ceph: add caps perf metric for each superblock

Count hits and misses in the caps cache. If the client has all of
the necessary caps when a task needs references, then it's counted
as a hit. Any other situation is a miss.

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

fs/ceph/acl.c

@@ -22,7 +22,7 @@ static inline void ceph_set_cached_acl(struct inode *inode,
 	struct ceph_inode_info *ci = ceph_inode(inode);
 
 	spin_lock(&ci->i_ceph_lock);
-	if (__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 0))
+	if (__ceph_caps_issued_mask_metric(ci, CEPH_CAP_XATTR_SHARED, 0))
 		set_cached_acl(inode, type, acl);
 	else
 		forget_cached_acl(inode, type);

fs/ceph/caps.c

@@ -912,6 +912,20 @@ int __ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask, int touch)
 	return 0;
 }
 
+int __ceph_caps_issued_mask_metric(struct ceph_inode_info *ci, int mask,
+				   int touch)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(ci->vfs_inode.i_sb);
+	int r;
+
+	r = __ceph_caps_issued_mask(ci, mask, touch);
+	if (r)
+		ceph_update_cap_hit(&fsc->mdsc->metric);
+	else
+		ceph_update_cap_mis(&fsc->mdsc->metric);
+	return r;
+}
+
 /*
  * Return true if mask caps are currently being revoked by an MDS.
  */
@@ -2685,6 +2699,11 @@ static int try_get_cap_refs(struct inode *inode, int need, int want,
 	if (snap_rwsem_locked)
 		up_read(&mdsc->snap_rwsem);
 
+	if (!ret)
+		ceph_update_cap_mis(&mdsc->metric);
+	else if (ret == 1)
+		ceph_update_cap_hit(&mdsc->metric);
+
 	dout("get_cap_refs %p ret %d got %s\n", inode,
 	     ret, ceph_cap_string(*got));
 	return ret;

fs/ceph/debugfs.c

@@ -129,6 +129,7 @@ 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;
+	int i, nr_caps = 0;
 
 	seq_printf(s, "item          total           miss            hit\n");
 	seq_printf(s, "-------------------------------------------------\n");
@@ -138,6 +139,21 @@ static int metric_show(struct seq_file *s, void *p)
 		   percpu_counter_sum(&m->d_lease_mis),
 		   percpu_counter_sum(&m->d_lease_hit));
 
+	mutex_lock(&mdsc->mutex);
+	for (i = 0; i < mdsc->max_sessions; i++) {
+		struct ceph_mds_session *s;
+
+		s = __ceph_lookup_mds_session(mdsc, i);
+		if (!s)
+			continue;
+		nr_caps += s->s_nr_caps;
+		ceph_put_mds_session(s);
+	}
+	mutex_unlock(&mdsc->mutex);
+	seq_printf(s, "%-14s%-16d%-16lld%lld\n", "caps", nr_caps,
+		   percpu_counter_sum(&m->i_caps_mis),
+		   percpu_counter_sum(&m->i_caps_hit));
+
 	return 0;
 }
 

fs/ceph/dir.c

@@ -349,8 +349,9 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
 	    !ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&
 	    ceph_snap(inode) != CEPH_SNAPDIR &&
 	    __ceph_dir_is_complete_ordered(ci) &&
-	    __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1)) {
+	    __ceph_caps_issued_mask_metric(ci, CEPH_CAP_FILE_SHARED, 1)) {
 		int shared_gen = atomic_read(&ci->i_shared_gen);
+
 		spin_unlock(&ci->i_ceph_lock);
 		err = __dcache_readdir(file, ctx, shared_gen);
 		if (err != -EAGAIN)
@@ -767,7 +768,7 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
 		    !is_root_ceph_dentry(dir, dentry) &&
 		    ceph_test_mount_opt(fsc, DCACHE) &&
 		    __ceph_dir_is_complete(ci) &&
-		    (__ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1))) {
+		    __ceph_caps_issued_mask_metric(ci, CEPH_CAP_FILE_SHARED, 1)) {
 			__ceph_touch_fmode(ci, mdsc, CEPH_FILE_MODE_RD);
 			spin_unlock(&ci->i_ceph_lock);
 			dout(" dir %p complete, -ENOENT\n", dir);

fs/ceph/inode.c

@@ -2288,8 +2288,8 @@ int __ceph_do_getattr(struct inode *inode, struct page *locked_page,
 
 	dout("do_getattr inode %p mask %s mode 0%o\n",
 	     inode, ceph_cap_string(mask), inode->i_mode);
-	if (!force && ceph_caps_issued_mask(ceph_inode(inode), mask, 1))
-		return 0;
+	if (!force && ceph_caps_issued_mask_metric(ceph_inode(inode), mask, 1))
+			return 0;
 
 	mode = (mask & CEPH_STAT_RSTAT) ? USE_AUTH_MDS : USE_ANY_MDS;
 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, mode);

fs/ceph/metric.c

@@ -16,13 +16,29 @@ int ceph_metric_init(struct ceph_client_metric *m)
 	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;
-	}
+	if (ret)
+		goto err_d_lease_mis;
+
+	ret = percpu_counter_init(&m->i_caps_hit, 0, GFP_KERNEL);
+	if (ret)
+		goto err_i_caps_hit;
+
+	ret = percpu_counter_init(&m->i_caps_mis, 0, GFP_KERNEL);
+	if (ret)
+		goto err_i_caps_mis;
 
 	return 0;
+
+err_i_caps_mis:
+	percpu_counter_destroy(&m->i_caps_hit);
+err_i_caps_hit:
+	percpu_counter_destroy(&m->d_lease_mis);
+err_d_lease_mis:
+	percpu_counter_destroy(&m->d_lease_hit);
+
+	return ret;
 }
 
 void ceph_metric_destroy(struct ceph_client_metric *m)
@@ -30,6 +46,8 @@ void ceph_metric_destroy(struct ceph_client_metric *m)
 	if (!m)
 		return;
 
+	percpu_counter_destroy(&m->i_caps_mis);
+	percpu_counter_destroy(&m->i_caps_hit);
 	percpu_counter_destroy(&m->d_lease_mis);
 	percpu_counter_destroy(&m->d_lease_hit);
 }

fs/ceph/metric.h

@@ -10,8 +10,21 @@ struct ceph_client_metric {
 	atomic64_t            total_dentries;
 	struct percpu_counter d_lease_hit;
 	struct percpu_counter d_lease_mis;
+
+	struct percpu_counter i_caps_hit;
+	struct percpu_counter i_caps_mis;
 };
 
 extern int ceph_metric_init(struct ceph_client_metric *m);
 extern void ceph_metric_destroy(struct ceph_client_metric *m);
+
+static inline void ceph_update_cap_hit(struct ceph_client_metric *m)
+{
+	percpu_counter_inc(&m->i_caps_hit);
+}
+
+static inline void ceph_update_cap_mis(struct ceph_client_metric *m)
+{
+	percpu_counter_inc(&m->i_caps_mis);
+}
 #endif /* _FS_CEPH_MDS_METRIC_H */

fs/ceph/super.h

@@ -645,6 +645,8 @@ static inline bool __ceph_is_any_real_caps(struct ceph_inode_info *ci)
 
 extern int __ceph_caps_issued(struct ceph_inode_info *ci, int *implemented);
 extern int __ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask, int t);
+extern int __ceph_caps_issued_mask_metric(struct ceph_inode_info *ci, int mask,
+					  int t);
 extern int __ceph_caps_issued_other(struct ceph_inode_info *ci,
 				    struct ceph_cap *cap);
 
@@ -657,12 +659,12 @@ static inline int ceph_caps_issued(struct ceph_inode_info *ci)
 	return issued;
 }
 
-static inline int ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask,
-					int touch)
+static inline int ceph_caps_issued_mask_metric(struct ceph_inode_info *ci,
+					       int mask, int touch)
 {
 	int r;
 	spin_lock(&ci->i_ceph_lock);
-	r = __ceph_caps_issued_mask(ci, mask, touch);
+	r = __ceph_caps_issued_mask_metric(ci, mask, touch);
 	spin_unlock(&ci->i_ceph_lock);
 	return r;
 }

fs/ceph/xattr.c

@@ -856,7 +856,7 @@ ssize_t __ceph_getxattr(struct inode *inode, const char *name, void *value,
 
 	if (ci->i_xattrs.version == 0 ||
 	    !((req_mask & CEPH_CAP_XATTR_SHARED) ||
-	      __ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 1))) {
+	      __ceph_caps_issued_mask_metric(ci, CEPH_CAP_XATTR_SHARED, 1))) {
 		spin_unlock(&ci->i_ceph_lock);
 
 		/* security module gets xattr while filling trace */
@@ -914,7 +914,7 @@ ssize_t ceph_listxattr(struct dentry *dentry, char *names, size_t size)
 	     ci->i_xattrs.version, ci->i_xattrs.index_version);
 
 	if (ci->i_xattrs.version == 0 ||
-	    !__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 1)) {
+	    !__ceph_caps_issued_mask_metric(ci, CEPH_CAP_XATTR_SHARED, 1)) {
 		spin_unlock(&ci->i_ceph_lock);
 		err = ceph_do_getattr(inode, CEPH_STAT_CAP_XATTR, true);
 		if (err)