Re: [Qemu-devel] [PATCH V3 10/11] vcpu: introduce lockmap

[liu ping fan]

On Tue, Sep 11, 2012 at 4:35 PM, Avi Kivity <address@hidden> wrote:
> On 09/11/2012 10:51 AM, Liu Ping Fan wrote:
>> From: Liu Ping Fan <address@hidden>
>>
>> The func call chain can suffer from recursively hold
>> qemu_mutex_lock_iothread. We introduce lockmap to record the
>> lock depth.
>
> What is the root cause?  io handlers initiating I/O?
>
cpu_physical_memory_rw() can be called nested, and when called, it can
be protected by no-lock/device lock/ big-lock.
I think without big lock, io-dispatcher should face the same issue.
As to main-loop, have not carefully consider, but at least, dma-helper
will call cpu_physical_memory_rw() with big-lock.

Regards,
pingfan

> Perhaps we can have a solution that is local to exec.c.
>
>
> --
> error compiling committee.c: too many arguments to function