linux-kernel - [PATCH tip/core/rcu 09/17] rcu: Shrink ->dynticks_{nmi

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Date:   Fri,  1 Dec 2017 11:36:40 -0800
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,
        "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 09/17] rcu: Shrink ->dynticks_{nmi_,}nesting from long long to long

Because the ->dynticks_nesting field now only contains the process-based
nesting level instead of a value encoding both the process nesting level
and the irq "nesting" level, we no longer need a long long, even on
32-bit systems.  This commit therefore changes both the ->dynticks_nesting
and ->dynticks_nmi_nesting fields to long.

Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
---
 include/trace/events/rcu.h | 8 ++++----
 kernel/rcu/rcu.h           | 2 +-
 kernel/rcu/tree.c          | 6 +++---
 kernel/rcu/tree.h          | 4 ++--
 kernel/rcu/tree_plugin.h   | 2 +-
 5 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index 4674b21247f7..b0a48231ea0e 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -436,14 +436,14 @@ TRACE_EVENT(rcu_fqs,
  */
 TRACE_EVENT(rcu_dyntick,
 
-	TP_PROTO(const char *polarity, long long oldnesting, long long newnesting),
+	TP_PROTO(const char *polarity, long oldnesting, long newnesting),
 
 	TP_ARGS(polarity, oldnesting, newnesting),
 
 	TP_STRUCT__entry(
 		__field(const char *, polarity)
-		__field(long long, oldnesting)
-		__field(long long, newnesting)
+		__field(long, oldnesting)
+		__field(long, newnesting)
 	),
 
 	TP_fast_assign(
@@ -452,7 +452,7 @@ TRACE_EVENT(rcu_dyntick,
 		__entry->newnesting = newnesting;
 	),
 
-	TP_printk("%s %llx %llx", __entry->polarity,
+	TP_printk("%s %lx %lx", __entry->polarity,
 		  __entry->oldnesting, __entry->newnesting)
 );
 
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index afe0559d1867..6334f2c1abd0 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -31,7 +31,7 @@
 #endif /* #else #ifdef CONFIG_RCU_TRACE */
 
 /* Offset to allow for unmatched rcu_irq_{enter,exit}(). */
-#define DYNTICK_IRQ_NONIDLE	((INT_MAX / 2) + 1)
+#define DYNTICK_IRQ_NONIDLE	((LONG_MAX / 2) + 1)
 
 
 /*
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index d069ba2d8412..92de3bacda07 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -946,7 +946,7 @@ void rcu_irq_exit_irqson(void)
  * we really have exited idle, and must do the appropriate accounting.
  * The caller must have disabled interrupts.
  */
-static void rcu_eqs_exit_common(long long newval, int user)
+static void rcu_eqs_exit_common(long newval, int user)
 {
 	RCU_TRACE(struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);)
 
@@ -979,7 +979,7 @@ static void rcu_eqs_exit_common(long long newval, int user)
 static void rcu_eqs_exit(bool user)
 {
 	struct rcu_dynticks *rdtp;
-	long long oldval;
+	long oldval;
 
 	lockdep_assert_irqs_disabled();
 	rdtp = this_cpu_ptr(&rcu_dynticks);
@@ -1043,7 +1043,7 @@ void rcu_user_exit(void)
 void rcu_nmi_enter(void)
 {
 	struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
-	int incby = 2;
+	long incby = 2;
 
 	/* Complain about underflow. */
 	WARN_ON_ONCE(rdtp->dynticks_nmi_nesting < 0);
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index dbd7e3753bed..6488a3b0e729 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -38,8 +38,8 @@
  * Dynticks per-CPU state.
  */
 struct rcu_dynticks {
-	long long dynticks_nesting; /* Track irq/process nesting level. */
-	int dynticks_nmi_nesting;   /* Track NMI nesting level. */
+	long dynticks_nesting;      /* Track process nesting level. */
+	long dynticks_nmi_nesting;  /* Track irq/NMI nesting level. */
 	atomic_t dynticks;	    /* Even value for idle, else odd. */
 	bool rcu_need_heavy_qs;     /* GP old, need heavy quiescent state. */
 	unsigned long rcu_qs_ctr;   /* Light universal quiescent state ctr. */
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index db85ca3975f1..e94e754464cd 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1687,7 +1687,7 @@ static void print_cpu_stall_info(struct rcu_state *rsp, int cpu)
 	}
 	print_cpu_stall_fast_no_hz(fast_no_hz, cpu);
 	delta = rdp->mynode->gpnum - rdp->rcu_iw_gpnum;
-	pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%llx/%d softirq=%u/%u fqs=%ld %s\n",
+	pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%ld softirq=%u/%u fqs=%ld %s\n",
 	       cpu,
 	       "O."[!!cpu_online(cpu)],
 	       "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)],
-- 
2.5.2