Merge branch 'core/urgent' into core/rcu

Merge reason: new patches to be queued up depend on:

   ef631b0: rcu: Make hierarchical RCU less IPI-happy

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 24 insertions, 15 deletions

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 97ce31579ec0..d2a372fb0b9b 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -78,6 +78,26 @@ DEFINE_PER_CPU(struct rcu_data, rcu_data);
 struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state);
 DEFINE_PER_CPU(struct rcu_data, rcu_bh_data);
 
+/*
+ * Increment the quiescent state counter.
+ * The counter is a bit degenerated: We do not need to know
+ * how many quiescent states passed, just if there was at least
+ * one since the start of the grace period. Thus just a flag.
+ */
+void rcu_qsctr_inc(int cpu)
+{
+        struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
+        rdp->passed_quiesc = 1;
+        rdp->passed_quiesc_completed = rdp->completed;
+}
+
+void rcu_bh_qsctr_inc(int cpu)
+{
+        struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu);
+        rdp->passed_quiesc = 1;
+        rdp->passed_quiesc_completed = rdp->completed;
+}
+
 #ifdef CONFIG_NO_HZ
 DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = {
         .dynticks_nesting = 1,
@@ -510,8 +530,6 @@ static void note_new_gpnum(struct rcu_state *rsp, struct rcu_data *rdp)
         rdp->qs_pending = 1;
         rdp->passed_quiesc = 0;
         rdp->gpnum = rsp->gpnum;
-        rdp->n_rcu_pending_force_qs = rdp->n_rcu_pending +
-                                      RCU_JIFFIES_TILL_FORCE_QS;
 }
 
 /*
@@ -558,8 +576,6 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
         rsp->gpnum++;
         rsp->signaled = RCU_GP_INIT; /* Hold off force_quiescent_state. */
         rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
-        rdp->n_rcu_pending_force_qs = rdp->n_rcu_pending +
-                                      RCU_JIFFIES_TILL_FORCE_QS;
         record_gp_stall_check_time(rsp);
         dyntick_record_completed(rsp, rsp->completed - 1);
         note_new_gpnum(rsp, rdp);
@@ -1035,7 +1051,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
 {
         unsigned long flags;
         long lastcomp;
-        struct rcu_data *rdp = rsp->rda[smp_processor_id()];
         struct rcu_node *rnp = rcu_get_root(rsp);
         u8 signaled;
 
@@ -1046,16 +1061,13 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
                 return; /* Someone else is already on the job. */
         }
         if (relaxed &&
-            (long)(rsp->jiffies_force_qs - jiffies) >= 0 &&
-            (rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending) >= 0)
+            (long)(rsp->jiffies_force_qs - jiffies) >= 0)
                 goto unlock_ret; /* no emergency and done recently. */
         rsp->n_force_qs++;
         spin_lock(&rnp->lock);
         lastcomp = rsp->completed;
         signaled = rsp->signaled;
         rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
-        rdp->n_rcu_pending_force_qs = rdp->n_rcu_pending +
-                                      RCU_JIFFIES_TILL_FORCE_QS;
         if (lastcomp == rsp->gpnum) {
                 rsp->n_force_qs_ngp++;
                 spin_unlock(&rnp->lock);
@@ -1124,8 +1136,7 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp)
          * If an RCU GP has gone long enough, go check for dyntick
          * idle CPUs and, if needed, send resched IPIs.
          */
-        if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0 ||
-            (rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending) < 0)
+        if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0)
                 force_quiescent_state(rsp, 1);
 
         /*
@@ -1210,8 +1221,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu),
         if (unlikely(++rdp->qlen > qhimark)) {
                 rdp->blimit = LONG_MAX;
                 force_quiescent_state(rsp, 0);
-        } else if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0 ||
-                   (rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending) < 0)
+        } else if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0)
                 force_quiescent_state(rsp, 1);
         local_irq_restore(flags);
 }
@@ -1270,8 +1280,7 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
 
         /* Has an RCU GP gone long enough to send resched IPIs &c? */
         if (ACCESS_ONCE(rsp->completed) != ACCESS_ONCE(rsp->gpnum) &&
-            ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0 ||
-             (rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending) < 0))
+            ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0))
                 return 1;
 
         /* nothing to do */