Date: Wed, 22 Jun 2011 18:49:27 +0300 From: Andriy Gapon <avg@FreeBSD.org> To: freebsd-current@FreeBSD.org, freebsd-stable@FreeBSD.org Subject: Re: [poll / rfc] kdb_stop_cpus Message-ID: <4E020F07.50504@FreeBSD.org> In-Reply-To: <4DE9EB61.3000006@FreeBSD.org> References: <4DE8FA2E.4030202@FreeBSD.org> <5E4D0F56-4338-4157-8BC6-17EE2831725F@FreeBSD.org> <4DE9EB61.3000006@FreeBSD.org>
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on 04/06/2011 11:22 Andriy Gapon said the following:
> commit 458ebd9aca7e91fc6e0825c727c7220ab9f61016
>
> generic_stop_cpus: move timeout detection code from under DIAGNOSTIC
>
> ... and also increase it a bit.
> IMO it's better to detect and report the (rather serious) condition and
> allow a system to proceed somehow rather than be stuck in an endless
> loop.
>
> diff --git a/sys/kern/subr_smp.c b/sys/kern/subr_smp.c
> index ae52f4b..4bd766b 100644
> --- a/sys/kern/subr_smp.c
> +++ b/sys/kern/subr_smp.c
> @@ -232,12 +232,10 @@ generic_stop_cpus(cpumask_t map, u_int type)
> /* spin */
> cpu_spinwait();
> i++;
> -#ifdef DIAGNOSTIC
> - if (i == 100000) {
> + if (i == 100000000) {
> printf("timeout stopping cpus\n");
> break;
> }
> -#endif
> }
>
> stopping_cpu = NOCPU;
>
>
I would like to commit the above, if nobody objects.
A to do item is adding some code to aid debugging of the timeout condition. I
discussed this with Attilio, he doesn't see this as a show-stopper and he plans to
add the code at a later time.
--
Andriy Gapon
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