Commit 9796e1ae authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu-tasks: Make RCU tasks trace also wait for idle tasks 



This commit scans the CPUs, adding each CPU's idle task to the list of
tasks that need quiescent states.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 7e3b70e0

kernel/rcu/tasks.h

+13 −5
Original line number Diff line number Diff line
@@ -15,7 +15,7 @@ struct rcu_tasks; 
typedef void (*rcu_tasks_gp_func_t)(struct rcu_tasks *rtp);

typedef void (*pregp_func_t)(void);

typedef void (*pertask_func_t)(struct task_struct *t, struct list_head *hop);

typedef void (*postscan_func_t)(void);

typedef void (*postscan_func_t)(struct list_head *hop);

typedef void (*holdouts_func_t)(struct list_head *hop, bool ndrpt, bool *frptp);

typedef void (*postgp_func_t)(struct rcu_tasks *rtp);
@@ -331,7 +331,7 @@ static void rcu_tasks_wait_gp(struct rcu_tasks *rtp) 
	rcu_read_unlock();



	set_tasks_gp_state(rtp, RTGS_POST_SCAN_TASKLIST);

	rtp->postscan_func();

	rtp->postscan_func(&holdouts);



	/*

	 * Each pass through the following loop scans the list of holdout
@@ -415,7 +415,7 @@ static void rcu_tasks_pertask(struct task_struct *t, struct list_head *hop) 
}



/* Processing between scanning taskslist and draining the holdout list. */

void rcu_tasks_postscan(void)

void rcu_tasks_postscan(struct list_head *hop)

{

	/*

	 * Wait for tasks that are in the process of exiting.  This
@@ -936,9 +936,17 @@ static void rcu_tasks_trace_pertask(struct task_struct *t, 
	trc_wait_for_one_reader(t, hop);

}



/* Do intermediate processing between task and holdout scans. */

static void rcu_tasks_trace_postscan(void)

/*

 * Do intermediate processing between task and holdout scans and

 * pick up the idle tasks.

 */

static void rcu_tasks_trace_postscan(struct list_head *hop)

{

	int cpu;



	for_each_possible_cpu(cpu)

		rcu_tasks_trace_pertask(idle_task(cpu), hop);



	// Re-enable CPU hotplug now that the tasklist scan has completed.

	cpus_read_unlock();