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Commit 0ef8cde5 authored by Steven Rostedt's avatar Steven Rostedt Committed by Ingo Molnar
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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: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent ea4e2bc4

kernel/trace/ftrace.c

+25 −3
Original line number Diff line number Diff line
@@ -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;



		/*

		 * 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 */