Re: [PATCH] tools/mm: Add madvise tool

[Kiryl Shutsemau <kirill@shutemov.name>]

On Fri, Sep 05, 2025 at 11:17:10AM +0200, Michal Hocko wrote:
> On Thu 04-09-25 18:57:29, Kirill A. Shutemov wrote:
> > From: Kiryl Shutsemau <kas@kernel.org>
> > 
> > Add a simple tool that allows to issue an advice on a process or a file.
> > 
> > It can be useful to experiment with effects of an advice on a workload
> > without modifying the workload itself.
> 
> Is there any reason to have this in the tree? This seems like a very
> trivial tools that doesn't really need to be in a lockstep with the
> kernel source.

There's no strong reason to move it in lockstep with kernel code. At
least for now.

The tool is useful to experiment with both kernel and workload behaviour
on an advice. Like, I see some oddities with MADV_COLLAPSE that makes it
give up easily where it shouldn't (will investigate later). I wouldn't
see them otherwise.

But you don't see it fitting kernel tree, I would not push back much.
I found the tool useful and decided to share.

> Also would it make more sense to send the pidfd fd to the tool directly
> so that it can benefit from a racefree pid->fd translation?

Hm. Do we have an easy way to open pidfd from shell?

I am not sure we care that much about the race for this tool.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov