[{"id":1767944,"web_url":"http://patchwork.ozlabs.org/comment/1767944/","msgid":"<20170913164624.6fc7b3e6@nial.brq.redhat.com>","list_archive_url":null,"date":"2017-09-13T14:46:24","subject":"Re: [Qemu-devel] [PATCH v5 22/22] s390x: allow CPU hotplug in\n\trandom core-id order","submitter":{"id":11305,"url":"http://patchwork.ozlabs.org/api/people/11305/","name":"Igor Mammedov","email":"imammedo@redhat.com"},"content":"On Wed, 13 Sep 2017 15:24:17 +0200\nDavid Hildenbrand wrote:\n\n> SCLP correctly indicates the core-id aka. CPU address for each available\n> CPU.\n> \n> As the core-id corresponds to cpu_index, also a newly created kvm vcpu\n> gets assigned this core-id as vcpu id. So SIGP in the kernel works\n> correctly (it uses the vcpu id to lookup the correct CPU).\n> \n> So there should be nothing hindering us from hotplugging CPUs in random\n> core-id order.\n> \n> This now makes sure that the output from \"query-hotpluggable-cpus\"\n> is completely true. Until now, a specific order is implicit. Performance\n> vice, hotplugging CPUs in non-sequential order might not be the best thing\n> to do, as VCPU lookup inside KVM might be a little slower. But that\n> doesn't hinder us from supporting it.\n> \n> next_core_id is now used by linux user only.\n> \n> Signed-off-by: David Hildenbrand \nReviewed-by: Igor Mammedov \n\n> ---\n> target/s390x/cpu.c | 8 +-------\n> 1 file changed, 1 insertion(+), 7 deletions(-)\n> \n> diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c\n> index 5724dffb88..34538c3ab9 100644\n> --- a/target/s390x/cpu.c\n> +++ b/target/s390x/cpu.c\n> @@ -199,6 +199,7 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp)\n> #else\n> /* implicitly set for linux-user only */\n> cpu->env.core_id = scc->next_core_id;\n> + scc->next_core_id++;\n> #endif\n> \n> if (cpu_exists(cpu->env.core_id)) {\n> @@ -206,12 +207,6 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp)\n> \", it already exists\", cpu->env.core_id);\n> goto out;\n> }\n> - if (cpu->env.core_id != scc->next_core_id) {\n> - error_setg(&err, \"Unable to add CPU with core-id: %\" PRIu32\n> - \", the next available core-id is %\" PRIu32, cpu->env.core_id,\n> - scc->next_core_id);\n> - goto out;\n> - }\n> \n> /* sync cs->cpu_index and env->core_id. The latter is needed for TCG. */\n> cs->cpu_index = env->core_id;\n> @@ -219,7 +214,6 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp)\n> if (err != NULL) {\n> goto out;\n> }\n> - scc->next_core_id++;\n> \n> #if !defined(CONFIG_USER_ONLY)\n> qemu_register_reset(s390_cpu_machine_reset_cb, cpu);","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=)","ext-mx01.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com","ext-mx01.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=imammedo@redhat.com"],"Received":["from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xskyz4Ccyz9s76\n\tfor ;\n\tThu, 14 Sep 2017 00:47:23 +1000 (AEST)","from localhost ([::1]:42940 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t)\n\tid 1ds8wj-0001Cv-Md\n\tfor incoming@patchwork.ozlabs.org; Wed, 13 Sep 2017 10:47:21 -0400","from eggs.gnu.org ([2001:4830:134:3::10]:46057)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from ) id 1ds8vz-0001AO-En\n\tfor qemu-devel@nongnu.org; Wed, 13 Sep 2017 10:46:36 -0400","from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from ) id 1ds8vv-0005gn-Fv\n\tfor qemu-devel@nongnu.org; Wed, 13 Sep 2017 10:46:35 -0400","from mx1.redhat.com ([209.132.183.28]:37186)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from ) id 1ds8vv-0005gH-7i\n\tfor qemu-devel@nongnu.org; Wed, 13 Sep 2017 10:46:31 -0400","from smtp.corp.redhat.com\n\t(int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id 2F97781229;\n\tWed, 13 Sep 2017 14:46:30 +0000 (UTC)","from nial.brq.redhat.com (unknown [10.43.2.209])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id B130E69FC4;\n\tWed, 13 Sep 2017 14:46:25 +0000 (UTC)"],"DMARC-Filter":"OpenDMARC Filter v1.3.2 mx1.redhat.com 2F97781229","Date":"Wed, 13 Sep 2017 16:46:24 +0200","From":"Igor Mammedov ","To":"David Hildenbrand ","Message-ID":"<20170913164624.6fc7b3e6@nial.brq.redhat.com>","In-Reply-To":"<20170913132417.24384-23-david@redhat.com>","References":"<20170913132417.24384-1-david@redhat.com>\n\t<20170913132417.24384-23-david@redhat.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=US-ASCII","Content-Transfer-Encoding":"7bit","X-Scanned-By":"MIMEDefang 2.79 on 10.5.11.11","X-Greylist":"Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.25]);\n\tWed, 13 Sep 2017 14:46:30 +0000 (UTC)","X-detected-operating-system":"by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic]\n\t[fuzzy]","X-Received-From":"209.132.183.28","Subject":"Re: [Qemu-devel] [PATCH v5 22/22] s390x: allow CPU hotplug in\n\trandom core-id order","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.21","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"Matthew Rosato , thuth@redhat.com,\n\tEduardo Habkost ,\n\tMarkus Armbruster , cohuck@redhat.com,\n\tRichard Henderson ,\n\tqemu-devel@nongnu.org, Alexander Graf ,\n\tborntraeger@de.ibm.com, Paolo Bonzini ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"\"Qemu-devel\"\n\t"}}]