GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-06-27 09:02:06 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

tracepoint: Give priority to probes of tracepoints

Browse source 
In order to guarantee that a probe will be called before other probes that
are attached to a tracepoint, there needs to be a mechanism to provide
priority of one probe over the others.

Adding a prio field to the struct tracepoint_func, which lets the probes be
sorted by the priority set in the structure. If no priority is specified,
then a priority of 10 is given (this is a macro, and perhaps may be changed
in the future).

Now probes may be added to affect other probes that are attached to a
tracepoint with a guaranteed order.

One use case would be to allow tracing of tracepoints be able to filter by
pid. A special (higher priority probe) may be added to the sched_switch
tracepoint and set the necessary flags of the other tracepoints to notify
them if they should be traced or not. In case a tracepoint is enabled at the
sched_switch tracepoint too, the order of the two are not random.

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat) 2015-09-22 17:13:19 -04:00 • committed by Steven Rostedt
parent 883a1e867e
commit 7904b5c498
2 changed files with 70 additions and 18 deletions
Download patch file Download diff file Expand all files Collapse all files

13
include/linux/tracepoint.h
View file

@ -26,6 +26,7 @@ struct notifier_block;
struct tracepoint_func {
void *func;
void *data;
int prio;
};
struct tracepoint {
@ -42,9 +43,14 @@ struct trace_enum_map {
unsigned long enum_value;
};
#define TRACEPOINT_DEFAULT_PRIO 10
extern int
tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
extern int
tracepoint_probe_register_prio(struct tracepoint *tp, void *probe, void *data,
int prio);
extern int
tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data);
extern void
for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
@ -207,6 +213,13 @@ extern void syscall_unregfunc(void);
(void *)probe, data); \
} \
static inline int \
register_trace_prio_##name(void (*probe)(data_proto), void *data,\
int prio) \
{ \
return tracepoint_probe_register_prio(&__tracepoint_##name, \
(void *)probe, data, prio); \
} \
static inline int \
unregister_trace_##name(void (*probe)(data_proto), void *data) \
{ \
return tracepoint_probe_unregister(&__tracepoint_##name,\