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ftrace: use task struct trace flag to filter on pid 

Impact: clean up

Use the new task struct trace flags to determine if a process should be
traced or not.

Note: this moves the searching of the pid to the slow path of setting
the pid field. This needs to be converted to the pid name space.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Steven Rostedt 2008-12-03 15:36:58 -05:00 committed by Ingo Molnar
parent ea4e2bc4d9
commit 0ef8cde56a
1 changed files with 25 additions and 3 deletions
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28
kernel/trace/ftrace.c
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@ -47,7 +47,7 @@
int ftrace_enabled __read_mostly;
static int last_ftrace_enabled;
/* ftrace_pid_trace >= 0 will only trace threads with this pid */
/* set when tracing only a pid */
static int ftrace_pid_trace = -1;
/* Quick disabling of function tracer. */
@ -90,7 +90,7 @@ static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
{
if (current->pid != ftrace_pid_trace)
if (!test_tsk_trace_trace(current))
return;
ftrace_pid_function(ip, parent_ip);
@ -1714,11 +1714,33 @@ ftrace_pid_write(struct file *filp, const char __user *ubuf,
ftrace_pid_trace = -1;
} else {
struct task_struct *p;
int found = 0;
if (ftrace_pid_trace == val)
goto out;
ftrace_pid_trace = val;
/*
* Find the task that matches this pid.
* TODO: use pid namespaces instead.
*/
rcu_read_lock();
for_each_process(p) {
if (p->pid == val) {
found = 1;
set_tsk_trace_trace(p);
} else if (test_tsk_trace_trace(p))
clear_tsk_trace_trace(p);
}
rcu_read_unlock();
if (found)
ftrace_pid_trace = val;
else {
if (ftrace_pid_trace < 0)
goto out;
ftrace_pid_trace = -1;
}
}
/* update the function call */