rcu: Rename qs_pending to core_needs_qs

An upcoming commit needs to invert the sense of the ->passed_quiesce
rcu_data structure field, so this commit is taking this opportunity
to clarify things a bit by renaming ->qs_pending to ->core_needs_qs.

So if !rdp->core_needs_qs, then this CPU need not concern itself with
quiescent states, in particular, it need not acquire its leaf rcu_node
structure's ->lock to check.  Otherwise, it needs to report the next
quiescent state.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index d2cdcada6fe00764954dd1fb15005ebbf86076bb..7c158ffc77699c16d13f1ebde5d6c28d5e8b2853 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1746,7 +1746,7 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp,
                trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpustart"));
                rdp->passed_quiesce = 0;
                rdp->rcu_qs_ctr_snap = __this_cpu_read(rcu_qs_ctr);
-               rdp->qs_pending = !!(rnp->qsmask & rdp->grpmask);
+               rdp->core_needs_qs = !!(rnp->qsmask & rdp->grpmask);
                zero_cpu_stall_ticks(rdp);
                WRITE_ONCE(rdp->gpwrap, false);
        }
@@ -2357,7 +2357,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp)
        if ((rnp->qsmask & mask) == 0) {
                raw_spin_unlock_irqrestore(&rnp->lock, flags);
        } else {
-               rdp->qs_pending = 0;
+               rdp->core_needs_qs = 0;
 
                /*
                 * This GP can't end until cpu checks in, so all of our
@@ -2388,7 +2388,7 @@ rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp)
         * Does this CPU still need to do its part for current grace period?
         * If no, return and let the other CPUs do their part as well.
         */
-       if (!rdp->qs_pending)
+       if (!rdp->core_needs_qs)
                return;
 
        /*
@@ -3828,10 +3828,10 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
 
        /* Is the RCU core waiting for a quiescent state from this CPU? */
        if (rcu_scheduler_fully_active &&
-           rdp->qs_pending && !rdp->passed_quiesce &&
+           rdp->core_needs_qs && !rdp->passed_quiesce &&
            rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr)) {
-               rdp->n_rp_qs_pending++;
-       } else if (rdp->qs_pending &&
+               rdp->n_rp_core_needs_qs++;
+       } else if (rdp->core_needs_qs &&
                   (rdp->passed_quiesce ||
                    rdp->rcu_qs_ctr_snap != __this_cpu_read(rcu_qs_ctr))) {
                rdp->n_rp_report_qs++;
@@ -4157,7 +4157,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
        rdp->completed = rnp->completed;
        rdp->passed_quiesce = false;
        rdp->rcu_qs_ctr_snap = per_cpu(rcu_qs_ctr, cpu);
-       rdp->qs_pending = false;
+       rdp->core_needs_qs = false;
        trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpuonl"));
        raw_spin_unlock_irqrestore(&rnp->lock, flags);
 }

diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index efe361c764ab5f8501d0a1ef3b0ba73dcbfa71bc..4a0f30676ba82d9de267a7e6f78a45eff29b4da3 100644 (file)
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -303,7 +303,7 @@ struct rcu_data {
        unsigned long   rcu_qs_ctr_snap;/* Snapshot of rcu_qs_ctr to check */
                                        /*  for rcu_all_qs() invocations. */
        bool            passed_quiesce; /* User-mode/idle loop etc. */
-       bool            qs_pending;     /* Core waits for quiesc state. */
+       bool            core_needs_qs;  /* Core waits for quiesc state. */
        bool            beenonline;     /* CPU online at least once. */
        bool            gpwrap;         /* Possible gpnum/completed wrap. */
        struct rcu_node *mynode;        /* This CPU's leaf of hierarchy */
@@ -368,7 +368,7 @@ struct rcu_data {
 
        /* 5) __rcu_pending() statistics. */
        unsigned long n_rcu_pending;    /* rcu_pending() calls since boot. */
-       unsigned long n_rp_qs_pending;
+       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;

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 6f7500f9387cdbe9e56a1c2de91b54262fd67392..e33b4f3b8e0a833d428e5d5eb90834104b1a2736 100644 (file)
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -619,7 +619,7 @@ static void rcu_preempt_check_callbacks(void)
                return;
        }
        if (t->rcu_read_lock_nesting > 0 &&
-           __this_cpu_read(rcu_data_p->qs_pending) &&
+           __this_cpu_read(rcu_data_p->core_needs_qs) &&
            !__this_cpu_read(rcu_data_p->passed_quiesce))
                t->rcu_read_unlock_special.b.need_qs = true;
 }

diff --git a/kernel/rcu/tree_trace.c b/kernel/rcu/tree_trace.c
index 6fc4c5ff3bb5cf55925a1da6ba73d269d3349d49..4ac25f8520d6c5d86e9d322ced0602fbe0b34af8 100644 (file)
--- a/kernel/rcu/tree_trace.c
+++ b/kernel/rcu/tree_trace.c
@@ -123,7 +123,7 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
                   ulong2long(rdp->completed), ulong2long(rdp->gpnum),
                   rdp->passed_quiesce,
                   rdp->rcu_qs_ctr_snap == per_cpu(rcu_qs_ctr, rdp->cpu),
-                  rdp->qs_pending);
+                  rdp->core_needs_qs);
        seq_printf(m, " dt=%d/%llx/%d df=%lu",
                   atomic_read(&rdp->dynticks->dynticks),
                   rdp->dynticks->dynticks_nesting,
@@ -361,7 +361,7 @@ static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
                   cpu_is_offline(rdp->cpu) ? '!' : ' ',
                   rdp->n_rcu_pending);
        seq_printf(m, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ",
-                  rdp->n_rp_qs_pending,
+                  rdp->n_rp_core_needs_qs,
                   rdp->n_rp_report_qs,
                   rdp->n_rp_cb_ready,
                   rdp->n_rp_cpu_needs_gp);