Re: [PATCH 0/2] ftrace: updates to tip

From: Ingo Molnar
Date: Fri Jan 16 2009 - 11:02:31 EST

* Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> On Fri, 16 Jan 2009, Ingo Molnar wrote:
> > >
> > > But I do notice that not all functions produce a valid stack trace.
> > > Maybe it would be better to add that api :-?
> >
> > yes - i think that API would be more intuitive, and that way people could
> > mix more interesting functions (with stack traces) with less important
> > functions (no stack traces).
> Ah, that's the point. We can't mix and match on these. Either all
> functions that are traced do the stack trace, or none do. This is where
> the new api may be confusing. [...]

that would be confusing indeed.

> [...] We can register a function to be traced via the function pointer,
> and we can pick which functions to trace, but we can not separate out
> different functions for different traces.

Why not? We could have a hash of all traced functions with metadata
attached. Since patching functions in/out would be a relatively rare
operation, this would be a highly efficient read-mostly hash.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at