[PATCH] ceph: clean-up metrics data structures to reduce code duplication

From: Luís Henriques
Date: Fri Oct 29 2021 - 10:09:42 EST

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This patch modifies struct ceph_client_metric so that each metric block
(read, write and metadata) becomes an element in a array. This allows to
also re-write the helper functions that handle these blocks, making them
simpler and, above all, reduce the amount of copy&paste every time a new
metric is added.

Thus, for each of these metrics there will be a new struct ceph_metric
entry that'll will contain all the sizes and latencies fields (and a lock).
Note however that the metadata metric doesn't really use the size_fields,
and thus this metric won't be shown in the debugfs '../metrics/size' file.

Signed-off-by: Luís Henriques <lhenriques@xxxxxxx>
---
fs/ceph/debugfs.c | 87 ++++++++++++++-----------------
fs/ceph/metric.c | 128 ++++++++++++----------------------------------
fs/ceph/metric.h | 80 ++++++++++++++++-------------
3 files changed, 115 insertions(+), 180 deletions(-)

diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index 55426514491b..72825ed3a0b8 100644
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -164,44 +164,34 @@ static int metrics_file_show(struct seq_file *s, void *p)
return 0;
}

+static const char * const metric_str[] = {
+ "read",
+ "write",
+ "metadata"
+};
static int metrics_latency_show(struct seq_file *s, void *p)
{
struct ceph_fs_client *fsc = s->private;
- struct ceph_client_metric *m = &fsc->mdsc->metric;
+ struct ceph_client_metric *cm = &fsc->mdsc->metric;
+ struct ceph_metric *m;
s64 total, sum, avg, min, max, sq;
+ int i;

seq_printf(s, "item total avg_lat(us) min_lat(us) max_lat(us) stdev(us)\n");
seq_printf(s, "-----------------------------------------------------------------------------------\n");

- spin_lock(&m->read_metric_lock);
- total = m->total_reads;
- sum = m->read_latency_sum;
- avg = total > 0 ? DIV64_U64_ROUND_CLOSEST(sum, total) : 0;
- min = m->read_latency_min;
- max = m->read_latency_max;
- sq = m->read_latency_sq_sum;
- spin_unlock(&m->read_metric_lock);
- CEPH_LAT_METRIC_SHOW("read", total, avg, min, max, sq);
-
- spin_lock(&m->write_metric_lock);
- total = m->total_writes;
- sum = m->write_latency_sum;
- avg = total > 0 ? DIV64_U64_ROUND_CLOSEST(sum, total) : 0;
- min = m->write_latency_min;
- max = m->write_latency_max;
- sq = m->write_latency_sq_sum;
- spin_unlock(&m->write_metric_lock);
- CEPH_LAT_METRIC_SHOW("write", total, avg, min, max, sq);
-
- spin_lock(&m->metadata_metric_lock);
- total = m->total_metadatas;
- sum = m->metadata_latency_sum;
- avg = total > 0 ? DIV64_U64_ROUND_CLOSEST(sum, total) : 0;
- min = m->metadata_latency_min;
- max = m->metadata_latency_max;
- sq = m->metadata_latency_sq_sum;
- spin_unlock(&m->metadata_metric_lock);
- CEPH_LAT_METRIC_SHOW("metadata", total, avg, min, max, sq);
+ for (i = 0; i < METRIC_MAX; i++) {
+ m = &cm->metric[i];
+ spin_lock(&m->lock);
+ total = m->total;
+ sum = m->latency_sum;
+ avg = total > 0 ? DIV64_U64_ROUND_CLOSEST(sum, total) : 0;
+ min = m->latency_min;
+ max = m->latency_max;
+ sq = m->latency_sq_sum;
+ spin_unlock(&m->lock);
+ CEPH_LAT_METRIC_SHOW(metric_str[i], total, avg, min, max, sq);
+ }

return 0;
}
@@ -209,30 +199,29 @@ static int metrics_latency_show(struct seq_file *s, void *p)
static int metrics_size_show(struct seq_file *s, void *p)
{
struct ceph_fs_client *fsc = s->private;
- struct ceph_client_metric *m = &fsc->mdsc->metric;
+ struct ceph_client_metric *cm = &fsc->mdsc->metric;
+ struct ceph_metric *m;
s64 total;
- u64 sum_sz, avg_sz, min_sz, max_sz;
+ u64 sum, avg, min, max;
+ int i;

seq_printf(s, "item total avg_sz(bytes) min_sz(bytes) max_sz(bytes) total_sz(bytes)\n");
seq_printf(s, "----------------------------------------------------------------------------------------\n");

- spin_lock(&m->read_metric_lock);
- total = m->total_reads;
- sum_sz = m->read_size_sum;
- avg_sz = total > 0 ? DIV64_U64_ROUND_CLOSEST(sum_sz, total) : 0;
- min_sz = m->read_size_min;
- max_sz = m->read_size_max;
- spin_unlock(&m->read_metric_lock);
- CEPH_SZ_METRIC_SHOW("read", total, avg_sz, min_sz, max_sz, sum_sz);
-
- spin_lock(&m->write_metric_lock);
- total = m->total_writes;
- sum_sz = m->write_size_sum;
- avg_sz = total > 0 ? DIV64_U64_ROUND_CLOSEST(sum_sz, total) : 0;
- min_sz = m->write_size_min;
- max_sz = m->write_size_max;
- spin_unlock(&m->write_metric_lock);
- CEPH_SZ_METRIC_SHOW("write", total, avg_sz, min_sz, max_sz, sum_sz);
+ for (i = 0; i < METRIC_MAX; i++) {
+ /* skip 'metadata' as it doesn't use the size metric */
+ if (i == METRIC_METADATA)
+ continue;
+ m = &cm->metric[i];
+ spin_lock(&m->lock);
+ total = m->total;
+ sum = m->size_sum;
+ avg = total > 0 ? DIV64_U64_ROUND_CLOSEST(sum, total) : 0;
+ min = m->size_min;
+ max = m->size_max;
+ spin_unlock(&m->lock);
+ CEPH_SZ_METRIC_SHOW(metric_str[i], total, avg, min, max, sum);
+ }

return 0;
}
diff --git a/fs/ceph/metric.c b/fs/ceph/metric.c
index 04d5df29bbbf..c57699d8408d 100644
--- a/fs/ceph/metric.c
+++ b/fs/ceph/metric.c
@@ -62,7 +62,7 @@ static bool ceph_mdsc_send_metrics(struct ceph_mds_client *mdsc,
read->header.ver = 1;
read->header.compat = 1;
read->header.data_len = cpu_to_le32(sizeof(*read) - header_len);
- sum = m->read_latency_sum;
+ sum = m->metric[METRIC_READ].latency_sum;
jiffies_to_timespec64(sum, &ts);
read->sec = cpu_to_le32(ts.tv_sec);
read->nsec = cpu_to_le32(ts.tv_nsec);
@@ -74,7 +74,7 @@ static bool ceph_mdsc_send_metrics(struct ceph_mds_client *mdsc,
write->header.ver = 1;
write->header.compat = 1;
write->header.data_len = cpu_to_le32(sizeof(*write) - header_len);
- sum = m->write_latency_sum;
+ sum = m->metric[METRIC_WRITE].latency_sum;
jiffies_to_timespec64(sum, &ts);
write->sec = cpu_to_le32(ts.tv_sec);
write->nsec = cpu_to_le32(ts.tv_nsec);
@@ -86,7 +86,7 @@ static bool ceph_mdsc_send_metrics(struct ceph_mds_client *mdsc,
meta->header.ver = 1;
meta->header.compat = 1;
meta->header.data_len = cpu_to_le32(sizeof(*meta) - header_len);
- sum = m->metadata_latency_sum;
+ sum = m->metric[METRIC_METADATA].latency_sum;
jiffies_to_timespec64(sum, &ts);
meta->sec = cpu_to_le32(ts.tv_sec);
meta->nsec = cpu_to_le32(ts.tv_nsec);
@@ -141,8 +141,8 @@ static bool ceph_mdsc_send_metrics(struct ceph_mds_client *mdsc,
rsize->header.ver = 1;
rsize->header.compat = 1;
rsize->header.data_len = cpu_to_le32(sizeof(*rsize) - header_len);
- rsize->total_ops = cpu_to_le64(m->total_reads);
- rsize->total_size = cpu_to_le64(m->read_size_sum);
+ rsize->total_ops = cpu_to_le64(m->metric[METRIC_READ].total);
+ rsize->total_size = cpu_to_le64(m->metric[METRIC_READ].size_sum);
items++;

/* encode the write io size metric */
@@ -151,8 +151,8 @@ static bool ceph_mdsc_send_metrics(struct ceph_mds_client *mdsc,
wsize->header.ver = 1;
wsize->header.compat = 1;
wsize->header.data_len = cpu_to_le32(sizeof(*wsize) - header_len);
- wsize->total_ops = cpu_to_le64(m->total_writes);
- wsize->total_size = cpu_to_le64(m->write_size_sum);
+ wsize->total_ops = cpu_to_le64(m->metric[METRIC_WRITE].total);
+ wsize->total_size = cpu_to_le64(m->metric[METRIC_WRITE].size_sum);
items++;

put_unaligned_le32(items, &head->num);
@@ -220,7 +220,8 @@ static void metric_delayed_work(struct work_struct *work)

int ceph_metric_init(struct ceph_client_metric *m)
{
- int ret;
+ struct ceph_metric *metric;
+ int ret, i;

if (!m)
return -EINVAL;
@@ -243,32 +244,18 @@ int ceph_metric_init(struct ceph_client_metric *m)
if (ret)
goto err_i_caps_mis;

- spin_lock_init(&m->read_metric_lock);
- m->read_latency_sq_sum = 0;
- m->read_latency_min = KTIME_MAX;
- m->read_latency_max = 0;
- m->total_reads = 0;
- m->read_latency_sum = 0;
- m->read_size_min = U64_MAX;
- m->read_size_max = 0;
- m->read_size_sum = 0;
-
- spin_lock_init(&m->write_metric_lock);
- m->write_latency_sq_sum = 0;
- m->write_latency_min = KTIME_MAX;
- m->write_latency_max = 0;
- m->total_writes = 0;
- m->write_latency_sum = 0;
- m->write_size_min = U64_MAX;
- m->write_size_max = 0;
- m->write_size_sum = 0;
-
- spin_lock_init(&m->metadata_metric_lock);
- m->metadata_latency_sq_sum = 0;
- m->metadata_latency_min = KTIME_MAX;
- m->metadata_latency_max = 0;
- m->total_metadatas = 0;
- m->metadata_latency_sum = 0;
+ for (i = 0; i < METRIC_MAX; i++) {
+ metric = &m->metric[i];
+ spin_lock_init(&metric->lock);
+ metric->size_sum = 0;
+ metric->size_min = U64_MAX;
+ metric->size_max = 0;
+ metric->total = 0;
+ metric->latency_sum = 0;
+ metric->latency_sq_sum = 0;
+ metric->latency_min = KTIME_MAX;
+ metric->latency_max = 0;
+ }

atomic64_set(&m->opened_files, 0);
ret = percpu_counter_init(&m->opened_inodes, 0, GFP_KERNEL);
@@ -338,9 +325,9 @@ static inline void __update_stdev(ktime_t total, ktime_t lsum,
*sq_sump += sq;
}

-void ceph_update_read_metrics(struct ceph_client_metric *m,
- ktime_t r_start, ktime_t r_end,
- unsigned int size, int rc)
+void ceph_update_metrics(struct ceph_metric *m,
+ ktime_t r_start, ktime_t r_end,
+ unsigned int size, int rc)
{
ktime_t lat = ktime_sub(r_end, r_start);
ktime_t total;
@@ -348,63 +335,12 @@ void ceph_update_read_metrics(struct ceph_client_metric *m,
if (unlikely(rc < 0 && rc != -ENOENT && rc != -ETIMEDOUT))
return;

- spin_lock(&m->read_metric_lock);
- total = ++m->total_reads;
- m->read_size_sum += size;
- m->read_latency_sum += lat;
- METRIC_UPDATE_MIN_MAX(m->read_size_min,
- m->read_size_max,
- size);
- 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);
-}
-
-void ceph_update_write_metrics(struct ceph_client_metric *m,
- ktime_t r_start, ktime_t r_end,
- unsigned int size, 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);
- total = ++m->total_writes;
- m->write_size_sum += size;
- m->write_latency_sum += lat;
- METRIC_UPDATE_MIN_MAX(m->write_size_min,
- m->write_size_max,
- size);
- 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);
-}
-
-void ceph_update_metadata_metrics(struct ceph_client_metric *m,
- ktime_t r_start, ktime_t r_end,
- 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);
- 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);
+ spin_lock(&m->lock);
+ total = ++m->total;
+ m->size_sum += size;
+ METRIC_UPDATE_MIN_MAX(m->size_min, m->size_max, size);
+ m->latency_sum += lat;
+ METRIC_UPDATE_MIN_MAX(m->latency_min, m->latency_max, lat);
+ __update_stdev(total, m->latency_sum, &m->latency_sq_sum, lat);
+ spin_unlock(&m->lock);
}
diff --git a/fs/ceph/metric.h b/fs/ceph/metric.h
index 0133955a3c6a..e67fc997760b 100644
--- a/fs/ceph/metric.h
+++ b/fs/ceph/metric.h
@@ -125,6 +125,25 @@ struct ceph_metric_head {
__le32 num; /* the number of metrics that will be sent */
} __packed;

+enum metric_type {
+ METRIC_READ,
+ METRIC_WRITE,
+ METRIC_METADATA,
+ METRIC_MAX
+};
+
+struct ceph_metric {
+ spinlock_t lock;
+ u64 total;
+ u64 size_sum;
+ u64 size_min;
+ u64 size_max;
+ ktime_t latency_sum;
+ ktime_t latency_sq_sum;
+ ktime_t latency_min;
+ ktime_t latency_max;
+};
+
/* This is the global metrics */
struct ceph_client_metric {
atomic64_t total_dentries;
@@ -135,32 +154,7 @@ struct ceph_client_metric {
struct percpu_counter i_caps_hit;
struct percpu_counter i_caps_mis;

- spinlock_t read_metric_lock;
- u64 total_reads;
- u64 read_size_sum;
- u64 read_size_min;
- u64 read_size_max;
- ktime_t read_latency_sum;
- ktime_t read_latency_sq_sum;
- ktime_t read_latency_min;
- ktime_t read_latency_max;
-
- spinlock_t write_metric_lock;
- u64 total_writes;
- u64 write_size_sum;
- u64 write_size_min;
- u64 write_size_max;
- ktime_t write_latency_sum;
- ktime_t write_latency_sq_sum;
- ktime_t write_latency_min;
- ktime_t write_latency_max;
-
- spinlock_t metadata_metric_lock;
- u64 total_metadatas;
- ktime_t metadata_latency_sum;
- ktime_t metadata_latency_sq_sum;
- ktime_t metadata_latency_min;
- ktime_t metadata_latency_max;
+ struct ceph_metric metric[METRIC_MAX];

/* The total number of directories and files that are opened */
atomic64_t opened_files;
@@ -195,13 +189,29 @@ static inline void ceph_update_cap_mis(struct ceph_client_metric *m)
percpu_counter_inc(&m->i_caps_mis);
}

-extern void ceph_update_read_metrics(struct ceph_client_metric *m,
- ktime_t r_start, ktime_t r_end,
- unsigned int size, int rc);
-extern void ceph_update_write_metrics(struct ceph_client_metric *m,
- ktime_t r_start, ktime_t r_end,
- unsigned int size, int rc);
-extern void ceph_update_metadata_metrics(struct ceph_client_metric *m,
- ktime_t r_start, ktime_t r_end,
- int rc);
+extern void ceph_update_metrics(struct ceph_metric *m,
+ ktime_t r_start, ktime_t r_end,
+ unsigned int size, int rc);
+
+static inline void ceph_update_read_metrics(struct ceph_client_metric *m,
+ ktime_t r_start, ktime_t r_end,
+ unsigned int size, int rc)
+{
+ ceph_update_metrics(&m->metric[METRIC_READ],
+ r_start, r_end, size, rc);
+}
+static inline void ceph_update_write_metrics(struct ceph_client_metric *m,
+ ktime_t r_start, ktime_t r_end,
+ unsigned int size, int rc)
+{
+ ceph_update_metrics(&m->metric[METRIC_WRITE],
+ r_start, r_end, size, rc);
+}
+static inline void ceph_update_metadata_metrics(struct ceph_client_metric *m,
+ ktime_t r_start, ktime_t r_end,
+ int rc)
+{
+ ceph_update_metrics(&m->metric[METRIC_METADATA],
+ r_start, r_end, 0, rc);
+}
#endif /* _FS_CEPH_MDS_METRIC_H */

Next message: David Howells: "[PATCH v4 01/10] fscache: Generalise the ->begin_read_operation method"
Previous message: David Howells: "[PATCH v4 00/10] fscache: Replace and remove old I/O API"
Next in thread: Xiubo Li: "Re: [PATCH] ceph: clean-up metrics data structures to reduce code duplication"
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