Commit 01c495f7 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Remove obsolete __rcu_pending() statistics for debugfs 



The debugfs interface displayed statistics on RCU-pending checks
but this interface has since been removed.  This commit therefore
removes the no-longer-used rcu_data structure's ->n_rcu_pending,
->n_rp_core_needs_qs, ->n_rp_report_qs, ->n_rp_cb_ready,
->n_rp_cpu_needs_gp, ->n_rp_gp_completed, ->n_rp_gp_started,
->n_rp_nocb_defer_wakeup, and ->n_rp_need_nothing fields along with
their updates.

If this information proves necessary in the future, the corresponding
event traces will be added.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 62df63e0

kernel/rcu/tree.c

+6 −25
Original line number Diff line number Diff line
@@ -3354,8 +3354,6 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) 
{

	struct rcu_node *rnp = rdp->mynode;



	rdp->n_rcu_pending++;



	/* Check for CPU stalls, if enabled. */

	check_cpu_stall(rsp, rdp);
@@ -3364,48 +3362,31 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) 
		return 0;



	/* Is the RCU core waiting for a quiescent state from this CPU? */

	if (rcu_scheduler_fully_active &&

	    rdp->core_needs_qs && rdp->cpu_no_qs.b.norm &&

	    rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_dynticks.rcu_qs_ctr)) {

		rdp->n_rp_core_needs_qs++;

	} else if (rdp->core_needs_qs && !rdp->cpu_no_qs.b.norm) {

		rdp->n_rp_report_qs++;

	if (rdp->core_needs_qs && !rdp->cpu_no_qs.b.norm)

		return 1;

	}



	/* Does this CPU have callbacks ready to invoke? */

	if (rcu_segcblist_ready_cbs(&rdp->cblist)) {

		rdp->n_rp_cb_ready++;

	if (rcu_segcblist_ready_cbs(&rdp->cblist))

		return 1;

	}



	/* Has RCU gone idle with this CPU needing another grace period? */

	if (cpu_needs_another_gp(rsp, rdp)) {

		rdp->n_rp_cpu_needs_gp++;

	if (cpu_needs_another_gp(rsp, rdp))

		return 1;

	}



	/* Has another RCU grace period completed?  */

	if (READ_ONCE(rnp->completed) != rdp->completed) { /* outside lock */

		rdp->n_rp_gp_completed++;

	if (READ_ONCE(rnp->completed) != rdp->completed) /* outside lock */

		return 1;

	}



	/* Has a new RCU grace period started? */

	if (READ_ONCE(rnp->gpnum) != rdp->gpnum ||

	    unlikely(READ_ONCE(rdp->gpwrap))) { /* outside lock */

		rdp->n_rp_gp_started++;

	    unlikely(READ_ONCE(rdp->gpwrap))) /* outside lock */

		return 1;

	}



	/* Does this CPU need a deferred NOCB wakeup? */

	if (rcu_nocb_need_deferred_wakeup(rdp)) {

		rdp->n_rp_nocb_defer_wakeup++;

	if (rcu_nocb_need_deferred_wakeup(rdp))

		return 1;

	}



	/* nothing to do */

	rdp->n_rp_need_nothing++;

	return 0;

}

kernel/rcu/tree.h

+3 −14
Original line number Diff line number Diff line
@@ -226,18 +226,7 @@ struct rcu_data { 
					/* Grace period that needs help */

					/*  from cond_resched(). */



	/* 5) __rcu_pending() statistics. */

	unsigned long n_rcu_pending;	/* rcu_pending() calls since boot. */

	unsigned long n_rp_core_needs_qs;

	unsigned long n_rp_report_qs;

	unsigned long n_rp_cb_ready;

	unsigned long n_rp_cpu_needs_gp;

	unsigned long n_rp_gp_completed;

	unsigned long n_rp_gp_started;

	unsigned long n_rp_nocb_defer_wakeup;

	unsigned long n_rp_need_nothing;



	/* 6) _rcu_barrier(), OOM callbacks, and expediting. */

	/* 5) _rcu_barrier(), OOM callbacks, and expediting. */

	struct rcu_head barrier_head;

#ifdef CONFIG_RCU_FAST_NO_HZ

	struct rcu_head oom_head;
@@ -248,7 +237,7 @@ struct rcu_data { 
	atomic_long_t exp_workdone3;	/* # done by others #3. */

	int exp_dynticks_snap;		/* Double-check need for IPI. */



	/* 7) Callback offloading. */

	/* 6) Callback offloading. */

#ifdef CONFIG_RCU_NOCB_CPU

	struct rcu_head *nocb_head;	/* CBs waiting for kthread. */

	struct rcu_head **nocb_tail;
@@ -275,7 +264,7 @@ struct rcu_data { 
					/* Leader CPU takes GP-end wakeups. */

#endif /* #ifdef CONFIG_RCU_NOCB_CPU */



	/* 8) RCU CPU stall data. */

	/* 7) RCU CPU stall data. */

	unsigned int softirq_snap;	/* Snapshot of softirq activity. */

	/* ->rcu_iw* fields protected by leaf rcu_node ->lock. */

	struct irq_work rcu_iw;		/* Check for non-irq activity. */

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