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| author | Steven Rostedt (Red Hat) <rostedt@goodmis.org> | 2015-09-22 17:13:19 -0400 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2015-10-25 21:33:54 -0400 |
| commit | 7904b5c4988e18b50056b5e71a3ffca752a8a451 (patch) | |
| tree | 4319a3e6fe143e6404420f885275cb1f7c87a1a4 /include/linux/tracepoint.h | |
| parent | 883a1e867e0fe7c2dc2e5844ef692f80177631d5 (diff) | |
| download | linux-7904b5c4988e18b50056b5e71a3ffca752a8a451.tar.gz linux-7904b5c4988e18b50056b5e71a3ffca752a8a451.tar.bz2 linux-7904b5c4988e18b50056b5e71a3ffca752a8a451.zip | |
tracepoint: Give priority to probes of tracepoints
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>
Diffstat (limited to 'include/linux/tracepoint.h')
| -rw-r--r-- | include/linux/tracepoint.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index afada369c5b7..6b79537a42b1 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -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,\ |