tracing: Implement event pid filtering
Add the necessary hooks to use the pids loaded in set_event_pid to filter
all the events enabled in the tracing instance that match the pids listed.
Two probes are added to both sched_switch and sched_wakeup tracepoints to be
called before other probes are called and after the other probes are called.
The first is used to set the necessary flags to let the probes know to test
if they should be traced or not.
The sched_switch pre probe will set the "ignore_pid" flag if neither the
previous or next task has a matching pid.
The sched_switch probe will set the "ignore_pid" flag if the next task
does not match the matching pid.
The pre probe allows for probes tracing sched_switch to be traced if
necessary.
The sched_wakeup pre probe will set the "ignore_pid" flag if neither the
current task nor the wakee task has a matching pid.
The sched_wakeup post probe will set the "ignore_pid" flag if the current
task does not have a matching pid.
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index f85693b..429fdfc 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -328,6 +328,7 @@
EVENT_FILE_FL_SOFT_DISABLED_BIT,
EVENT_FILE_FL_TRIGGER_MODE_BIT,
EVENT_FILE_FL_TRIGGER_COND_BIT,
+ EVENT_FILE_FL_PID_FILTER_BIT,
};
/*
@@ -341,6 +342,7 @@
* tracepoint may be enabled)
* TRIGGER_MODE - When set, invoke the triggers associated with the event
* TRIGGER_COND - When set, one or more triggers has an associated filter
+ * PID_FILTER - When set, the event is filtered based on pid
*/
enum {
EVENT_FILE_FL_ENABLED = (1 << EVENT_FILE_FL_ENABLED_BIT),
@@ -351,6 +353,7 @@
EVENT_FILE_FL_SOFT_DISABLED = (1 << EVENT_FILE_FL_SOFT_DISABLED_BIT),
EVENT_FILE_FL_TRIGGER_MODE = (1 << EVENT_FILE_FL_TRIGGER_MODE_BIT),
EVENT_FILE_FL_TRIGGER_COND = (1 << EVENT_FILE_FL_TRIGGER_COND_BIT),
+ EVENT_FILE_FL_PID_FILTER = (1 << EVENT_FILE_FL_PID_FILTER_BIT),
};
struct trace_event_file {
@@ -429,6 +432,8 @@
extern void event_triggers_post_call(struct trace_event_file *file,
enum event_trigger_type tt);
+bool trace_event_ignore_this_pid(struct trace_event_file *trace_file);
+
/**
* trace_trigger_soft_disabled - do triggers and test if soft disabled
* @file: The file pointer of the event to test
@@ -448,6 +453,8 @@
event_triggers_call(file, NULL);
if (eflags & EVENT_FILE_FL_SOFT_DISABLED)
return true;
+ if (eflags & EVENT_FILE_FL_PID_FILTER)
+ return trace_event_ignore_this_pid(file);
}
return false;
}