Re: [PATCH v4 16/27] tracing: Remove regular RCU context for _rcuidle tracepoints (again)

[Steven Rostedt]

On Fri, 6 Mar 2020 15:55:24 -0500 (EST)
Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> wrote:

> ----- On Mar 6, 2020, at 3:45 PM, rostedt rostedt@xxxxxxxxxxx wrote:
> 
> > On Fri, 6 Mar 2020 15:22:46 -0500 (EST)
> > Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> wrote:
> >   
> >> I agree with the overall approach. Just a bit of nitpicking on the API:
> >> 
> >> I understand that the "prio" argument is a separate argument because it can take
> >> many values. However, "rcu" is just a boolean, so I wonder if we should not
> >> rather
> >> introduce a "int flags" with a bitmask enum, e.g.  
> > 
> > I thought about this approach, but thought it was a bit overkill. As the
> > kernel doesn't have an internal API, I figured we can switch this over to
> > flags when we get another flag to add. Unless you can think of one in the
> > near future.  
> 
> The additional feature I have in mind for near future would be to register
> a probe which can take a page fault to a "sleepable" tracepoint. This would
> require preemption to be enabled and use of SRCU.
> 
> We can always change things when we get there.

Yeah, let's rename it if we get there.

-- Steve