From 3ddf20c953520203c42dbed1f091ed52080e1cd2 Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Date: Fri, 21 Apr 2017 13:33:20 -0700
Subject: [PATCH] srcu: Shrink Tiny SRCU a bit more
This commit rearranges Tiny SRCU's srcu_struct structure, substitutes
u8 for bool, and shrinks counters down to short.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
include/linux/srcutiny.h | 8 ++++----
kernel/rcu/rcutorture.c | 2 +-
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h
index 42311ee0334fd..b8859179b001e 100644
--- a/include/linux/srcutiny.h
+++ b/include/linux/srcutiny.h
@@ -27,15 +27,15 @@
#include <linux/swait.h>
struct srcu_struct {
- int srcu_lock_nesting[2]; /* srcu_read_lock() nesting depth. */
+ short srcu_lock_nesting[2]; /* srcu_read_lock() nesting depth. */
+ short srcu_idx; /* Current reader array element. */
+ u8 srcu_gp_running; /* GP workqueue running? */
+ u8 srcu_gp_waiting; /* GP waiting for readers? */
struct swait_queue_head srcu_wq;
/* Last srcu_read_unlock() wakes GP. */
unsigned long srcu_gp_seq; /* GP seq # for callback tagging. */
struct rcu_segcblist srcu_cblist;
/* Pending SRCU callbacks. */
- int srcu_idx; /* Current reader array element. */
- bool srcu_gp_running; /* GP workqueue running? */
- bool srcu_gp_waiting; /* GP waiting for readers? */
struct work_struct srcu_work; /* For driving grace periods. */
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index ae6e574d4cf5c..a58592b73f19e 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -609,7 +609,7 @@ static void srcu_torture_stats(void)
pr_cont("\n");
#elif defined(CONFIG_TINY_SRCU)
idx = READ_ONCE(srcu_ctlp->srcu_idx) & 0x1;
- pr_alert("%s%s Tiny SRCU per-CPU(idx=%d): (%d,%d)\n",
+ pr_alert("%s%s Tiny SRCU per-CPU(idx=%d): (%hd,%hd)\n",
torture_type, TORTURE_FLAG, idx,
READ_ONCE(srcu_ctlp->srcu_lock_nesting[!idx]),
READ_ONCE(srcu_ctlp->srcu_lock_nesting[idx]));
--
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