Re: [PATCH] ceph: clean-up metrics data structures to reduce code duplication
From: Jeff Layton
Date: Thu Nov 04 2021 - 09:12:24 EST
On Thu, 2021-11-04 at 09:10 -0400, Jeff Layton wrote:
> On Fri, 2021-10-29 at 15:09 +0100, Luís Henriques wrote:
> > 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];
> >
>
> Shouldn't this be:
>
> struct ceph_metric metric[METRIC_MAX - 1];
>
> We want an array of 3 fields at this point, but METRIC_MAX == 4.
>
Duh...disregard. I temporarily forgot that enums start at 0.
METRIC_MAX == 3 here.
> > /* 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 */
>
--
Jeff Layton <jlayton@xxxxxxxxxx>