Re: [PATCH v4 1/3] perf: add PERF_RECORD_NAMESPACES to include namespaces related info

[Hari Bathini]

On Friday 16 December 2016 12:16 AM, Peter Zijlstra wrote:
> On Fri, Dec 16, 2016 at 12:07:06AM +0530, Hari Bathini wrote:
> > +struct perf_ns_link_info {
> > +	__u64	dev;
> > +	__u64	ino;
> > +};
> > +
> > +enum {
> > +	NET_NS_INDEX		= 0,
> > +	UTS_NS_INDEX		= 1,
> > +	IPC_NS_INDEX		= 2,
> > +	PID_NS_INDEX		= 3,
> > +	USER_NS_INDEX		= 4,
> > +	MNT_NS_INDEX		= 5,
> > +	CGROUP_NS_INDEX		= 6,
> > +
> > +	NAMESPACES_MAX,		/* maximum available namespaces */
> > +};
> > +
> >   enum perf_event_type {
> >   
> >   	/*
> > @@ -862,6 +880,17 @@ enum perf_event_type {
> >   	 */
> >   	PERF_RECORD_SWITCH_CPU_WIDE		= 15,
> >   
> > +	/*
> > +	 * struct {
> > +	 *	struct perf_event_header	header;
> > +	 *	u32				pid;
> > +	 *	u32				tid;
> > +	 *	struct namespace_link_info	link_info[NAMESPACES_MAX];
> > +	 *	struct sample_id		sample_id;
> > +	 * };
> > +	 */
> > +	PERF_RECORD_NAMESPACES			= 16,
> > +
> >   	PERF_RECORD_MAX,			/* non-ABI */
> >   };
> What happens if a future kernel adds another namespace?

No impact unless NAMESPACES_MAX in include/uapi/linux/perf_event.h is 
updated to accommodate that..
And if it is updated, the corresponding change is expected in perf-tool 
as well..

Thanks
Hari