Re: [patch 1/2] QEMU: use SIGARLM for alarm timers, enable SIGIO on qemu_set_fd_handler2()

Avi Kivity
2008-04-13T15:05:38Z

Marcelo Tosatti wrote:
> On Fri, Apr 11, 2008 at 01:59:35PM -0500, Anthony Liguori wrote:
>
>> With the IO thread, shouldn't we be striving to perform the select()s
>> within the IO thread itself to completely avoid the need to use SIGIO at
>> all?
>>
>
> Fully agree. Problem with it are the fundamental changes in qemu that
> are required (and the difficulty merging those in qemu).
>
>

One is tempted to use pselect() to temporarily unblock the signals while
waiting. This has two problems, though: one, pselect() is emulated in
libc with older kernels, and this emulation has an (unavoidable) race.
Two, I think pselect() will deliver the signal in addition to returning,
which we want to avoid. Not sure about this though.

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error compiling committee.c: too many arguments to function