Re: [RFC PATCH 0/8][Sorted-buddy] mm: Linux VM Infrastructure to support Memory Power Management

["Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>]

Hi Srinivas,

It looks like your email did not get delivered to the mailing
lists (and the people in the CC list) properly. So quoting your
entire mail as-it-is here. And thanks a lot for taking a look
at this patchset!

Regards,
Srivatsa S. Bhat

On 11/09/2012 10:18 PM, SrinivasPandruvada wrote:
> I did like this implementation and think it is valuable.
> I am experimenting with one of our HW. This type of partition does help in
> saving power. We believe we can save up-to 1W power per DIM with the help
> of some HW/BIOS changes. We are only talking about content preserving memory,
> so we don't have to be 100% correct.
> In my experiments, I tried two methods:
> - Similar to approach suggested by Mel Gorman. I have a special sticky
> migrate type like CMA.
> - Buddy buckets: Buddies are organized into memory region aware buckets.
> During allocation it prefers higher order buckets. I made sure that there is
> no affect of my change if there are no power saving memory DIMs. The advantage
> of this bucket is that I can keep the memory in close proximity for a related
> task groups by direct hashing to a bucket. The free list if organized as two
> dimensional array with bucket and migrate type for each order.
> 
> In both methods, currently reclaim is targetted to be done by a sysfs interface
> similar to memory compaction for a node allowing user space to initiate reclaim. 
> 
> Thanks,
> Srinivas Pandruvada
> Open Source Technology Center,
> Intel Corp.
>