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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 536C8C433B4 for ; Mon, 17 May 2021 14:40:07 +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 0CDEB61360 for ; Mon, 17 May 2021 14:40:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0CDEB61360 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]:60512 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1liePe-0003aN-2B for qemu-devel@archiver.kernel.org; Mon, 17 May 2021 10:40:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58140) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lieJi-0004qv-VP for qemu-devel@nongnu.org; Mon, 17 May 2021 10:33:58 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:51277) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lieJd-0001vw-Sh for qemu-devel@nongnu.org; Mon, 17 May 2021 10:33:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1621262032; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VAvkzY0OjZyD+6OPL3fyPKncl3mSnowN+/HLYDu533U=; b=jVHPkS77/F6IjvceL6uUH1NT+0HCrc1LX14w4yGlzBLa6e8cekYwMNipTd0IwN+NLxREZx zgz03dKKoLNRMgHX0gVDmzLs+K8iYVh6MGd9Pp1ilk6H7scR44VytuGEJF8aRKRt8xsUVC NGkVcX/AjeTD7Ht5yLKO1FFw1BB3EQU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-592-6rcwxvM3OJCj3lKIMAb-5Q-1; Mon, 17 May 2021 10:33:51 -0400 X-MC-Unique: 6rcwxvM3OJCj3lKIMAb-5Q-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4B458107ACF5; Mon, 17 May 2021 14:33:50 +0000 (UTC) Received: from localhost (unknown [10.40.208.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id E5EA35D6D7; Mon, 17 May 2021 14:33:48 +0000 (UTC) Date: Mon, 17 May 2021 16:33:45 +0200 From: Igor Mammedov To: Denis Plotnikov Subject: Re: [PATCH v1] softmmu/vl: make default prealloc-threads work w/o -mem-prealloc Message-ID: <20210517163345.61ce8b3b@redhat.com> In-Reply-To: <20210311085918.284903-1-den-plotnikov@yandex-team.ru> References: <20210311085918.284903-1-den-plotnikov@yandex-team.ru> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=imammedo@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=imammedo@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.374, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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: pbonzini@redhat.com, qemu-devel@nongnu.org, yc-core@yandex-team.ru Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 11 Mar 2021 11:59:18 +0300 Denis Plotnikov wrote: > Preallocation in memory backends can be specified with either global > QEMU option "-mem-prealloc", or with per-backend property > "prealloc=true". In the latter case, however, the default for the > number of preallocation threads is not set to the number of vcpus, but > remains at 1 instead. > > Fix it by setting the "prealloc-threads" sugar property of > "memory-backend" to the number of vcpus unconditionally. well, number of prealloc-threads are policy that should be set by user. it was kept equal to vcpus for compat reasons with "-mem-prealloc", for if one goes with supplying memory backends explicitly, one is supposed to set prealloc-threads explicitly as well if default(==1) doesn't suit user. It could be equal to #vcpus or be a different numbers depending on host CPU configuration. That was intent when commit ffac16fab3 was introduced. Imagine one has a VM with a lot of VCPUs but not so much of of RAM, setting prealloc-threads to #VCPUs will be wasting CPU resources at least. > Fixes: ffac16fab3 ("hostmem: introduce "prealloc-threads" property") > > Signed-off-by: Denis Plotnikov > --- > softmmu/vl.c | 17 ++++++++++------- > 1 file changed, 10 insertions(+), 7 deletions(-) > > diff --git a/softmmu/vl.c b/softmmu/vl.c > index ff488ea3e7db..e392e226a2d3 100644 > --- a/softmmu/vl.c > +++ b/softmmu/vl.c > @@ -2300,14 +2300,17 @@ static void qemu_validate_options(void) > > static void qemu_process_sugar_options(void) > { > - if (mem_prealloc) { > - char *val; > + char *val; > > - val = g_strdup_printf("%d", > - (uint32_t) qemu_opt_get_number(qemu_find_opts_singleton("smp-opts"), "cpus", 1)); > - object_register_sugar_prop("memory-backend", "prealloc-threads", val, > - false); > - g_free(val); > + val = g_strdup_printf("%d", > + (uint32_t) qemu_opt_get_number( > + qemu_find_opts_singleton("smp-opts"), "cpus", 1)); > + > + object_register_sugar_prop("memory-backend", "prealloc-threads", val, > + false); > + g_free(val); > + > + if (mem_prealloc) { > object_register_sugar_prop("memory-backend", "prealloc", "on", false); > } >