Re: [PATCH 1/9] perf/core: Add PERF_RECORD_CGROUP event

[Tejun Heo]

Hello, Namhyung.

On Wed, Aug 28, 2019 at 04:31:22PM +0900, Namhyung Kim wrote:
> +	 * struct {
> +	 *	struct perf_event_header	header;
> +	 *	u64				ino;
> +	 *	u64				path_len;
> +	 *	char				path[];

ino and path aren't great identifers for cgroups because both can get
recycled pretty quickly.  Can you please take a look at
KERNFS_ROOT_SUPPORT_EXPORTOP?  That's the fhandle that cgroup uses,
currently the standard ino+gen which isn't ideal but good enough.
Another benefit is that the path can also be resolved efficiently from
userspace given the handle.

Thanks.

-- 
tejun