Re: [patch 3/4] Linux Kernel Markers - Documentation

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

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

> [...]
> +A marker placed in your code provides a hook to call a function (probe) that
> +you can provide at runtime. A marker can be "on" (a probe is connected to it)
> +or "off" (no probe is attached). When a marker is "off" it has no
> +effect. [...]

Add something like, ", except for a (how?) small time/space penalty."

> +[...]
> +trace_mark(subsystem_event, "%d %s", someint, somestring);
> +Where :
> +- subsystem_event is an identifier unique to your event
> +    - subsystem is the name of your subsystem.
> +    - event is the name of the event to mark.
> +[...]

It would be useful to clarify that this "subsystem_event" scheme is
only a suggested naming convention intended to limit collisions.

> +Connecting a function (probe) to a marker is done by providing a
> probe +(function to call) for the specific marker through
> marker_probe_register() and +can be activated by calling
> marker_arm().

It would help to spell out the nature of the marker namespace.  Is it
global to the kernel?  Per-module?  Are conflicting "subsystem_event"
names but different format strings considered separate markers?

> + [...] Marker disactivation [...]

"deactivation"

- FChE