ceph: add dentry lease metric support

For dentry leases, only count the hit/miss info triggered from the vfs
calls. For the cases like request reply handling and ceph_trim_dentries,
ignore them.

For now, these are only viewable using debugfs. Future patches will
allow the client to send the stats to the MDS.

The output looks like:

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

URL: https://tracker.ceph.com/issues/43215
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/Makefile b/fs/ceph/Makefile
index 0a0823d..50c635d 100644 (file)
--- a/fs/ceph/Makefile
+++ b/fs/ceph/Makefile
@@ -8,7 +8,7 @@ obj-$(CONFIG_CEPH_FS) += ceph.o
 ceph-y := super.o inode.o dir.o file.o locks.o addr.o ioctl.o \
        export.o caps.o snap.o xattr.o quota.o io.o \
        mds_client.o mdsmap.o strings.o ceph_frag.o \
-       debugfs.o util.o
+       debugfs.o util.o metric.o
 
 ceph-$(CONFIG_CEPH_FSCACHE) += cache.o
 ceph-$(CONFIG_CEPH_FS_POSIX_ACL) += acl.o

diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index dcaed75..1e7ea58 100644 (file)
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -124,6 +124,23 @@ 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;
+       struct ceph_client_metric *m = &mdsc->metric;
+
+       seq_printf(s, "item          total           miss            hit\n");
+       seq_printf(s, "-------------------------------------------------\n");
+
+       seq_printf(s, "%-14s%-16lld%-16lld%lld\n", "d_lease",
+                  atomic64_read(&m->total_dentries),
+                  percpu_counter_sum(&m->d_lease_mis),
+                  percpu_counter_sum(&m->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 +239,7 @@ DEFINE_SHOW_ATTRIBUTE(mdsmap);
 DEFINE_SHOW_ATTRIBUTE(mdsc);
 DEFINE_SHOW_ATTRIBUTE(caps);
 DEFINE_SHOW_ATTRIBUTE(mds_sessions);
+DEFINE_SHOW_ATTRIBUTE(metric);
 
 
 /*
@@ -255,6 +273,7 @@ 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 +314,17 @@ 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 4c4202c..44cf851 100644 (file)
--- 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;
 }
 
@@ -1709,6 +1714,8 @@ 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);
@@ -1740,6 +1747,8 @@ 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");
@@ -1782,9 +1791,12 @@ 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 7c63abf..39a27c5 100644 (file)
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4323,6 +4323,7 @@ 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)
@@ -4331,8 +4332,8 @@ 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;
@@ -4371,6 +4372,9 @@ 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_metric_init(&mdsc->metric);
+       if (err)
+               goto err_mdsmap;
 
        spin_lock_init(&mdsc->dentry_list_lock);
        INIT_LIST_HEAD(&mdsc->dentry_leases);
@@ -4389,6 +4393,12 @@ 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;
 }
 
 /*
@@ -4646,6 +4656,8 @@ void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
 
        ceph_mdsc_stop(mdsc);
 
+       ceph_metric_destroy(&mdsc->metric);
+
        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 903d9ed..605995a 100644 (file)
--- 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,
@@ -454,6 +456,8 @@ 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.c b/fs/ceph/metric.c
new file mode 100644 (file)
index 0000000..873a376
--- /dev/null
+++ b/fs/ceph/metric.c
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/types.h>
+#include <linux/percpu_counter.h>
+
+#include "metric.h"
+
+int ceph_metric_init(struct ceph_client_metric *m)
+{
+       int ret;
+
+       if (!m)
+               return -EINVAL;
+
+       atomic64_set(&m->total_dentries, 0);
+       ret = percpu_counter_init(&m->d_lease_hit, 0, GFP_KERNEL);
+       if (ret)
+               return ret;
+       ret = percpu_counter_init(&m->d_lease_mis, 0, GFP_KERNEL);
+       if (ret) {
+               percpu_counter_destroy(&m->d_lease_hit);
+               return ret;
+       }
+
+       return 0;
+}
+
+void ceph_metric_destroy(struct ceph_client_metric *m)
+{
+       if (!m)
+               return;
+
+       percpu_counter_destroy(&m->d_lease_mis);
+       percpu_counter_destroy(&m->d_lease_hit);
+}

diff --git a/fs/ceph/metric.h b/fs/ceph/metric.h
new file mode 100644 (file)
index 0000000..da725da
--- /dev/null
+++ b/fs/ceph/metric.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _FS_CEPH_MDS_METRIC_H
+#define _FS_CEPH_MDS_METRIC_H
+
+#include <linux/types.h>
+#include <linux/percpu_counter.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;
+};
+
+extern int ceph_metric_init(struct ceph_client_metric *m);
+extern void ceph_metric_destroy(struct ceph_client_metric *m);
+#endif /* _FS_CEPH_MDS_METRIC_H */

diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 60aac3a..5c73cf1 100644 (file)
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -128,6 +128,7 @@ 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