Re: [Qemu-devel] [PATCH] coroutine: Fix win32 variant for older mingw32 compilers

[Paolo Bonzini]

Il 21/11/2012 16:44, Jan Kiszka ha scritto:
>>>>>>>> Leaking leader is a bit bad, but it looks ok for 1.3.
>>>>>> >>>>>
>>>>>> >>>>> Hmm. A TLS destructor is apparently not available. Is there some 
>>>>>> >>>>> "on
>>>>>> >>>>> thread termination" callback mechanism on Windows? Didn't find one 
>>>>>> >>>>> on
>>>>>> >>>>> first glance.
>>>>>> >>>>>
>>>> >>> Dlls receive something like THREAD_DETTACH in it's startup routine or
>>>> >>> something like that if my memory serves me.
>>> >>
>>> >> Only DLLs.
>>> >>
>>> >> But this sounds like deja-vu.  I'm pretty sure in the past we just
>>> >> decided that this compiler is not supported (of course it's bad that
>>> >> it's silent).  Stefan, do you remember the details?
>> > 
>> > Current Debian delivers 4.4-based mingw unfortunately.
> I think we practically do not leak, at least as long as we continue to
> use coroutines only over cpu and iothread context. Those threads stay as
> long as qemu is running. And to my understanding, those contexts are the
> only target of coroutines anyway. Anything that already uses its own
> proper threads has no need for this problematic concept, no?

Kind of... when Stefan (Hajnoczi) finishes the full version of
virtio-blk dataplane, there will be one thread per device running
coroutines.

But it's still a minor leak, it's ok for 1.3 and we can get it right
later using the Windows run-time linker's TLS support, like on Linux.

Paolo