[PATCH v8 1/5] ceph: add global dentry lease metric support

[xiubli@redhat.com]

From: Xiubo Li <xiubli@redhat.com>

For the dentry lease we will only count the hit/miss info triggered
from the vfs calls, for the cases like request reply handling and
perodically ceph_trim_dentries() we will ignore them.

Currently only the debugfs is support:

The output will be:

item          total           miss            hit
-------------------------------------------------
d_lease       11              7               141

URL: https://tracker.ceph.com/issues/43215
Signed-off-by: Xiubo Li <xiubli@redhat.com>
---
 fs/ceph/debugfs.c    | 32 ++++++++++++++++++++++++++++----
 fs/ceph/dir.c        | 16 ++++++++++++++--
 fs/ceph/mds_client.c | 37 +++++++++++++++++++++++++++++++++++--
 fs/ceph/mds_client.h |  4 ++++
 fs/ceph/metric.h     | 11 +++++++++++
 fs/ceph/super.h      |  1 +
 6 files changed, 93 insertions(+), 8 deletions(-)
 create mode 100644 fs/ceph/metric.h

diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index 481ac97b4d25..15975ba95d9a 100644
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -124,6 +124,22 @@ static int mdsc_show(struct seq_file *s, void *p)
 	return 0;
 }
 
+static int metric_show(struct seq_file *s, void *p)
+{
+	struct ceph_fs_client *fsc = s->private;
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+
+	seq_printf(s, "item          total           miss            hit\n");
+	seq_printf(s, "-------------------------------------------------\n");
+
+	seq_printf(s, "%-14s%-16lld%-16lld%lld\n", "d_lease",
+		   atomic64_read(&mdsc->metric.total_dentries),
+		   percpu_counter_sum(&mdsc->metric.d_lease_mis),
+		   percpu_counter_sum(&mdsc->metric.d_lease_hit));
+
+	return 0;
+}
+
 static int caps_show_cb(struct inode *inode, struct ceph_cap *cap, void *p)
 {
 	struct seq_file *s = p;
@@ -222,6 +238,7 @@ DEFINE_SHOW_ATTRIBUTE(mdsmap);
 DEFINE_SHOW_ATTRIBUTE(mdsc);
 DEFINE_SHOW_ATTRIBUTE(caps);
 DEFINE_SHOW_ATTRIBUTE(mds_sessions);
+DEFINE_SHOW_ATTRIBUTE(metric);
 
 
 /*
@@ -255,6 +272,7 @@ void ceph_fs_debugfs_cleanup(struct ceph_fs_client *fsc)
 	debugfs_remove(fsc->debugfs_mdsmap);
 	debugfs_remove(fsc->debugfs_mds_sessions);
 	debugfs_remove(fsc->debugfs_caps);
+	debugfs_remove(fsc->debugfs_metric);
 	debugfs_remove(fsc->debugfs_mdsc);
 }
 
@@ -295,11 +313,17 @@ void ceph_fs_debugfs_init(struct ceph_fs_client *fsc)
 						fsc,
 						&mdsc_fops);
 
+	fsc->debugfs_metric = debugfs_create_file("metrics",
+						  0400,
+						  fsc->client->debugfs_dir,
+						  fsc,
+						  &metric_fops);
+
 	fsc->debugfs_caps = debugfs_create_file("caps",
-						   0400,
-						   fsc->client->debugfs_dir,
-						   fsc,
-						   &caps_fops);
+						0400,
+						fsc->client->debugfs_dir,
+						fsc,
+						&caps_fops);
 }
 
 
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index d0cd0aba5843..ff1714fe03aa 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -38,6 +38,8 @@ static int __dir_lease_try_check(const struct dentry *dentry);
 static int ceph_d_init(struct dentry *dentry)
 {
 	struct ceph_dentry_info *di;
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
 
 	di = kmem_cache_zalloc(ceph_dentry_cachep, GFP_KERNEL);
 	if (!di)
@@ -48,6 +50,9 @@ static int ceph_d_init(struct dentry *dentry)
 	di->time = jiffies;
 	dentry->d_fsdata = di;
 	INIT_LIST_HEAD(&di->lease_list);
+
+	atomic64_inc(&mdsc->metric.total_dentries);
+
 	return 0;
 }
 
@@ -1551,6 +1556,7 @@ static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry)
  */
 static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
 {
+	struct ceph_mds_client *mdsc;
 	int valid = 0;
 	struct dentry *parent;
 	struct inode *dir, *inode;
@@ -1589,9 +1595,8 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
 		}
 	}
 
+	mdsc = ceph_sb_to_client(dir->i_sb)->mdsc;
 	if (!valid) {
-		struct ceph_mds_client *mdsc =
-			ceph_sb_to_client(dir->i_sb)->mdsc;
 		struct ceph_mds_request *req;
 		int op, err;
 		u32 mask;
@@ -1599,6 +1604,8 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
 		if (flags & LOOKUP_RCU)
 			return -ECHILD;
 
+		percpu_counter_inc(&mdsc->metric.d_lease_mis);
+
 		op = ceph_snap(dir) == CEPH_SNAPDIR ?
 			CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_LOOKUP;
 		req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS);
@@ -1630,6 +1637,8 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
 			dout("d_revalidate %p lookup result=%d\n",
 			     dentry, err);
 		}
+	} else {
+		percpu_counter_inc(&mdsc->metric.d_lease_hit);
 	}
 
 	dout("d_revalidate %p %s\n", dentry, valid ? "valid" : "invalid");
@@ -1672,9 +1681,12 @@ static int ceph_d_delete(const struct dentry *dentry)
 static void ceph_d_release(struct dentry *dentry)
 {
 	struct ceph_dentry_info *di = ceph_dentry(dentry);
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
 
 	dout("d_release %p\n", dentry);
 
+	atomic64_dec(&fsc->mdsc->metric.total_dentries);
+
 	spin_lock(&dentry->d_lock);
 	__dentry_lease_unlist(di);
 	dentry->d_fsdata = NULL;
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 2980e57ca7b9..82060afd5dca 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4156,10 +4156,31 @@ static void delayed_work(struct work_struct *work)
 	schedule_delayed(mdsc);
 }
 
+static int ceph_mdsc_metric_init(struct ceph_client_metric *metric)
+{
+	int ret;
+
+	if (!metric)
+		return -EINVAL;
+
+	atomic64_set(&metric->total_dentries, 0);
+	ret = percpu_counter_init(&metric->d_lease_hit, 0, GFP_KERNEL);
+	if (ret)
+		return ret;
+	ret = percpu_counter_init(&metric->d_lease_mis, 0, GFP_KERNEL);
+	if (ret) {
+		percpu_counter_destroy(&metric->d_lease_hit);
+		return ret;
+	}
+
+	return 0;
+}
+
 int ceph_mdsc_init(struct ceph_fs_client *fsc)
 
 {
 	struct ceph_mds_client *mdsc;
+	int err;
 
 	mdsc = kzalloc(sizeof(struct ceph_mds_client), GFP_NOFS);
 	if (!mdsc)
@@ -4168,8 +4189,8 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
 	mutex_init(&mdsc->mutex);
 	mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
 	if (!mdsc->mdsmap) {
-		kfree(mdsc);
-		return -ENOMEM;
+		err = -ENOMEM;
+		goto err_mdsc;
 	}
 
 	fsc->mdsc = mdsc;
@@ -4208,6 +4229,9 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
 	init_waitqueue_head(&mdsc->cap_flushing_wq);
 	INIT_WORK(&mdsc->cap_reclaim_work, ceph_cap_reclaim_work);
 	atomic_set(&mdsc->cap_reclaim_pending, 0);
+	err = ceph_mdsc_metric_init(&mdsc->metric);
+	if (err)
+		goto err_mdsmap;
 
 	spin_lock_init(&mdsc->dentry_list_lock);
 	INIT_LIST_HEAD(&mdsc->dentry_leases);
@@ -4226,6 +4250,12 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
 	strscpy(mdsc->nodename, utsname()->nodename,
 		sizeof(mdsc->nodename));
 	return 0;
+
+err_mdsmap:
+	kfree(mdsc->mdsmap);
+err_mdsc:
+	kfree(mdsc);
+	return err;
 }
 
 /*
@@ -4483,6 +4513,9 @@ void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
 
 	ceph_mdsc_stop(mdsc);
 
+	percpu_counter_destroy(&mdsc->metric.d_lease_mis);
+	percpu_counter_destroy(&mdsc->metric.d_lease_hit);
+
 	fsc->mdsc = NULL;
 	kfree(mdsc);
 	dout("mdsc_destroy %p done\n", mdsc);
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 27a7446e10d3..674fc7725913 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -16,6 +16,8 @@
 #include <linux/ceph/mdsmap.h>
 #include <linux/ceph/auth.h>
 
+#include "metric.h"
+
 /* The first 8 bits are reserved for old ceph releases */
 enum ceph_feature_type {
 	CEPHFS_FEATURE_MIMIC = 8,
@@ -446,6 +448,8 @@ struct ceph_mds_client {
 	struct list_head  dentry_leases;     /* fifo list */
 	struct list_head  dentry_dir_leases; /* lru list */
 
+	struct ceph_client_metric metric;
+
 	spinlock_t		snapid_map_lock;
 	struct rb_root		snapid_map_tree;
 	struct list_head	snapid_map_lru;
diff --git a/fs/ceph/metric.h b/fs/ceph/metric.h
new file mode 100644
index 000000000000..998fe2a643cf
--- /dev/null
+++ b/fs/ceph/metric.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _FS_CEPH_MDS_METRIC_H
+#define _FS_CEPH_MDS_METRIC_H
+
+/* This is the global metrics */
+struct ceph_client_metric {
+	atomic64_t            total_dentries;
+	struct percpu_counter d_lease_hit;
+	struct percpu_counter d_lease_mis;
+};
+#endif /* _FS_CEPH_MDS_METRIC_H */
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 37dc1ac8f6c3..ebcf7612eac9 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -125,6 +125,7 @@ struct ceph_fs_client {
 	struct dentry *debugfs_congestion_kb;
 	struct dentry *debugfs_bdi;
 	struct dentry *debugfs_mdsc, *debugfs_mdsmap;
+	struct dentry *debugfs_metric;
 	struct dentry *debugfs_mds_sessions;
 #endif
 
-- 
2.21.0