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

From: Tejun Heo
Date: Wed Aug 28 2019 - 10:48:39 EST


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