Re: [REGRESSION][BISECTED] Long boot time with Xen HVM guests during PV spinlock initialization
Teddy Astie <[email protected]>
| Newsgroups | dev.linux.lists.regressions,org.kernel.vger.linux-kernel,org.xenproject.lists.xen-devel |
|---|---|
| Message-ID | <1781254947.8631fc262581453bbf619ec5b2062170.19ebb118330000701b@vates.tech> |
Le 09/06/2026 à 17:17, Thomas Gleixner a écrit :
> On Tue, Jun 09 2026 at 11:27, Teddy Astie wrote:
>> Le 08/06/2026 à 17:15, Thomas Gleixner a écrit :
>>> struct clocksource * __init __weak clocksource_default_clock(void)
>>> {
>>> + clocksource_register(&clocksource_jiffies);
>>> return &clocksource_jiffies;
>>> }
>>>
>>>
>>>
>>
>> Hmm, there's a case where clocksource_mutex gets taken twice (both in
>> __clocksource_register_scale() (through clocksource_register()) and
>> clocksource_done_booting()).
>
> Bah.
>
>> What about making clocksource_jiffies gain ->enable() to setup what ever
>> needs to be (like calling __clocksource_update_freq_scale()) ?
>
> Doesn't work either.
>
> Updated version below. It's not pretty, but it should cure your
> problem. If that's confirmed I think about a less ugly solution.
>
> Thanks,
>
> tglx
> ---
> --- a/kernel/time/jiffies.c
> +++ b/kernel/time/jiffies.c
> @@ -60,15 +60,14 @@ EXPORT_SYMBOL(get_jiffies_64);
>
> EXPORT_SYMBOL(jiffies);
>
> -static int __init init_jiffies_clocksource(void)
> -{
> - return __clocksource_register(&clocksource_jiffies);
> -}
> -
> -core_initcall(init_jiffies_clocksource);
> +static bool cs_jiffies_registered __initdata;
>
> struct clocksource * __init __weak clocksource_default_clock(void)
> {
> + if (!cs_jiffies_registered) {
> + __clocksource_register(&clocksource_jiffies);
> + cs_jiffies_registered = true;
> + }
> return &clocksource_jiffies;
> }
>
>
Yes, that fixes it.
Teddy
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