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Re: [Qemu-devel] QEMU question: is eventfd not thread safe?
From: |
Alexey Kardashevskiy |
Subject: |
Re: [Qemu-devel] QEMU question: is eventfd not thread safe? |
Date: |
Mon, 02 Jul 2012 10:06:19 +1000 |
User-agent: |
Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 |
On 02/07/12 09:07, Benjamin Herrenschmidt wrote:
>>>> diff --git a/iohandler.c b/iohandler.c
>>>> index 3c74de6..54f4c48 100644
>>>> --- a/iohandler.c
>>>> +++ b/iohandler.c
>>>> @@ -77,6 +77,7 @@ int qemu_set_fd_handler2(int fd,
>>>> ioh->fd_write = fd_write;
>>>> ioh->opaque = opaque;
>>>> ioh->deleted = 0;
>>>> + kill(getpid(), SIGUSR2);
>>>> }
>>>> return 0;
>>>> }
>
> That probably wants to be a pthread_kill targetted at the main loop.
>
>>>> +static void sigusr2_print(int signal)
>>>> +{
>>>> +}
>>>> +
>>>> +static void sigusr2_init(void)
>>>> +{
>>>> + struct sigaction action;
>>>> +
>>>> + memset(&action, 0, sizeof(action));
>>>> + sigfillset(&action.sa_mask);
>>>> + action.sa_handler = sigusr2_print;
>>>> + action.sa_flags = 0;
>>>> + sigaction(SIGUSR2, &action, NULL);
>>>> +}
>>>> +
>
> Won't that conflict with the business in coroutine-sigaltstack.c ?
The code which touches SIGUSR2 does not compile on power.
> Hrm... looking at it, it looks like it will save/restore the handler,
> so that should be good.
>
> Still, one might want to wrap that into something, like
> qemu_wake_main_loop();
I already posted another patch with qemu_notify_event() in this mail thread
later :)
>
> Cheers,
> Ben.
>
>>>> int main_loop_init(void)
>>>> {
>>>> int ret;
>>>>
>>>> + sigusr2_init();
>>>> +
>>>> qemu_mutex_lock_iothread();
>>>> ret = qemu_signal_init();
>>>> if (ret) {
>>>> --
>>>> 1.7.10
>>
>>
>
>
--
Alexey
Re: [Qemu-devel] QEMU question: is eventfd not thread safe?, Benjamin Herrenschmidt, 2012/07/01
Re: [Qemu-devel] QEMU question: is eventfd not thread safe?, Paolo Bonzini, 2012/07/01