Rename struct avl to avl_element and the typedef to avl_t (#10735)

Before:

```
struct foobar {
    avl avl;
    ...
}
```

After:

```
struct foobar {
    avl_t avl;
    ...
};
```

Which makes figuring out the type from field name easier.

29 files changed, 136 insertions, 136 deletions

diff --git a/collectors/apps.plugin/apps_plugin.c b/collectors/apps.plugin/apps_plugin.c
index 7cbbb075c4..4d4626e6b9 100644
--- a/collectors/apps.plugin/apps_plugin.c
+++ b/collectors/apps.plugin/apps_plugin.c
@@ -491,7 +491,7 @@ typedef enum fd_filetype {
 } FD_FILETYPE;
 
 struct file_descriptor {
-    avl avl;
+    avl_t avl;
 
 #ifdef NETDATA_INTERNAL_CHECKS
     uint32_t magic;
@@ -514,7 +514,7 @@ static int
 // read users and groups from files
 
 struct user_or_group_id {
-    avl avl;
+    avl_t avl;
 
     union {
         uid_t uid;
@@ -639,7 +639,7 @@ int read_user_or_group_ids(struct user_or_group_ids *ids, struct timespec *last_
         struct user_or_group_id *existing_user_id = NULL;
 
         if(likely(ids->root))
-            existing_user_id = (struct user_or_group_id *)avl_search(&ids->index, (avl *) user_or_group_id);
+            existing_user_id = (struct user_or_group_id *)avl_search(&ids->index, (avl_t *) user_or_group_id);
 
         if(unlikely(existing_user_id)) {
             freez(existing_user_id->name);
@@ -648,7 +648,7 @@ int read_user_or_group_ids(struct user_or_group_ids *ids, struct timespec *last_
             freez(user_or_group_id);
         }
         else {
-            if(unlikely(avl_insert(&ids->index, (avl *) user_or_group_id) != (void *) user_or_group_id)) {
+            if(unlikely(avl_insert(&ids->index, (avl_t *) user_or_group_id) != (void *) user_or_group_id)) {
                 error("INTERNAL ERROR: duplicate indexing of id during realloc");
             };
 
@@ -664,7 +664,7 @@ int read_user_or_group_ids(struct user_or_group_ids *ids, struct timespec *last_
 
     while(user_or_group_id) {
         if(unlikely(!user_or_group_id->updated)) {
-            if(unlikely((struct user_or_group_id *)avl_remove(&ids->index, (avl *) user_or_group_id) != user_or_group_id))
+            if(unlikely((struct user_or_group_id *)avl_remove(&ids->index, (avl_t *) user_or_group_id) != user_or_group_id))
                 error("INTERNAL ERROR: removal of unused id from index, removed a different id");
 
             if(prev_user_id)
@@ -716,7 +716,7 @@ static struct target *get_users_target(uid_t uid) {
         int ret = read_user_or_group_ids(&all_user_ids, &last_passwd_modification_time);
 
         if(likely(!ret && all_user_ids.index.root))
-                user_or_group_id = (struct user_or_group_id *)avl_search(&all_user_ids.index, (avl *) &user_id_to_find);
+                user_or_group_id = (struct user_or_group_id *)avl_search(&all_user_ids.index, (avl_t *) &user_id_to_find);
     }
 
     if(user_or_group_id && user_or_group_id->name && *user_or_group_id->name) {
@@ -764,7 +764,7 @@ struct target *get_groups_target(gid_t gid)
         int ret = read_user_or_group_ids(&all_group_ids, &last_group_modification_time);
 
         if(likely(!ret && all_group_ids.index.root))
-                group_id = (struct user_or_group_id *)avl_search(&all_group_ids.index, (avl *) &group_id_to_find);
+                group_id = (struct user_or_group_id *)avl_search(&all_group_ids.index, (avl_t *) &group_id_to_find);
     }
 
     if(group_id && group_id->name && *group_id->name) {
@@ -1690,7 +1690,7 @@ int file_descriptor_compare(void* a, void* b) {
         return strcmp(((struct file_descriptor *)a)->name, ((struct file_descriptor *)b)->name);
 }
 
-// int file_descriptor_iterator(avl *a) { if(a) {}; return 0; }
+// int file_descriptor_iterator(avl_t *a) { if(a) {}; return 0; }
 
 avl_tree_type all_files_index = {
         NULL,
@@ -1707,11 +1707,11 @@ static struct file_descriptor *file_descriptor_find(const char *name, uint32_t h
     tmp.magic = 0x0BADCAFE;
 #endif /* NETDATA_INTERNAL_CHECKS */
 
-    return (struct file_descriptor *)avl_search(&all_files_index, (avl *) &tmp);
+    return (struct file_descriptor *)avl_search(&all_files_index, (avl_t *) &tmp);
 }
 
-#define file_descriptor_add(fd) avl_insert(&all_files_index, (avl *)(fd))
-#define file_descriptor_remove(fd) avl_remove(&all_files_index, (avl *)(fd))
+#define file_descriptor_add(fd) avl_insert(&all_files_index, (avl_t *)(fd))
+#define file_descriptor_remove(fd) avl_remove(&all_files_index, (avl_t *)(fd))
 
 // ----------------------------------------------------------------------------
 
diff --git a/collectors/ebpf.plugin/ebpf_socket.c b/collectors/ebpf.plugin/ebpf_socket.c
index 9776fb7cdc..0c33416ffa 100644
--- a/collectors/ebpf.plugin/ebpf_socket.c
+++ b/collectors/ebpf.plugin/ebpf_socket.c
@@ -1148,7 +1148,7 @@ static void store_socket_inside_avl(netdata_vector_plot_t *out, netdata_socket_t
     memcpy(&test.index, lindex, sizeof(netdata_socket_idx_t));
     test.flags = flags;
 
-    ret = (netdata_socket_plot_t *) avl_search_lock(&out->tree, (avl *)&test);
+    ret = (netdata_socket_plot_t *) avl_search_lock(&out->tree, (avl_t *)&test);
     if (ret) {
         if (lvalues->ct > ret->plot.last_time) {
             update_socket_data(&ret->sock, lvalues);
@@ -1186,7 +1186,7 @@ static void store_socket_inside_avl(netdata_vector_plot_t *out, netdata_socket_t
 
         w->flags = flags;
         netdata_socket_plot_t *check ;
-        check = (netdata_socket_plot_t *) avl_insert_lock(&out->tree, (avl *)w);
+        check = (netdata_socket_plot_t *) avl_insert_lock(&out->tree, (avl_t *)w);
         if (check != w)
             error("Internal error, cannot insert the AVL tree.");
 
diff --git a/collectors/ebpf.plugin/ebpf_socket.h b/collectors/ebpf.plugin/ebpf_socket.h
index 1316c003a4..5bd8b2c145 100644
--- a/collectors/ebpf.plugin/ebpf_socket.h
+++ b/collectors/ebpf.plugin/ebpf_socket.h
@@ -232,7 +232,7 @@ typedef struct netdata_socket_idx {
  */
 typedef struct netdata_socket_plot {
     // Search
-    avl avl;
+    avl_t avl;
     netdata_socket_idx_t index;
 
     // Current data
diff --git a/collectors/statsd.plugin/statsd.c b/collectors/statsd.plugin/statsd.c
index a8f94130ab..e895857193 100644
--- a/collectors/statsd.plugin/statsd.c
+++ b/collectors/statsd.plugin/statsd.c
@@ -107,7 +107,7 @@ typedef enum statsd_metric_type {
 
 
 typedef struct statsd_metric {
-    avl avl;                        // indexing - has to be first
+    avl_t avl;                      // indexing - has to be first
 
     const char *name;               // the name of the metric
     uint32_t hash;                  // hash of the name
@@ -376,7 +376,7 @@ static inline STATSD_METRIC *statsd_metric_index_find(STATSD_INDEX *index, const
     tmp.name = name;
     tmp.hash = (hash)?hash:simple_hash(tmp.name);
 
-    return (STATSD_METRIC *)STATSD_AVL_SEARCH(&index->index, (avl *)&tmp);
+    return (STATSD_METRIC *)STATSD_AVL_SEARCH(&index->index, (avl_t *)&tmp);
 }
 
 static inline STATSD_METRIC *statsd_find_or_add_metric(STATSD_INDEX *index, const char *name, STATSD_METRIC_TYPE type) {
@@ -398,7 +398,7 @@ static inline STATSD_METRIC *statsd_find_or_add_metric(STATSD_INDEX *index, cons
             m->histogram.ext = callocz(sizeof(STATSD_METRIC_HISTOGRAM_EXTENSIONS), 1);
             netdata_mutex_init(&m->histogram.ext->mutex);
         }
-        STATSD_METRIC *n = (STATSD_METRIC *)STATSD_AVL_INSERT(&index->index, (avl *)m);
+        STATSD_METRIC *n = (STATSD_METRIC *)STATSD_AVL_INSERT(&index->index, (avl_t *)m);
         if(unlikely(n != m)) {
             freez((void *)m->histogram.ext);
             freez((void *)m->name);
diff --git a/collectors/tc.plugin/plugin_tc.c b/collectors/tc.plugin/plugin_tc.c
index b92450efe7..26affee09c 100644
--- a/collectors/tc.plugin/plugin_tc.c
+++ b/collectors/tc.plugin/plugin_tc.c
@@ -12,7 +12,7 @@
 #define TC_LINE_MAX 1024
 
 struct tc_class {
-    avl avl;
+    avl_t avl;
 
     char *id;
     uint32_t hash;
@@ -56,7 +56,7 @@ struct tc_class {
 };
 
 struct tc_device {
-    avl avl;
+    avl_t avl;
 
     char *id;
     uint32_t hash;
@@ -107,15 +107,15 @@ avl_tree_type tc_device_root_index = {
         tc_device_compare
 };
 
-#define tc_device_index_add(st) (struct tc_device *)avl_insert(&tc_device_root_index, (avl *)(st))
-#define tc_device_index_del(st) (struct tc_device *)avl_remove(&tc_device_root_index, (avl *)(st))
+#define tc_device_index_add(st) (struct tc_device *)avl_insert(&tc_device_root_index, (avl_t *)(st))
+#define tc_device_index_del(st) (struct tc_device *)avl_remove(&tc_device_root_index, (avl_t *)(st))
 
 static inline struct tc_device *tc_device_index_find(const char *id, uint32_t hash) {
     struct tc_device tmp;
     tmp.id = (char *)id;
     tmp.hash = (hash)?hash:simple_hash(tmp.id);
 
-    return (struct tc_device *)avl_search(&(tc_device_root_index), (avl *)&tmp);
+    return (struct tc_device *)avl_search(&(tc_device_root_index), (avl_t *)&tmp);
 }
 
 
@@ -128,15 +128,15 @@ static int tc_class_compare(void* a, void* b) {
     else return strcmp(((struct tc_class *)a)->id, ((struct tc_class *)b)->id);
 }
 
-#define tc_class_index_add(st, rd) (struct tc_class *)avl_insert(&((st)->classes_index), (avl *)(rd))
-#define tc_class_index_del(st, rd) (struct tc_class *)avl_remove(&((st)->classes_index), (avl *)(rd))
+#define tc_class_index_add(st, rd) (struct tc_class *)avl_insert(&((st)->classes_index), (avl_t *)(rd))
+#define tc_class_index_del(st, rd) (struct tc_class *)avl_remove(&((st)->classes_index), (avl_t *)(rd))
 
 static inline struct tc_class *tc_class_index_find(struct tc_device *st, const char *id, uint32_t hash) {
     struct tc_class tmp;
     tmp.id = (char *)id;
     tmp.hash = (hash)?hash:simple_hash(tmp.id);
 
-    return (struct tc_class *)avl_search(&(st->classes_index), (avl *) &tmp);
+    return (struct tc_class *)avl_search(&(st->classes_index), (avl_t *) &tmp);
 }
 
 // ----------------------------------------------------------------------------
diff --git a/database/engine/rrdengine.h b/database/engine/rrdengine.h
index a2003636e5..2d48665f83 100644
--- a/database/engine/rrdengine.h
+++ b/database/engine/rrdengine.h
@@ -234,4 +234,4 @@ extern void rrdeng_worker(void* arg);
 extern void rrdeng_enq_cmd(struct rrdengine_worker_config* wc, struct rrdeng_cmd *cmd);
 extern struct rrdeng_cmd rrdeng_deq_cmd(struct rrdengine_worker_config* wc);
 
-#endif /* NETDATA_RRDENGINE_H */
\ No newline at end of file
+#endif /* NETDATA_RRDENGINE_H */
diff --git a/database/rrd.h b/database/rrd.h
index b826aff280..fd7e4275e3 100644
--- a/database/rrd.h
+++ b/database/rrd.h
@@ -130,7 +130,7 @@ extern const char *rrd_algorithm_name(RRD_ALGORITHM algorithm);
 // RRD FAMILY
 
 struct rrdfamily {
-    avl avl;
+    avl_t avl;
 
     const char *family;
     uint32_t hash_family;
@@ -235,7 +235,7 @@ struct rrddim {
     // ------------------------------------------------------------------------
     // binary indexing structures
 
-    avl avl;                                        // the binary index - this has to be first member!
+    avl_t avl;                                      // the binary index - this has to be first member!
 
     // ------------------------------------------------------------------------
     // the dimension definition
@@ -474,8 +474,8 @@ struct rrdset {
     // ------------------------------------------------------------------------
     // binary indexing structures
 
-    avl avl;                                        // the index, with key the id - this has to be first!
-    avl avlname;                                    // the index, with key the name
+    avl_t avl;                                      // the index, with key the id - this has to be first!
+    avl_t avlname;                                  // the index, with key the name
 
     // ------------------------------------------------------------------------
     // the set configuration
@@ -727,7 +727,7 @@ struct rrdhost_system_info {
 };
 
 struct rrdhost {
-    avl avl;                                        // the index of hosts
+    avl_t avl;                                      // the index of hosts
 
     // ------------------------------------------------------------------------
     // host information
@@ -1286,8 +1286,8 @@ extern int rrdfamily_compare(void *a, void *b);
 extern RRDFAMILY *rrdfamily_create(RRDHOST *host, const char *id);
 extern void rrdfamily_free(RRDHOST *host, RRDFAMILY *rc);
 
-#define rrdset_index_add(host, st) (RRDSET *)avl_insert_lock(&((host)->rrdset_root_index), (avl *)(st))
-#define rrdset_index_del(host, st) (RRDSET *)avl_remove_lock(&((host)->rrdset_root_index), (avl *)(st))
+#define rrdset_index_add(host, st) (RRDSET *)avl_insert_lock(&((host)->rrdset_root_index), (avl_t *)(st))
+#define rrdset_index_del(host, st) (RRDSET *)avl_remove_lock(&((host)->rrdset_root_index), (avl_t *)(st))
 extern RRDSET *rrdset_index_del_name(RRDHOST *host, RRDSET *st);
 
 extern void rrdset_free(RRDSET *st);
diff --git a/database/rrdcalc.c b/database/rrdcalc.c
index 935ee9c055..bc91da64f3 100644
--- a/database/rrdcalc.c
+++ b/database/rrdcalc.c
@@ -472,7 +472,7 @@ inline RRDCALC *rrdcalc_create_from_template(RRDHOST *host, RRDCALCTEMPLATE *rt,
 
     rrdcalc_add_to_host(host, rc);
     if(!rt->foreachdim) {
-        RRDCALC *rdcmp  = (RRDCALC *) avl_insert_lock(&(host)->alarms_idx_health_log,(avl *)rc);
+        RRDCALC *rdcmp  = (RRDCALC *) avl_insert_lock(&(host)->alarms_idx_health_log,(avl_t *)rc);
         if (rdcmp != rc) {
             error("Cannot insert the alarm index ID %s",rc->name);
         }
@@ -605,17 +605,17 @@ void rrdcalc_unlink_and_free(RRDHOST *host, RRDCALC *rc) {
             error("Cannot unlink alarm '%s.%s' from host '%s': not found", rc->chart?rc->chart:"NOCHART", rc->name, host->hostname);
     }
 
-    RRDCALC *rdcmp = (RRDCALC *) avl_search_lock(&(host)->alarms_idx_health_log, (avl *)rc);
+    RRDCALC *rdcmp = (RRDCALC *) avl_search_lock(&(host)->alarms_idx_health_log, (avl_t *)rc);
     if (rdcmp) {
-        rdcmp = (RRDCALC *) avl_remove_lock(&(host)->alarms_idx_health_log, (avl *)rc);
+        rdcmp = (RRDCALC *) avl_remove_lock(&(host)->alarms_idx_health_log, (avl_t *)rc);
         if (!rdcmp) {
             error("Cannot remove the health alarm index from health_log");
         }
     }
 
-    rdcmp = (RRDCALC *) avl_search_lock(&(host)->alarms_idx_name, (avl *)rc);
+    rdcmp = (RRDCALC *) avl_search_lock(&(host)->alarms_idx_name, (avl_t *)rc);
     if (rdcmp) {
-        rdcmp = (RRDCALC *) avl_remove_lock(&(host)->alarms_idx_name, (avl *)rc);
+        rdcmp = (RRDCALC *) avl_remove_lock(&(host)->alarms_idx_name, (avl_t *)rc);
         if (!rdcmp) {
             error("Cannot remove the health alarm index from idx_name");
         }
@@ -727,7 +727,7 @@ void rrdcalc_labels_unlink() {
 int alarm_isrepeating(RRDHOST *host, uint32_t alarm_id) {
     RRDCALC findme;
     findme.id = alarm_id;
-    RRDCALC *rc = (RRDCALC *)avl_search_lock(&host->alarms_idx_health_log, (avl *)&findme);
+    RRDCALC *rc = (RRDCALC *)avl_search_lock(&host->alarms_idx_health_log, (avl_t *)&findme);
     if (!rc) {
         return 0;
     }
@@ -761,7 +761,7 @@ RRDCALC *alarm_max_last_repeat(RRDHOST *host, char *alarm_name,uint32_t hash) {
     RRDCALC findme;
     findme.name = alarm_name;
     findme.hash = hash;
-    RRDCALC *rc = (RRDCALC *)avl_search_lock(&host->alarms_idx_name, (avl *)&findme);
+    RRDCALC *rc = (RRDCALC *)avl_search_lock(&host->alarms_idx_name, (avl_t *)&findme);
 
     return rc;
 }
diff --git a/database/rrdcalc.h b/database/rrdcalc.h
index cd0d70049f..27ff99a89b 100644
--- a/database/rrdcalc.h
+++ b/database/rrdcalc.h
@@ -32,7 +32,7 @@
 
 
 struct rrdcalc {
-    avl avl;                        // the index, with key the id - this has to be first!
+    avl_t avl;                      // the index, with key the id - this has to be first!
     uint32_t id;                    // the unique id of this alarm
     uint32_t next_event_id;         // the next event id that will be used for this alarm
 
diff --git a/database/rrddim.c b/database/rrddim.c
index 6a1408595c..621d6cfa75 100644
--- a/database/rrddim.c
+++ b/database/rrddim.c
@@ -38,15 +38,15 @@ int rrddim_compare(void* a, void* b) {
     else return strcmp(((RRDDIM *)a)->id, ((RRDDIM *)b)->id);
 }
 
-#define rrddim_index_add(st, rd) (RRDDIM *)avl_insert_lock(&((st)->dimensions_index), (avl *)(rd))
-#define rrddim_index_del(st,rd ) (RRDDIM *)avl_remove_lock(&((st)->dimensions_index), (avl *)(rd))
+#define rrddim_index_add(st, rd) (RRDDIM *)avl_insert_lock(&((st)->dimensions_index), (avl_t *)(rd))
+#define rrddim_index_del(st,rd ) (RRDDIM *)avl_remove_lock(&((st)->dimensions_index), (avl_t *)(rd))
 
 static inline RRDDIM *rrddim_index_find(RRDSET *st, const char *id, uint32_t hash) {
     RRDDIM tmp = {
             .id = id,
             .hash = (hash)?hash:simple_hash(id)
     };
-    return (RRDDIM *)avl_search_lock(&(st->dimensions_index), (avl *) &tmp);
+    return (RRDDIM *)avl_search_lock(&(st->dimensions_index), (avl_t *) &tmp);
 }
 
 
@@ -197,7 +197,7 @@ void rrdcalc_link_to_rrddim(RRDDIM *rd, RRDSET *st, RRDHOST *host) {
                     RRDCALC *child = rrdcalc_create_from_rrdcalc(rrdc, host, usename, rd->name);
                     if (child) {
                         rrdcalc_add_to_host(host, child);
-                        RRDCALC *rdcmp  = (RRDCALC *) avl_insert_lock(&(host)->alarms_idx_health_log,(avl *)child);
+                        RRDCALC *rdcmp  = (RRDCALC *) avl_insert_lock(&(host)->alarms_idx_health_log,(avl_t *)child);
                         if (rdcmp != child) {
                             error("Cannot insert the alarm index ID %s",child->name);
                         }
@@ -277,7 +277,7 @@ RRDDIM *rrddim_add_custom(RRDSET *st, const char *id, const char *name, collecte
         if(likely(rd)) {
             // we have a file mapped for rd
 
-            memset(&rd->avl, 0, sizeof(avl));
+            memset(&rd->avl, 0, sizeof(avl_t));
             rd->id = NULL;
             rd->name = NULL;
             rd->cache_filename = NULL;
diff --git a/database/rrdfamily.c b/database/rrdfamily.c
index f75f0adc3e..3d91c37887 100644
--- a/database/rrdfamily.c
+++ b/database/rrdfamily.c
@@ -12,15 +12,15 @@ int rrdfamily_compare(void *a, void *b) {
     else return strcmp(((RRDFAMILY *)a)->family, ((RRDFAMILY *)b)->family);
 }
 
-#define rrdfamily_index_add(host, rc) (RRDFAMILY *)avl_insert_lock(&((host)->rrdfamily_root_index), (avl *)(rc))
-#define rrdfamily_index_del(host, rc) (RRDFAMILY *)avl_remove_lock(&((host)->rrdfamily_root_index), (avl *)(rc))
+#define rrdfamily_index_add(host, rc) (RRDFAMILY *)avl_insert_lock(&((host)->rrdfamily_root_index), (avl_t *)(rc))
+#define rrdfamily_index_del(host, rc) (RRDFAMILY *)avl_remove_lock(&((host)->rrdfamily_root_index), (avl_t *)(rc))
 
 static RRDFAMILY *rrdfamily_index_find(RRDHOST *host, const char *id, uint32_t hash) {
     RRDFAMILY tmp;
     tmp.family = id;
     tmp.hash_family = (hash)?hash:simple_hash(tmp.family);
 
-    return (RRDFAMILY *)avl_search_lock(&(host->rrdfamily_root_index), (avl *) &tmp);
+    return (RRDFAMILY *)avl_search_lock(&(host->rrdfamily_root_index), (avl_t *) &tmp);
 }
 
 RRDFAMILY *rrdfamily_create(RRDHOST *host, const char *id) {
diff --git a/database/rrdhost.c b/database/rrdhost.c
index b9a5a002e4..79a0aab14a 100644
--- a/database/rrdhost.c
+++ b/database/rrdhost.c
@@ -31,7 +31,7 @@ RRDHOST *rrdhost_find_by_guid(const char *guid, uint32_t hash) {
     strncpyz(tmp.machine_guid, guid, GUID_LEN);
     tmp.hash_machine_guid = (hash)?hash:simple_hash(tmp.machine_guid);
 
-    return (RRDHOST *)avl_search_lock(&(rrdhost_root_index), (avl *) &tmp);
+    return (RRDHOST *)avl_search_lock(&(rrdhost_root_index), (avl_t *) &tmp);
 }
 
 RRDHOST *rrdhost_find_by_hostname(const char *hostname, uint32_t hash) {
@@ -53,8 +53,8 @@ RRDHOST *rrdhost_find_by_hostname(const char *hostname, uint32_t hash) {
     return NULL;
 }
 
-#define rrdhost_index_add(rrdhost) (RRDHOST *)avl_insert_lock(&(rrdhost_root_index), (avl *)(rrdhost))
-#define rrdhost_index_del(rrdhost) (RRDHOST *)avl_remove_lock(&(rrdhost_root_index), (avl *)(rrdhost))
+#define rrdhost_index_add(rrdhost) (RRDHOST *)avl_insert_lock(&(rrdhost_root_index), (avl_t *)(rrdhost))
+#define rrdhost_index_del(rrdhost) (RRDHOST *)avl_remove_lock(&(rrdhost_root_index), (avl_t *)(rrdhost))
 
 
 // ----------------------------------------------------------------------------
diff --git a/database/rrdset.c b/database/rrdset.c
index e9c6eee5cf..5fb178b093 100644
--- a/database/rrdset.c
+++ b/database/rrdset.c
@@ -35,7 +35,7 @@ static RRDSET *rrdset_index_find(RRDHOST *host, const char *id, uint32_t hash) {
     strncpyz(tmp.id, id, RRD_ID_LENGTH_MAX);
     tmp.hash = (hash)?hash:simple_hash(tmp.id);
 
-    return (RRDSET *)avl_search_lock(&(host->rrdset_root_index), (avl *) &tmp);
+    return (RRDSET *)avl_search_lock(&(host->rrdset_root_index), (avl_t *) &tmp);
 }
 
 // ----------------------------------------------------------------------------
@@ -57,7 +57,7 @@ int rrdset_compare_name(void* a, void* b) {
 RRDSET *rrdset_index_add_name(RRDHOST *host, RRDSET *st) {
     void *result;
     // fprintf(stderr, "ADDING: %s (name: %s)\n", st->id, st->name);
-    result = avl_insert_lock(&host->rrdset_root_index_name, (avl *) (&st->avlname));
+    result = avl_insert_lock(&host->rrdset_root_index_name, (avl_t *) (&st->avlname));
     if(result) return rrdset_from_avlname(result);
     return NULL;
 }
@@ -65,7 +65,7 @@ RRDSET *rrdset_index_add_name(RRDHOST *host, RRDSET *st) {
 RRDSET *rrdset_index_del_name(RRDHOST *host, RRDSET *st) {
     void *result;
     // fprintf(stderr, "DELETING: %s (name: %s)\n", st->id, st->name);
-    result = (RRDSET *)avl_remove_lock(&((host)->rrdset_root_index_name), (avl *)(&st->avlname));
+    result = (RRDSET *)avl_remove_lock(&((host)->rrdset_root_index_name), (avl_t *)(&st->avlname));
     if(result) return rrdset_from_avlname(result);
     return NULL;
 }
@@ -81,7 +81,7 @@ static inline RRDSET *rrdset_index_find_name(RRDHOST *host, const char *name, ui
     tmp.hash_name = (hash)?hash:simple_hash(tmp.name);
 
     // fprintf(stderr, "SEARCHING: %s\n", name);
-    result = avl_search_lock(&host->rrdset_root_index_name, (avl *) (&(tmp.avlname)));
+    result = avl_search_lock(&host->rrdset_root_index_name, (avl_t *) (&(tmp.avlname)));
     if(result) {
         RRDSET *st = rrdset_from_avlname(result);
         if(strcmp(st->magic, RRDSET_MAGIC) != 0)
@@ -744,8 +744,8 @@ RRDSET *rrdset_create_custom(
         );
 
         if(st) {
-            memset(&st->avl, 0, sizeof(avl));
-            memset(&st->avlname, 0, sizeof(avl));
+            memset(&st->avl, 0, sizeof(avl_t));
+            memset(&st->avlname, 0, sizeof(avl_t));
             memset(&st->rrdvar_root_index, 0, sizeof(avl_tree_lock));
             memset(&st->dimensions_index, 0, sizeof(avl_tree_lock));
             memset(&st->rrdset_rwlock, 0, sizeof(netdata_rwlock_t));
diff --git a/database/rrdvar.c b/database/rrdvar.c
index 6b824d0d3f..25b8ca69ee 100644
--- a/database/rrdvar.c
+++ b/database/rrdvar.c
@@ -27,7 +27,7 @@ int rrdvar_compare(void* a, void* b) {
 }
 
 static inline RRDVAR *rrdvar_index_add(avl_tree_lock *tree, RRDVAR *rv) {
-    RRDVAR *ret = (RRDVAR *)avl_insert_lock(tree, (avl *)(rv));
+    RRDVAR *ret = (RRDVAR *)avl_insert_lock(tree, (avl_t *)(rv));
     if(ret != rv)
         debug(D_VARIABLES, "Request to insert RRDVAR '%s' into index failed. Already exists.", rv->name);
 
@@ -35,7 +35,7 @@ static inline RRDVAR *rrdvar_index_add(avl_tree_lock *tree, RRDVAR *rv) {
 }
 
 static inline RRDVAR *rrdvar_index_del(avl_tree_lock *tree, RRDVAR *rv) {
-    RRDVAR *ret = (RRDVAR *)avl_remove_lock(tree, (avl *)(rv));
+    RRDVAR *ret = (RRDVAR *)avl_remove_lock(tree, (avl_t *)(rv));
     if(!ret)
         error("Request to remove RRDVAR '%s' from index failed. Not Found.", rv->name);
 
@@ -47,7 +47,7 @@ static inline RRDVAR *rrdvar_index_find(avl_tree_lock *tree, const char *name, u
     tmp.name = (char *)name;
     tmp.hash = (hash)?hash:simple_hash(tmp.name);
 
-    return (RRDVAR *)avl_search_lock(tree, (avl *)&tmp);
+    return (RRDVAR *)avl_search_lock(tree, (avl_t *)&tmp);
 }
 
 inline void rrdvar_free(RRDHOST *host, avl_tree_lock *tree, RRDVAR *rv) {
diff --git a/database/rrdvar.h b/database/rrdvar.h
index 6d1461b2aa..ec6e80a432 100644
--- a/database/rrdvar.h
+++ b/database/rrdvar.h
@@ -32,7 +32,7 @@ typedef enum rrdvar_options {
 // 2. at each context (RRDFAMILY.rrdvar_root_index)
 // 3. at each host    (RRDHOST.rrdvar_root_index)
 struct rrdvar {
-    avl avl;
+    avl_t avl;
 
     char *name;
     uint32_t hash;
diff --git a/health/health_log.c b/health/health_log.c
index 8c0bc5c34f..de216c89a1 100644
--- a/health/health_log.c
+++ b/health/health_log.c
@@ -243,7 +243,7 @@ static inline ssize_t health_alarm_log_read(RRDHOST *host, FILE *fp, const char
                 RRDCALC *rc = alarm_max_last_repeat(host, alarm_name,simple_hash(alarm_name));
                 if (!rc) {
                     for(rc = host->alarms; rc ; rc = rc->next) {
-                        RRDCALC *rdcmp  = (RRDCALC *) avl_insert_lock(&(host)->alarms_idx_name, (avl *)rc);
+                        RRDCALC *rdcmp  = (RRDCALC *) avl_insert_lock(&(host)->alarms_idx_name, (avl_t *)rc);
                         if(rdcmp != rc) {
                             error("Cannot insert the alarm index ID using log %s", rc->name);
                         }
diff --git a/libnetdata/avl/avl.c b/libnetdata/avl/avl.c
index 5219851896..b05b97acb5 100644
--- a/libnetdata/avl/avl.c
+++ b/libnetdata/avl/avl.c
@@ -17,8 +17,8 @@
 
 /* Search |tree| for an item matching |item|, and return it if found.
      Otherwise return |NULL|. */
-avl *avl_search(avl_tree_type *tree, avl *item) {
-    avl *p;
+avl_t *avl_search(avl_tree_type *tree, avl_t *item) {
+    avl_t *p;
 
     // assert (tree != NULL && item != NULL);
 
@@ -40,11 +40,11 @@ avl *avl_search(avl_tree_type *tree, avl *item) {
      If a duplicate item is found in the tree,
      returns a pointer to the duplicate without inserting |item|.
  */
-avl *avl_insert(avl_tree_type *tree, avl *item) {
-    avl *y, *z; /* Top node to update balance factor, and parent. */
-    avl *p, *q; /* Iterator, and parent. */
-    avl *n;     /* Newly inserted node. */
-    avl *w;     /* New root of rebalanced subtree. */
+avl_t *avl_insert(avl_tree_type *tree, avl_t *item) {
+    avl_t *y, *z; /* Top node to update balance factor, and parent. */
+    avl_t *p, *q; /* Iterator, and parent. */
+    avl_t *n;     /* Newly inserted node. */
+    avl_t *w;     /* New root of rebalanced subtree. */
     unsigned char dir; /* Direction to descend. */
 
     unsigned char da[AVL_MAX_HEIGHT]; /* Cached comparison results. */
@@ -52,7 +52,7 @@ avl *avl_insert(avl_tree_type *tree, avl *item) {
 
     // assert(tree != NULL && item != NULL);
 
-    z = (avl *) &tree->root;
+    z = (avl_t *) &tree->root;
     y = tree->root;
     dir = 0;
     for (q = z, p = y; p != NULL; q = p, p = p->avl_link[dir]) {
@@ -79,7 +79,7 @@ avl *avl_insert(avl_tree_type *tree, avl *item) {
             p->avl_balance++;
 
     if (y->avl_balance == -2) {
-        avl *x = y->avl_link[0];
+        avl_t *x = y->avl_link[0];
         if (x->avl_balance == -1) {
             w = x;
             y->avl_link[0] = x->avl_link[1];
@@ -103,7 +103,7 @@ avl *avl_insert(avl_tree_type *tree, avl *item) {
         }
     }
     else if (y->avl_balance == +2) {
-        avl *x = y->avl_link[1];
+        avl_t *x = y->avl_link[1];
         if (x->avl_balance == +1) {
             w = x;
             y->avl_link[1] = x->avl_link[0];
@@ -136,19 +136,19 @@ avl *avl_insert(avl_tree_type *tree, avl *item) {
 
 /* Deletes from |tree| and returns an item matching |item|.
      Returns a null pointer if no matching it