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

[Jan Kiszka]

On 2012-11-21 16:54, Paolo Bonzini wrote:
> 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.

So it's a non-leak for current QEMU. :)

Jan

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