From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>, dev@dpdk.org
Cc: Ilya Maximets <i.maximets@samsung.com>, stable@dpdk.org
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH 1/8] net/virtio: revert "virtio: fix restart"
Date: Thu, 3 Nov 2016 21:36:52 +0100 [thread overview]
Message-ID: <915489cd-7e1a-9a0c-ab9d-780f6103501b@redhat.com> (raw)
In-Reply-To: <1478189400-14606-2-git-send-email-yuanhan.liu@linux.intel.com>
Hi Yuanhan,
On 11/03/2016 05:09 PM, Yuanhan Liu wrote:
> This reverts commit 9a0615af7746 ("virtio: fix restart"); conflict is
> manually addressed.
>
> Kyle reported an issue with above commit
>
> qemu-kvm: Guest moved used index from 5 to 1
>
> with following steps,
>
> 1) Start my virtio interfaces
> 2) Send some traffic into/out of the interfaces
> 3) Stop the interfaces
> 4) Start the interfaces
> 5) Send some more traffic
>
> And here are some quotes from Kyle's analysis,
>
> Prior to the patch, if an interface were stopped then started, without
> restarting the application, the queues would be left as-is, because
> hw->started would be set to 1. Now, calling stop sets hw->started to 0,
> which means the next call to start will "touch the queues". This is the
> unintended side-effect that causes the problem.
Maybe a good idea to explain what is the problem the revert aims to fix.
It does not seem to be clearly stated in the commit message.
>
> Fixes: 9a0615af7746 ("virtio: fix restart")
>
> Cc: Jianfeng Tan <jianfeng.tan@intel.com>
> Cc: <stable@dpdk.org>
> Reported-by: Kyle Larose <klarose@sandvine.com>
> Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Thanks,
Maxime
next prev parent reply other threads:[~2016-11-03 20:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1478189400-14606-1-git-send-email-yuanhan.liu@linux.intel.com>
2016-11-03 16:09 ` [dpdk-stable] " Yuanhan Liu
2016-11-03 20:36 ` Maxime Coquelin [this message]
2016-11-04 2:00 ` [dpdk-stable] [dpdk-dev] " Yuanhan Liu
2016-11-04 8:09 ` Maxime Coquelin
2016-11-04 14:28 ` Yuanhan Liu
2016-11-04 8:10 ` Maxime Coquelin
[not found] ` <1478338865-26126-1-git-send-email-yuanhan.liu@linux.intel.com>
2016-11-05 9:40 ` [dpdk-stable] [PATCH v2 01/10] net/virtio: revert fix restart Yuanhan Liu
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