From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH] virtio_net: Add schedule check to napi_enable call Date: Thu, 10 Feb 2011 19:57:26 +0200 Message-ID: <20110210175725.GA9674@redhat.com> References: <201102101232.50526.rusty@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Herbert Xu , netdev@vger.kernel.org, David Miller , virtualization@lists.linux-foundation.org, Ken Stailey To: Rusty Russell Return-path: Received: from mx1.redhat.com ([209.132.183.28]:24708 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751450Ab1BJR6D (ORCPT ); Thu, 10 Feb 2011 12:58:03 -0500 Content-Disposition: inline In-Reply-To: <201102101232.50526.rusty@rustcorp.com.au> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Feb 10, 2011 at 12:32:50PM +1030, Rusty Russell wrote: > From: "Bruce Rogers" > > Under harsh testing conditions, including low memory, the guest would > stop receiving packets. With this patch applied we no longer see any > problems in the driver while performing these tests for extended periods > of time. > > Make sure napi is scheduled subsequent to each napi_enable. > > Signed-off-by: Bruce Rogers > Signed-off-by: Olaf Kirch > Cc: stable@kernel.org > Signed-off-by: Rusty Russell Rusty, so this is 2.6.38 material - you'll send this to Linus? Or DaveM? > --- > drivers/net/virtio_net.c | 27 ++++++++++++++++----------- > 1 file changed, 16 insertions(+), 11 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -446,6 +446,20 @@ static void skb_recv_done(struct virtque > } > } > > +static void virtnet_napi_enable(struct virtnet_info *vi) > +{ > + napi_enable(&vi->napi); > + > + /* If all buffers were filled by other side before we napi_enabled, we > + * won't get another interrupt, so process any outstanding packets > + * now. virtnet_poll wants re-enable the queue, so we disable here. > + * We synchronize against interrupts via NAPI_STATE_SCHED */ > + if (napi_schedule_prep(&vi->napi)) { > + virtqueue_disable_cb(vi->rvq); > + __napi_schedule(&vi->napi); > + } > +} > + > static void refill_work(struct work_struct *work) > { > struct virtnet_info *vi; > @@ -454,7 +468,7 @@ static void refill_work(struct work_stru > vi = container_of(work, struct virtnet_info, refill.work); > napi_disable(&vi->napi); > still_empty = !try_fill_recv(vi, GFP_KERNEL); > - napi_enable(&vi->napi); > + virtnet_napi_enable(vi); > > /* In theory, this can happen: if we don't get any buffers in > * we will *never* try to fill again. */ > @@ -638,16 +652,7 @@ static int virtnet_open(struct net_devic > { > struct virtnet_info *vi = netdev_priv(dev); > > - napi_enable(&vi->napi); > - > - /* If all buffers were filled by other side before we napi_enabled, we > - * won't get another interrupt, so process any outstanding packets > - * now. virtnet_poll wants re-enable the queue, so we disable here. > - * We synchronize against interrupts via NAPI_STATE_SCHED */ > - if (napi_schedule_prep(&vi->napi)) { > - virtqueue_disable_cb(vi->rvq); > - __napi_schedule(&vi->napi); > - } > + virtnet_napi_enable(vi); > return 0; > } > > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html