Re: [PATCH 1/2] cgroup: Make operations on the cgroup root_list RCU safe

Greg Kroah-Hartman
2024-12-02T10:17:04Z

On Mon, Dec 02, 2024 at 03:41:01PM +0530, Siddh Raman Pant wrote:
> From: Yafang Shao <laoar.shao@gmail.com>
>
> commit d23b5c577715892c87533b13923306acc6243f93 upstream.
>
> At present, when we perform operations on the cgroup root_list, we must
> hold the cgroup_mutex, which is a relatively heavyweight lock. In reality,
> we can make operations on this list RCU-safe, eliminating the need to hold
> the cgroup_mutex during traversal. Modifications to the list only occur in
> the cgroup root setup and destroy paths, which should be infrequent in a
> production environment. In contrast, traversal may occur frequently.
> Therefore, making it RCU-safe would be beneficial.
>
> Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> [fp: adapt to 5.10 mainly because of changes made by e210a89f5b07
> ("cgroup.c: add helper __cset_cgroup_from_root to cleanup duplicated
> codes")]
> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
> [Shivani: Modified to apply on v5.4.y]
> Signed-off-by: Shivani Agarwal <shivani.agarwal@broadcom.com>
> Reviewed-by: Siddh Raman Pant <siddh.raman.pant@oracle.com>

I'm confused. You do know what signed-off-by means, right? When
sending a patch on, you MUST sign off on it.

Please work with other developers of the Oracle Linux kernel team to get
this right and send it as a whole new series, properly versioned, and
tested in in a format that we can take this in.

thanks,

greg k-h