Re: [PATCH v4 19/20] x86/mm: Add speculative pagefault handling

[Andrew Morton]

On Mon,  9 Oct 2017 12:07:51 +0200 Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx> wrote:

> +/*
> + * Advertise that we call the Speculative Page Fault handler.
> + */
> +#if defined(CONFIG_X86_64) && defined(CONFIG_SMP)
> +#define __HAVE_ARCH_CALL_SPF
> +#endif

Here's where I mess up your life ;)

It would be more idiomatic to define this in arch/XXX/Kconfig:

config SPF
	def_bool y if SMP

then use CONFIG_SPF everywhere.

Also, it would be better if CONFIG_SPF were defined at the start of the
patch series rather than the end, so that as the patches add new code,
that code is actually compilable.  For bisection purposes.  I can
understand if this is too much work and effort - we can live with
things the way they are now.

This patchset is a ton of new code in very sensitive areas and seems to
have received little review and test.  I can do a
merge-and-see-what-happens but it would be quite a risk to send all
this upstream based only on my sketchy review and linux-next runtime
testing.  Can we bribe someone?