Re: [PATCHv4 00/13] Heterogeneuos memory node attributes

From: Balbir Singh
Date: Thu Jan 17 2019 - 07:58:29 EST


On Wed, Jan 16, 2019 at 10:57:51AM -0700, Keith Busch wrote:
> The series seems quite calm now. I've received some approvals of the
> on the proposal, and heard no objections on the new core interfaces.
>
> Please let me know if there is anyone or group of people I should request
> and wait for a review. And if anyone reading this would like additional
> time as well before I post a potentially subsequent version, please let
> me know.
>
> I also wanted to inquire on upstream strategy if/when all desired
> reviews are received. The series is spanning a few subsystems, so I'm
> not sure who's tree is the best candidate. I could see an argument for
> driver-core, acpi, or mm as possible paths. Please let me know if there's
> a more appropriate option or any other gating concerns.
>
> == Changes from v3 ==
>
> I've fixed the documentation issues that have been raised for v3
>
> Moved the hmat files according to Rafael's recommendation
>
> Added received Reviewed-by's
>
> Otherwise this v4 is much the same as v3.
>
> == Background ==
>
> Platforms may provide multiple types of cpu attached system memory. The
> memory ranges for each type may have different characteristics that
> applications may wish to know about when considering what node they want
> their memory allocated from.
>
> It had previously been difficult to describe these setups as memory
> rangers were generally lumped into the NUMA node of the CPUs. New
> platform attributes have been created and in use today that describe
> the more complex memory hierarchies that can be created.
>

Could you please expand on this text -- how are these attributes
exposed/consumed by both the kernel and user space?

> This series' objective is to provide the attributes from such systems
> that are useful for applications to know about, and readily usable with
> existing tools and libraries.

I presume these tools and libraries are numactl and mbind()?

Balbir Singh.