On Tue, May 30, 2017 at 10:37:46AM -0700, Alexei Starovoitov wrote: > On 5/30/17 9:51 AM, Peter Zijlstra wrote:
> > I'm not entirely sure I see how that is required. Should per task not > > already work? The WARN that's there will only trigger if you call them > > on the wrong task, which is something you shouldn't do anyway. > > The kernel WARN is considered to be a bug of bpf infra. That's the > reason we do all these checks at map update time and at run-time. > The bpf program authors should be able to do all possible experiments > until their scripts work. Dealing with kernel warns and reboots is not > something user space folks like to do. > Today bpf_perf_event_read() for per-task events isn't really > working due to event->oncpu != cpu runtime check in there. > If we convert warns to returns the existing scripts will continue > to work as-is and per-task will be possible. Ah yes.. I always forget that side of things (not ever having seen a bpf thing working doesn't help either of course). Let me consider that for a bit..
