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Commit 2927a689 authored by Paul E. McKenney's avatar Paul E. McKenney
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rcu: Create an immutable rcu_data_p pointer to default rcu_data structure 



This commit creates an immutable rcu_data_p pointer that references
rcu_preempt_data for TREE_PREEMPT_RCU builds and that references
rcu_sched_data for TREE_RCU builds.  This rcu_data_p pointer will enable
more code to move from #ifdef to IS_ENABLED().

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent b28a7c01

kernel/rcu/tree.c

+1 −0
Original line number Diff line number Diff line
@@ -111,6 +111,7 @@ RCU_STATE_INITIALIZER(rcu_sched, 's', call_rcu_sched); 
RCU_STATE_INITIALIZER(rcu_bh, 'b', call_rcu_bh);



static struct rcu_state *const rcu_state_p;

static struct rcu_data __percpu *const rcu_data_p;

LIST_HEAD(rcu_struct_flavors);



/* Increase (but not decrease) the CONFIG_RCU_FANOUT_LEAF at boot time. */

kernel/rcu/tree_plugin.h

+9 −7
Original line number Diff line number Diff line
@@ -101,6 +101,7 @@ static void __init rcu_bootup_announce_oddness(void) 


RCU_STATE_INITIALIZER(rcu_preempt, 'p', call_rcu);

static struct rcu_state *const rcu_state_p = &rcu_preempt_state;

static struct rcu_data __percpu *const rcu_data_p = &rcu_preempt_data;



static int rcu_preempted_readers_exp(struct rcu_node *rnp);

static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
@@ -126,11 +127,11 @@ static void __init rcu_bootup_announce(void) 
 */

static void rcu_preempt_qs(void)

{

	if (!__this_cpu_read(rcu_preempt_data.passed_quiesce)) {

	if (!__this_cpu_read(rcu_data_p->passed_quiesce)) {

		trace_rcu_grace_period(TPS("rcu_preempt"),

				       __this_cpu_read(rcu_preempt_data.gpnum),

				       __this_cpu_read(rcu_data_p->gpnum),

				       TPS("cpuqs"));

		__this_cpu_write(rcu_preempt_data.passed_quiesce, 1);

		__this_cpu_write(rcu_data_p->passed_quiesce, 1);

		barrier(); /* Coordinate with rcu_preempt_check_callbacks(). */

		current->rcu_read_unlock_special.b.need_qs = false;

	}
@@ -495,8 +496,8 @@ static void rcu_preempt_check_callbacks(void) 
		return;

	}

	if (t->rcu_read_lock_nesting > 0 &&

	    __this_cpu_read(rcu_preempt_data.qs_pending) &&

	    !__this_cpu_read(rcu_preempt_data.passed_quiesce))

	    __this_cpu_read(rcu_data_p->qs_pending) &&

	    !__this_cpu_read(rcu_data_p->passed_quiesce))

		t->rcu_read_unlock_special.b.need_qs = true;

}
@@ -504,7 +505,7 @@ static void rcu_preempt_check_callbacks(void) 


static void rcu_preempt_do_callbacks(void)

{

	rcu_do_batch(rcu_state_p, this_cpu_ptr(&rcu_preempt_data));

	rcu_do_batch(rcu_state_p, this_cpu_ptr(rcu_data_p));

}



#endif /* #ifdef CONFIG_RCU_BOOST */
@@ -811,7 +812,7 @@ EXPORT_SYMBOL_GPL(rcu_barrier); 
 */

static void __init __rcu_init_preempt(void)

{

	rcu_init_one(rcu_state_p, &rcu_preempt_data);

	rcu_init_one(rcu_state_p, rcu_data_p);

}



/*
@@ -835,6 +836,7 @@ void exit_rcu(void) 
#else /* #ifdef CONFIG_PREEMPT_RCU */



static struct rcu_state *const rcu_state_p = &rcu_sched_state;

static struct rcu_data __percpu *const rcu_data_p = &rcu_sched_data;



/*

 * Tell them what RCU they are running.