[PATCH v6 5/9] ceph: add global metadata perf metric support

[xiubli@redhat.com]

From: Xiubo Li <xiubli@redhat.com>

It will calculate the latency for the metedata requests, which only
include the time cousumed by network and the ceph.

item          total       sum_lat(us)     avg_lat(us)
-----------------------------------------------------
metadata      113         220000          1946

URL: https://tracker.ceph.com/issues/43215
Signed-off-by: Xiubo Li <xiubli@redhat.com>
---
 fs/ceph/debugfs.c    |  6 ++++++
 fs/ceph/mds_client.c | 20 ++++++++++++++++++++
 fs/ceph/metric.h     | 13 +++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index 464bfbdb970d..60f3e307fca1 100644
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -146,6 +146,12 @@ static int metric_show(struct seq_file *s, void *p)
 	avg = total ? sum / total : 0;
 	seq_printf(s, "%-14s%-12lld%-16lld%lld\n", "write", total, sum, avg);
 
+	total = percpu_counter_sum(&mdsc->metric.total_metadatas);
+	sum = percpu_counter_sum(&mdsc->metric.metadata_latency_sum);
+	sum = jiffies_to_usecs(sum);
+	avg = total ? sum / total : 0;
+	seq_printf(s, "%-14s%-12lld%-16lld%lld\n", "metadata", total, sum, avg);
+
 	seq_printf(s, "\n");
 	seq_printf(s, "item          total           miss            hit\n");
 	seq_printf(s, "-------------------------------------------------\n");
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index cc2b426cd8e4..d414eded6810 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -3019,6 +3019,12 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 
 	/* kick calling process */
 	complete_request(mdsc, req);
+
+	if (!result || result == -ENOENT) {
+		s64 latency = jiffies - req->r_started;
+
+		ceph_update_metadata_latency(&mdsc->metric, latency);
+	}
 out:
 	ceph_mdsc_put_request(req);
 	return;
@@ -4198,8 +4204,20 @@ static int ceph_mdsc_metric_init(struct ceph_client_metric *metric)
 	if (ret)
 		goto err_write_latency_sum;
 
+	ret = percpu_counter_init(&metric->total_metadatas, 0, GFP_KERNEL);
+	if (ret)
+		goto err_total_metadatas;
+
+	ret = percpu_counter_init(&metric->metadata_latency_sum, 0, GFP_KERNEL);
+	if (ret)
+		goto err_metadata_latency_sum;
+
 	return 0;
 
+err_metadata_latency_sum:
+	percpu_counter_destroy(&metric->total_metadatas);
+err_total_metadatas:
+	percpu_counter_destroy(&metric->write_latency_sum);
 err_write_latency_sum:
 	percpu_counter_destroy(&metric->total_writes);
 err_total_writes:
@@ -4555,6 +4573,8 @@ void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
 
 	ceph_mdsc_stop(mdsc);
 
+	percpu_counter_destroy(&mdsc->metric.metadata_latency_sum);
+	percpu_counter_destroy(&mdsc->metric.total_metadatas);
 	percpu_counter_destroy(&mdsc->metric.write_latency_sum);
 	percpu_counter_destroy(&mdsc->metric.total_writes);
 	percpu_counter_destroy(&mdsc->metric.read_latency_sum);
diff --git a/fs/ceph/metric.h b/fs/ceph/metric.h
index a87197f3e915..9de8beb436c7 100644
--- a/fs/ceph/metric.h
+++ b/fs/ceph/metric.h
@@ -18,6 +18,9 @@ struct ceph_client_metric {
 
 	struct percpu_counter total_writes;
 	struct percpu_counter write_latency_sum;
+
+	struct percpu_counter total_metadatas;
+	struct percpu_counter metadata_latency_sum;
 };
 
 static inline void ceph_update_read_latency(struct ceph_client_metric *m,
@@ -49,4 +52,14 @@ static inline void ceph_update_write_latency(struct ceph_client_metric *m,
 		percpu_counter_add(&m->write_latency_sum, latency);
 	}
 }
+
+static inline void ceph_update_metadata_latency(struct ceph_client_metric *m,
+						s64 latency)
+{
+	if (!m)
+		return;
+
+	percpu_counter_inc(&m->total_metadatas);
+	percpu_counter_add(&m->metadata_latency_sum, latency);
+}
 #endif /* _FS_CEPH_MDS_METRIC_H */
-- 
2.21.0