On Wed, Jan 28, 2015 at 10:41 PM, Namhyung Kim <namhyung@xxxxxxxxxx> wrote: > > I think it's not a problem of bpf. An user process can be killed > anytime while it enabed events without bpf. The only thing it should > care is the auto-unload IMHO. ok. I think it does indeed make sense to decouple the logic. We can add 'auto_enable' file to achieve desired Ctrl-C behavior. While the 'auto_enable' file is open the event will be enabled and writes to 'enable' file will be ignored. As soon as file closes, the event is auto-disabled. Then user space will use 'bpf' file to attach/auto-unload and 'auto_enable' file together. Seem there would be a use for such 'auto_enable' without bpf as well. > I'm okay for not calling bpf program in NMI but not for disabling events. > > Suppose an user was collecting an event (including in NMI) and then > [s]he also wanted to run a bpf program. So [s]he wrote a program > always return 1. But after attaching the program, it didn't record > the event in NMI.. Isn't that a problem? ok, I think 'if (in_nmi()) return 1;' will work then, right? Or you're thinking something else ? > Right. I think bpf programs belong to a user process but events are > global resource. Maybe you also need to consider attaching bpf > program via perf (ioctl?) interface.. yes. I did. Please see my reply to Masami. ioctl only works for tracepoints. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
