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

From: Greg Kroah-Hartman
Date: Mon Nov 26 2018 - 14:06:57 EST


On Wed, Nov 14, 2018 at 03:49:17PM -0700, 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.
>
> In preparation for such systems, provide a new API for the kernel to
> register these memory side caches under the memory node that provides it.
>
> The kernel's sysfs representation is modeled from the cpu cacheinfo
> attributes, as seen from /sys/devices/system/cpu/cpuX/cache/. Unlike CPU
> cacheinfo, though, a higher node's memory cache level is nearer to the
> CPU, while lower levels are closer to the backing memory. Also unlike
> CPU cache, the system handles flushing any dirty cached memory to the
> last level the memory on a power failure if the range is persistent.
>
> The exported attributes are the cache size, the line size, associativity,
> and write back policy.

You also didn't document your new sysfs attributes/layout in a
Documentation/ABI/ entry which is required for any sysfs change...

thanks,

greg k-h