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authorMichael Wang <wangyun@linux.vnet.ibm.com>2012-09-20 08:51:06 +0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-11-08 11:50:17 -0800
commit51d0f16d49f6a99189e80c50e18a12325664ef41 (patch)
tree2d7e28e39eff3d1d169ccca95e18a0f06cc574af /kernel/rcutree_trace.c
parentd29200efa2ad7a1dc516a1048faf98dcc01b9fef (diff)
downloadlinaro-lsk-51d0f16d49f6a99189e80c50e18a12325664ef41.tar.gz
rcu: Optimize the 'rcu_pending' for RCU trace
This patch implements the new 'rcu_pending' interface under each rsp directory, by using the 'CPU units sequence reading', thus avoiding loss of tracing data. Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcutree_trace.c')
-rw-r--r--kernel/rcutree_trace.c41
1 files changed, 35 insertions, 6 deletions
diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c
index e387a642632..8b248672221 100644
--- a/kernel/rcutree_trace.c
+++ b/kernel/rcutree_trace.c
@@ -467,6 +467,8 @@ static const struct file_operations rcugp_fops = {
static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
{
+ if (!rdp->beenonline)
+ return;
seq_printf(m, "%3d%cnp=%ld ",
rdp->cpu,
cpu_is_offline(rdp->cpu) ? '!' : ' ',
@@ -485,16 +487,12 @@ static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
static int show_rcu_pending(struct seq_file *m, void *unused)
{
int cpu;
- struct rcu_data *rdp;
struct rcu_state *rsp;
for_each_rcu_flavor(rsp) {
seq_printf(m, "%s:\n", rsp->name);
- for_each_possible_cpu(cpu) {
- rdp = per_cpu_ptr(rsp->rda, cpu);
- if (rdp->beenonline)
- print_one_rcu_pending(m, rdp);
- }
+ for_each_possible_cpu(cpu)
+ print_one_rcu_pending(m, per_cpu_ptr(rsp->rda, cpu));
}
return 0;
}
@@ -512,6 +510,32 @@ static const struct file_operations rcu_pending_fops = {
.release = single_release,
};
+static int new_show_rcu_pending(struct seq_file *m, void *v)
+{
+ print_one_rcu_pending(m, (struct rcu_data *)v);
+ return 0;
+}
+
+static const struct seq_operations new_rcu_pending_op = {
+ .start = r_start,
+ .next = r_next,
+ .stop = r_stop,
+ .show = new_show_rcu_pending,
+};
+
+static int new_rcu_pending_open(struct inode *inode, struct file *file)
+{
+ return r_open(inode, file, &new_rcu_pending_op);
+}
+
+static const struct file_operations new_rcu_pending_fops = {
+ .owner = THIS_MODULE,
+ .open = new_rcu_pending_open,
+ .read = seq_read,
+ .llseek = no_llseek,
+ .release = seq_release,
+};
+
static int show_rcutorture(struct seq_file *m, void *unused)
{
seq_printf(m, "rcutorture test sequence: %lu %s\n",
@@ -561,6 +585,11 @@ static int __init rcutree_trace_init(void)
rspdir, rsp, &new_rcudata_csv_fops);
if (!retval)
goto free_out;
+
+ retval = debugfs_create_file("rcu_pending", 0444,
+ rspdir, rsp, &new_rcu_pending_fops);
+ if (!retval)
+ goto free_out;
}
retval = debugfs_create_file("rcubarrier", 0444, rcudir,