Re: [PATCHv10 09/15] x86: Expose untagging mask in /proc/$PID/arch_status

From: Kirill A. Shutemov
Date: Tue Oct 18 2022 - 18:24:43 EST


On Tue, Oct 18, 2022 at 02:02:43PM -0700, Dave Hansen wrote:
> On 10/18/22 04:33, Kirill A. Shutemov wrote:
> > Add a line in /proc/$PID/arch_status to report untag_mask. It can be
> > used to find out LAM status of the process from the outside. It is
> > useful for debuggers.
>
> Considering that address masking is not x86-specific, it seems like this
> needs a better home (another file in /proc).

In generic /proc/$PID/status?

And I'm not sure if it is a good idea at this stage. Semantics around tags
is not settled across architectures: somewhere it is per-thread, somewhere
per-process, somewhere it is global.

Maybe keep it arch-specific?

> This could even be left out of the series for now, right? Nothing,
> including the selftests, depends on it.

GDB folks wanted to know the mask.

--
Kiryl Shutsemau / Kirill A. Shutemov