Re: shared code: was: Re: [PATCH v3] hardlockup: detect hard lockups using secondary (buddy) CPUs

Hi,

On Tue, May 2, 2023 at 8:26 AM Petr Mladek [off-list ref] wrote:

quoted

+int __weak watchdog_nmi_enable(unsigned int cpu) { return 0; }
+void __weak watchdog_nmi_disable(unsigned int cpu) { return; }

Honestly, the mix of softlockup and hardlockup code was a hard to
follow even before this patch. And it is going to be worse.

Anyway, the buddy watchdog is not using NMI at all. It should not
get enable using a function called *_nmi_enabled().

Thanks for your review! I'm not going to individually reply to all
your comments below, but I've sent out a v4 [1] where I think I've
done a semi-decent job of making this a little cleaner (not perfect,
but hopefully a step in the right direction). Please take a look.

[1] https://lore.kernel.org/r/20230504221349.1535669-1-dianders@chromium.org (local)

Also some comments are not longer valid, for example:

static void watchdog_enable(unsigned int cpu)
{
[...]
        /* Enable the perf event */
        if (watchdog_enabled & NMI_WATCHDOG_ENABLED)
                watchdog_nmi_enable(cpu);

Ugh, after I sent the new version I just realized that I missed
updating the above comment. :( If I need to send a v5 I can update it
then, or if v4 lands I can send a follow-on patch to update that
comment. My eyes are glazed over enough from trying to organize a
17-patch series, so I somewhat imagine it's not the only comment I
missed...

-Doug

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