ceph: update and rename __update_latency helper to __update_stdev

The new __update_stdev() helper will only compute the standard
deviation.

Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/metric.c b/fs/ceph/metric.c
index 77417b4148adc59873b8c270209a39ba8c3fe610..afa5b1f8730fcbd8a884aa35032039263020ff03 100644 (file)
--- a/fs/ceph/metric.c
+++ b/fs/ceph/metric.c
@@ -286,19 +286,18 @@ void ceph_metric_destroy(struct ceph_client_metric *m)
                ceph_put_mds_session(m->session);
 }
 
-static inline void __update_latency(ktime_t *totalp, ktime_t *lsump,
-                                   ktime_t *min, ktime_t *max,
-                                   ktime_t *sq_sump, ktime_t lat)
-{
-       ktime_t total, avg, sq, lsum;
-
-       total = ++(*totalp);
-       lsum = (*lsump += lat);
+#define METRIC_UPDATE_MIN_MAX(min, max, new)   \
+{                                              \
+       if (unlikely(new < min))                \
+               min = new;                      \
+       if (unlikely(new > max))                \
+               max = new;                      \
+}
 
-       if (unlikely(lat < *min))
-               *min = lat;
-       if (unlikely(lat > *max))
-               *max = lat;
+static inline void __update_stdev(ktime_t total, ktime_t lsum,
+                                 ktime_t *sq_sump, ktime_t lat)
+{
+       ktime_t avg, sq;
 
        if (unlikely(total == 1))
                return;
@@ -316,14 +315,19 @@ void ceph_update_read_metrics(struct ceph_client_metric *m,
                              int rc)
 {
        ktime_t lat = ktime_sub(r_end, r_start);
+       ktime_t total;
 
        if (unlikely(rc < 0 && rc != -ENOENT && rc != -ETIMEDOUT))
                return;
 
        spin_lock(&m->read_metric_lock);
-       __update_latency(&m->total_reads, &m->read_latency_sum,
-                        &m->read_latency_min, &m->read_latency_max,
-                        &m->read_latency_sq_sum, lat);
+       total = ++m->total_reads;
+       m->read_latency_sum += lat;
+       METRIC_UPDATE_MIN_MAX(m->read_latency_min,
+                             m->read_latency_max,
+                             lat);
+       __update_stdev(total, m->read_latency_sum,
+                      &m->read_latency_sq_sum, lat);
        spin_unlock(&m->read_metric_lock);
 }
 
@@ -332,14 +336,19 @@ void ceph_update_write_metrics(struct ceph_client_metric *m,
                               int rc)
 {
        ktime_t lat = ktime_sub(r_end, r_start);
+       ktime_t total;
 
        if (unlikely(rc && rc != -ETIMEDOUT))
                return;
 
        spin_lock(&m->write_metric_lock);
-       __update_latency(&m->total_writes, &m->write_latency_sum,
-                        &m->write_latency_min, &m->write_latency_max,
-                        &m->write_latency_sq_sum, lat);
+       total = ++m->total_writes;
+       m->write_latency_sum += lat;
+       METRIC_UPDATE_MIN_MAX(m->write_latency_min,
+                             m->write_latency_max,
+                             lat);
+       __update_stdev(total, m->write_latency_sum,
+                      &m->write_latency_sq_sum, lat);
        spin_unlock(&m->write_metric_lock);
 }
 
@@ -348,13 +357,18 @@ void ceph_update_metadata_metrics(struct ceph_client_metric *m,
                                  int rc)
 {
        ktime_t lat = ktime_sub(r_end, r_start);
+       ktime_t total;
 
        if (unlikely(rc && rc != -ENOENT))
                return;
 
        spin_lock(&m->metadata_metric_lock);
-       __update_latency(&m->total_metadatas, &m->metadata_latency_sum,
-                        &m->metadata_latency_min, &m->metadata_latency_max,
-                        &m->metadata_latency_sq_sum, lat);
+       total = ++m->total_metadatas;
+       m->metadata_latency_sum += lat;
+       METRIC_UPDATE_MIN_MAX(m->metadata_latency_min,
+                             m->metadata_latency_max,
+                             lat);
+       __update_stdev(total, m->metadata_latency_sum,
+                      &m->metadata_latency_sq_sum, lat);
        spin_unlock(&m->metadata_metric_lock);
 }