Re: [RFC PATCH]vhost-blk: In-kernel accelerator for virtio block device

[Badari Pulavarty <pbadari@us.ibm.com>]

On 8/5/2011 4:04 AM, Liu Yuan wrote:
> On 08/05/2011 05:58 AM, Badari Pulavarty wrote:
>> Hi Liu Yuan,
>>
>> I started testing your patches. I applied your kernel patch to 3.0
>> and applied QEMU to latest git.
>>
>> I passed 6 blockdevices from the host to guest (4 vcpu, 4GB RAM).
>> I ran simple "dd" read tests from the guest on all block devices
>> (with various blocksizes, iflag=direct).
>>
>> Unfortunately, system doesn't stay up. I immediately get into
>> panic on the host. I didn't get time to debug the problem. Wondering
>> if you have seen this issue before and/or you have new patchset
>> to try ?
>>
>> Let me know.
>>
>> Thanks,
>> Badari
>>
>
> Okay, it is actually a bug pointed out by MST on the other thread, 
> that it needs a mutex for completion thread.
>
> Now would you please this attachment?This patch only applies to kernel 
> part, on top of v1 kernel patch.
>
> This patch mainly moves completion thread into vhost thread as a 
> function. As a result, both requests submitting and completion 
> signalling is in the same thread.
>
> Yuan

Unfortunately, "dd" tests (4 out of 6) in the guest hung. I see 
following messages

virtio_blk virtio2: requests: id 0 is not a head !
virtio_blk virtio3: requests: id 1 is not a head !
virtio_blk virtio5: requests: id 1 is not a head !
virtio_blk virtio1: requests: id 1 is not a head !

I still see host panics. I will collect the host panic and see if its 
still same or not.

Thanks,
Badari