Re: [Qemu-devel] [PATCH v2 0/3] New sigaltstack backend for coroutine

[Stefan Hajnoczi]

On Wed, Mar 7, 2012 at 10:44 PM, Alex Barcelo <address@hidden> wrote:
> On Wed, Mar 7, 2012 at 23:17, Peter Maydell <address@hidden> wrote:
>> On 7 March 2012 22:01, Alex Barcelo <address@hidden> wrote:
>>> Is this patch okay? The first version had some comments, and now the
>>> v2 has been a bit too silent, not sure if that's a good sign or a bad
>>> sign.
>>
>> Did you see the comment I added to an earlier thread regarding
>> FORTIFY_SOURCE?
>
> Sorry about that! Yes, I got the comment mixed between some other
> threads, and now I was checking and didn't remember it.
>
> About the FORTIFY_SOURCE... I don't know very well what does that mean
> and what it does, I kept it from the ucontext code without thinking a
> lot (irresponsibly? yes, maybe a bit).
>
>> I think in general my opinion is swinging round to:
>>  * coroutines are a portability nightmare
> agreed ;)
>>  * so we should either (a) ideally avoid them altogether
> seems better the coroutines than state machines on every I/O process

Going back to callbacks is moving in the wrong direction.  Instead we
could take a step forward and come up with a proper threading model
for QEMU and convert coroutine code to execute in worker threads.

In fact, Paolo has already posted some ideas about a threaded block
layer and a prototype git branch.

I think this is the right approach to follow.

Stefan