On Tuesday 15 November 2016 02:27 AM, Eric W. Biederman wrote:
Peter Zijlstra <[email protected]> writes:
On Mon, Nov 14, 2016 at 04:02:30PM +0530, Hari Bathini wrote:
PERF_RECORD_SWITCH_CPU_WIDE = 15,
+ /*
+ * struct {
+ * struct perf_event_header header;
+ *
+ * u32 pid, tid;
+ * u64 time;
+ * u32 uts_ns_inum;
+ * u32 ipc_ns_inum;
+ * u32 mnt_ns_inum;
+ * u32 pid_ns_inum;
+ * u32 net_ns_inum;
+ * u32 cgroup_ns_inum;
+ * u32 user_ns_inum;
+ * struct sample_id sample_id;
+ * };
+ */
+ PERF_RECORD_NAMESPACES = 16,
So this format is not extensible, that is, if someone adds yet another
namespace, we'll need to introduce PERF_RECORD_NAMESPACES2.
Is there a 'natural' and exposed namespace index that we can use to
change it like:
u32 nr_nss;
u32 namespace[nr_nss];
?
Nothing of that sort exists, currently.
Maybe, time to introduce with this patch-set..?
Would be good, but you'll have to sort that with the namespace folks.
The somewhat easy answer is to use the unshare flags. AKA CLONE_NEWNS,
CLONE_NEWUSER, ...
In the worst case things may get extended to the point where perf would
have to use a different set of values than we use to unshare, clone, and
setns (as the clone flags are effectively all used up) but for the
existing namespaces that index should work just fine.
That won't allow for a natural array in the record but it will allow for
an array with that has a tag for which namespace it is in, or
alternative it will allow for one record per namespace.
struct namespace_info {
u64 flags;
u32 inode_num;
/* any other essential namespace info */
};
struct {
struct perf_event_header header;
u32 pid, tid;
u64 time;
struct namespace_info ns_info[];
struct sample_id sample_id;
};
Something of this sort should do..?
Thanks
Hari
