interfaces and you'd like me to read the non-x86 archs - I think it's time I read them, because it's still possible that non-x86 archs will still need the per-vm ring... then that could be another problem if we want to at last spread the dirty ring idea outside of x86. -- Peter Xu