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

[Namhyung Kim]

Hi Tejun,

On Wed, Aug 28, 2019 at 11:48 PM Tejun Heo <tj@xxxxxxxxxx> wrote:
>
> 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 for the info, I'll take a look at it.
Namhyung