[Qemu-devel] Re: [CFT PATCH 06/12] exit round-robin vcpu loop if cpu->stopped is true

[Jan Kiszka <jan.kiszka@web.de>]

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On 2011-02-09 08:24, Paolo Bonzini wrote:
> On 02/08/2011 09:24 PM, Jan Kiszka wrote:
>> Hmm, does this path actually trigger? If yes, does it happen to obsolete
>> the global exit_request hack?
> 
> No idea, I wanted to make the initial work as mechanical as possible. By
> inspection, cpu_stop_current is doing
> 
>          cpu_single_env->stopped = 1;
>          cpu_exit(cpu_single_env);
> 
> without setting ->stop.  (I'm changing that in patch 7, but I'm setting
> ->stop to 0, not 1).

Checked my own patches again: :) exit_request is not obsoleted this way,
at least as long as we have !CONFIG_IOTHREAD hanging around.

Also, I don't see any compelling reason now why that test should be
unneeded. Rather, this looks like a sleeping race between asynchronous
and synchronous vcpu stop, probably papered over by polling the cond
variables so far.

Jan


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