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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 3BE4BC10F14 for ; Tue, 15 Oct 2019 12:58:30 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0C5FC217F9 for ; Tue, 15 Oct 2019 12:58:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0C5FC217F9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44320 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iKMPF-00044l-65 for qemu-devel@archiver.kernel.org; Tue, 15 Oct 2019 08:58:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45133) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iKMOa-0003c7-0K for qemu-devel@nongnu.org; Tue, 15 Oct 2019 08:57:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iKMOY-0000F3-W5 for qemu-devel@nongnu.org; Tue, 15 Oct 2019 08:57:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41112) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iKMOY-0000Eo-Ql for qemu-devel@nongnu.org; Tue, 15 Oct 2019 08:57:46 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 00937BB9C2 for ; Tue, 15 Oct 2019 12:57:46 +0000 (UTC) Received: from redhat.com (ovpn-117-212.ams2.redhat.com [10.36.117.212]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DB71060C80; Tue, 15 Oct 2019 12:57:42 +0000 (UTC) From: Juan Quintela To: "Dr. David Alan Gilbert" Subject: Re: [PATCH 1/2] migration: Boost SaveStateEntry.instance_id to 64 bits In-Reply-To: <20191015085705.GB3073@work-vm> (David Alan Gilbert's message of "Tue, 15 Oct 2019 09:57:05 +0100") References: <20191015075444.10955-1-peterx@redhat.com> <20191015075444.10955-2-peterx@redhat.com> <87lftmqtvi.fsf@trasno.org> <20191015085705.GB3073@work-vm> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) Date: Tue, 15 Oct 2019 14:57:40 +0200 Message-ID: <87h84aqi7v.fsf@trasno.org> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Tue, 15 Oct 2019 12:57:46 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: quintela@redhat.com Cc: Paolo Bonzini , Eduardo Habkost , qemu-devel@nongnu.org, Peter Xu , Igor Mammedov Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" "Dr. David Alan Gilbert" wrote: > * Juan Quintela (quintela@redhat.com) wrote: >> Peter Xu wrote: >> > It was "int" and used as 32bits fields (see save_section_header()). >> > It's unsafe already because sizeof(int) could be 2 on i386, I think. >> > So at least uint32_t would suite more. While it also uses "-1" as a >> > placeholder of "we want to generate the instance ID automatically". >> > Hence a more proper value should be int64_t. >> > >> > This will start to be useful after next patch in which we can start to >> > convert a real uint32_t value as instance ID. >> > >> > Signed-off-by: Peter Xu >> >> Hi >> >> Being more helpful, I think that it is better to just: >> >> * change instance_id to be an uint32_t (notice that for all architectures >> that we support, it is actually int32_t). >> >> * export calculate_new_instance_id() and adjust callers that use -1. >> >> or >> >> * export a new function that just use the calculate_new_instance_id() > > Do you mean that we end up with two functions, one that does it > automatically, and one that takes an ID? That is one option. The other is that we export calculate_new_instance_id(), and we use that instead of -1. Later, Juan.