Re: [PATCH v3 6/6] pid: drop irq disablement around pidmap_lock

Matthew Wilcox
2025-02-01T22:00:17Z

On Sat, Feb 01, 2025 at 09:51:05PM +0000, David Laight wrote:
> I'm not sure what you mean.
> Disabling interrupts isn't as cheap as it ought to be, but probably isn't
> that bad.

Time it. You'll see.

> > So while this is indeed a tradeoff, as I understand the sane default
> > is to *not* disable interrupts unless necessary.
>
> I bet to differ.

You're wrong. It is utterly standard to take spinlocks without
disabling IRQs. We do it all over the kernel. If you think that needs
to change, then make your case, don't throw a driveby review.

And I don't mean by arguing. Make a change, measure the difference.