Commit 1bb33644 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Rename rcu_data's ->deferred_qs to ->exp_deferred_qs 



The rcu_data structure's ->deferred_qs field is used to indicate that the
current CPU is blocking an expedited grace period (perhaps a future one).
Given that it is used only for expedited grace periods, its current name
is misleading, so this commit renames it to ->exp_deferred_qs.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
parent eddded80

kernel/rcu/tree.h

+1 −1
Original line number Diff line number Diff line
@@ -154,7 +154,7 @@ struct rcu_data { 
	bool		core_needs_qs;	/* Core waits for quiesc state. */

	bool		beenonline;	/* CPU online at least once. */

	bool		gpwrap;		/* Possible ->gp_seq wrap. */

	bool		deferred_qs;	/* This CPU awaiting a deferred QS? */

	bool		exp_deferred_qs; /* This CPU awaiting a deferred QS? */

	struct rcu_node *mynode;	/* This CPU's leaf of hierarchy */

	unsigned long grpmask;		/* Mask to apply to leaf qsmask. */

	unsigned long	ticks_this_gp;	/* The number of scheduling-clock */

kernel/rcu/tree_exp.h

+4 −4
Original line number Diff line number Diff line
@@ -250,7 +250,7 @@ static void rcu_report_exp_cpu_mult(struct rcu_node *rnp, 
 */

static void rcu_report_exp_rdp(struct rcu_data *rdp)

{

	WRITE_ONCE(rdp->deferred_qs, false);

	WRITE_ONCE(rdp->exp_deferred_qs, false);

	rcu_report_exp_cpu_mult(rdp->mynode, rdp->grpmask, true);

}
@@ -616,7 +616,7 @@ static void rcu_exp_handler(void *unused) 
		    rcu_dynticks_curr_cpu_in_eqs()) {

			rcu_report_exp_rdp(rdp);

		} else {

			rdp->deferred_qs = true;

			rdp->exp_deferred_qs = true;

			set_tsk_need_resched(t);

			set_preempt_need_resched();

		}
@@ -638,7 +638,7 @@ static void rcu_exp_handler(void *unused) 
	if (t->rcu_read_lock_nesting > 0) {

		raw_spin_lock_irqsave_rcu_node(rnp, flags);

		if (rnp->expmask & rdp->grpmask) {

			rdp->deferred_qs = true;

			rdp->exp_deferred_qs = true;

			t->rcu_read_unlock_special.b.exp_hint = true;

		}

		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
@@ -661,7 +661,7 @@ static void rcu_exp_handler(void *unused) 
	 *

	 * Otherwise, force a context switch after the CPU enables everything.

	 */

	rdp->deferred_qs = true;

	rdp->exp_deferred_qs = true;

	if (!(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK)) ||

	    WARN_ON_ONCE(rcu_dynticks_curr_cpu_in_eqs())) {

		rcu_preempt_deferred_qs(t);

kernel/rcu/tree_plugin.h

+7 −7
Original line number Diff line number Diff line
@@ -237,10 +237,10 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp) 
	 * no need to check for a subsequent expedited GP.  (Though we are

	 * still in a quiescent state in any case.)

	 */

	if (blkd_state & RCU_EXP_BLKD && rdp->deferred_qs)

	if (blkd_state & RCU_EXP_BLKD && rdp->exp_deferred_qs)

		rcu_report_exp_rdp(rdp);

	else

		WARN_ON_ONCE(rdp->deferred_qs);

		WARN_ON_ONCE(rdp->exp_deferred_qs);

}



/*
@@ -337,7 +337,7 @@ void rcu_note_context_switch(bool preempt) 
	 * means that we continue to block the current grace period.

	 */

	rcu_qs();

	if (rdp->deferred_qs)

	if (rdp->exp_deferred_qs)

		rcu_report_exp_rdp(rdp);

	trace_rcu_utilization(TPS("End context switch"));

	barrier(); /* Avoid RCU read-side critical sections leaking up. */
@@ -451,7 +451,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) 
	 */

	special = t->rcu_read_unlock_special;

	rdp = this_cpu_ptr(&rcu_data);

	if (!special.s && !rdp->deferred_qs) {

	if (!special.s && !rdp->exp_deferred_qs) {

		local_irq_restore(flags);

		return;

	}
@@ -459,7 +459,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) 
	if (special.b.need_qs) {

		rcu_qs();

		t->rcu_read_unlock_special.b.need_qs = false;

		if (!t->rcu_read_unlock_special.s && !rdp->deferred_qs) {

		if (!t->rcu_read_unlock_special.s && !rdp->exp_deferred_qs) {

			local_irq_restore(flags);

			return;

		}
@@ -471,7 +471,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) 
	 * tasks are handled when removing the task from the

	 * blocked-tasks list below.

	 */

	if (rdp->deferred_qs) {

	if (rdp->exp_deferred_qs) {

		rcu_report_exp_rdp(rdp);

		if (!t->rcu_read_unlock_special.s) {

			local_irq_restore(flags);
@@ -560,7 +560,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) 
 */

static bool rcu_preempt_need_deferred_qs(struct task_struct *t)

{

	return (__this_cpu_read(rcu_data.deferred_qs) ||

	return (__this_cpu_read(rcu_data.exp_deferred_qs) ||

		READ_ONCE(t->rcu_read_unlock_special.s)) &&

	       t->rcu_read_lock_nesting <= 0;

}

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