Re: [Qemu-devel] [PATCH 0/3] make bh safe with hot-unplug

[liu ping fan]

On Tue, Jun 25, 2013 at 2:24 PM, Paolo Bonzini <address@hidden> wrote:
> Il 25/06/2013 19:38, Liu Ping Fan ha scritto:
>> This series relies on refcnt of object used by bh callback to run against 
>> unplug.
>>
>> Open issue:
>> Another choice may be rcu, but I think some issues are hard to resolve.
>> Using rcu, we have two choice:
>>   when holding object refcnt, call qemu_bh_delete(); then after grace 
>> period, we can release.
>>   Or making qemu_bh_delete() sync in the path of DeviceState's finalization.
>
> What do you mean exactly?  qemu_bh_delete() is async, but it operates on
> dynamically-allocated memory.
>
Before DeviceState is freed, we should make sure the bh is delete, and
not related bh is in fly.

> Paolo
>
>> but currently, the callers of qemu_bh_delete() can not satisfy any of the 
>> two condition.
>