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

- From: Stephen Boyd \<hidden\>
- Date: 2014-09-19 22:24:26 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2014/09/4337389
- Thread: https://ratatoskr.run/linux-api/2014/09/4326079/t.md

```text
On 09/03/14 10:00, 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.
>
> Signed-off-by: Sudeep Holla <redacted>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Stephen Boyd <redacted>
> Cc: <redacted>
> Cc: <redacted>
> Cc: <redacted>
> Cc: <redacted>
> Cc: <redacted>
> Cc: <redacted>
> Cc: x86@kernel.org
>

Reviewed-by: Stephen Boyd <redacted>
Tested-by: Stephen Boyd <redacted>

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