Re: [PATCH v2] ceph: metrics for opened files, pinned caps and opened inodes

[Jeff Layton <jlayton@kernel.org>]

On Mon, 2020-08-24 at 03:01 -0400, xiubli@redhat.com wrote:
> From: Xiubo Li <xiubli@redhat.com>
> 
> In client for each inode, it may have many opened files and may
> have been pinned in more than one MDS servers. And some inodes
> are idle, which have no any opened files.
> 
> This patch will show these metrics in the debugfs, likes:
> 
> item                               total
> -----------------------------------------
> opened files  / total inodes       14 / 5
> pinned i_caps / total inodes       7  / 5
> opened inodes / total inodes       3  / 5
> 
> Will send these metrics to ceph, which will be used by the `fs top`,
> later.
> 
> URL: https://tracker.ceph.com/issues/47005
> Signed-off-by: Xiubo Li <xiubli@redhat.com>
> ---
> 
> Changed in V2:
> - Add number of inodes that have opened files.
> - Remove the dir metrics and fold into files.
> 
> 
>  fs/ceph/caps.c    | 27 +++++++++++++++++++++++++--
>  fs/ceph/debugfs.c | 11 +++++++++++
>  fs/ceph/file.c    |  5 +++--
>  fs/ceph/inode.c   |  7 +++++++
>  fs/ceph/metric.c  | 14 ++++++++++++++
>  fs/ceph/metric.h  |  7 +++++++
>  fs/ceph/super.h   |  1 +
>  7 files changed, 68 insertions(+), 4 deletions(-)
> 

This doesn't compile. See inline below...

> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
> index ad69c411afba..6916def40b3d 100644
> --- a/fs/ceph/caps.c
> +++ b/fs/ceph/caps.c
> @@ -4283,13 +4283,23 @@ void __ceph_touch_fmode(struct ceph_inode_info *ci,
>  
>  void ceph_get_fmode(struct ceph_inode_info *ci, int fmode, int count)
>  {
> -	int i;
> +	struct ceph_mds_client *mdsc = ceph_ci_to_mdsc(ci);


fs/ceph/caps.c:4287:33: error: implicit declaration of function ‘ceph_ci_to_mdsc’ [-Werror=implicit-function-declaration]


>  	int bits = (fmode << 1) | 1;
> +	int i;
> +
> +	if (count == 1)
> +		atomic64_inc(&mdsc->metric.opened_files);
> +
>  	spin_lock(&ci->i_ceph_lock);
>  	for (i = 0; i < CEPH_FILE_MODE_BITS; i++) {
>  		if (bits & (1 << i))
>  			ci->i_nr_by_mode[i] += count;
>  	}
> +
> +	if (!ci->is_opened && fmode) {
> +		ci->is_opened = true;
> +		percpu_counter_inc(&mdsc->metric.opened_inodes);
> +	}
>  	spin_unlock(&ci->i_ceph_lock);
>  }
>  
> @@ -4300,15 +4310,28 @@ void ceph_get_fmode(struct ceph_inode_info *ci, int fmode, int count)
>   */
>  void ceph_put_fmode(struct ceph_inode_info *ci, int fmode, int count)
>  {
> -	int i;
> +	struct ceph_mds_client *mdsc = ceph_ci_to_mdsc(ci);
>  	int bits = (fmode << 1) | 1;
> +	bool empty = true;
> +	int i;
> +
> +	if (count == 1)
> +		atomic64_dec(&mdsc->metric.opened_files);
> +
>  	spin_lock(&ci->i_ceph_lock);
>  	for (i = 0; i < CEPH_FILE_MODE_BITS; i++) {
>  		if (bits & (1 << i)) {
>  			BUG_ON(ci->i_nr_by_mode[i] < count);
>  			ci->i_nr_by_mode[i] -= count;
> +			if (ci->i_nr_by_mode[i] && i) /* Skip the pin ref */
> +				empty = false;
>  		}
>  	}
> +
> +	if (ci->is_opened && empty && fmode) {
> +		ci->is_opened = false;
> +		percpu_counter_dec(&mdsc->metric.opened_inodes);
> +	}
>  	spin_unlock(&ci->i_ceph_lock);
>  }
>  
> diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
> index 97539b497e4c..9efd3982230d 100644
> --- a/fs/ceph/debugfs.c
> +++ b/fs/ceph/debugfs.c
> @@ -148,6 +148,17 @@ static int metric_show(struct seq_file *s, void *p)
>  	int nr_caps = 0;
>  	s64 total, sum, avg, min, max, sq;
>  
> +	sum = percpu_counter_sum(&m->total_inodes);
> +	seq_printf(s, "item                               total\n");
> +	seq_printf(s, "------------------------------------------\n");
> +	seq_printf(s, "%-35s%lld / %lld\n", "opened files  / total inodes",
> +		   atomic64_read(&m->opened_files), sum);
> +	seq_printf(s, "%-35s%lld / %lld\n", "pinned i_caps / total inodes",
> +		   atomic64_read(&m->total_caps), sum);
> +	seq_printf(s, "%-35s%lld / %lld\n", "opened inodes / total inodes",
> +		   percpu_counter_sum(&m->opened_inodes), sum);
> +
> +	seq_printf(s, "\n");
>  	seq_printf(s, "item          total       avg_lat(us)     min_lat(us)     max_lat(us)     stdev(us)\n");
>  	seq_printf(s, "-----------------------------------------------------------------------------------\n");
>  
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index c788cce7885b..6e2aed0f7f75 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -211,8 +211,9 @@ static int ceph_init_file_info(struct inode *inode, struct file *file,
>  	BUG_ON(inode->i_fop->release != ceph_release);
>  
>  	if (isdir) {
> -		struct ceph_dir_file_info *dfi =
> -			kmem_cache_zalloc(ceph_dir_file_cachep, GFP_KERNEL);
> +		struct ceph_dir_file_info *dfi;
> +
> +		dfi = kmem_cache_zalloc(ceph_dir_file_cachep, GFP_KERNEL);
>  		if (!dfi)
>  			return -ENOMEM;
>  
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index 39b1007903d9..1bedbe4737ec 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -426,6 +426,7 @@ static int ceph_fill_fragtree(struct inode *inode,
>   */
>  struct inode *ceph_alloc_inode(struct super_block *sb)
>  {
> +	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(sb);

fs/ceph/inode.c:428:33: error: implicit declaration of function ‘ceph_sb_to_mdsc’; did you mean ‘ceph_sb_to_client’? [-Werror=implicit-function-declaration]


>  	struct ceph_inode_info *ci;
>  	int i;
>  
> @@ -485,6 +486,7 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
>  	ci->i_last_rd = ci->i_last_wr = jiffies - 3600 * HZ;
>  	for (i = 0; i < CEPH_FILE_MODE_BITS; i++)
>  		ci->i_nr_by_mode[i] = 0;
> +	ci->is_opened = false;
>  
>  	mutex_init(&ci->i_truncate_mutex);
>  	ci->i_truncate_seq = 0;
> @@ -525,6 +527,8 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
>  
>  	ci->i_meta_err = 0;
>  
> +	percpu_counter_inc(&mdsc->metric.total_inodes);
> +
>  	return &ci->vfs_inode;
>  }
>  
> @@ -539,6 +543,7 @@ void ceph_free_inode(struct inode *inode)
>  void ceph_evict_inode(struct inode *inode)
>  {
>  	struct ceph_inode_info *ci = ceph_inode(inode);
> +	struct ceph_mds_client *mdsc = ceph_inode_to_mdsc(inode);
>  	struct ceph_inode_frag *frag;
>  	struct rb_node *n;
>  
> @@ -592,6 +597,8 @@ void ceph_evict_inode(struct inode *inode)
>  
>  	ceph_put_string(rcu_dereference_raw(ci->i_layout.pool_ns));
>  	ceph_put_string(rcu_dereference_raw(ci->i_cached_layout.pool_ns));
> +
> +	percpu_counter_dec(&mdsc->metric.total_inodes);
>  }
>  
>  static inline blkcnt_t calc_inode_blocks(u64 size)
> diff --git a/fs/ceph/metric.c b/fs/ceph/metric.c
> index 2466b261fba2..c7c6fe6a383b 100644
> --- a/fs/ceph/metric.c
> +++ b/fs/ceph/metric.c
> @@ -192,11 +192,23 @@ int ceph_metric_init(struct ceph_client_metric *m)
>  	m->total_metadatas = 0;
>  	m->metadata_latency_sum = 0;
>  
> +	atomic64_set(&m->opened_files, 0);
> +	ret = percpu_counter_init(&m->opened_inodes, 0, GFP_KERNEL);
> +	if (ret)
> +		goto err_opened_inodes;
> +	ret = percpu_counter_init(&m->opened_inodes, 0, GFP_KERNEL);
> +	if (ret)
> +		goto err_total_inodes;
> +
>  	m->session = NULL;
>  	INIT_DELAYED_WORK(&m->delayed_work, metric_delayed_work);
>  
>  	return 0;
>  
> +err_total_inodes:
> +	percpu_counter_destroy(&m->opened_inodes);
> +err_opened_inodes:
> +	percpu_counter_destroy(&m->i_caps_mis);
>  err_i_caps_mis:
>  	percpu_counter_destroy(&m->i_caps_hit);
>  err_i_caps_hit:
> @@ -212,6 +224,8 @@ void ceph_metric_destroy(struct ceph_client_metric *m)
>  	if (!m)
>  		return;
>  
> +	percpu_counter_destroy(&m->total_inodes);
> +	percpu_counter_destroy(&m->opened_inodes);
>  	percpu_counter_destroy(&m->i_caps_mis);
>  	percpu_counter_destroy(&m->i_caps_hit);
>  	percpu_counter_destroy(&m->d_lease_mis);
> diff --git a/fs/ceph/metric.h b/fs/ceph/metric.h
> index 1d0959d669d7..710f3f1dceab 100644
> --- a/fs/ceph/metric.h
> +++ b/fs/ceph/metric.h
> @@ -115,6 +115,13 @@ struct ceph_client_metric {
>  	ktime_t metadata_latency_min;
>  	ktime_t metadata_latency_max;
>  
> +	/* The total number of directories and files that are opened */
> +	atomic64_t opened_files;
> +
> +	/* The total number of inodes that have opened files or directories */
> +	struct percpu_counter opened_inodes;
> +	struct percpu_counter total_inodes;
> +
>  	struct ceph_mds_session *session;
>  	struct delayed_work delayed_work;  /* delayed work */
>  };
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index 476d182c2ff0..852b755e2224 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -387,6 +387,7 @@ struct ceph_inode_info {
>  	unsigned long i_last_rd;
>  	unsigned long i_last_wr;
>  	int i_nr_by_mode[CEPH_FILE_MODE_BITS];  /* open file counts */
> +	bool is_opened; /* has opened files or directors */
>  
>  	struct mutex i_truncate_mutex;
>  	u32 i_truncate_seq;        /* last truncate to smaller size */

-- 
Jeff Layton <jlayton@kernel.org>