From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751446AbdGZKxr (ORCPT ); Wed, 26 Jul 2017 06:53:47 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:38747 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750921AbdGZKxp (ORCPT ); Wed, 26 Jul 2017 06:53:45 -0400 Subject: Re: [PATCH net] Revert "vhost: cache used event for better performance" To: Jason Wang , mst@redhat.com Cc: virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <1501056197-3368-1-git-send-email-jasowang@redhat.com> From: Christian Borntraeger Date: Wed, 26 Jul 2017 12:53:38 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <1501056197-3368-1-git-send-email-jasowang@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 17072610-0012-0000-0000-00000566702B X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17072610-0013-0000-0000-000018DB8668 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-07-26_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1706020000 definitions=main-1707260154 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/26/2017 10:03 AM, Jason Wang wrote: > This reverts commit 809ecb9bca6a9424ccd392d67e368160f8b76c92. Since it > was reported to break vhost_net. We want to cache used event and use > it to check for notification. We try to valid cached used event by > checking whether or not it was ahead of new, but this is not correct > all the time, it could be stale and there's no way to know about this. > > Signed-off-by: Jason Wang This would then qualify for stable ?