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Message-ID: <5149dde8-b6b2-e720-2e32-5c79684a99db@linux.alibaba.com>
Date:   Sat, 10 Jun 2023 11:19:03 +0800
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Subject: Re: [PATCH 2/3] virtio_console: fixup potential cpu stall when free
 unused bufs
To:     "Michael S. Tsirkin" <mst@redhat.com>
Cc:     arei.gonglei@huawei.com, jasowang@redhat.com,
        xuanzhuo@linux.alibaba.com, herbert@gondor.apana.org.au,
        davem@davemloft.net, amit@kernel.org, arnd@arndb.de,
        gregkh@linuxfoundation.org, marcel@holtmann.org,
        johan.hedberg@gmail.com, luiz.dentz@gmail.com,
        linux-bluetooth@vger.kernel.org,
        virtualization@lists.linux-foundation.org,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230609131817.712867-1-xianting.tian@linux.alibaba.com>
 <20230609131817.712867-3-xianting.tian@linux.alibaba.com>
 <20230609120332-mutt-send-email-mst@kernel.org>
From:   Xianting Tian <xianting.tian@linux.alibaba.com>
In-Reply-To: <20230609120332-mutt-send-email-mst@kernel.org>
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在 2023/6/10 上午12:05, Michael S. Tsirkin 写道:
> On Fri, Jun 09, 2023 at 09:18:16PM +0800, Xianting Tian wrote:
>> Cpu stall issue may happen if device is configured with multi queues
>> and large queue depth, so fix it.
> "may happen" is ambigous.
>
> So is this: "for virtio-net we were getting
> stall on CPU was observed message, this driver is similar
> so theoretically the same logic applies"

It is this one

  “this driver is similar so theoretically the same logic applies”

>
> or is this
>
> "the following error occured: ....."
>
> ?
>
>
>> Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
>> ---
>>   drivers/char/virtio_console.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
>> index b65c809a4e97..5ec4cf4ea919 100644
>> --- a/drivers/char/virtio_console.c
>> +++ b/drivers/char/virtio_console.c
>> @@ -1935,6 +1935,7 @@ static void remove_vqs(struct ports_device *portdev)
>>   		flush_bufs(vq, true);
>>   		while ((buf = virtqueue_detach_unused_buf(vq)))
>>   			free_buf(buf, true);
>> +		cond_resched();
>>   	}
>>   	portdev->vdev->config->del_vqs(portdev->vdev);
>>   	kfree(portdev->in_vqs);
>> -- 
>> 2.17.1