Re: [PATCHv16 0/9] Contiguous Memory Allocator

Andrew Morton
2011-10-10T22:56:48Z

On Fri, 7 Oct 2011 18:27:06 +0200
Arnd Bergmann <arnd@arndb.de> wrote:

> On Thursday 06 October 2011, Marek Szyprowski wrote:
> > Once again I decided to post an updated version of the Contiguous Memory
> > Allocator patches.
> >
> > This version provides mainly a bugfix for a very rare issue that might
> > have changed migration type of the CMA page blocks resulting in dropping
> > CMA features from the affected page block and causing memory allocation
> > to fail. Also the issue reported by Dave Hansen has been fixed.
> >
> > This version also introduces basic support for x86 architecture, what
> > allows wide testing on KVM/QEMU emulators and all common x86 boxes. I
> > hope this will result in wider testing, comments and easier merging to
> > mainline.
>
> Hi Marek,
>
> I think we need to finally get this into linux-next now, to get some
> broader testing. Having the x86 patch definitely helps here becauses
> it potentially exposes the code to many more testers.
>
> IMHO it would be good to merge the entire series into 3.2, since
> the ARM portion fixes an important bug (double mapping of memory
> ranges with conflicting attributes) that we've lived with for far
> too long, but it really depends on how everyone sees the risk
> for regressions here. If something breaks in unfixable ways before
> the 3.2 release, we can always revert the patches and have another
> try later.
>
> It's also not clear how we should merge it. Ideally the first bunch
> would go through linux-mm, and the architecture specific patches
> through the respective architecture trees, but there is an obvious
> inderdependency between these sets.
>
> Russell, Andrew, are you both comfortable with putting the entire
> set into linux-mm to solve this? Do you see this as 3.2 or rather
> as 3.3 material?
>

Russell's going to hate me, but...

I do know that he had substantial objections to at least earlier
versions of this, and he is a guy who knows of what he speaks.

So I would want to get a nod from rmk on this work before proceeding.
If that nod isn't available then let's please identify the issues and
see what we can do about them.