> diff --git a/kernel/Makefile b/kernel/Makefile
> index 4e1d7df..e0bfce7 100644
> --- a/kernel/Makefile
> +++ b/kernel/Makefile
> @@ -77,6 +77,8 @@ obj-$(CONFIG_CLASSIC_RCU) += rcuclassic.o
> obj-$(CONFIG_PREEMPT_RCU) += rcupreempt.o
> ifeq ($(CONFIG_PREEMPT_RCU),y)
> obj-$(CONFIG_RCU_TRACE) += rcupreempt_trace.o
> +else
> +obj-$(CONFIG_RCU_TRACE) += rcuclassic_trace.o
> endif
> obj-$(CONFIG_RELAY) += relay.o
> obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
> diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c
> index aad93cd..517eaa9 100644
> --- a/kernel/rcuclassic.c
> +++ b/kernel/rcuclassic.c
> @@ -57,13 +57,13 @@ EXPORT_SYMBOL_GPL(rcu_lock_map);
>
>
> /* Definition for rcupdate control block. */
> -static struct rcu_ctrlblk rcu_ctrlblk = {
> +struct rcu_ctrlblk rcu_ctrlblk = {
> .cur = -300,
> .completed = -300,
> .lock = __SPIN_LOCK_UNLOCKED(&rcu_ctrlblk.lock),
> .cpumask = CPU_MASK_NONE,
> };
> -static struct rcu_ctrlblk rcu_bh_ctrlblk = {
> +struct rcu_ctrlblk rcu_bh_ctrlblk = {
> .cur = -300,
> .completed = -300,
> .lock = __SPIN_LOCK_UNLOCKED(&rcu_bh_ctrlblk.lock),
> diff --git a/kernel/rcuclassic_trace.c b/kernel/rcuclassic_trace.c
> new file mode 100644
> index 0000000..f8b9313
> --- /dev/null
> +++ b/kernel/rcuclassic_trace.c
> @@ -0,0 +1,126 @@
> +/*
> + * Read-Copy Update tracing for classic implementation
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
> + *
> + * Copyright IBM Corporation, 2008
> + *
> + * Papers:
http://www.rdrop.com/users/paulmck/RCU
> + *
> + * For detailed explanation of Read-Copy Update mechanism see -
> + * Documentation/RCU
> + *
> + */
> +#include <linux/types.h>
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/spinlock.h>
> +#include <linux/smp.h>
> +#include <linux/rcupdate.h>
> +#include <linux/interrupt.h>
> +#include <linux/sched.h>
> +#include <asm/atomic.h>
> +#include <linux/bitops.h>
> +#include <linux/module.h>
> +#include <linux/completion.h>
> +#include <linux/moduleparam.h>
> +#include <linux/percpu.h>
> +#include <linux/notifier.h>
> +#include <linux/cpu.h>
> +#include <linux/mutex.h>
> +#include <linux/debugfs.h>
> +
> +static DEFINE_MUTEX(rcuclassic_trace_mutex);
> +static char *rcuclassic_trace_buf;
> +#define RCUCLASSIC_TRACE_BUF_SIZE (20*NR_CPUS + 100)
> +
> +static int print_one_rcu_ctrlblk(struct rcu_ctrlblk *rcp, char *buf, char *ebuf)
> +{
> + int cnt = 0;
> +
> + cnt += snprintf(&buf[cnt], ebuf - &buf[cnt], "cur=%ld completed=%ld "
> + "np=%d s=%d\n\t",
> + rcp->cur, rcp->completed,
> + rcp->next_pending, rcp->signaled);
> + cnt += cpulist_scnprintf(&buf[cnt], ebuf - &buf[cnt], rcp->cpumask);
> + cnt += snprintf(&buf[cnt], ebuf - &buf[cnt], "\n");
> + return cnt;
> +}
> +
> +static ssize_t rcucb_read(struct file *filp, char __user *buffer,
> + size_t count, loff_t *ppos)
> +{
> + ssize_t bcount;
> + char *buf = rcuclassic_trace_buf;
> + char *ebuf = &rcuclassic_trace_buf[RCUCLASSIC_TRACE_BUF_SIZE];
> +
> + mutex_lock(&rcuclassic_trace_mutex);
> + buf += snprintf(buf, ebuf - buf, "rcu: ");
> + buf += print_one_rcu_ctrlblk(&rcu_ctrlblk, buf, ebuf);
> + buf += snprintf(buf, ebuf - buf, "rcu_bh: ");
> + buf += print_one_rcu_ctrlblk(&rcu_bh_ctrlblk, buf, ebuf);
> + buf += snprintf(buf, ebuf - buf, "online: ");
> + buf += cpulist_scnprintf(buf, ebuf - buf, cpu_online_map);
> + buf += snprintf(buf, ebuf - buf, "\n");
> + bcount = simple_read_from_buffer(buffer, count, ppos,
> + rcuclassic_trace_buf, strlen(rcuclassic_trace_buf));
> + mutex_unlock(&rcuclassic_trace_mutex);
> + return bcount;
> +}
> +
> +static struct file_operations rcucb_fops = {
> + .owner = THIS_MODULE,
> + .read = rcucb_read,
> +};
> +
> +static struct dentry *rcudir, *cbdir;
> +static int rcuclassic_debugfs_init(void)
