Re: [patch 0/5] genirq: Forced threaded interrupt handlers

From: Ingo Molnar
Date: Thu Feb 24 2011 - 02:13:01 EST



* Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:

> Some time ago when the threaded interrupt handlers infrastructure was
> about to be merged, Andrew asked me where that command line switch was
> which magically runs all interrupt handlers and the softirqs in
> threads.
>
> While we were doing that brute force in preempt-rt for quite a while
> it took some time to come up with a reasonable non intrusive
> implementation for mainline. We also had to find a solution which fits
> Linus' recently issued "palatable Trojan horse" requirement (see:
> https://lwn.net/Articles/370998/).
>
> The gift of this patch series is the ability to add "threadirqs" to
> the kernel command line and magically (almost) all interrupt handlers
> - except those which are explicitely marked IRQF_NO_THREAD - are
> confined into threads along with all soft interrupts.
>
> That allows to enhance the debugability of the kernel as a bug in an
> interrupt handler is not necessarily taking the whole machine
> down. It's just the particular irq thread which goes into nirwana. Bad
> luck if that's the one which is crucial to retrieve the bug report,
> but in most cases - yes, I analysed quite a lot of bugzilla reports -
> it will be helpful for reporters not to be forced to transcribe the
> bug from the screen.

Just a quick bike shed painting suggestion: could we please name it anything but
'forced' threaded irqs? Something like 'irqthread debugging' or 'full irqthreads'?

Thanks,

Ingo
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