Commit 3a592405 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Allow task-level idle entry/exit nesting 



The current task-level idle entry/exit code forces an entry/exit on
each call, regardless of the nesting level.  This commit therefore
properly accounts for nesting.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent 96d3fd0d

kernel/rcu/tree.c

+8 −6
Original line number Diff line number Diff line
@@ -418,11 +418,12 @@ static void rcu_eqs_enter(bool user) 
	rdtp = this_cpu_ptr(&rcu_dynticks);

	oldval = rdtp->dynticks_nesting;

	WARN_ON_ONCE((oldval & DYNTICK_TASK_NEST_MASK) == 0);

	if ((oldval & DYNTICK_TASK_NEST_MASK) == DYNTICK_TASK_NEST_VALUE)

	if ((oldval & DYNTICK_TASK_NEST_MASK) == DYNTICK_TASK_NEST_VALUE) {

		rdtp->dynticks_nesting = 0;

	else

		rdtp->dynticks_nesting -= DYNTICK_TASK_NEST_VALUE;

		rcu_eqs_enter_common(rdtp, oldval, user);

	} else {

		rdtp->dynticks_nesting -= DYNTICK_TASK_NEST_VALUE;

	}

}



/**
@@ -540,12 +541,13 @@ static void rcu_eqs_exit(bool user) 
	rdtp = this_cpu_ptr(&rcu_dynticks);

	oldval = rdtp->dynticks_nesting;

	WARN_ON_ONCE(oldval < 0);

	if (oldval & DYNTICK_TASK_NEST_MASK)

	if (oldval & DYNTICK_TASK_NEST_MASK) {

		rdtp->dynticks_nesting += DYNTICK_TASK_NEST_VALUE;

	else

	} else {

		rdtp->dynticks_nesting = DYNTICK_TASK_EXIT_IDLE;

		rcu_eqs_exit_common(rdtp, oldval, user);

	}

}



/**

 * rcu_idle_exit - inform RCU that current CPU is leaving idle