Re: [RFC] Memory Tiering

[David Hildenbrand <david@redhat.com>]

On 17.10.19 19:07, Verma, Vishal L wrote:
> 
> On Thu, 2019-10-17 at 07:17 -0700, Dave Hansen wrote:
>> On 10/17/19 1:07 AM, David Hildenbrand wrote:
>>> Very interesting topic. I heard similar demand from HPC folks
>>> (especially involving other memory types ("tiers")). There, I think
>>> you often want to let the application manage that. But of course, for
>>> many applications an automatic management might already be
>>> beneficial.
>>>
>>> Am I correct that you are using PMEM in this area along with
>>> ZONE_DEVICE and not by giving PMEM to the buddy (add_memory())?
>>
>> The PMEM starts out as ZONE_DEVICE, but we unbind it from its original
>> driver and bind it to this stub of a "driver": drivers/dax/kmem.c which
>> uses add_memory() on it.
>>
>> There's some nice tooling inside the daxctl component of ndctl to do all
>> the sysfs magic to make this happen.
>>
> Here is more info about the daxctl command in question:
> 
> https://pmem.io/ndctl/daxctl-reconfigure-device.html
> 

Thanks, yeah I saw the patches back then (I though they were by Pavel 
but they were actually by you :) ) to add the memory to the buddy (via 
add_memory()).

Will explore some more, thanks!

-- 

Thanks,

David / dhildenb