Re: [PATCH] Linux Kernel Markers 0.2 for Linux 2.6.17

[fche@redhat.com (Frank Ch. Eigler)]

Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> writes:

> Following some very interesting ideas from Martin that shows that
> even static function calls and inlined functions can be used in
> interesting ways with markers to deploy dynamic tracers with easy
> access to local function variables [...]

While that has been an interesting idea, its implementation would need
to be sketched out far beyond the speculative, in order to override
what I perceive as the rough consensus reached during earlier in the
thread.

> [...]  These last emails convince me even more that a markup
> mechanism must interface with every kind of instrumentation hooking
> we can think about, both dynamic and static. [...]

If you don't allow yourself to presume on-the-fly function
recompilation, then these markers would need to be made run-time
rather than compile-time configurable.  That is, not like this:

> +/* Menu configured markers */
> +#ifndef CONFIG_MARK
> +#define MARK	MARK_INACTIVE
> +#elif defined(CONFIG_MARK_PRINT)
> +#define MARK	MARK_PRINT
> +#elif defined(CONFIG_MARK_FPROBE)
> +#define MARK	MARK_FPROBE
> +#elif defined(CONFIG_MARK_KPROBE)
> +#define MARK	MARK_KPROBE
> +#elif defined(CONFIG_MARK_JPROBE)
> +#define MARK	MARK_JPROBE
> +#endif

- FChE