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=-7.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 1E183C43441 for ; Wed, 10 Oct 2018 15:09:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B188C2150D for ; Wed, 10 Oct 2018 15:09:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="UMbUM0M/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B188C2150D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726871AbeJJWbt (ORCPT ); Wed, 10 Oct 2018 18:31:49 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:55952 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726503AbeJJWbt (ORCPT ); Wed, 10 Oct 2018 18:31:49 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w9AEx5Tw025207; Wed, 10 Oct 2018 15:09:09 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=YegHVM7DqawRuc0xkrr8YgLxRPBZmWJfnOD9RUSve4s=; b=UMbUM0M/dlV3SWxWuTwIhyq8IeZ2Y4jL5m6PXF/9cLNTw+xonP1j0UydNQn4LRFv0vUy 1zzU79Ow/geKZZwjVMgBK3aRIOGrE9OSSTFM45d7bCrj7mqsK4EI/I7Io8oGqPwkAbXJ AQUx6KRP3J3W8CVdaTtMBbrCYzlaN/NxJJ1mO7tGnhMh3l/jP4eaZeLAu/dkaz1KStba ZhlzptKPibPyyiepCjPEaXrg20lBCJu7F3/1mcL1qjMQZTvaGULcHjpL2+THE313yEms +v7LKh1Q6XsZxPRU458QdII5c4y68r4yEPr2G73bHgV8bemxXvUhBhh83UDQoxeosyrz Zw== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2120.oracle.com with ESMTP id 2mxnpr4kny-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 10 Oct 2018 15:09:08 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w9AF97Cc013241 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 10 Oct 2018 15:09:07 GMT Received: from abhmp0016.oracle.com (abhmp0016.oracle.com [141.146.116.22]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w9AF96QB005048; Wed, 10 Oct 2018 15:09:07 GMT Received: from [10.175.193.46] (/10.175.193.46) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 10 Oct 2018 15:09:06 +0000 Subject: Re: [Xen-devel] [PATCH] xen: drop writing error messages to xenstore To: Juergen Gross Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, boris.ostrovsky@oracle.com References: <20181009160959.31076-1-jgross@suse.com> From: Joao Martins Message-ID: <5126873e-ade5-86b0-4ebf-58cb47c9cbe7@oracle.com> Date: Wed, 10 Oct 2018 16:09:02 +0100 MIME-Version: 1.0 In-Reply-To: <20181009160959.31076-1-jgross@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9041 signatures=668706 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810100149 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/09/2018 05:09 PM, Juergen Gross wrote: > xenbus_va_dev_error() will try to write error messages to Xenstore > under the error//error node (with something like > "device/vbd/51872"). This will fail normally and another message > about this failure is added to dmesg. > > I believe this is a remnant from very ancient times, as it was added > in the first pvops rush of commits in 2007. > > So remove the additional message when writing to Xenstore failed as > a minimum step. > > Signed-off-by: Juergen Gross > --- > I am considering removing the Xenstore write altogether, but I'm > not sure it isn't needed e.g. by xend based installations. So please > speak up in case you know why this write is there. So this: "This will fail normally and another message about this failure is added to dmesg." Brings me to the question: What about {stub,driver}domains? Ideally you shouldn't be looking at domU's dmesg as a control domain no? I can't remember any other error node, but if something fails e.g. netfront fails to allocate an unbound event channel - how do you know the cause from the control domain perspective? Irrespective of xend or not: isn't this 'error' node the only one that propagates error causes per device from domU? Joao > --- > drivers/xen/xenbus/xenbus_client.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c > index a1c17000129b..e17ca8156171 100644 > --- a/drivers/xen/xenbus/xenbus_client.c > +++ b/drivers/xen/xenbus/xenbus_client.c > @@ -278,10 +278,8 @@ static void xenbus_va_dev_error(struct xenbus_device *dev, int err, > dev_err(&dev->dev, "%s\n", printf_buffer); > > path_buffer = kasprintf(GFP_KERNEL, "error/%s", dev->nodename); > - if (!path_buffer || > - xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer)) > - dev_err(&dev->dev, "failed to write error node for %s (%s)\n", > - dev->nodename, printf_buffer); > + if (path_buffer) > + xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer); > > kfree(printf_buffer); > kfree(path_buffer); >