Re: [PATCH V2 03/14] x86/set_memory: Add x86_set_memory_enc static call support

Dave Hansen
2021-08-05T14:29:38Z

On 8/5/21 7:23 AM, Peter Zijlstra wrote:
> This is assuming any of this is actually performance critical, based off
> of this using static_call() to begin with.

This code is not performance critical.

I think I sent folks off on a wild goose chase when I asked that we make
an effort to optimize code that does:

if (some_hyperv_check())
foo();

if (some_amd_feature_check())
bar();

with checks that will actually compile away when Hyper-V or
some_amd_feature() is disabled. That's less about performance and just
about good hygiene. I *wanted* to see
cpu_feature_enabled(X86_FEATURE...) checks.

Someone suggested using static calls, and off we went...

Could we please just use cpu_feature_enabled()?