[lttv.git] / ltt / branches / poly / doc / developer / hook_prio.txt

Linux Trace Toolkit

Mathieu Desnoyers 18-05-2004


Seeing that a very precise hook call ordering is needed when processing events
(especially the order for calling state update hooks and event delivery hooks),
this document defines a new type and interface that permits to merge all kind of
hooks, eventually sorted by the priority associated to them.

- Type LttvHooks with priorities

This is a modification to the actual LttvHooks that associates a priority with
each hook. The container for this type would be a garray, just like hook.c, but
a lttv_hooks_prio_sort would be called every time a hook is added to a list. It
would sort the hooks in a hook list by priority : from highest priority (-19) to
lowest (20). The default priority is 0.

In order to make lttv_hooks_call aware of the different kind of hooks it has to
call, the LttvHooksById will be modified to integrate a new "main" list : a
pointer to a LttvHooks that will be called for any Id.

A new lttv_hooks_by_id_call that will get the hooks from the main and by_id
lists in the right order will deal with the multiple lists priority problem.
Commit	Line	Data
6ea2aecb	1	Linux Trace Toolkit
	2
	3	Mathieu Desnoyers 18-05-2004
	4
	5
	6	Seeing that a very precise hook call ordering is needed when processing events
	7	(especially the order for calling state update hooks and event delivery hooks),
	8	this document defines a new type and interface that permits to merge all kind of
	9	hooks, eventually sorted by the priority associated to them.
	10
b5e8b4a6	11	- Type LttvHooks with priorities
	12
	13	This is a modification to the actual LttvHooks that associates a priority with
	14	each hook. The container for this type would be a garray, just like hook.c, but
	15	a lttv_hooks_prio_sort would be called every time a hook is added to a list. It
	16	would sort the hooks in a hook list by priority : from highest priority (-19) to
	17	lowest (20). The default priority is 0.
	18
	19	In order to make lttv_hooks_call aware of the different kind of hooks it has to
	20	call, the LttvHooksById will be modified to integrate a new "main" list : a
	21	pointer to a LttvHooks that will be called for any Id.
	22
	23	A new lttv_hooks_by_id_call that will get the hooks from the main and by_id
	24	lists in the right order will deal with the multiple lists priority problem.
	25
	26
6ea2aecb	27
6ea2aecb	28