Re: [RFC PATCH 00/16] Page Alloc Hogger

[Lorenzo Stoakes (ARM)]

On Fri, Jul 31, 2026 at 08:32:35AM -0700, Juan Yescas wrote:
> On Thu, Jul 30, 2026 at 12:51 AM Lorenzo Stoakes (ARM) <ljs@xxxxxxxxxx> wrote:
> >
> > On Tue, Jul 28, 2026 at 05:36:03PM -0700, Juan Yescas wrote:
> > > On Tue, Jul 28, 2026 at 12:29 PM David Hildenbrand (Arm)
> > > <david@xxxxxxxxxx> wrote:
> > > >
> > > > On 7/23/26 09:47, Juan Yescas wrote:
> > > > > This patch series introduces the Page Alloc Hogger. The Page Alloc Hogger
> > > > > allows you to allocate memory pages from specific nodes, zones, migration
> > > > > types, and orders directly via debugfs. This provides key benefits for
> > > > > testing and debugging:
> > > >
> > > > Would it be feasible to carry this as an OOT debugging module? Would a lot of
> > > > symbols be missing to achieve that?
> > > >
> > >
> > > Thanks David for the comment.
> > >
> > > The only symbol that would be needed to have this module as OOT is
> > > "migratetype_names".
> >
> > I mean you could hardcode these and be pretty safe :) I don't we're going
> > to add any time soon and if we did you'd probably need to change the module
> > code anyway?
>
> Thanks Lorenzo, I agree, the names can be hardcoded.

Yeah :) I think not such an issue.

>
> > I feel this debug module should be a noop in core.
>
> What would be the main concern here?
>
> The reason I wrote this module is because my team and system teams who
> work in memory,
> have programs to alloc/free memory to debug memory issues. These
> programs are not shared and
> depending on the memory issue, developers customize their programs. If we want
> to allocate memory that is not MOVABLE, we need to write custom kernel
> drivers for that. This code
> is reinvented constantly by developers.

Exposing internal implementation details via debugfs is problematic as a core
feature.

It's not impossible for this to be upstream however as a separate driver on the
basis of people re-inventing?

>
> With this self contained module, we can allocate any valid memory from
> any node/zone/order/migrate type
> without needing custom programs or drivers.
>
> Greetings
> Juan
>
> > Cheers, Lorenzo

--
Cheers, Lorenzo