On Wed, Jan 21, 2015 at 5:56 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > On Wed, 21 Jan 2015 17:49:08 -0800 > Alexei Starovoitov <ast@xxxxxxxxxxxx> wrote: > > >> > This also makes it keeping events in the soft-disabled state. >> >> I was never able to figure out the use case for soft-disabled state. >> Probably historical before static_key was done. > > No, it's not historical at all. The "soft-disable" is a way to enable > from any context. You can't enable a static key from NMI or interrupt > context, but you can enable a "soft-disable" there. > > As you can enable or disable events from any function that the function > tracer may trace, I needed a way to enable them (make the tracepoint > active), but do nothing until something else turns them on. Thanks for explanation. Makes sense. Speaking of nmi... I think I will add a check that if (in_nmi()) just skip running the program, since supporting this use case is not needed at the moment. -- 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
