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=-8.2 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 2B014C43331 for ; Thu, 26 Mar 2020 10:30:42 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 E3E3C20714 for ; Thu, 26 Mar 2020 10:30:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E3E3C20714 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jHPlz-0005dT-Od; Thu, 26 Mar 2020 10:30:03 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jHPly-0005Yc-OD for xen-devel@lists.xenproject.org; Thu, 26 Mar 2020 10:30:02 +0000 X-Inumbo-ID: bf4f07ce-6f4c-11ea-879b-12813bfff9fa Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id bf4f07ce-6f4c-11ea-879b-12813bfff9fa; Thu, 26 Mar 2020 10:30:01 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id EE899AD08; Thu, 26 Mar 2020 10:29:59 +0000 (UTC) To: xen-devel@lists.xenproject.org References: <20200326094557.13822-1-jgross@suse.com> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: <1a94286a-a164-27dd-3f1f-2d19ba5d547c@suse.com> Date: Thu, 26 Mar 2020 11:29:59 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200326094557.13822-1-jgross@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Xen-devel] [PATCH] tools/libxl: make default of max event channels dependant on vcpus X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Anthony PERARD , Ian Jackson , Wei Liu Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 26.03.20 10:45, Juergen Gross wrote: > Today the maximum number of event channels for a guest is defaulting > to 1023. For large guests with lots of vcpus this is not enough, as > e.g. the Linux kernel uses 7 event channels per vcpu, limiting the > guest to about 140 vcpus. > > Instead of requiring to specify the allowed number of event channels > via the "event_channels" domain config option, make the default > depend on the maximum number of vcpus of the guest. > > In order not to regress current configs use 1023 as the minimum > default setting. > > Signed-off-by: Juergen Gross > --- > tools/libxl/libxl_create.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c > index e7cb2dbc2b..eddd0e98e5 100644 > --- a/tools/libxl/libxl_create.c > +++ b/tools/libxl/libxl_create.c > @@ -226,7 +226,7 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc, > b_info->iomem[i].gfn = b_info->iomem[i].start; > > if (!b_info->event_channels) > - b_info->event_channels = 1023; > + b_info->event_channels = min(1023, b_info->max_vcpus * 8 + 255); Sorry, forgot to do "stg refresh", this should be max(), of course. Juergen