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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 ADC3AC43387 for ; Thu, 3 Jan 2019 12:18:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B23B20675 for ; Thu, 3 Jan 2019 12:18:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730772AbfACMQh (ORCPT ); Thu, 3 Jan 2019 07:16:37 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:35158 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729618AbfACMQh (ORCPT ); Thu, 3 Jan 2019 07:16:37 -0500 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id x03CACxj019671 for ; Thu, 3 Jan 2019 07:16:36 -0500 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 2psj368f5k-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 03 Jan 2019 07:16:36 -0500 Received: from localhost by e06smtp02.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 3 Jan 2019 12:16:34 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (9.149.109.194) by e06smtp02.uk.ibm.com (192.168.101.132) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 3 Jan 2019 12:16:30 -0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x03CGTUU46333962 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 3 Jan 2019 12:16:29 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7FCD452050; Thu, 3 Jan 2019 12:16:29 +0000 (GMT) Received: from oc2783563651 (unknown [9.152.224.202]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 3733A52052; Thu, 3 Jan 2019 12:16:29 +0000 (GMT) Date: Thu, 3 Jan 2019 13:16:28 +0100 From: Halil Pasic To: Wei Wang Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, mst@redhat.com, cohuck@redhat.com, borntraeger@de.ibm.com, pbonzini@redhat.com, dgilbert@redhat.com Subject: Re: [PATCH v1 1/2] virtio-balloon: tweak config_changed implementation In-Reply-To: <1546493462-32244-2-git-send-email-wei.w.wang@intel.com> References: <1546493462-32244-1-git-send-email-wei.w.wang@intel.com> <1546493462-32244-2-git-send-email-wei.w.wang@intel.com> Organization: IBM X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 19010312-0008-0000-0000-000002A975BE X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19010312-0009-0000-0000-000022158D7E Message-Id: <20190103131628.3674a50d@oc2783563651> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-01-03_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901030109 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 3 Jan 2019 13:31:01 +0800 Wei Wang wrote: > virtio-ccw has deadlock issues with reading config registers inside the > interrupt context I would say something like 'virtio-ccw does not support using virtio_config_ops from an atomic context' as the limitation is not limited to read config (aka. get()). But I'm fine with your formulation as well. > , so we tweak the virtballoon_changed implementation > by moving the config read operations into the related workqueue contexts. > > Signed-off-by: Wei Wang Reviewed-by: Halil Pasic [..]