# Re: \[PATCH v4 04/11\] drivers: base: support cpu cache information interface to userspace via sysfs

- From: Greg Kroah-Hartman \<gregkh@linuxfoundation.org\>
- Date: 2014-09-17 19:01:39 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2014/09/4335989
- Thread: https://ratatoskr.run/linux-api/2014/09/4326079/t.md

```text
On Wed, Sep 17, 2014 at 06:25:10PM +0100, Sudeep Holla wrote:
> Hi Greg,
> 
> On 03/09/14 18:00, Sudeep Holla wrote:
> >From: Sudeep Holla <redacted>
> >
> >This patch adds initial support for providing processor cache information
> >to userspace through sysfs interface. This is based on already existing
> >implementations(x86, ia64, s390 and powerpc) and hence the interface is
> >intended to be fully compatible.
> >
> >The main purpose of this generic support is to avoid further code
> >duplication to support new architectures and also to unify all the existing
> >different implementations.
> >
> >This implementation maintains the hierarchy of cache objects which reflects
> >the system's cache topology. Cache devices are instantiated as needed as
> >CPUs come online. The cache information is replicated per-cpu even if they are
> >shared. A per-cpu array of cache information maintained is used mainly for
> >sysfs-related book keeping.
> >
> >It also implements the shared_cpu_map attribute, which is essential for
> >enabling both kernel and user-space to discover the system's overall cache
> >topology.
> >
> >This patch also add the missing ABI documentation for the cacheinfo sysfs
> >interface already, which is well defined and widely used.
> >
> 
> Can you review the first 4 patches in this series please ?

It's in my todo queue, which is really long at the moment due to me
going to conferences (at one right now...)  Will be working on this
soon, thanks for your patience.

greg k-h
```