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Commit f7b8eb84 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Consolidate expedited grace period machinery 



The functions synchronize_rcu_expedited() and synchronize_sched_expedited()
have nearly identical code.  This commit therefore consolidates this code
into a new _synchronize_rcu_expedited() function.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 29b4817d

kernel/rcu/tree_exp.h

+29 −33
Original line number Diff line number Diff line
@@ -516,6 +516,33 @@ static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s) 
	mutex_unlock(&rsp->exp_wake_mutex);

}



/*

 * Given an rcu_state pointer and a smp_call_function() handler, kick

 * off the specified flavor of expedited grace period.

 */

static void _synchronize_rcu_expedited(struct rcu_state *rsp,

				       smp_call_func_t func)

{

	unsigned long s;



	/* If expedited grace periods are prohibited, fall back to normal. */

	if (rcu_gp_is_normal()) {

		wait_rcu_gp(rsp->call);

		return;

	}



	/* Take a snapshot of the sequence number.  */

	s = rcu_exp_gp_seq_snap(rsp);

	if (exp_funnel_lock(rsp, s))

		return;  /* Someone else did our work for us. */



	/* Initialize the rcu_node tree in preparation for the wait. */

	sync_rcu_exp_select_cpus(rsp, func);



	/* Wait and clean up, including waking everyone. */

	rcu_exp_wait_wake(rsp, s);

}



/**

 * synchronize_sched_expedited - Brute-force RCU-sched grace period

 *
@@ -534,29 +561,13 @@ static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s) 
 */

void synchronize_sched_expedited(void)

{

	unsigned long s;

	struct rcu_state *rsp = &rcu_sched_state;



	/* If only one CPU, this is automatically a grace period. */

	if (rcu_blocking_is_gp())

		return;



	/* If expedited grace periods are prohibited, fall back to normal. */

	if (rcu_gp_is_normal()) {

		wait_rcu_gp(call_rcu_sched);

		return;

	}



	/* Take a snapshot of the sequence number.  */

	s = rcu_exp_gp_seq_snap(rsp);

	if (exp_funnel_lock(rsp, s))

		return;  /* Someone else did our work for us. */



	/* Initialize the rcu_node tree in preparation for the wait. */

	sync_rcu_exp_select_cpus(rsp, sync_sched_exp_handler);



	/* Wait and clean up, including waking everyone. */

	rcu_exp_wait_wake(rsp, s);

	_synchronize_rcu_expedited(rsp, sync_sched_exp_handler);

}

EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
@@ -620,23 +631,8 @@ static void sync_rcu_exp_handler(void *info) 
void synchronize_rcu_expedited(void)

{

	struct rcu_state *rsp = rcu_state_p;

	unsigned long s;



	/* If expedited grace periods are prohibited, fall back to normal. */

	if (rcu_gp_is_normal()) {

		wait_rcu_gp(call_rcu);

		return;

	}



	s = rcu_exp_gp_seq_snap(rsp);

	if (exp_funnel_lock(rsp, s))

		return;  /* Someone else did our work for us. */



	/* Initialize the rcu_node tree in preparation for the wait. */

	sync_rcu_exp_select_cpus(rsp, sync_rcu_exp_handler);



	/* Wait for ->blkd_tasks lists to drain, then wake everyone up. */

	rcu_exp_wait_wake(rsp, s);

	_synchronize_rcu_expedited(rsp, sync_rcu_exp_handler);

}

EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);