Re: [PATCH 4/7] node: Add memory caching attributes

[Keith Busch]

On Thu, Nov 22, 2018 at 06:59:21PM +0530, Anshuman Khandual wrote:
> 
> 
> On 11/20/2018 04:36 AM, Keith Busch wrote:
> > On Mon, Nov 19, 2018 at 09:44:00AM +0530, Anshuman Khandual wrote:
> >> On 11/15/2018 04:19 AM, Keith Busch wrote:
> >>> System memory may have side caches to help improve access speed. While
> >>> the system provided cache is transparent to the software accessing
> >>> these memory ranges, applications can optimize their own access based
> >>> on cache attributes.
> >>
> >> Cache is not a separate memory attribute. It impacts how the real attributes
> >> like bandwidth, latency e.g which are already captured in the previous patch.
> >> What is the purpose of adding this as a separate attribute ? Can you explain
> >> how this is going to help the user space apart from the hints it has already
> >> received with bandwidth, latency etc properties.
> > 
> > I am not sure I understand the question here. Access bandwidth and latency
> > are entirely attributes different than what this patch provides. If the
> > system side-caches memory, the associativity, line size, and total size
> > can optionally be used by software to improve performance.
> 
> Okay but then does this belong to this series which about memory attributes ?

This patch series is about exporting memory attributes, and this system
memory caching is  one such attribute, so yes, I think it belongs.