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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 3AE4AC77B7A for ; Fri, 26 May 2023 11:56:44 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1q2W3R-0008TP-J3; Fri, 26 May 2023 07:56:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q2W3M-0008Ot-5A for qemu-devel@nongnu.org; Fri, 26 May 2023 07:56:17 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q2W3K-00018e-E0 for qemu-devel@nongnu.org; Fri, 26 May 2023 07:56:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1685102173; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Tj3bPHgQUygW4vkM/m7RuVDN2EAu7BfagOs8r7Ie/GY=; b=HfQntK/W+6Xej/No4mCZhpdpzJeqOhDi7B32mPSJo7CM/0A8HhqwQ8JY+zPt541jw3vB5H 7FjuRItFxPYgixU7dJ5HFhNIlY+y9PrJ9sfsidGISchoODfaEBBS7qV7Taj09onQGzULAO lDUe9a9Id8f4i/Tpvms21M/7ixdEvvE= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-605-qz-87vSyOO2aujeZCZYNtw-1; Fri, 26 May 2023 07:56:12 -0400 X-MC-Unique: qz-87vSyOO2aujeZCZYNtw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D1CA72A2AD5C; Fri, 26 May 2023 11:56:11 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.51]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DD60C7C2A; Fri, 26 May 2023 11:56:07 +0000 (UTC) Date: Fri, 26 May 2023 12:56:01 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Juan Quintela , qemu-devel@nongnu.org, qemu-block@nongnu.org, Paolo Bonzini , Thomas Huth , John Snow , Li Zhijian , Stefan Hajnoczi , Zhang Chen , Laurent Vivier Subject: Re: [PATCH v2 3/6] tests/qtest: capture RESUME events during migration Message-ID: References: <20230421171411.566300-1-berrange@redhat.com> <20230421171411.566300-4-berrange@redhat.com> <87leikgama.fsf@secure.mitica> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.9 (2022-11-12) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, Apr 24, 2023 at 10:53:36AM +0100, Daniel P. Berrangé wrote: > On Fri, Apr 21, 2023 at 11:59:25PM +0200, Juan Quintela wrote: > > Daniel P. Berrangé wrote: > > > When running migration tests we monitor for a STOP event so we can skip > > > redundant waits. This will be needed for the RESUME event too shortly. > > > > > > Signed-off-by: Daniel P. Berrangé > > > > Reviewed-by: Juan Quintela > > > > i.e. it is better that what we have now. > > > > But > > > > > > > diff --git a/tests/qtest/migration-helpers.c b/tests/qtest/migration-helpers.c > > > index f6f3c6680f..61396335cc 100644 > > > --- a/tests/qtest/migration-helpers.c > > > +++ b/tests/qtest/migration-helpers.c > > > @@ -24,14 +24,20 @@ > > > #define MIGRATION_STATUS_WAIT_TIMEOUT 120 > > > > > > bool got_stop; > > > +bool got_resume; > > > > > > -static void check_stop_event(QTestState *who) > > > +static void check_events(QTestState *who) > > > { > > > QDict *event = qtest_qmp_event_ref(who, "STOP"); > > > if (event) { > > > got_stop = true; > > > qobject_unref(event); > > > } > > > + event = qtest_qmp_event_ref(who, "RESUME"); > > > + if (event) { > > > + got_resume = true; > > > + qobject_unref(event); > > > + } > > > } > > > > What happens if we receive the events in the order RESUME/STOP (I mean > > in the big scheme of things, not that it makes sense in this particular > > case). > > > > QDict *qtest_qmp_event_ref(QTestState *s, const char *event) > > { > > while (s->pending_events) { > > > > GList *first = s->pending_events; > > QDict *response = (QDict *)first->data; > > > > s->pending_events = g_list_delete_link(s->pending_events, first); > > > > if (!strcmp(qdict_get_str(response, "event"), event)) { > > return response; > > } > > qobject_unref(response); > > } > > return NULL; > > } > > > > if we don't found the event that we are searching for, we just drop it. > > Does this makes sense if we are searching only for more than one event? > > You are right about this code being broken in general for multiple events. > > In this particular series though we're looking at STOP on the src host and > RESUME on the dst host, so there's no ordering problem to worry about. What I wrote is nonsense. This is broken, because on the dst host, check_events will look for STOP and discard all remaining events, so we'll never find the RESUME that we are looking for. qtest_qmp_event_ref is essentially broken by design right now and I'll need to fix it. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|