linux-kernel - [PATCH tip/core/rcu 04/10] rcu: Switch last accelerate/advance to rcu

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Date:   Wed, 29 Aug 2018 16:07:29 -0700
From:   "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:     linux-kernel@...r.kernel.org
Cc:     mingo@...nel.org, jiangshanlai@...il.com, dipankar@...ibm.com,
        akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
        josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
        rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
        fweisbec@...il.com, oleg@...hat.com, joel@...lfernandes.org,
        "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 04/10] rcu: Switch last accelerate/advance to rcu_data structure

This commit removes ->last_accelerate and ->last_advance_all from the
rcu_dynticks structure and updates the code to access them from the
rcu_data structure.

Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
---
 kernel/rcu/tree.h        |  4 ----
 kernel/rcu/tree_plugin.h | 17 ++++++++---------
 2 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 5d447ceba769..69bd6bec05bb 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -49,10 +49,6 @@ struct rcu_dynticks {
 				    /* # times non-lazy CBs posted to CPU. */
 	unsigned long nonlazy_posted_snap;
 				    /* idle-period nonlazy_posted snapshot. */
-	unsigned long last_accelerate;
-				    /* Last jiffy CBs were accelerated. */
-	unsigned long last_advance_all;
-				    /* Last jiffy CBs were all advanced. */
 #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
 };
 
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 6511032371c1..45708164ddf9 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1597,16 +1597,14 @@ module_param(rcu_idle_lazy_gp_delay, int, 0644);
 static bool __maybe_unused rcu_try_advance_all_cbs(void)
 {
 	bool cbs_ready = false;
-	struct rcu_data *rdp;
-	struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
 	struct rcu_node *rnp;
 
 	/* Exit early if we advanced recently. */
-	if (jiffies == rdtp->last_advance_all)
+	if (jiffies == rdp->last_advance_all)
 		return false;
-	rdtp->last_advance_all = jiffies;
+	rdp->last_advance_all = jiffies;
 
-	rdp = this_cpu_ptr(&rcu_data);
 	rnp = rdp->mynode;
 
 	/*
@@ -1635,6 +1633,7 @@ static bool __maybe_unused rcu_try_advance_all_cbs(void)
  */
 int rcu_needs_cpu(u64 basemono, u64 *nextevt)
 {
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
 	struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
 	unsigned long dj;
 
@@ -1655,7 +1654,7 @@ int rcu_needs_cpu(u64 basemono, u64 *nextevt)
 		invoke_rcu_core();
 		return 1;
 	}
-	rdtp->last_accelerate = jiffies;
+	rdp->last_accelerate = jiffies;
 
 	/* Request timer delay depending on laziness, and round. */
 	if (!rdtp->all_lazy) {
@@ -1718,9 +1717,9 @@ static void rcu_prepare_for_idle(void)
 	 * If we have not yet accelerated this jiffy, accelerate all
 	 * callbacks on this CPU.
 	 */
-	if (rdtp->last_accelerate == jiffies)
+	if (rdp->last_accelerate == jiffies)
 		return;
-	rdtp->last_accelerate = jiffies;
+	rdp->last_accelerate = jiffies;
 	if (rcu_segcblist_pend_cbs(&rdp->cblist)) {
 		rnp = rdp->mynode;
 		raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
@@ -1769,7 +1768,7 @@ static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
 	unsigned long nlpd = rdtp->nonlazy_posted - rdtp->nonlazy_posted_snap;
 
 	sprintf(cp, "last_accelerate: %04lx/%04lx, nonlazy_posted: %ld, %c%c",
-		rdtp->last_accelerate & 0xffff, jiffies & 0xffff,
+		rdp->last_accelerate & 0xffff, jiffies & 0xffff,
 		ulong2long(nlpd),
 		rdtp->all_lazy ? 'L' : '.',
 		rdp->tick_nohz_enabled_snap ? '.' : 'D');
-- 
2.17.1