From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by dpdk.org (Postfix) with ESMTP id 708E84C74; Wed, 27 Feb 2019 11:55:15 +0100 (CET) X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Feb 2019 02:55:14 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,419,1544515200"; d="scan'208";a="125577701" Received: from dpdk-tbie.sh.intel.com ([10.67.104.173]) by fmsmga007.fm.intel.com with ESMTP; 27 Feb 2019 02:55:12 -0800 Date: Wed, 27 Feb 2019 18:55:11 +0800 From: Tiwei Bie To: "Hu, Jiayu" Cc: "dev@dpdk.org" , "maxime.coquelin@redhat.com" , "stable@dpdk.org" Message-ID: <20190227105511.GA12253@dpdk-tbie.sh.intel.com> References: <1550823230-16809-1-git-send-email-jiayu.hu@intel.com> <20190225070654.GA22485@dpdk-tbie.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Subject: Re: [dpdk-dev] [PATCH] vhost: fix interrupt suppression for the split ring X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Feb 2019 10:55:16 -0000 On Wed, Feb 27, 2019 at 01:38:28PM +0800, Hu, Jiayu wrote: > > -----Original Message----- > > From: Bie, Tiwei > > Sent: Monday, February 25, 2019 3:07 PM > > To: Hu, Jiayu > > Cc: dev@dpdk.org; maxime.coquelin@redhat.com; stable@dpdk.org > > Subject: Re: [PATCH] vhost: fix interrupt suppression for the split ring > > > > On Fri, Feb 22, 2019 at 04:13:50PM +0800, Jiayu Hu wrote: > > > The VIRTIO_RING_F_EVENT_IDX feature of split ring might > > > be broken, as the value of signalled_used is unpredictable > > > after live migration or start up. This patch fixes it by > > > using signalled_used_valid. > > > > Seems you also need to invalidate the signalled_used in e.g. > > set_vring_base, as signalled_used may not match last_used_idx > > anymore e.g. when guest driver is reloaded. > > To handle the virtio device reload case, how about setting > signalled_used_valid to false in get_vring_base()? Sounds good. > > Thanks, > Jiayu > > > > > > > > > In addition, this patch makes the VIRTIO_RING_F_EVENT_IDX > > > implementation of split ring match kernel backend to suppress > > > more interrupts. > > > > > > Fixes: e37ff954405a ("vhost: support virtqueue interrupt/notification > > suppression") > > > Cc: stable@dpdk.org > > > > > > Signed-off-by: Jiayu Hu > > > --- > > > lib/librte_vhost/vhost.h | 12 ++++++++---- > > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > > > diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h > > > index fc31796..c4e5e34 100644 > > > --- a/lib/librte_vhost/vhost.h > > > +++ b/lib/librte_vhost/vhost.h > > > @@ -633,16 +633,20 @@ vhost_vring_call_split(struct virtio_net *dev, > > struct vhost_virtqueue *vq) > > > if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) { > > > uint16_t old = vq->signalled_used; > > > uint16_t new = vq->last_used_idx; > > > + bool signalled_used_valid = vq->signalled_used_valid; > > > + > > > + vq->signalled_used = new; > > > + vq->signalled_used_valid = true; > > > > > > VHOST_LOG_DEBUG(VHOST_DATA, "%s: > > used_event_idx=%d, old=%d, new=%d\n", > > > __func__, > > > vhost_used_event(vq), > > > old, new); > > > - if (vhost_need_event(vhost_used_event(vq), new, old) > > > - && (vq->callfd >= 0)) { > > > - vq->signalled_used = vq->last_used_idx; > > > + > > > + if ((vhost_need_event(vhost_used_event(vq), new, old) && > > > + (vq->callfd >= 0)) || > > > + unlikely(!signalled_used_valid)) > > > eventfd_write(vq->callfd, (eventfd_t) 1); > > > - } > > > } else { > > > /* Kick the guest if necessary. */ > > > if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT) > > > -- > > > 2.7.4 > > >