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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-05-25 11:49:15 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-07-02 12:33:23 -0700
commitd7e187c8e9f30543f9cadfed094896ff414acb8f (patch)
tree071503440393317c78fad16dbf1ca4e9ce2807e7 /kernel/rcutree_trace.c
parenta83eff0a82a7f3f14fea477fd41e6c082e7fc96a (diff)
downloadlinux-d7e187c8e9f30543f9cadfed094896ff414acb8f.tar.gz
rcu: Add rcu_barrier() statistics to debugfs tracing
This commit adds an rcubarrier file to RCU's debugfs statistical tracing
directory, providing diagnostic information on rcu_barrier().

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/rcutree_trace.c')
-rw-r--r--kernel/rcutree_trace.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c
index a3556a2d842c..057408be6c3b 100644
--- a/kernel/rcutree_trace.c
+++ b/kernel/rcutree_trace.c
@@ -46,6 +46,40 @@
 #define RCU_TREE_NONCORE
 #include "rcutree.h"
 
+static void print_rcubarrier(struct seq_file *m, struct rcu_state *rsp)
+{
+	seq_printf(m, "%c bcc: %d nbd: %lu\n",
+		   rsp->rcu_barrier_in_progress ? 'B' : '.',
+		   atomic_read(&rsp->barrier_cpu_count),
+		   rsp->n_barrier_done);
+}
+
+static int show_rcubarrier(struct seq_file *m, void *unused)
+{
+#ifdef CONFIG_TREE_PREEMPT_RCU
+	seq_puts(m, "rcu_preempt: ");
+	print_rcubarrier(m, &rcu_preempt_state);
+#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
+	seq_puts(m, "rcu_sched: ");
+	print_rcubarrier(m, &rcu_sched_state);
+	seq_puts(m, "rcu_bh: ");
+	print_rcubarrier(m, &rcu_bh_state);
+	return 0;
+}
+
+static int rcubarrier_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, show_rcubarrier, NULL);
+}
+
+static const struct file_operations rcubarrier_fops = {
+	.owner = THIS_MODULE,
+	.open = rcubarrier_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
 #ifdef CONFIG_RCU_BOOST
 
 static char convert_kthread_status(unsigned int kthread_status)
@@ -453,6 +487,11 @@ static int __init rcutree_trace_init(void)
 	if (!rcudir)
 		goto free_out;
 
+	retval = debugfs_create_file("rcubarrier", 0444, rcudir,
+						NULL, &rcubarrier_fops);
+	if (!retval)
+		goto free_out;
+
 	retval = debugfs_create_file("rcudata", 0444, rcudir,
 						NULL, &rcudata_fops);
 	if (!retval)