Date:   Mon, 01 Nov 2021 08:13:41 -0400
From:   Jeff Layton <jlayton@...nel.org>
To:     Luís Henriques <lhenriques@...e.de>,
        Ilya Dryomov <idryomov@...il.com>, Xiubo Li <xiubli@...hat.com>
Cc:     ceph-devel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ceph: clean-up metrics data structures to reduce code
 duplication

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@...e.de>
> ---
>  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 */

Thanks, merged into testing.

Cheers,
-- 
Jeff Layton <jlayton@...nel.org>

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