Re: [RFC PATCH v3 0/7] DAMON based tiered memory management for CXL memory

Honggyu Kim
2024-04-08T10:57:02Z

Hi SeongJae,

On Fri, 5 Apr 2024 12:28:00 -0700 SeongJae Park <sj@kernel.org> wrote:
> Hello Honggyu,
>
> On Fri, 5 Apr 2024 15:08:49 +0900 Honggyu Kim <honggyu.kim@sk.com> wrote:
>
> > There was an RFC IDEA "DAMOS-based Tiered-Memory Management" previously
> > posted at [1].
> >
> > It says there is no implementation of the demote/promote DAMOS action
> > are made. This RFC is about its implementation for physical address
> > space.
> >
> >
> > Changes from RFC v2:
> > 1. Rename DAMOS_{PROMOTE,DEMOTE} actions to DAMOS_MIGRATE_{HOT,COLD}.
> > 2. Create 'target_nid' to set the migration target node instead of
> > depending on node distance based information.
> > 3. Instead of having page level access check in this patch series,
> > delegate the job to a new DAMOS filter type YOUNG[2].
> > 4. Introduce vmstat counters "damon_migrate_{hot,cold}".
> > 5. Rebase from v6.7 to v6.8.
>
> Thank you for patiently keeping discussion and making this great version! I
> left comments on each patch, but found no special concerns. Per-page access
> recheck for MIGRATE_HOT and vmstat change are taking my eyes, though. I doubt
> if those really needed. It would be nice if you could answer to the comments.

I will answer them where you made the comments.

> Once my comments on this version are addressed, I would have no reason to
> object at dropping the RFC tag from this patchset.

Thanks. I will drop the RFC after addressing your comments.

> Nonetheless, I show some warnings and errors from checkpatch.pl. I don't
> really care about those for RFC patches, so no problem at all. But if you
> agree to my opinion about RFC tag dropping, and therefore if you will send next
> version without RFC tag, please make sure you also run checkpatch.pl before
> posting.

Sure. I will run checkpatch.pl from the next revision.

Thanks,
Honggyu

>
> Thanks,
> SJ
>
> …