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Date: Wed, 17 Dec 2014 11:27:02 +0100
From: Frederic Konrad <fred.konrad@greensocs.com>
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Subject: Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*.
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: mttcg@listserver.greensocs.com, Paolo Bonzini <pbonzini@redhat.com>, Mark Burton <mark.burton@greensocs.com>, QEMU Developers <qemu-devel@nongnu.org>, =?UTF-8?B?TGx1w61zIFZpbGFub3Zh?= <vilanova@ac.upc.edu>

On 16/12/2014 17:37, Peter Maydell wrote:
> On 16 December 2014 at 09:13,  <fred.konrad@greensocs.com> wrote:
>> From: KONRAD Frederic <fred.konrad@greensocs.com>
>>
>> This adds a lock to avoid multiple exclusive access at the same time in case of
>> TCG multithread.
Hi Peter,

> This feels to me like it's not really possible to review on
> its own, since you can't see how it fits into the design of
> the rest of the multithreading support.
true the only thing we observe is that it didn't change anything right now.

> The other approach here rather than having a pile of mutexes
> in the target-* code would be to have TCG IR support for
> "begin critical section"/"end critical section". Then you
> could have the main loop ensure that no other CPU is running
> at the same time as the critical-section code. (linux-user
> already has an ad-hoc implementation of this for the
> exclusives.)
>
> -- PMM
>
What do you mean by TCG IR?

Thanks,
Fred