From: "Michael S. Tsirkin" <mst@redhat.com>
To: Qin Chuanyu <qinchuanyu@huawei.com>
Cc: Jason Wang <jasowang@redhat.com>,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org
Subject: Re: [PATCH V2 5/6] vhost_net: poll vhost queue after marking DMA is done
Date: Wed, 12 Feb 2014 18:01:17 +0200 [thread overview]
Message-ID: <20140212160117.GA25440@redhat.com> (raw)
In-Reply-To: <52FB24EA.3060001@huawei.com>
On Wed, Feb 12, 2014 at 03:38:18PM +0800, Qin Chuanyu wrote:
> another question is that vhost_zerocopy_callback is called by kfree_skb,
> it may called in different thread context.
> vhost_poll_queue is called decided by ubufs->kref.refcount, this may
> cause there isn't any thread call vhost_poll_queue, but at least
> one is needed. and this cause network break.
> We could repeat it by using 8 netperf thread in guest to xmit tcp to
> its host.
Thanks a lot for the report, will send the patch soon.
>
> I think if using atomic_read to decide while do vhost_poll_queue or not,
> at least a spink_lock is needed.
No, nothing so drastic.
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Qin Chuanyu <qinchuanyu@huawei.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH V2 5/6] vhost_net: poll vhost queue after marking DMA is done
Date: Wed, 12 Feb 2014 18:01:17 +0200 [thread overview]
Message-ID: <20140212160117.GA25440@redhat.com> (raw)
In-Reply-To: <52FB24EA.3060001@huawei.com>
On Wed, Feb 12, 2014 at 03:38:18PM +0800, Qin Chuanyu wrote:
> another question is that vhost_zerocopy_callback is called by kfree_skb,
> it may called in different thread context.
> vhost_poll_queue is called decided by ubufs->kref.refcount, this may
> cause there isn't any thread call vhost_poll_queue, but at least
> one is needed. and this cause network break.
> We could repeat it by using 8 netperf thread in guest to xmit tcp to
> its host.
Thanks a lot for the report, will send the patch soon.
>
> I think if using atomic_read to decide while do vhost_poll_queue or not,
> at least a spink_lock is needed.
No, nothing so drastic.
next prev parent reply other threads:[~2014-02-12 15:56 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-30 4:29 [PATCH V2 0/6] vhost code cleanup and minor enhancement Jason Wang
2013-08-30 4:29 ` Jason Wang
2013-08-30 4:29 ` [PATCH V2 1/6] vhost_net: make vhost_zerocopy_signal_used() returns void Jason Wang
2013-08-30 4:29 ` Jason Wang
2013-09-02 5:51 ` Michael S. Tsirkin
2013-09-02 5:51 ` Michael S. Tsirkin
2013-09-02 6:29 ` Jason Wang
2013-09-02 6:29 ` Jason Wang
2013-08-30 4:29 ` [PATCH V2 2/6] vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal_used() Jason Wang
2013-08-30 4:29 ` Jason Wang
2013-09-02 5:50 ` Michael S. Tsirkin
2013-09-02 5:50 ` Michael S. Tsirkin
2013-09-02 6:28 ` Jason Wang
2013-09-02 6:28 ` Jason Wang
2013-08-30 4:29 ` [PATCH V2 3/6] vhost: switch to use vhost_add_used_n() Jason Wang
2013-08-30 4:29 ` Jason Wang
2013-08-30 4:29 ` [PATCH V2 4/6] vhost_net: determine whether or not to use zerocopy at one time Jason Wang
2013-08-30 4:29 ` Jason Wang
2013-08-30 18:35 ` Sergei Shtylyov
2013-08-30 18:35 ` Sergei Shtylyov
2013-09-02 3:15 ` Jason Wang
2013-09-02 3:15 ` Jason Wang
2013-08-30 4:29 ` [PATCH V2 5/6] vhost_net: poll vhost queue after marking DMA is done Jason Wang
2013-08-30 4:29 ` Jason Wang
2013-08-30 16:44 ` Ben Hutchings
2013-08-30 16:44 ` Ben Hutchings
2013-09-02 3:06 ` Jason Wang
2013-09-02 3:06 ` Jason Wang
2014-02-12 7:38 ` Qin Chuanyu
2014-02-12 7:38 ` Qin Chuanyu
2014-02-12 10:06 ` Jason Wang
2014-02-12 10:06 ` Jason Wang
2014-02-12 16:01 ` Michael S. Tsirkin [this message]
2014-02-12 16:01 ` Michael S. Tsirkin
2013-08-30 4:29 ` [PATCH V2 6/6] vhost_net: correctly limit the max pending buffers Jason Wang
2013-08-30 4:29 ` Jason Wang
2013-09-02 5:56 ` Michael S. Tsirkin
2013-09-02 5:56 ` Michael S. Tsirkin
2013-09-02 6:30 ` Jason Wang
2013-09-02 6:30 ` Jason Wang
2013-09-02 8:37 ` Jason Wang
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