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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 4C61AECE58E for ; Tue, 15 Oct 2019 08:57:56 +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 1D9552089C for ; Tue, 15 Oct 2019 08:57:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1D9552089C 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]:37926 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iKIeR-0007fK-8T for qemu-devel@archiver.kernel.org; Tue, 15 Oct 2019 04:57:55 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33664) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iKIdp-0007C5-Fr for qemu-devel@nongnu.org; Tue, 15 Oct 2019 04:57:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iKIdn-0005xX-GX for qemu-devel@nongnu.org; Tue, 15 Oct 2019 04:57:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38662) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iKIdn-0005xM-7x for qemu-devel@nongnu.org; Tue, 15 Oct 2019 04:57:15 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 14EEB81DE0 for ; Tue, 15 Oct 2019 08:57:14 +0000 (UTC) Received: from work-vm (ovpn-117-145.ams2.redhat.com [10.36.117.145]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2181219C58; Tue, 15 Oct 2019 08:57:07 +0000 (UTC) Date: Tue, 15 Oct 2019 09:57:05 +0100 From: "Dr. David Alan Gilbert" To: Juan Quintela Subject: Re: [PATCH 1/2] migration: Boost SaveStateEntry.instance_id to 64 bits Message-ID: <20191015085705.GB3073@work-vm> References: <20191015075444.10955-1-peterx@redhat.com> <20191015075444.10955-2-peterx@redhat.com> <87lftmqtvi.fsf@trasno.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87lftmqtvi.fsf@trasno.org> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 15 Oct 2019 08:57:14 +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: , 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" * 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? Dave > A fast search shows: > > 10 callers of vmstate_register() with -1 > 1 caller of vmstate_register_with_alias_id with -1 (but it is the one > that sets all qdev devices). > 1 caller of vmstate_register_with_alias_id in apic, where it can be -1. > 1 caller of register_savevm_live() with -1 (spapr) > > And call it a day? > > What do you think, Juan. > > > --- > > include/migration/register.h | 2 +- > > include/migration/vmstate.h | 4 ++-- > > migration/savevm.c | 10 +++++----- > > stubs/vmstate.c | 2 +- > > 4 files changed, 9 insertions(+), 9 deletions(-) > > > > diff --git a/include/migration/register.h b/include/migration/register.h > > index a13359a08d..54f42c7413 100644 > > --- a/include/migration/register.h > > +++ b/include/migration/register.h > > @@ -69,7 +69,7 @@ typedef struct SaveVMHandlers { > > } SaveVMHandlers; > > > > int register_savevm_live(const char *idstr, > > - int instance_id, > > + int64_t instance_id, > > int version_id, > > const SaveVMHandlers *ops, > > void *opaque); > > diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h > > index 1fbfd099dd..6a7498463c 100644 > > --- a/include/migration/vmstate.h > > +++ b/include/migration/vmstate.h > > @@ -1114,14 +1114,14 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd, > > bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque); > > > > /* Returns: 0 on success, -1 on failure */ > > -int vmstate_register_with_alias_id(DeviceState *dev, int instance_id, > > +int vmstate_register_with_alias_id(DeviceState *dev, int64_t instance_id, > > const VMStateDescription *vmsd, > > void *base, int alias_id, > > int required_for_version, > > Error **errp); > > > > /* Returns: 0 on success, -1 on failure */ > > -static inline int vmstate_register(DeviceState *dev, int instance_id, > > +static inline int vmstate_register(DeviceState *dev, int64_t instance_id, > > const VMStateDescription *vmsd, > > void *opaque) > > { > > diff --git a/migration/savevm.c b/migration/savevm.c > > index bb9462a54d..dc9281c897 100644 > > --- a/migration/savevm.c > > +++ b/migration/savevm.c > > @@ -233,7 +233,7 @@ typedef struct CompatEntry { > > typedef struct SaveStateEntry { > > QTAILQ_ENTRY(SaveStateEntry) entry; > > char idstr[256]; > > - int instance_id; > > + int64_t instance_id; > > int alias_id; > > int version_id; > > /* version id read from the stream */ > > @@ -668,7 +668,7 @@ void dump_vmstate_json_to_file(FILE *out_file) > > static int calculate_new_instance_id(const char *idstr) > > { > > SaveStateEntry *se; > > - int instance_id = 0; > > + int64_t instance_id = 0; > > > > QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { > > if (strcmp(idstr, se->idstr) == 0 > > @@ -730,7 +730,7 @@ static void savevm_state_handler_insert(SaveStateEntry *nse) > > Meanwhile pass -1 as instance_id if you do not already have a clearly > > distinguishing id for all instances of your device class. */ > > int register_savevm_live(const char *idstr, > > - int instance_id, > > + int64_t instance_id, > > int version_id, > > const SaveVMHandlers *ops, > > void *opaque) > > @@ -784,7 +784,7 @@ void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque) > > } > > } > > > > -int vmstate_register_with_alias_id(DeviceState *dev, int instance_id, > > +int vmstate_register_with_alias_id(DeviceState *dev, int64_t instance_id, > > const VMStateDescription *vmsd, > > void *opaque, int alias_id, > > int required_for_version, > > @@ -1566,7 +1566,7 @@ int qemu_save_device_state(QEMUFile *f) > > return qemu_file_get_error(f); > > } > > > > -static SaveStateEntry *find_se(const char *idstr, int instance_id) > > +static SaveStateEntry *find_se(const char *idstr, int64_t instance_id) > > { > > SaveStateEntry *se; > > > > diff --git a/stubs/vmstate.c b/stubs/vmstate.c > > index e1e89b87f0..699003f3b0 100644 > > --- a/stubs/vmstate.c > > +++ b/stubs/vmstate.c > > @@ -4,7 +4,7 @@ > > const VMStateDescription vmstate_dummy = {}; > > > > int vmstate_register_with_alias_id(DeviceState *dev, > > - int instance_id, > > + int64_t instance_id, > > const VMStateDescription *vmsd, > > void *base, int alias_id, > > int required_for_version, -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK