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Commit 51d0f16d authored by Michael Wang's avatar Michael Wang Committed by Paul E. McKenney
Browse files

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: default avatarMichael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent d29200ef

kernel/rcutree_trace.c

+35 −6
Original line number Diff line number Diff line
@@ -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,