RE: [RFC PATCH 0/4]: affinity-on-next-touch

From: Lee Schermerhorn
Date: Mon Jun 15 2009 - 22:40:27 EST


On Fri, 2009-06-12 at 13:46 +0200, Stefan Lankes wrote:
> > > I analyze Lee Schermerhorn's migrate memory on cpu migration patches
> > > (http://free.linux.hp.com/~lts/Patches/PageMigration/). I think that
> > Lee
> > > Schermerhorn add similar functionalities to the kernel. He called the
> > > "affinity-on-next-touch" functionality "migrate_on_fault" and uses in
> > his
> > > patches the normal NUMA memory policies. Therefore, his solution fits
> > better
> > > to the Linux kernel. I tested his patches with our test applications
> > and got
> > > nearly the same performance results.
> >
> > That's great to know.
> >
> > I didn't think he had a per process setting though, did he?
>
> He enables the support of migration-on-fault via cpusets (echo 1 >
> /dev/cpuset/migrate_on_fault).
> Afterwards, every process could initiate migration-on-fault via mbind(...,
> MPOL_MF_MOVE|MPOL_MF_LAZY).

I should have read through the entire thread before responding Andi's
mail.

>
> > > I found only patches for the kernel 2.6.25-rc2-mm1. Does someone
> > develop
> > > these patches further?
> >
> > Not to much knowledge. Maybe Lee will pick them up again now that there
> > are more use cases.
> >
> > If he doesn't have time maybe you could update them?
>
> We are planning to work in this area. I think that I could update these
> patches.
> At least, I am able to support Lee.

I would like to get these patches working with latest mmotm to test on
some newer hardware where I think they will help more. And I would
welcome your support. However, I think we'll need to get Balbir and
Kamezawa-san involved to sort out the interaction with memory control
group.

I can send you the more recent rebase that I've done. This is getting
pretty old now: 2.6.28-rc4-mmotm-081110-081117. I'll try to rebase to
the most recent mmotm [that boots on my platforms], at least so that we
can build and boot with migrate-on-fault disabled, within the next
couple of weeks.

Regards,
Lee

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