Re: [PATCH 2/2] perf: arm_pmuv3: Uninvert dependency between {asm,perf}/arm_pmuv3.h

[Colton Lewis]

Oliver Upton <oliver.upton@xxxxxxxxx> writes:

> On Tue, Feb 04, 2025 at 07:57:08PM +0000, Colton Lewis wrote:
> > perf/arm_pmuv3.h includes asm/arm_pmuv3.h at the bottom of the
> > file. This counterintiutive decision was presumably made so
> > asm/arm_pmuv3.h would be included everywhere perf/arm_pmuv3.h was even
> > though the actual dependency relationship goes the other way because
> > asm/arm_pmuv3.h depends on the PMEVN_SWITCH macro that was presumably
> > put there to avoid duplicating it in the asm files for arm and arm64.

> > Extract the relevant macro to its own file to avoid this unusual
> > structure so it may be included in the asm headers without worrying
> > about ordering issues.

> > Signed-off-by: Colton Lewis <coltonlewis@xxxxxxxxxx>

> Is the intention of this change to allow asm/arm_pmuv3.h to be directly
> included? If yes, what's the issue with using perf/arm_pmuv3.h?

That isn't the primary intent, but it's a good side effect. Headers that
can't be directly included violate people's expectations.

> We already use definitions from the non-arch header in KVM anyway...

My intention here was just reorganizing a counterintuitive use of
headers. The arch header depends on definitions in the non-arch header
even though the inclusion relationship is the other way around.

But this patch doesn't matter as much as fixing the cyclical dependency.