Rename "tsc" to "timestamp"
[lttng-modules.git] / src / lttng-events.c
index d64440d3fcc30a3b6652ffcbdf29831b0bd0ab53..a0bd232228c8dd6a3120134bce7cd16d2c5db33e 100644 (file)
 #include <linux/seq_file.h>
 #include <linux/file.h>
 #include <linux/anon_inodes.h>
-#include <wrapper/file.h>
 #include <linux/uaccess.h>
 #include <linux/vmalloc.h>
 #include <linux/dmi.h>
 
+#include <wrapper/compiler_attributes.h>
 #include <wrapper/uuid.h>
 #include <wrapper/vmalloc.h>   /* for wrapper_vmalloc_sync_mappings() */
 #include <wrapper/random.h>
 #include <lttng/utils.h>
 #include <ringbuffer/backend.h>
 #include <ringbuffer/frontend.h>
-#include <wrapper/time.h>
+
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,16,0) \
+       || LTTNG_RHEL_KERNEL_RANGE(5,14,0,162,0,0, 5,15,0,0,0,0))
+#include <linux/stdarg.h>
+#else
+#include <stdarg.h>
+#endif
 
 #define METADATA_CACHE_DEFAULT_SIZE 4096
 
@@ -58,54 +64,47 @@ static LIST_HEAD(lttng_counter_transport_list);
  * Protect the sessions and metadata caches.
  */
 static DEFINE_MUTEX(sessions_mutex);
-static struct kmem_cache *event_cache;
+static struct kmem_cache *event_recorder_cache;
+static struct kmem_cache *event_recorder_private_cache;
 static struct kmem_cache *event_notifier_cache;
+static struct kmem_cache *event_notifier_private_cache;
 
-static void lttng_session_lazy_sync_event_enablers(struct lttng_session *session);
-static void lttng_session_sync_event_enablers(struct lttng_session *session);
-static void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler);
-static void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler);
+static void lttng_session_lazy_sync_event_enablers(struct lttng_kernel_session *session);
+static void lttng_session_sync_event_enablers(struct lttng_kernel_session *session);
 static void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group);
+static void lttng_event_enabler_sync(struct lttng_event_enabler_common *event_enabler);
 
-static void _lttng_event_destroy(struct lttng_event *event);
-static void _lttng_event_notifier_destroy(struct lttng_event_notifier *event_notifier);
-static void _lttng_channel_destroy(struct lttng_channel *chan);
-static int _lttng_event_unregister(struct lttng_event *event);
-static int _lttng_event_notifier_unregister(struct lttng_event_notifier *event_notifier);
+static void _lttng_event_destroy(struct lttng_kernel_event_common *event);
+static void _lttng_channel_destroy(struct lttng_kernel_channel_buffer *chan);
+static void _lttng_event_unregister(struct lttng_kernel_event_common *event);
 static
-int _lttng_event_metadata_statedump(struct lttng_session *session,
-                                 struct lttng_channel *chan,
-                                 struct lttng_event *event);
+int _lttng_event_recorder_metadata_statedump(struct lttng_kernel_event_common *event);
 static
-int _lttng_session_metadata_statedump(struct lttng_session *session);
+int _lttng_session_metadata_statedump(struct lttng_kernel_session *session);
 static
 void _lttng_metadata_channel_hangup(struct lttng_metadata_stream *stream);
 static
-int _lttng_type_statedump(struct lttng_session *session,
-               const struct lttng_type *type,
+int _lttng_type_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_type_common *type,
+               enum lttng_kernel_string_encoding parent_encoding,
                size_t nesting);
 static
-int _lttng_field_statedump(struct lttng_session *session,
-               const struct lttng_event_field *field,
-               size_t nesting);
+int _lttng_field_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_event_field *field,
+               size_t nesting, const char **prev_field_name_p);
 
 void synchronize_trace(void)
 {
-#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,1,0))
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,1,0) || \
+       LTTNG_RHEL_KERNEL_RANGE(4,18,0,193,0,0, 4,19,0,0,0,0))
        synchronize_rcu();
 #else
        synchronize_sched();
 #endif
 
-#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,4,0))
 #ifdef CONFIG_PREEMPT_RT_FULL
        synchronize_rcu();
 #endif
-#else /* (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,4,0)) */
-#ifdef CONFIG_PREEMPT_RT
-       synchronize_rcu();
-#endif
-#endif /* (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,4,0)) */
 }
 
 void lttng_lock_sessions(void)
@@ -134,64 +133,83 @@ static struct lttng_transport *lttng_transport_find(const char *name)
  */
 int lttng_session_active(void)
 {
-       struct lttng_session *iter;
+       struct lttng_kernel_session_private *iter;
 
        list_for_each_entry(iter, &sessions, list) {
-               if (iter->active)
+               if (iter->pub->active)
                        return 1;
        }
        return 0;
 }
 
-struct lttng_session *lttng_session_create(void)
+struct lttng_kernel_session *lttng_session_create(void)
 {
-       struct lttng_session *session;
+       struct lttng_kernel_session *session;
+       struct lttng_kernel_session_private *session_priv;
        struct lttng_metadata_cache *metadata_cache;
        int i;
 
        mutex_lock(&sessions_mutex);
-       session = lttng_kvzalloc(sizeof(struct lttng_session), GFP_KERNEL);
+       session = lttng_kvzalloc(sizeof(*session), GFP_KERNEL);
        if (!session)
                goto err;
-       INIT_LIST_HEAD(&session->chan);
-       INIT_LIST_HEAD(&session->events);
-       lttng_guid_gen(&session->uuid);
+       session_priv = lttng_kvzalloc(sizeof(*session_priv), GFP_KERNEL);
+       if (!session_priv)
+               goto err_free_session;
+       session->priv = session_priv;
+       session_priv->pub = session;
+
+       INIT_LIST_HEAD(&session_priv->chan);
+       INIT_LIST_HEAD(&session_priv->events);
+       lttng_guid_gen(&session_priv->uuid);
 
        metadata_cache = kzalloc(sizeof(struct lttng_metadata_cache),
                        GFP_KERNEL);
        if (!metadata_cache)
-               goto err_free_session;
+               goto err_free_session_private;
        metadata_cache->data = vzalloc(METADATA_CACHE_DEFAULT_SIZE);
        if (!metadata_cache->data)
                goto err_free_cache;
        metadata_cache->cache_alloc = METADATA_CACHE_DEFAULT_SIZE;
        kref_init(&metadata_cache->refcount);
        mutex_init(&metadata_cache->lock);
-       session->metadata_cache = metadata_cache;
+       session_priv->metadata_cache = metadata_cache;
        INIT_LIST_HEAD(&metadata_cache->metadata_stream);
-       memcpy(&metadata_cache->uuid, &session->uuid,
+       memcpy(&metadata_cache->uuid, &session_priv->uuid,
                sizeof(metadata_cache->uuid));
-       INIT_LIST_HEAD(&session->enablers_head);
+       INIT_LIST_HEAD(&session_priv->enablers_head);
        for (i = 0; i < LTTNG_EVENT_HT_SIZE; i++)
-               INIT_HLIST_HEAD(&session->events_ht.table[i]);
-       list_add(&session->list, &sessions);
-       session->pid_tracker.session = session;
-       session->pid_tracker.tracker_type = TRACKER_PID;
-       session->vpid_tracker.session = session;
-       session->vpid_tracker.tracker_type = TRACKER_VPID;
-       session->uid_tracker.session = session;
-       session->uid_tracker.tracker_type = TRACKER_UID;
-       session->vuid_tracker.session = session;
-       session->vuid_tracker.tracker_type = TRACKER_VUID;
-       session->gid_tracker.session = session;
-       session->gid_tracker.tracker_type = TRACKER_GID;
-       session->vgid_tracker.session = session;
-       session->vgid_tracker.tracker_type = TRACKER_VGID;
+               INIT_HLIST_HEAD(&session_priv->events_ht.table[i]);
+       list_add(&session_priv->list, &sessions);
+
+       if (lttng_id_tracker_init(&session->pid_tracker, session, TRACKER_PID))
+               goto tracker_alloc_error;
+       if (lttng_id_tracker_init(&session->vpid_tracker, session, TRACKER_VPID))
+               goto tracker_alloc_error;
+       if (lttng_id_tracker_init(&session->uid_tracker, session, TRACKER_UID))
+               goto tracker_alloc_error;
+       if (lttng_id_tracker_init(&session->vuid_tracker, session, TRACKER_VUID))
+               goto tracker_alloc_error;
+       if (lttng_id_tracker_init(&session->gid_tracker, session, TRACKER_GID))
+               goto tracker_alloc_error;
+       if (lttng_id_tracker_init(&session->vgid_tracker, session, TRACKER_VGID))
+               goto tracker_alloc_error;
+
        mutex_unlock(&sessions_mutex);
+
        return session;
 
+tracker_alloc_error:
+       lttng_id_tracker_fini(&session->pid_tracker);
+       lttng_id_tracker_fini(&session->vpid_tracker);
+       lttng_id_tracker_fini(&session->uid_tracker);
+       lttng_id_tracker_fini(&session->vuid_tracker);
+       lttng_id_tracker_fini(&session->gid_tracker);
+       lttng_id_tracker_fini(&session->vgid_tracker);
 err_free_cache:
        kfree(metadata_cache);
+err_free_session_private:
+       lttng_kvfree(session_priv);
 err_free_session:
        lttng_kvfree(session);
 err:
@@ -289,7 +307,7 @@ struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
         * notifications.
         */
        event_notifier_group->ops = &transport->ops;
-       event_notifier_group->chan = transport->ops.channel_create(
+       event_notifier_group->chan = transport->ops.priv->channel_create(
                        transport_name, event_notifier_group, NULL,
                        subbuf_size, num_subbuf, switch_timer_interval,
                        read_timer_interval);
@@ -300,8 +318,8 @@ struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 
        INIT_LIST_HEAD(&event_notifier_group->enablers_head);
        INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
-       for (i = 0; i < LTTNG_EVENT_NOTIFIER_HT_SIZE; i++)
-               INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
+       for (i = 0; i < LTTNG_EVENT_HT_SIZE; i++)
+               INIT_HLIST_HEAD(&event_notifier_group->events_ht.table[i]);
 
        list_add(&event_notifier_group->node, &event_notifier_groups);
 
@@ -327,59 +345,57 @@ void metadata_cache_destroy(struct kref *kref)
        kfree(cache);
 }
 
-void lttng_session_destroy(struct lttng_session *session)
+void lttng_session_destroy(struct lttng_kernel_session *session)
 {
-       struct lttng_channel *chan, *tmpchan;
-       struct lttng_event *event, *tmpevent;
+       struct lttng_kernel_channel_buffer_private *chan_priv, *tmpchan_priv;
+       struct lttng_kernel_event_recorder_private *event_recorder_priv, *tmpevent_recorder_priv;
        struct lttng_metadata_stream *metadata_stream;
-       struct lttng_event_enabler *event_enabler, *tmp_event_enabler;
+       struct lttng_event_enabler_common *event_enabler, *tmp_event_enabler;
        int ret;
 
        mutex_lock(&sessions_mutex);
        WRITE_ONCE(session->active, 0);
-       list_for_each_entry(chan, &session->chan, list) {
-               ret = lttng_syscalls_unregister_channel(chan);
-               WARN_ON(ret);
-       }
-       list_for_each_entry(event, &session->events, list) {
-               ret = _lttng_event_unregister(event);
+       list_for_each_entry(chan_priv, &session->priv->chan, node) {
+               ret = lttng_syscalls_unregister_syscall_table(&chan_priv->parent.syscall_table);
                WARN_ON(ret);
        }
+       list_for_each_entry(event_recorder_priv, &session->priv->events, parent.node)
+               _lttng_event_unregister(&event_recorder_priv->pub->parent);
        synchronize_trace();    /* Wait for in-flight events to complete */
-       list_for_each_entry(chan, &session->chan, list) {
-               ret = lttng_syscalls_destroy_event(chan);
+       list_for_each_entry(chan_priv, &session->priv->chan, node) {
+               ret = lttng_syscalls_destroy_syscall_table(&chan_priv->parent.syscall_table);
                WARN_ON(ret);
        }
-       list_for_each_entry_safe(event_enabler, tmp_event_enabler,
-                       &session->enablers_head, node)
+       list_for_each_entry_safe(event_enabler, tmp_event_enabler, &session->priv->enablers_head, node)
                lttng_event_enabler_destroy(event_enabler);
-       list_for_each_entry_safe(event, tmpevent, &session->events, list)
-               _lttng_event_destroy(event);
-       list_for_each_entry_safe(chan, tmpchan, &session->chan, list) {
-               BUG_ON(chan->channel_type == METADATA_CHANNEL);
-               _lttng_channel_destroy(chan);
-       }
-       mutex_lock(&session->metadata_cache->lock);
-       list_for_each_entry(metadata_stream, &session->metadata_cache->metadata_stream, list)
+       list_for_each_entry_safe(event_recorder_priv, tmpevent_recorder_priv, &session->priv->events, parent.node)
+               _lttng_event_destroy(&event_recorder_priv->pub->parent);
+       list_for_each_entry_safe(chan_priv, tmpchan_priv, &session->priv->chan, node) {
+               BUG_ON(chan_priv->channel_type == METADATA_CHANNEL);
+               _lttng_channel_destroy(chan_priv->pub);
+       }
+       mutex_lock(&session->priv->metadata_cache->lock);
+       list_for_each_entry(metadata_stream, &session->priv->metadata_cache->metadata_stream, list)
                _lttng_metadata_channel_hangup(metadata_stream);
-       mutex_unlock(&session->metadata_cache->lock);
-       lttng_id_tracker_destroy(&session->pid_tracker, false);
-       lttng_id_tracker_destroy(&session->vpid_tracker, false);
-       lttng_id_tracker_destroy(&session->uid_tracker, false);
-       lttng_id_tracker_destroy(&session->vuid_tracker, false);
-       lttng_id_tracker_destroy(&session->gid_tracker, false);
-       lttng_id_tracker_destroy(&session->vgid_tracker, false);
-       kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
-       list_del(&session->list);
+       mutex_unlock(&session->priv->metadata_cache->lock);
+       lttng_id_tracker_fini(&session->pid_tracker);
+       lttng_id_tracker_fini(&session->vpid_tracker);
+       lttng_id_tracker_fini(&session->uid_tracker);
+       lttng_id_tracker_fini(&session->vuid_tracker);
+       lttng_id_tracker_fini(&session->gid_tracker);
+       lttng_id_tracker_fini(&session->vgid_tracker);
+       kref_put(&session->priv->metadata_cache->refcount, metadata_cache_destroy);
+       list_del(&session->priv->list);
        mutex_unlock(&sessions_mutex);
+       lttng_kvfree(session->priv);
        lttng_kvfree(session);
 }
 
 void lttng_event_notifier_group_destroy(
                struct lttng_event_notifier_group *event_notifier_group)
 {
-       struct lttng_event_notifier_enabler *event_notifier_enabler, *tmp_event_notifier_enabler;
-       struct lttng_event_notifier *event_notifier, *tmpevent_notifier;
+       struct lttng_event_enabler_common *event_enabler, *tmp_event_enabler;
+       struct lttng_kernel_event_notifier_private *event_notifier_priv, *tmpevent_notifier_priv;
        int ret;
 
        if (!event_notifier_group)
@@ -387,29 +403,28 @@ void lttng_event_notifier_group_destroy(
 
        mutex_lock(&sessions_mutex);
 
-       ret = lttng_syscalls_unregister_event_notifier_group(event_notifier_group);
+       ret = lttng_syscalls_unregister_syscall_table(&event_notifier_group->syscall_table);
        WARN_ON(ret);
 
-       list_for_each_entry_safe(event_notifier, tmpevent_notifier,
-                       &event_notifier_group->event_notifiers_head, list) {
-               ret = _lttng_event_notifier_unregister(event_notifier);
-               WARN_ON(ret);
-       }
+       list_for_each_entry_safe(event_notifier_priv, tmpevent_notifier_priv,
+                       &event_notifier_group->event_notifiers_head, parent.node)
+               _lttng_event_unregister(&event_notifier_priv->pub->parent);
 
        /* Wait for in-flight event notifier to complete */
        synchronize_trace();
 
        irq_work_sync(&event_notifier_group->wakeup_pending);
 
-       kfree(event_notifier_group->sc_filter);
+       ret = lttng_syscalls_destroy_syscall_table(&event_notifier_group->syscall_table);
+       WARN_ON(ret);
 
-       list_for_each_entry_safe(event_notifier_enabler, tmp_event_notifier_enabler,
+       list_for_each_entry_safe(event_enabler, tmp_event_enabler,
                        &event_notifier_group->enablers_head, node)
-               lttng_event_notifier_enabler_destroy(event_notifier_enabler);
+               lttng_event_enabler_destroy(event_enabler);
 
-       list_for_each_entry_safe(event_notifier, tmpevent_notifier,
-                       &event_notifier_group->event_notifiers_head, list)
-               _lttng_event_notifier_destroy(event_notifier);
+       list_for_each_entry_safe(event_notifier_priv, tmpevent_notifier_priv,
+                       &event_notifier_group->event_notifiers_head, parent.node)
+               _lttng_event_destroy(&event_notifier_priv->pub->parent);
 
        if (event_notifier_group->error_counter) {
                struct lttng_counter *error_counter = event_notifier_group->error_counter;
@@ -420,7 +435,7 @@ void lttng_event_notifier_group_destroy(
                event_notifier_group->error_counter = NULL;
        }
 
-       event_notifier_group->ops->channel_destroy(event_notifier_group->chan);
+       event_notifier_group->ops->priv->channel_destroy(event_notifier_group->chan);
        module_put(event_notifier_group->transport->owner);
        list_del(&event_notifier_group->node);
 
@@ -428,7 +443,7 @@ void lttng_event_notifier_group_destroy(
        lttng_kvfree(event_notifier_group);
 }
 
-int lttng_session_statedump(struct lttng_session *session)
+int lttng_session_statedump(struct lttng_kernel_session *session)
 {
        int ret;
 
@@ -438,10 +453,10 @@ int lttng_session_statedump(struct lttng_session *session)
        return ret;
 }
 
-int lttng_session_enable(struct lttng_session *session)
+int lttng_session_enable(struct lttng_kernel_session *session)
 {
        int ret = 0;
-       struct lttng_channel *chan;
+       struct lttng_kernel_channel_buffer_private *chan_priv;
 
        mutex_lock(&sessions_mutex);
        if (session->active) {
@@ -450,7 +465,7 @@ int lttng_session_enable(struct lttng_session *session)
        }
 
        /* Set transient enabler state to "enabled" */
-       session->tstate = 1;
+       session->priv->tstate = 1;
 
        /* We need to sync enablers with session before activation. */
        lttng_session_sync_event_enablers(session);
@@ -459,23 +474,23 @@ int lttng_session_enable(struct lttng_session *session)
         * Snapshot the number of events per channel to know the type of header
         * we need to use.
         */
-       list_for_each_entry(chan, &session->chan, list) {
-               if (chan->header_type)
-                       continue;               /* don't change it if session stop/restart */
-               if (chan->free_event_id < 31)
-                       chan->header_type = 1;  /* compact */
+       list_for_each_entry(chan_priv, &session->priv->chan, node) {
+               if (chan_priv->header_type)
+                       continue;                       /* don't change it if session stop/restart */
+               if (chan_priv->free_event_id < 31)
+                       chan_priv->header_type = 1;     /* compact */
                else
-                       chan->header_type = 2;  /* large */
+                       chan_priv->header_type = 2;     /* large */
        }
 
        /* Clear each stream's quiescent state. */
-       list_for_each_entry(chan, &session->chan, list) {
-               if (chan->channel_type != METADATA_CHANNEL)
-                       lib_ring_buffer_clear_quiescent_channel(chan->chan);
+       list_for_each_entry(chan_priv, &session->priv->chan, node) {
+               if (chan_priv->channel_type != METADATA_CHANNEL)
+                       lib_ring_buffer_clear_quiescent_channel(chan_priv->rb_chan);
        }
 
        WRITE_ONCE(session->active, 1);
-       WRITE_ONCE(session->been_active, 1);
+       WRITE_ONCE(session->priv->been_active, 1);
        ret = _lttng_session_metadata_statedump(session);
        if (ret) {
                WRITE_ONCE(session->active, 0);
@@ -489,10 +504,10 @@ end:
        return ret;
 }
 
-int lttng_session_disable(struct lttng_session *session)
+int lttng_session_disable(struct lttng_kernel_session *session)
 {
        int ret = 0;
-       struct lttng_channel *chan;
+       struct lttng_kernel_channel_buffer_private *chan_priv;
 
        mutex_lock(&sessions_mutex);
        if (!session->active) {
@@ -502,25 +517,25 @@ int lttng_session_disable(struct lttng_session *session)
        WRITE_ONCE(session->active, 0);
 
        /* Set transient enabler state to "disabled" */
-       session->tstate = 0;
+       session->priv->tstate = 0;
        lttng_session_sync_event_enablers(session);
 
        /* Set each stream's quiescent state. */
-       list_for_each_entry(chan, &session->chan, list) {
-               if (chan->channel_type != METADATA_CHANNEL)
-                       lib_ring_buffer_set_quiescent_channel(chan->chan);
+       list_for_each_entry(chan_priv, &session->priv->chan, node) {
+               if (chan_priv->channel_type != METADATA_CHANNEL)
+                       lib_ring_buffer_set_quiescent_channel(chan_priv->rb_chan);
        }
 end:
        mutex_unlock(&sessions_mutex);
        return ret;
 }
 
-int lttng_session_metadata_regenerate(struct lttng_session *session)
+int lttng_session_metadata_regenerate(struct lttng_kernel_session *session)
 {
        int ret = 0;
-       struct lttng_channel *chan;
-       struct lttng_event *event;
-       struct lttng_metadata_cache *cache = session->metadata_cache;
+       struct lttng_kernel_channel_buffer_private *chan_priv;
+       struct lttng_kernel_event_recorder_private *event_recorder_priv;
+       struct lttng_metadata_cache *cache = session->priv->metadata_cache;
        struct lttng_metadata_stream *stream;
 
        mutex_lock(&sessions_mutex);
@@ -533,19 +548,19 @@ int lttng_session_metadata_regenerate(struct lttng_session *session)
        memset(cache->data, 0, cache->cache_alloc);
        cache->metadata_written = 0;
        cache->version++;
-       list_for_each_entry(stream, &session->metadata_cache->metadata_stream, list) {
+       list_for_each_entry(stream, &session->priv->metadata_cache->metadata_stream, list) {
                stream->metadata_out = 0;
                stream->metadata_in = 0;
        }
        mutex_unlock(&cache->lock);
 
-       session->metadata_dumped = 0;
-       list_for_each_entry(chan, &session->chan, list) {
-               chan->metadata_dumped = 0;
+       session->priv->metadata_dumped = 0;
+       list_for_each_entry(chan_priv, &session->priv->chan, node) {
+               chan_priv->metadata_dumped = 0;
        }
 
-       list_for_each_entry(event, &session->events, list) {
-               event->metadata_dumped = 0;
+       list_for_each_entry(event_recorder_priv, &session->priv->events, parent.node) {
+               event_recorder_priv->metadata_dumped = 0;
        }
 
        ret = _lttng_session_metadata_statedump(session);
@@ -555,12 +570,25 @@ end:
        return ret;
 }
 
-int lttng_channel_enable(struct lttng_channel *channel)
+static
+bool is_channel_buffer_metadata(struct lttng_kernel_channel_common *channel)
+{
+       struct lttng_kernel_channel_buffer *chan_buf;
+
+       if (channel->type != LTTNG_KERNEL_CHANNEL_TYPE_BUFFER)
+               return false;
+       chan_buf = container_of(channel, struct lttng_kernel_channel_buffer, parent);
+       if (chan_buf->priv->channel_type == METADATA_CHANNEL)
+               return true;
+       return false;
+}
+
+int lttng_channel_enable(struct lttng_kernel_channel_common *channel)
 {
        int ret = 0;
 
        mutex_lock(&sessions_mutex);
-       if (channel->channel_type == METADATA_CHANNEL) {
+       if (is_channel_buffer_metadata(channel)) {
                ret = -EPERM;
                goto end;
        }
@@ -569,7 +597,7 @@ int lttng_channel_enable(struct lttng_channel *channel)
                goto end;
        }
        /* Set transient enabler state to "enabled" */
-       channel->tstate = 1;
+       channel->priv->tstate = 1;
        lttng_session_sync_event_enablers(channel->session);
        /* Set atomically the state to "enabled" */
        WRITE_ONCE(channel->enabled, 1);
@@ -578,12 +606,12 @@ end:
        return ret;
 }
 
-int lttng_channel_disable(struct lttng_channel *channel)
+int lttng_channel_disable(struct lttng_kernel_channel_common *channel)
 {
        int ret = 0;
 
        mutex_lock(&sessions_mutex);
-       if (channel->channel_type == METADATA_CHANNEL) {
+       if (is_channel_buffer_metadata(channel)) {
                ret = -EPERM;
                goto end;
        }
@@ -594,43 +622,68 @@ int lttng_channel_disable(struct lttng_channel *channel)
        /* Set atomically the state to "disabled" */
        WRITE_ONCE(channel->enabled, 0);
        /* Set transient enabler state to "enabled" */
-       channel->tstate = 0;
+       channel->priv->tstate = 0;
        lttng_session_sync_event_enablers(channel->session);
 end:
        mutex_unlock(&sessions_mutex);
        return ret;
 }
 
-int lttng_event_enable(struct lttng_event *event)
+int lttng_event_enable(struct lttng_kernel_event_common *event)
 {
        int ret = 0;
 
        mutex_lock(&sessions_mutex);
-       if (event->chan->channel_type == METADATA_CHANNEL) {
-               ret = -EPERM;
-               goto end;
+       switch (event->type) {
+       case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+       {
+               struct lttng_kernel_event_recorder *event_recorder =
+                       container_of(event, struct lttng_kernel_event_recorder, parent);
+
+               if (event_recorder->chan->priv->channel_type == METADATA_CHANNEL) {
+                       ret = -EPERM;
+                       goto end;
+               }
+               break;
+       }
+       case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
+               switch (event->priv->instrumentation) {
+               case LTTNG_KERNEL_ABI_KRETPROBE:
+                       ret = -EINVAL;
+                       goto end;
+               default:
+                       break;
+               }
+               break;
+       default:
+               break;
        }
+
        if (event->enabled) {
                ret = -EEXIST;
                goto end;
        }
-       switch (event->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:   /* Fall-through */
-       case LTTNG_KERNEL_SYSCALL:
+       switch (event->priv->instrumentation) {
+       case LTTNG_KERNEL_ABI_TRACEPOINT:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_SYSCALL:
                ret = -EINVAL;
                break;
 
-       case LTTNG_KERNEL_KPROBE:       /* Fall-through */
-       case LTTNG_KERNEL_UPROBE:
+       case LTTNG_KERNEL_ABI_KPROBE:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_UPROBE:
                WRITE_ONCE(event->enabled, 1);
                break;
 
-       case LTTNG_KERNEL_KRETPROBE:
+       case LTTNG_KERNEL_ABI_KRETPROBE:
                ret = lttng_kretprobes_event_enable_state(event, 1);
                break;
 
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
+       case LTTNG_KERNEL_ABI_FUNCTION:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_NOOP:
+               lttng_fallthrough;
        default:
                WARN_ON_ONCE(1);
                ret = -EINVAL;
@@ -640,101 +693,61 @@ end:
        return ret;
 }
 
-int lttng_event_disable(struct lttng_event *event)
+int lttng_event_disable(struct lttng_kernel_event_common *event)
 {
        int ret = 0;
 
        mutex_lock(&sessions_mutex);
-       if (event->chan->channel_type == METADATA_CHANNEL) {
-               ret = -EPERM;
-               goto end;
-       }
-       if (!event->enabled) {
-               ret = -EEXIST;
-               goto end;
-       }
-       switch (event->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:   /* Fall-through */
-       case LTTNG_KERNEL_SYSCALL:
-               ret = -EINVAL;
-               break;
+       switch (event->type) {
+       case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+       {
+               struct lttng_kernel_event_recorder *event_recorder =
+                       container_of(event, struct lttng_kernel_event_recorder, parent);
 
-       case LTTNG_KERNEL_KPROBE:       /* Fall-through */
-       case LTTNG_KERNEL_UPROBE:
-               WRITE_ONCE(event->enabled, 0);
+               if (event_recorder->chan->priv->channel_type == METADATA_CHANNEL) {
+                       ret = -EPERM;
+                       goto end;
+               }
                break;
-
-       case LTTNG_KERNEL_KRETPROBE:
-
-               ret = lttng_kretprobes_event_enable_state(event, 0);
+       }
+       case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
+               switch (event->priv->instrumentation) {
+               case LTTNG_KERNEL_ABI_KRETPROBE:
+                       ret = -EINVAL;
+                       goto end;
+               default:
+                       break;
+               }
                break;
-
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
        default:
-               WARN_ON_ONCE(1);
-               ret = -EINVAL;
+               break;
        }
-end:
-       mutex_unlock(&sessions_mutex);
-       return ret;
-}
-
-int lttng_event_notifier_enable(struct lttng_event_notifier *event_notifier)
-{
-       int ret = 0;
 
-       mutex_lock(&sessions_mutex);
-       if (event_notifier->enabled) {
+       if (!event->enabled) {
                ret = -EEXIST;
                goto end;
        }
-       switch (event_notifier->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:   /* Fall-through */
-       case LTTNG_KERNEL_SYSCALL:
+       switch (event->priv->instrumentation) {
+       case LTTNG_KERNEL_ABI_TRACEPOINT:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_SYSCALL:
                ret = -EINVAL;
                break;
 
-       case LTTNG_KERNEL_KPROBE:       /* Fall-through */
-       case LTTNG_KERNEL_UPROBE:
-               WRITE_ONCE(event_notifier->enabled, 1);
-               break;
-
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_KRETPROBE:    /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
-       default:
-               WARN_ON_ONCE(1);
-               ret = -EINVAL;
-       }
-end:
-       mutex_unlock(&sessions_mutex);
-       return ret;
-}
-
-int lttng_event_notifier_disable(struct lttng_event_notifier *event_notifier)
-{
-       int ret = 0;
-
-       mutex_lock(&sessions_mutex);
-       if (!event_notifier->enabled) {
-               ret = -EEXIST;
-               goto end;
-       }
-       switch (event_notifier->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:   /* Fall-through */
-       case LTTNG_KERNEL_SYSCALL:
-               ret = -EINVAL;
+       case LTTNG_KERNEL_ABI_KPROBE:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_UPROBE:
+               WRITE_ONCE(event->enabled, 0);
                break;
 
-       case LTTNG_KERNEL_KPROBE:       /* Fall-through */
-       case LTTNG_KERNEL_UPROBE:
-               WRITE_ONCE(event_notifier->enabled, 0);
+       case LTTNG_KERNEL_ABI_KRETPROBE:
+               ret = lttng_kretprobes_event_enable_state(event, 0);
                break;
 
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_KRETPROBE:    /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
+       case LTTNG_KERNEL_ABI_FUNCTION:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_NOOP:
+               lttng_fallthrough;
        default:
                WARN_ON_ONCE(1);
                ret = -EINVAL;
@@ -744,7 +757,7 @@ end:
        return ret;
 }
 
-struct lttng_channel *lttng_channel_create(struct lttng_session *session,
+struct lttng_kernel_channel_buffer *lttng_channel_buffer_create(struct lttng_kernel_session *session,
                                       const char *transport_name,
                                       void *buf_addr,
                                       size_t subbuf_size, size_t num_subbuf,
@@ -752,11 +765,12 @@ struct lttng_channel *lttng_channel_create(struct lttng_session *session,
                                       unsigned int read_timer_interval,
                                       enum channel_type channel_type)
 {
-       struct lttng_channel *chan;
+       struct lttng_kernel_channel_buffer *chan;
+       struct lttng_kernel_channel_buffer_private *chan_priv;
        struct lttng_transport *transport = NULL;
 
        mutex_lock(&sessions_mutex);
-       if (session->been_active && channel_type != METADATA_CHANNEL)
+       if (session->priv->been_active && channel_type != METADATA_CHANNEL)
                goto active;    /* Refuse to add channel to active session */
        transport = lttng_transport_find(transport_name);
        if (!transport) {
@@ -768,31 +782,39 @@ struct lttng_channel *lttng_channel_create(struct lttng_session *session,
                printk(KERN_WARNING "LTTng: Can't lock transport module.\n");
                goto notransport;
        }
-       chan = kzalloc(sizeof(struct lttng_channel), GFP_KERNEL);
+       chan = kzalloc(sizeof(struct lttng_kernel_channel_buffer), GFP_KERNEL);
        if (!chan)
                goto nomem;
-       chan->session = session;
-       chan->id = session->free_chan_id++;
+       chan_priv = kzalloc(sizeof(struct lttng_kernel_channel_buffer_private), GFP_KERNEL);
+       if (!chan_priv)
+               goto nomem_priv;
+       chan->priv = chan_priv;
+       chan_priv->pub = chan;
+       chan->parent.type = LTTNG_KERNEL_CHANNEL_TYPE_BUFFER;
+       chan->parent.session = session;
+       chan->priv->id = session->priv->free_chan_id++;
        chan->ops = &transport->ops;
        /*
         * Note: the channel creation op already writes into the packet
         * headers. Therefore the "chan" information used as input
         * should be already accessible.
         */
-       chan->chan = transport->ops.channel_create(transport_name,
+       chan->priv->rb_chan = transport->ops.priv->channel_create(transport_name,
                        chan, buf_addr, subbuf_size, num_subbuf,
                        switch_timer_interval, read_timer_interval);
-       if (!chan->chan)
+       if (!chan->priv->rb_chan)
                goto create_error;
-       chan->tstate = 1;
-       chan->enabled = 1;
-       chan->transport = transport;
-       chan->channel_type = channel_type;
-       list_add(&chan->list, &session->chan);
+       chan->priv->parent.tstate = 1;
+       chan->parent.enabled = 1;
+       chan->priv->transport = transport;
+       chan->priv->channel_type = channel_type;
+       list_add(&chan->priv->node, &session->priv->chan);
        mutex_unlock(&sessions_mutex);
        return chan;
 
 create_error:
+       kfree(chan_priv);
+nomem_priv:
        kfree(chan);
 nomem:
        if (transport)
@@ -809,18 +831,19 @@ active:
  * Needs to be called with sessions mutex held.
  */
 static
-void _lttng_channel_destroy(struct lttng_channel *chan)
+void _lttng_channel_destroy(struct lttng_kernel_channel_buffer *chan)
 {
-       chan->ops->channel_destroy(chan->chan);
-       module_put(chan->transport->owner);
-       list_del(&chan->list);
-       lttng_destroy_context(chan->ctx);
+       chan->ops->priv->channel_destroy(chan->priv->rb_chan);
+       module_put(chan->priv->transport->owner);
+       list_del(&chan->priv->node);
+       lttng_kernel_destroy_context(chan->priv->ctx);
+       kfree(chan->priv);
        kfree(chan);
 }
 
-void lttng_metadata_channel_destroy(struct lttng_channel *chan)
+void lttng_metadata_channel_destroy(struct lttng_kernel_channel_buffer *chan)
 {
-       BUG_ON(chan->channel_type != METADATA_CHANNEL);
+       BUG_ON(chan->priv->channel_type != METADATA_CHANNEL);
 
        /* Protect the metadata cache with the sessions_mutex. */
        mutex_lock(&sessions_mutex);
@@ -836,80 +859,267 @@ void _lttng_metadata_channel_hangup(struct lttng_metadata_stream *stream)
        wake_up_interruptible(&stream->read_wait);
 }
 
+static
+bool lttng_kernel_event_id_available(struct lttng_event_enabler_common *event_enabler)
+{
+       struct lttng_kernel_abi_event *event_param = &event_enabler->event_param;
+        enum lttng_kernel_abi_instrumentation itype = event_param->instrumentation;
+
+       switch (event_enabler->enabler_type) {
+       case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
+       {
+               struct lttng_event_recorder_enabler *event_recorder_enabler =
+                       container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
+               struct lttng_kernel_channel_buffer *chan = event_recorder_enabler->chan;
+
+               switch (itype) {
+               case LTTNG_KERNEL_ABI_TRACEPOINT:
+                       lttng_fallthrough;
+               case LTTNG_KERNEL_ABI_KPROBE:
+                       lttng_fallthrough;
+               case LTTNG_KERNEL_ABI_SYSCALL:
+                       lttng_fallthrough;
+               case LTTNG_KERNEL_ABI_UPROBE:
+                       if (chan->priv->free_event_id == -1U)
+                               return false;
+                       return true;
+               case LTTNG_KERNEL_ABI_KRETPROBE:
+                       /* kretprobes require 2 event IDs. */
+                       if (chan->priv->free_event_id >= -2U)
+                               return false;
+                       return true;
+               default:
+                       WARN_ON_ONCE(1);
+                       return false;
+               }
+       }
+       case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
+               return true;
+       default:
+               WARN_ON_ONCE(1);
+               return false;
+       }
+}
+
+static
+struct lttng_kernel_event_common *lttng_kernel_event_alloc(struct lttng_event_enabler_common *event_enabler)
+{
+       struct lttng_kernel_abi_event *event_param = &event_enabler->event_param;
+        enum lttng_kernel_abi_instrumentation itype = event_param->instrumentation;
+
+       switch (event_enabler->enabler_type) {
+       case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
+       {
+               struct lttng_event_recorder_enabler *event_recorder_enabler =
+                       container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
+               struct lttng_kernel_event_recorder *event_recorder;
+               struct lttng_kernel_event_recorder_private *event_recorder_priv;
+               struct lttng_kernel_channel_buffer *chan = event_recorder_enabler->chan;
+
+               event_recorder = kmem_cache_zalloc(event_recorder_cache, GFP_KERNEL);
+               if (!event_recorder)
+                       return NULL;
+               event_recorder_priv = kmem_cache_zalloc(event_recorder_private_cache, GFP_KERNEL);
+               if (!event_recorder_priv) {
+                       kmem_cache_free(event_recorder_private_cache, event_recorder);
+                       return NULL;
+               }
+               event_recorder_priv->pub = event_recorder;
+               event_recorder_priv->parent.pub = &event_recorder->parent;
+               event_recorder->priv = event_recorder_priv;
+               event_recorder->parent.priv = &event_recorder_priv->parent;
+
+               event_recorder->parent.type = LTTNG_KERNEL_EVENT_TYPE_RECORDER;
+               event_recorder->parent.run_filter = lttng_kernel_interpret_event_filter;
+               event_recorder->priv->parent.instrumentation = itype;
+               INIT_LIST_HEAD(&event_recorder->priv->parent.filter_bytecode_runtime_head);
+               INIT_LIST_HEAD(&event_recorder->priv->parent.enablers_ref_head);
+
+               event_recorder->chan = chan;
+               event_recorder->priv->id = chan->priv->free_event_id++;
+               return &event_recorder->parent;
+       }
+       case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
+       {
+               struct lttng_event_notifier_enabler *event_notifier_enabler =
+                       container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
+               struct lttng_kernel_event_notifier *event_notifier;
+               struct lttng_kernel_event_notifier_private *event_notifier_priv;
+
+               event_notifier = kmem_cache_zalloc(event_notifier_cache, GFP_KERNEL);
+               if (!event_notifier)
+                       return NULL;
+               event_notifier_priv = kmem_cache_zalloc(event_notifier_private_cache, GFP_KERNEL);
+               if (!event_notifier_priv) {
+                       kmem_cache_free(event_notifier_private_cache, event_notifier);
+                       return NULL;
+               }
+               event_notifier_priv->pub = event_notifier;
+               event_notifier_priv->parent.pub = &event_notifier->parent;
+               event_notifier->priv = event_notifier_priv;
+               event_notifier->parent.priv = &event_notifier_priv->parent;
+
+               event_notifier->parent.type = LTTNG_KERNEL_EVENT_TYPE_NOTIFIER;
+               event_notifier->parent.run_filter = lttng_kernel_interpret_event_filter;
+               event_notifier->priv->parent.instrumentation = itype;
+               event_notifier->priv->parent.user_token = event_enabler->user_token;
+               INIT_LIST_HEAD(&event_notifier->priv->parent.filter_bytecode_runtime_head);
+               INIT_LIST_HEAD(&event_notifier->priv->parent.enablers_ref_head);
+
+               event_notifier->priv->group = event_notifier_enabler->group;
+               event_notifier->priv->error_counter_index = event_notifier_enabler->error_counter_index;
+               event_notifier->priv->num_captures = 0;
+               event_notifier->notification_send = lttng_event_notifier_notification_send;
+               INIT_LIST_HEAD(&event_notifier->priv->capture_bytecode_runtime_head);
+               return &event_notifier->parent;
+       }
+       default:
+               return NULL;
+       }
+}
+
+static
+void lttng_kernel_event_free(struct lttng_kernel_event_common *event)
+{
+       switch (event->type) {
+       case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+       {
+               struct lttng_kernel_event_recorder *event_recorder =
+                       container_of(event, struct lttng_kernel_event_recorder, parent);
+
+               kmem_cache_free(event_recorder_private_cache, event_recorder->priv);
+               kmem_cache_free(event_recorder_cache, event_recorder);
+               break;
+       }
+       case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
+       {
+               struct lttng_kernel_event_notifier *event_notifier =
+                       container_of(event, struct lttng_kernel_event_notifier, parent);
+
+               kmem_cache_free(event_notifier_private_cache, event_notifier->priv);
+               kmem_cache_free(event_notifier_cache, event_notifier);
+               break;
+       }
+       default:
+               WARN_ON_ONCE(1);
+       }
+}
+
+static
+int lttng_kernel_event_notifier_clear_error_counter(struct lttng_kernel_event_common *event)
+{
+       switch (event->type) {
+       case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+               return 0;
+       case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
+       {
+               struct lttng_kernel_event_notifier *event_notifier =
+                       container_of(event, struct lttng_kernel_event_notifier, parent);
+               struct lttng_counter *error_counter;
+               struct lttng_event_notifier_group *event_notifier_group = event_notifier->priv->group;
+               size_t dimension_index[1];
+               int ret;
+
+               /*
+                * Clear the error counter bucket. The sessiond keeps track of which
+                * bucket is currently in use. We trust it. The session lock
+                * synchronizes against concurrent creation of the error
+                * counter.
+                */
+               error_counter = event_notifier_group->error_counter;
+               if (!error_counter)
+                       return 0;
+               /*
+                * Check that the index is within the boundary of the counter.
+                */
+               if (event_notifier->priv->error_counter_index >= event_notifier_group->error_counter_len) {
+                       printk(KERN_INFO "LTTng: event_notifier: Error counter index out-of-bound: counter-len=%zu, index=%llu\n",
+                               event_notifier_group->error_counter_len, event_notifier->priv->error_counter_index);
+                       return -EINVAL;
+               }
+
+               dimension_index[0] = event_notifier->priv->error_counter_index;
+               ret = error_counter->ops->counter_clear(error_counter->counter, dimension_index);
+               if (ret) {
+                       printk(KERN_INFO "LTTng: event_notifier: Unable to clear error counter bucket %llu\n",
+                               event_notifier->priv->error_counter_index);
+                       return -EINVAL;
+               }
+               return 0;
+       }
+       default:
+               return -EINVAL;
+       }
+}
 
 /*
  * Supports event creation while tracing session is active.
  * Needs to be called with sessions mutex held.
  */
-struct lttng_event *_lttng_event_create(struct lttng_channel *chan,
-                               struct lttng_kernel_event *event_param,
-                               void *filter,
-                               const struct lttng_event_desc *event_desc,
-                               enum lttng_kernel_instrumentation itype)
-{
-       struct lttng_session *session = chan->session;
-       struct lttng_event *event;
+struct lttng_kernel_event_common *_lttng_kernel_event_create(struct lttng_event_enabler_common *event_enabler,
+                               const struct lttng_kernel_event_desc *event_desc)
+{
+       struct lttng_event_ht *events_ht = lttng_get_event_ht_from_enabler(event_enabler);
+       struct list_head *event_list_head = lttng_get_event_list_head_from_enabler(event_enabler);
+       struct lttng_kernel_abi_event *event_param = &event_enabler->event_param;
+       enum lttng_kernel_abi_instrumentation itype = event_param->instrumentation;
+       struct lttng_kernel_event_common_private *event_priv;
+       struct lttng_kernel_event_common *event;
        const char *event_name;
        struct hlist_head *head;
        int ret;
 
-       if (chan->free_event_id == -1U) {
+       if (!lttng_kernel_event_id_available(event_enabler)) {
                ret = -EMFILE;
                goto full;
        }
 
        switch (itype) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               event_name = event_desc->name;
+       case LTTNG_KERNEL_ABI_TRACEPOINT:
+               event_name = event_desc->event_name;
                break;
 
-       case LTTNG_KERNEL_KPROBE:       /* Fall-through */
-       case LTTNG_KERNEL_UPROBE:       /* Fall-through */
-       case LTTNG_KERNEL_KRETPROBE:    /* Fall-through */
-       case LTTNG_KERNEL_SYSCALL:
+       case LTTNG_KERNEL_ABI_KPROBE:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_UPROBE:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_KRETPROBE:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_SYSCALL:
                event_name = event_param->name;
                break;
 
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
+       case LTTNG_KERNEL_ABI_FUNCTION:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_NOOP:
+               lttng_fallthrough;
        default:
                WARN_ON_ONCE(1);
                ret = -EINVAL;
                goto type_error;
        }
 
-       head = utils_borrow_hash_table_bucket(session->events_ht.table,
-               LTTNG_EVENT_HT_SIZE, event_name);
-       lttng_hlist_for_each_entry(event, head, hlist) {
-               WARN_ON_ONCE(!event->desc);
-               if (!strncmp(event->desc->name, event_name,
-                                       LTTNG_KERNEL_SYM_NAME_LEN - 1)
-                               && chan == event->chan) {
+       head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, event_name);
+       lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
+               if (lttng_event_enabler_event_name_match_event(event_enabler, event_name, event_priv->pub)) {
                        ret = -EEXIST;
                        goto exist;
                }
        }
 
-       event = kmem_cache_zalloc(event_cache, GFP_KERNEL);
+       event = lttng_kernel_event_alloc(event_enabler);
        if (!event) {
                ret = -ENOMEM;
-               goto cache_error;
+               goto alloc_error;
        }
-       event->chan = chan;
-       event->filter = filter;
-       event->id = chan->free_event_id++;
-       event->instrumentation = itype;
-       event->evtype = LTTNG_TYPE_EVENT;
-       INIT_LIST_HEAD(&event->filter_bytecode_runtime_head);
-       INIT_LIST_HEAD(&event->enablers_ref_head);
 
        switch (itype) {
-       case LTTNG_KERNEL_TRACEPOINT:
+       case LTTNG_KERNEL_ABI_TRACEPOINT:
                /* Event will be enabled by enabler sync. */
                event->enabled = 0;
-               event->registered = 0;
-               event->desc = lttng_event_desc_get(event_name);
-               if (!event->desc) {
+               event->priv->registered = 0;
+               event->priv->desc = lttng_event_desc_get(event_name);
+               if (!event->priv->desc) {
                        ret = -ENOENT;
                        goto register_error;
                }
@@ -917,13 +1127,13 @@ struct lttng_event *_lttng_event_create(struct lttng_channel *chan,
                smp_wmb();
                break;
 
-       case LTTNG_KERNEL_KPROBE:
+       case LTTNG_KERNEL_ABI_KPROBE:
                /*
                 * Needs to be explicitly enabled after creation, since
                 * we may want to apply filters.
                 */
                event->enabled = 0;
-               event->registered = 1;
+               event->priv->registered = 1;
                /*
                 * Populate lttng_event structure before event
                 * registration.
@@ -938,13 +1148,13 @@ struct lttng_event *_lttng_event_create(struct lttng_channel *chan,
                        ret = -EINVAL;
                        goto register_error;
                }
-               ret = try_module_get(event->desc->owner);
+               ret = try_module_get(event->priv->desc->owner);
                WARN_ON_ONCE(!ret);
                break;
 
-       case LTTNG_KERNEL_KRETPROBE:
+       case LTTNG_KERNEL_ABI_KRETPROBE:
        {
-               struct lttng_event *event_return;
+               struct lttng_kernel_event_common *event_return;
 
                /* kretprobe defines 2 events */
                /*
@@ -952,21 +1162,17 @@ struct lttng_event *_lttng_event_create(struct lttng_channel *chan,
                 * we may want to apply filters.
                 */
                event->enabled = 0;
-               event->registered = 1;
-               event_return =
-                       kmem_cache_zalloc(event_cache, GFP_KERNEL);
-               if (!event_return) {
+               event->priv->registered = 1;
+
+               event_return = lttng_kernel_event_alloc(event_enabler);
+               if (!event) {
                        ret = -ENOMEM;
-                       goto register_error;
+                       goto alloc_error;
                }
-               event_return->chan = chan;
-               event_return->filter = filter;
-               event_return->id = chan->free_event_id++;
+
                event_return->enabled = 0;
-               event_return->registered = 1;
-               event_return->instrumentation = itype;
-               INIT_LIST_HEAD(&event_return->filter_bytecode_runtime_head);
-               INIT_LIST_HEAD(&event_return->enablers_ref_head);
+               event_return->priv->registered = 1;
+
                /*
                 * Populate lttng_event structure before kretprobe registration.
                 */
@@ -977,71 +1183,70 @@ struct lttng_event *_lttng_event_create(struct lttng_channel *chan,
                                event_param->u.kretprobe.addr,
                                event, event_return);
                if (ret) {
-                       kmem_cache_free(event_cache, event_return);
+                       lttng_kernel_event_free(event_return);
                        ret = -EINVAL;
                        goto register_error;
                }
                /* Take 2 refs on the module: one per event. */
-               ret = try_module_get(event->desc->owner);
+               ret = try_module_get(event->priv->desc->owner);
                WARN_ON_ONCE(!ret);
-               ret = try_module_get(event->desc->owner);
+               ret = try_module_get(event_return->priv->desc->owner);
                WARN_ON_ONCE(!ret);
-               ret = _lttng_event_metadata_statedump(chan->session, chan,
-                                                   event_return);
+               ret = _lttng_event_recorder_metadata_statedump(event_return);
                WARN_ON_ONCE(ret > 0);
                if (ret) {
-                       kmem_cache_free(event_cache, event_return);
-                       module_put(event->desc->owner);
-                       module_put(event->desc->owner);
+                       lttng_kernel_event_free(event_return);
+                       module_put(event_return->priv->desc->owner);
+                       module_put(event->priv->desc->owner);
                        goto statedump_error;
                }
-               list_add(&event_return->list, &chan->session->events);
+               list_add(&event_return->priv->node, event_list_head);
                break;
        }
 
-       case LTTNG_KERNEL_SYSCALL:
+       case LTTNG_KERNEL_ABI_SYSCALL:
                /*
                 * Needs to be explicitly enabled after creation, since
                 * we may want to apply filters.
                 */
                event->enabled = 0;
-               event->registered = 0;
-               event->desc = event_desc;
+               event->priv->registered = 0;
+               event->priv->desc = event_desc;
                switch (event_param->u.syscall.entryexit) {
-               case LTTNG_KERNEL_SYSCALL_ENTRYEXIT:
+               case LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT:
                        ret = -EINVAL;
                        goto register_error;
-               case LTTNG_KERNEL_SYSCALL_ENTRY:
-                       event->u.syscall.entryexit = LTTNG_SYSCALL_ENTRY;
+               case LTTNG_KERNEL_ABI_SYSCALL_ENTRY:
+                       event->priv->u.syscall.entryexit = LTTNG_SYSCALL_ENTRY;
                        break;
-               case LTTNG_KERNEL_SYSCALL_EXIT:
-                       event->u.syscall.entryexit = LTTNG_SYSCALL_EXIT;
+               case LTTNG_KERNEL_ABI_SYSCALL_EXIT:
+                       event->priv->u.syscall.entryexit = LTTNG_SYSCALL_EXIT;
                        break;
                }
                switch (event_param->u.syscall.abi) {
-               case LTTNG_KERNEL_SYSCALL_ABI_ALL:
+               case LTTNG_KERNEL_ABI_SYSCALL_ABI_ALL:
                        ret = -EINVAL;
                        goto register_error;
-               case LTTNG_KERNEL_SYSCALL_ABI_NATIVE:
-                       event->u.syscall.abi = LTTNG_SYSCALL_ABI_NATIVE;
+               case LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE:
+                       event->priv->u.syscall.abi = LTTNG_SYSCALL_ABI_NATIVE;
                        break;
-               case LTTNG_KERNEL_SYSCALL_ABI_COMPAT:
-                       event->u.syscall.abi = LTTNG_SYSCALL_ABI_COMPAT;
+               case LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT:
+                       event->priv->u.syscall.abi = LTTNG_SYSCALL_ABI_COMPAT;
                        break;
                }
-               if (!event->desc) {
+               if (!event->priv->desc) {
                        ret = -EINVAL;
                        goto register_error;
                }
                break;
 
-       case LTTNG_KERNEL_UPROBE:
+       case LTTNG_KERNEL_ABI_UPROBE:
                /*
                 * Needs to be explicitly enabled after creation, since
                 * we may want to apply filters.
                 */
                event->enabled = 0;
-               event->registered = 1;
+               event->priv->registered = 1;
 
                /*
                 * Populate lttng_event structure before event
@@ -1054,562 +1259,295 @@ struct lttng_event *_lttng_event_create(struct lttng_channel *chan,
                                event);
                if (ret)
                        goto register_error;
-               ret = try_module_get(event->desc->owner);
+               ret = try_module_get(event->priv->desc->owner);
                WARN_ON_ONCE(!ret);
                break;
 
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
        default:
                WARN_ON_ONCE(1);
                ret = -EINVAL;
                goto register_error;
        }
-       ret = _lttng_event_metadata_statedump(chan->session, chan, event);
+
+       ret = _lttng_event_recorder_metadata_statedump(event);
        WARN_ON_ONCE(ret > 0);
        if (ret) {
                goto statedump_error;
        }
-       hlist_add_head(&event->hlist, head);
-       list_add(&event->list, &chan->session->events);
+
+       ret = lttng_kernel_event_notifier_clear_error_counter(event);
+       if (ret)
+               goto register_error;
+
+       hlist_add_head(&event->priv->hlist_node, head);
+       list_add(&event->priv->node, event_list_head);
+
        return event;
 
 statedump_error:
        /* If a statedump error occurs, events will not be readable. */
 register_error:
-       kmem_cache_free(event_cache, event);
-cache_error:
+       lttng_kernel_event_free(event);
+alloc_error:
 exist:
 type_error:
 full:
        return ERR_PTR(ret);
 }
 
-struct lttng_event_notifier *_lttng_event_notifier_create(
-               const struct lttng_event_desc *event_desc,
-               uint64_t token, uint64_t error_counter_index,
-               struct lttng_event_notifier_group *event_notifier_group,
-               struct lttng_kernel_event_notifier *event_notifier_param,
-               void *filter, enum lttng_kernel_instrumentation itype)
+struct lttng_kernel_event_common *lttng_kernel_event_create(struct lttng_event_enabler_common *event_enabler,
+                               const struct lttng_kernel_event_desc *event_desc)
 {
-       struct lttng_event_notifier *event_notifier;
-       struct lttng_counter *error_counter;
-       const char *event_name;
-       struct hlist_head *head;
-       int ret;
+       struct lttng_kernel_event_common *event;
 
-       switch (itype) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               event_name = event_desc->name;
+       mutex_lock(&sessions_mutex);
+       event = _lttng_kernel_event_create(event_enabler, event_desc);
+       mutex_unlock(&sessions_mutex);
+       return event;
+}
+
+int lttng_kernel_counter_read(struct lttng_counter *counter,
+               const size_t *dim_indexes, int32_t cpu,
+               int64_t *val, bool *overflow, bool *underflow)
+{
+       return counter->ops->counter_read(counter->counter, dim_indexes,
+                       cpu, val, overflow, underflow);
+}
+
+int lttng_kernel_counter_aggregate(struct lttng_counter *counter,
+               const size_t *dim_indexes, int64_t *val,
+               bool *overflow, bool *underflow)
+{
+       return counter->ops->counter_aggregate(counter->counter, dim_indexes,
+                       val, overflow, underflow);
+}
+
+int lttng_kernel_counter_clear(struct lttng_counter *counter,
+               const size_t *dim_indexes)
+{
+       return counter->ops->counter_clear(counter->counter, dim_indexes);
+}
+
+/* Only used for tracepoints and system calls for now. */
+static
+void register_event(struct lttng_kernel_event_common *event)
+{
+       const struct lttng_kernel_event_desc *desc;
+       int ret = -EINVAL;
+
+       WARN_ON_ONCE(event->priv->registered);
+
+       desc = event->priv->desc;
+       switch (event->priv->instrumentation) {
+       case LTTNG_KERNEL_ABI_TRACEPOINT:
+               ret = lttng_tracepoint_probe_register(desc->event_kname,
+                                                 desc->tp_class->probe_callback,
+                                                 event);
+               break;
+
+       case LTTNG_KERNEL_ABI_SYSCALL:
+               ret = lttng_syscall_filter_enable_event(event);
                break;
 
-       case LTTNG_KERNEL_KPROBE:       /* Fall-through */
-       case LTTNG_KERNEL_UPROBE:       /* Fall-through */
-       case LTTNG_KERNEL_SYSCALL:
-               event_name = event_notifier_param->event.name;
+       case LTTNG_KERNEL_ABI_KPROBE:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_UPROBE:
+               ret = 0;
+               break;
+
+       case LTTNG_KERNEL_ABI_KRETPROBE:
+               switch (event->type) {
+               case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+                       ret = 0;
+                       break;
+               case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
+                       WARN_ON_ONCE(1);
+                       break;
+               }
                break;
 
-       case LTTNG_KERNEL_KRETPROBE:    /* Fall-through */
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
+       case LTTNG_KERNEL_ABI_FUNCTION:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_NOOP:
+               lttng_fallthrough;
        default:
                WARN_ON_ONCE(1);
-               ret = -EINVAL;
-               goto type_error;
        }
+       WARN_ON_ONCE(ret);
+       if (!ret)
+               event->priv->registered = 1;
+}
 
-       head = utils_borrow_hash_table_bucket(event_notifier_group->event_notifiers_ht.table,
-               LTTNG_EVENT_NOTIFIER_HT_SIZE, event_name);
-       lttng_hlist_for_each_entry(event_notifier, head, hlist) {
-               WARN_ON_ONCE(!event_notifier->desc);
-               if (!strncmp(event_notifier->desc->name, event_name,
-                                       LTTNG_KERNEL_SYM_NAME_LEN - 1)
-                               && event_notifier_group == event_notifier->group
-                               && token == event_notifier->user_token) {
-                       ret = -EEXIST;
-                       goto exist;
-               }
-       }
+static
+void unregister_event(struct lttng_kernel_event_common *event)
+{
+       struct lttng_kernel_event_common_private *event_priv = event->priv;
+       const struct lttng_kernel_event_desc *desc;
+       int ret = -EINVAL;
 
-       event_notifier = kmem_cache_zalloc(event_notifier_cache, GFP_KERNEL);
-       if (!event_notifier) {
-               ret = -ENOMEM;
-               goto cache_error;
-       }
+       WARN_ON_ONCE(!event->priv->registered);
 
-       event_notifier->group = event_notifier_group;
-       event_notifier->user_token = token;
-       event_notifier->error_counter_index = error_counter_index;
-       event_notifier->num_captures = 0;
-       event_notifier->filter = filter;
-       event_notifier->instrumentation = itype;
-       event_notifier->evtype = LTTNG_TYPE_EVENT;
-       event_notifier->send_notification = lttng_event_notifier_notification_send;
-       INIT_LIST_HEAD(&event_notifier->filter_bytecode_runtime_head);
-       INIT_LIST_HEAD(&event_notifier->capture_bytecode_runtime_head);
-       INIT_LIST_HEAD(&event_notifier->enablers_ref_head);
+       desc = event_priv->desc;
+       switch (event_priv->instrumentation) {
+       case LTTNG_KERNEL_ABI_TRACEPOINT:
+               ret = lttng_tracepoint_probe_unregister(event_priv->desc->event_kname,
+                                                 event_priv->desc->tp_class->probe_callback,
+                                                 event);
+               break;
 
-       switch (itype) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               /* Event will be enabled by enabler sync. */
-               event_notifier->enabled = 0;
-               event_notifier->registered = 0;
-               event_notifier->desc = lttng_event_desc_get(event_name);
-               if (!event_notifier->desc) {
-                       ret = -ENOENT;
-                       goto register_error;
+       case LTTNG_KERNEL_ABI_KPROBE:
+               lttng_kprobes_unregister_event(event);
+               ret = 0;
+               break;
+
+       case LTTNG_KERNEL_ABI_KRETPROBE:
+               switch (event->type) {
+               case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+                       lttng_kretprobes_unregister(event);
+                       ret = 0;
+                       break;
+               case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
+                       WARN_ON_ONCE(1);
+                       break;
                }
-               /* Populate lttng_event_notifier structure before event registration. */
-               smp_wmb();
                break;
 
-       case LTTNG_KERNEL_KPROBE:
-               /*
-                * Needs to be explicitly enabled after creation, since
-                * we may want to apply filters.
-                */
-               event_notifier->enabled = 0;
-               event_notifier->registered = 1;
-               /*
-                * Populate lttng_event_notifier structure before event
-                * registration.
-                */
-               smp_wmb();
-               ret = lttng_kprobes_register_event_notifier(
-                               event_notifier_param->event.u.kprobe.symbol_name,
-                               event_notifier_param->event.u.kprobe.offset,
-                               event_notifier_param->event.u.kprobe.addr,
-                               event_notifier);
-               if (ret) {
-                       ret = -EINVAL;
-                       goto register_error;
-               }
-               ret = try_module_get(event_notifier->desc->owner);
-               WARN_ON_ONCE(!ret);
+       case LTTNG_KERNEL_ABI_SYSCALL:
+               ret = lttng_syscall_filter_disable_event(event);
                break;
 
-       case LTTNG_KERNEL_SYSCALL:
-               /*
-                * Needs to be explicitly enabled after creation, since
-                * we may want to apply filters.
-                */
-               event_notifier->enabled = 0;
-               event_notifier->registered = 0;
-               event_notifier->desc = event_desc;
-               switch (event_notifier_param->event.u.syscall.entryexit) {
-               case LTTNG_KERNEL_SYSCALL_ENTRYEXIT:
-                       ret = -EINVAL;
-                       goto register_error;
-               case LTTNG_KERNEL_SYSCALL_ENTRY:
-                       event_notifier->u.syscall.entryexit = LTTNG_SYSCALL_ENTRY;
-                       break;
-               case LTTNG_KERNEL_SYSCALL_EXIT:
-                       event_notifier->u.syscall.entryexit = LTTNG_SYSCALL_EXIT;
-                       break;
-               }
-               switch (event_notifier_param->event.u.syscall.abi) {
-               case LTTNG_KERNEL_SYSCALL_ABI_ALL:
-                       ret = -EINVAL;
-                       goto register_error;
-               case LTTNG_KERNEL_SYSCALL_ABI_NATIVE:
-                       event_notifier->u.syscall.abi = LTTNG_SYSCALL_ABI_NATIVE;
+       case LTTNG_KERNEL_ABI_NOOP:
+               switch (event->type) {
+               case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+                       ret = 0;
                        break;
-               case LTTNG_KERNEL_SYSCALL_ABI_COMPAT:
-                       event_notifier->u.syscall.abi = LTTNG_SYSCALL_ABI_COMPAT;
+               case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
+                       WARN_ON_ONCE(1);
                        break;
                }
-
-               if (!event_notifier->desc) {
-                       ret = -EINVAL;
-                       goto register_error;
-               }
-               break;
-
-       case LTTNG_KERNEL_UPROBE:
-               /*
-                * Needs to be explicitly enabled after creation, since
-                * we may want to apply filters.
-                */
-               event_notifier->enabled = 0;
-               event_notifier->registered = 1;
-
-               /*
-                * Populate lttng_event_notifier structure before
-                * event_notifier registration.
-                */
-               smp_wmb();
-
-               ret = lttng_uprobes_register_event_notifier(
-                               event_notifier_param->event.name,
-                               event_notifier_param->event.u.uprobe.fd,
-                               event_notifier);
-               if (ret)
-                       goto register_error;
-               ret = try_module_get(event_notifier->desc->owner);
-               WARN_ON_ONCE(!ret);
                break;
 
-       case LTTNG_KERNEL_KRETPROBE:    /* Fall-through */
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
-       default:
-               WARN_ON_ONCE(1);
-               ret = -EINVAL;
-               goto register_error;
-       }
-
-       list_add(&event_notifier->list, &event_notifier_group->event_notifiers_head);
-       hlist_add_head(&event_notifier->hlist, head);
-
-       /*
-        * Clear the error counter bucket. The sessiond keeps track of which
-        * bucket is currently in use. We trust it. The session lock
-        * synchronizes against concurrent creation of the error
-        * counter.
-        */
-       error_counter = event_notifier_group->error_counter;
-       if (error_counter) {
-               size_t dimension_index[1];
-
-               /*
-                * Check that the index is within the boundary of the counter.
-                */
-               if (event_notifier->error_counter_index >= event_notifier_group->error_counter_len) {
-                       printk(KERN_INFO "LTTng: event_notifier: Error counter index out-of-bound: counter-len=%zu, index=%llu\n",
-                               event_notifier_group->error_counter_len, event_notifier->error_counter_index);
-                       ret = -EINVAL;
-                       goto register_error;
-               }
-
-               dimension_index[0] = event_notifier->error_counter_index;
-               ret = error_counter->ops->counter_clear(error_counter->counter, dimension_index);
-               if (ret) {
-                       printk(KERN_INFO "LTTng: event_notifier: Unable to clear error counter bucket %llu\n",
-                               event_notifier->error_counter_index);
-                       goto register_error;
-               }
-       }
-
-       return event_notifier;
-
-register_error:
-       kmem_cache_free(event_notifier_cache, event_notifier);
-cache_error:
-exist:
-type_error:
-       return ERR_PTR(ret);
-}
-
-int lttng_kernel_counter_read(struct lttng_counter *counter,
-               const size_t *dim_indexes, int32_t cpu,
-               int64_t *val, bool *overflow, bool *underflow)
-{
-       return counter->ops->counter_read(counter->counter, dim_indexes,
-                       cpu, val, overflow, underflow);
-}
-
-int lttng_kernel_counter_aggregate(struct lttng_counter *counter,
-               const size_t *dim_indexes, int64_t *val,
-               bool *overflow, bool *underflow)
-{
-       return counter->ops->counter_aggregate(counter->counter, dim_indexes,
-                       val, overflow, underflow);
-}
-
-int lttng_kernel_counter_clear(struct lttng_counter *counter,
-               const size_t *dim_indexes)
-{
-       return counter->ops->counter_clear(counter->counter, dim_indexes);
-}
-
-struct lttng_event *lttng_event_create(struct lttng_channel *chan,
-                               struct lttng_kernel_event *event_param,
-                               void *filter,
-                               const struct lttng_event_desc *event_desc,
-                               enum lttng_kernel_instrumentation itype)
-{
-       struct lttng_event *event;
-
-       mutex_lock(&sessions_mutex);
-       event = _lttng_event_create(chan, event_param, filter, event_desc,
-                               itype);
-       mutex_unlock(&sessions_mutex);
-       return event;
-}
-
-struct lttng_event_notifier *lttng_event_notifier_create(
-               const struct lttng_event_desc *event_desc,
-               uint64_t id, uint64_t error_counter_index,
-               struct lttng_event_notifier_group *event_notifier_group,
-               struct lttng_kernel_event_notifier *event_notifier_param,
-               void *filter, enum lttng_kernel_instrumentation itype)
-{
-       struct lttng_event_notifier *event_notifier;
-
-       mutex_lock(&sessions_mutex);
-       event_notifier = _lttng_event_notifier_create(event_desc, id,
-               error_counter_index, event_notifier_group,
-               event_notifier_param, filter, itype);
-       mutex_unlock(&sessions_mutex);
-       return event_notifier;
-}
-
-/* Only used for tracepoints for now. */
-static
-void register_event(struct lttng_event *event)
-{
-       const struct lttng_event_desc *desc;
-       int ret = -EINVAL;
-
-       if (event->registered)
-               return;
-
-       desc = event->desc;
-       switch (event->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               ret = lttng_wrapper_tracepoint_probe_register(desc->kname,
-                                                 desc->probe_callback,
-                                                 event);
-               break;
-
-       case LTTNG_KERNEL_SYSCALL:
-               ret = lttng_syscall_filter_enable_event(event->chan, event);
-               break;
-
-       case LTTNG_KERNEL_KPROBE:       /* Fall-through */
-       case LTTNG_KERNEL_UPROBE:       /* Fall-through */
-       case LTTNG_KERNEL_KRETPROBE:
-               ret = 0;
-               break;
-
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
-       default:
-               WARN_ON_ONCE(1);
-       }
-       if (!ret)
-               event->registered = 1;
-}
-
-/*
- * Only used internally at session destruction.
- */
-int _lttng_event_unregister(struct lttng_event *event)
-{
-       const struct lttng_event_desc *desc;
-       int ret = -EINVAL;
-
-       if (!event->registered)
-               return 0;
-
-       desc = event->desc;
-       switch (event->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               ret = lttng_wrapper_tracepoint_probe_unregister(event->desc->kname,
-                                                 event->desc->probe_callback,
-                                                 event);
-               break;
-
-       case LTTNG_KERNEL_KPROBE:
-               lttng_kprobes_unregister_event(event);
-               ret = 0;
-               break;
-
-       case LTTNG_KERNEL_KRETPROBE:
-               lttng_kretprobes_unregister(event);
-               ret = 0;
-               break;
-
-       case LTTNG_KERNEL_SYSCALL:
-               ret = lttng_syscall_filter_disable_event(event->chan, event);
-               break;
-
-       case LTTNG_KERNEL_NOOP:
-               ret = 0;
-               break;
-
-       case LTTNG_KERNEL_UPROBE:
+       case LTTNG_KERNEL_ABI_UPROBE:
                lttng_uprobes_unregister_event(event);
                ret = 0;
                break;
 
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
+       case LTTNG_KERNEL_ABI_FUNCTION:
+               lttng_fallthrough;
        default:
                WARN_ON_ONCE(1);
        }
+       WARN_ON_ONCE(ret);
        if (!ret)
-               event->registered = 0;
-       return ret;
+               event_priv->registered = 0;
 }
 
-/* Only used for tracepoints for now. */
 static
-void register_event_notifier(struct lttng_event_notifier *event_notifier)
+void _lttng_event_unregister(struct lttng_kernel_event_common *event)
 {
-       const struct lttng_event_desc *desc;
-       int ret = -EINVAL;
-
-       if (event_notifier->registered)
-               return;
-
-       desc = event_notifier->desc;
-       switch (event_notifier->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               ret = lttng_wrapper_tracepoint_probe_register(desc->kname,
-                                                 desc->event_notifier_callback,
-                                                 event_notifier);
-               break;
-
-       case LTTNG_KERNEL_SYSCALL:
-               ret = lttng_syscall_filter_enable_event_notifier(event_notifier);
-               break;
-
-       case LTTNG_KERNEL_KPROBE:       /* Fall-through */
-       case LTTNG_KERNEL_UPROBE:
-               ret = 0;
-               break;
-
-       case LTTNG_KERNEL_KRETPROBE:    /* Fall-through */
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
-       default:
-               WARN_ON_ONCE(1);
-       }
-       if (!ret)
-               event_notifier->registered = 1;
-}
-
-static
-int _lttng_event_notifier_unregister(
-               struct lttng_event_notifier *event_notifier)
-{
-       const struct lttng_event_desc *desc;
-       int ret = -EINVAL;
-
-       if (!event_notifier->registered)
-               return 0;
-
-       desc = event_notifier->desc;
-       switch (event_notifier->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               ret = lttng_wrapper_tracepoint_probe_unregister(event_notifier->desc->kname,
-                                                 event_notifier->desc->event_notifier_callback,
-                                                 event_notifier);
-               break;
-
-       case LTTNG_KERNEL_KPROBE:
-               lttng_kprobes_unregister_event_notifier(event_notifier);
-               ret = 0;
-               break;
-
-       case LTTNG_KERNEL_UPROBE:
-               lttng_uprobes_unregister_event_notifier(event_notifier);
-               ret = 0;
-               break;
-
-       case LTTNG_KERNEL_SYSCALL:
-               ret = lttng_syscall_filter_disable_event_notifier(event_notifier);
-               break;
-
-       case LTTNG_KERNEL_KRETPROBE:    /* Fall-through */
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
-       default:
-               WARN_ON_ONCE(1);
-       }
-       if (!ret)
-               event_notifier->registered = 0;
-       return ret;
+       if (event->priv->registered)
+               unregister_event(event);
 }
 
 /*
  * Only used internally at session destruction.
  */
 static
-void _lttng_event_destroy(struct lttng_event *event)
+void _lttng_event_destroy(struct lttng_kernel_event_common *event)
 {
+       struct lttng_kernel_event_common_private *event_priv = event->priv;
        struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 
-       switch (event->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               lttng_event_desc_put(event->desc);
-               break;
+       lttng_free_event_filter_runtime(event);
+       /* Free event enabler refs */
+       list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
+                                &event_priv->enablers_ref_head, node)
+               kfree(enabler_ref);
 
-       case LTTNG_KERNEL_KPROBE:
-               module_put(event->desc->owner);
-               lttng_kprobes_destroy_event_private(event);
-               break;
+       switch (event->type) {
+       case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+       {
+               struct lttng_kernel_event_recorder *event_recorder =
+                       container_of(event, struct lttng_kernel_event_recorder, parent);
 
-       case LTTNG_KERNEL_KRETPROBE:
-               module_put(event->desc->owner);
-               lttng_kretprobes_destroy_private(event);
-               break;
+               switch (event_priv->instrumentation) {
+               case LTTNG_KERNEL_ABI_TRACEPOINT:
+                       lttng_event_desc_put(event_priv->desc);
+                       break;
 
-       case LTTNG_KERNEL_SYSCALL:
-               break;
+               case LTTNG_KERNEL_ABI_KPROBE:
+                       module_put(event_priv->desc->owner);
+                       lttng_kprobes_destroy_event_private(&event_recorder->parent);
+                       break;
 
-       case LTTNG_KERNEL_UPROBE:
-               module_put(event->desc->owner);
-               lttng_uprobes_destroy_event_private(event);
-               break;
+               case LTTNG_KERNEL_ABI_KRETPROBE:
+                       module_put(event_priv->desc->owner);
+                       lttng_kretprobes_destroy_private(&event_recorder->parent);
+                       break;
 
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
-       default:
-               WARN_ON_ONCE(1);
-       }
-       list_del(&event->list);
-       lttng_destroy_context(event->ctx);
-       lttng_free_event_filter_runtime(event);
-       /* Free event enabler refs */
-       list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
-                                &event->enablers_ref_head, node)
-               kfree(enabler_ref);
-       kmem_cache_free(event_cache, event);
-}
+               case LTTNG_KERNEL_ABI_SYSCALL:
+                       break;
 
-/*
- * Only used internally at session destruction.
- */
-static
-void _lttng_event_notifier_destroy(struct lttng_event_notifier *event_notifier)
-{
-       struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
+               case LTTNG_KERNEL_ABI_UPROBE:
+                       module_put(event_priv->desc->owner);
+                       lttng_uprobes_destroy_event_private(&event_recorder->parent);
+                       break;
 
-       switch (event_notifier->instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               lttng_event_desc_put(event_notifier->desc);
+               case LTTNG_KERNEL_ABI_FUNCTION:
+                       lttng_fallthrough;
+               case LTTNG_KERNEL_ABI_NOOP:
+                       lttng_fallthrough;
+               default:
+                       WARN_ON_ONCE(1);
+               }
+               list_del(&event_recorder->priv->parent.node);
+               kmem_cache_free(event_recorder_private_cache, event_recorder->priv);
+               kmem_cache_free(event_recorder_cache, event_recorder);
                break;
+       }
+       case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
+       {
+               struct lttng_kernel_event_notifier *event_notifier =
+                       container_of(event, struct lttng_kernel_event_notifier, parent);
 
-       case LTTNG_KERNEL_KPROBE:
-               module_put(event_notifier->desc->owner);
-               lttng_kprobes_destroy_event_notifier_private(event_notifier);
-               break;
+               switch (event_notifier->priv->parent.instrumentation) {
+               case LTTNG_KERNEL_ABI_TRACEPOINT:
+                       lttng_event_desc_put(event_notifier->priv->parent.desc);
+                       break;
 
-       case LTTNG_KERNEL_SYSCALL:
-               break;
+               case LTTNG_KERNEL_ABI_KPROBE:
+                       module_put(event_notifier->priv->parent.desc->owner);
+                       lttng_kprobes_destroy_event_private(&event_notifier->parent);
+                       break;
 
-       case LTTNG_KERNEL_UPROBE:
-               module_put(event_notifier->desc->owner);
-               lttng_uprobes_destroy_event_notifier_private(event_notifier);
-               break;
+               case LTTNG_KERNEL_ABI_SYSCALL:
+                       break;
+
+               case LTTNG_KERNEL_ABI_UPROBE:
+                       module_put(event_notifier->priv->parent.desc->owner);
+                       lttng_uprobes_destroy_event_private(&event_notifier->parent);
+                       break;
 
-       case LTTNG_KERNEL_KRETPROBE:    /* Fall-through */
-       case LTTNG_KERNEL_FUNCTION:     /* Fall-through */
-       case LTTNG_KERNEL_NOOP:         /* Fall-through */
+               case LTTNG_KERNEL_ABI_KRETPROBE:
+                       lttng_fallthrough;
+               case LTTNG_KERNEL_ABI_FUNCTION:
+                       lttng_fallthrough;
+               case LTTNG_KERNEL_ABI_NOOP:
+                       lttng_fallthrough;
+               default:
+                       WARN_ON_ONCE(1);
+               }
+               list_del(&event_notifier->priv->parent.node);
+               kmem_cache_free(event_notifier_private_cache, event_notifier->priv);
+               kmem_cache_free(event_notifier_cache, event_notifier);
+               break;
+       }
        default:
                WARN_ON_ONCE(1);
        }
-       list_del(&event_notifier->list);
-       lttng_free_event_notifier_filter_runtime(event_notifier);
-       /* Free event enabler refs */
-       list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
-                                &event_notifier->enablers_ref_head, node)
-               kfree(enabler_ref);
-       kmem_cache_free(event_notifier_cache, event_notifier);
 }
 
-struct lttng_id_tracker *get_tracker(struct lttng_session *session,
+struct lttng_kernel_id_tracker *get_tracker(struct lttng_kernel_session *session,
                enum tracker_type tracker_type)
 {
        switch (tracker_type) {
@@ -1631,10 +1569,10 @@ struct lttng_id_tracker *get_tracker(struct lttng_session *session,
        }
 }
 
-int lttng_session_track_id(struct lttng_session *session,
+int lttng_session_track_id(struct lttng_kernel_session *session,
                enum tracker_type tracker_type, int id)
 {
-       struct lttng_id_tracker *tracker;
+       struct lttng_kernel_id_tracker *tracker;
        int ret;
 
        tracker = get_tracker(session, tracker_type);
@@ -1654,10 +1592,10 @@ int lttng_session_track_id(struct lttng_session *session,
        return ret;
 }
 
-int lttng_session_untrack_id(struct lttng_session *session,
+int lttng_session_untrack_id(struct lttng_kernel_session *session,
                enum tracker_type tracker_type, int id)
 {
-       struct lttng_id_tracker *tracker;
+       struct lttng_kernel_id_tracker *tracker;
        int ret;
 
        tracker = get_tracker(session, tracker_type);
@@ -1679,8 +1617,8 @@ int lttng_session_untrack_id(struct lttng_session *session,
 static
 void *id_list_start(struct seq_file *m, loff_t *pos)
 {
-       struct lttng_id_tracker *id_tracker = m->private;
-       struct lttng_id_tracker_rcu *id_tracker_p = id_tracker->p;
+       struct lttng_kernel_id_tracker *id_tracker = m->private;
+       struct lttng_kernel_id_tracker_rcu *id_tracker_p = id_tracker->p;
        struct lttng_id_hash_node *e;
        int iter = 0, i;
 
@@ -1709,8 +1647,8 @@ void *id_list_start(struct seq_file *m, loff_t *pos)
 static
 void *id_list_next(struct seq_file *m, void *p, loff_t *ppos)
 {
-       struct lttng_id_tracker *id_tracker = m->private;
-       struct lttng_id_tracker_rcu *id_tracker_p = id_tracker->p;
+       struct lttng_kernel_id_tracker *id_tracker = m->private;
+       struct lttng_kernel_id_tracker_rcu *id_tracker_p = id_tracker->p;
        struct lttng_id_hash_node *e;
        int iter = 0, i;
 
@@ -1744,8 +1682,8 @@ void id_list_stop(struct seq_file *m, void *p)
 static
 int id_list_show(struct seq_file *m, void *p)
 {
-       struct lttng_id_tracker *id_tracker = m->private;
-       struct lttng_id_tracker_rcu *id_tracker_p = id_tracker->p;
+       struct lttng_kernel_id_tracker *id_tracker = m->private;
+       struct lttng_kernel_id_tracker_rcu *id_tracker_p = id_tracker->p;
        int id;
 
        if (p == id_tracker_p) {
@@ -1756,7 +1694,7 @@ int id_list_show(struct seq_file *m, void *p)
 
                id = lttng_id_tracker_get_node_id(e);
        }
-       switch (id_tracker->tracker_type) {
+       switch (id_tracker->priv->tracker_type) {
        case TRACKER_PID:
                seq_printf(m,   "process { pid = %d; };\n", id);
                break;
@@ -1799,13 +1737,13 @@ static
 int lttng_tracker_ids_list_release(struct inode *inode, struct file *file)
 {
        struct seq_file *m = file->private_data;
-       struct lttng_id_tracker *id_tracker = m->private;
+       struct lttng_kernel_id_tracker *id_tracker = m->private;
        int ret;
 
        WARN_ON_ONCE(!id_tracker);
        ret = seq_release(inode, file);
        if (!ret)
-               fput(id_tracker->session->file);
+               fput(id_tracker->priv->session->priv->file);
        return ret;
 }
 
@@ -1817,14 +1755,14 @@ const struct file_operations lttng_tracker_ids_list_fops = {
        .release = lttng_tracker_ids_list_release,
 };
 
-int lttng_session_list_tracker_ids(struct lttng_session *session,
+int lttng_session_list_tracker_ids(struct lttng_kernel_session *session,
                enum tracker_type tracker_type)
 {
        struct file *tracker_ids_list_file;
        struct seq_file *m;
        int file_fd, ret;
 
-       file_fd = lttng_get_unused_fd();
+       file_fd = get_unused_fd_flags(0);
        if (file_fd < 0) {
                ret = file_fd;
                goto fd_error;
@@ -1837,7 +1775,7 @@ int lttng_session_list_tracker_ids(struct lttng_session *session,
                ret = PTR_ERR(tracker_ids_list_file);
                goto file_error;
        }
-       if (!atomic_long_add_unless(&session->file->f_count, 1, LONG_MAX)) {
+       if (!atomic_long_add_unless(&session->priv->file->f_count, 1, LONG_MAX)) {
                ret = -EOVERFLOW;
                goto refcount_error;
        }
@@ -1853,7 +1791,7 @@ int lttng_session_list_tracker_ids(struct lttng_session *session,
        return file_fd;
 
 open_error:
-       atomic_long_dec(&session->file->f_count);
+       atomic_long_dec(&session->priv->file->f_count);
 refcount_error:
        fput(tracker_ids_list_file);
 file_error:
@@ -1884,16 +1822,17 @@ int lttng_match_enabler_name(const char *desc_name,
        return 1;
 }
 
-int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
-               struct lttng_enabler *enabler)
+static
+int lttng_desc_match_enabler_check(const struct lttng_kernel_event_desc *desc,
+               struct lttng_event_enabler_common *enabler)
 {
        const char *desc_name, *enabler_name;
        bool compat = false, entry = false;
 
        enabler_name = enabler->event_param.name;
        switch (enabler->event_param.instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               desc_name = desc->name;
+       case LTTNG_KERNEL_ABI_TRACEPOINT:
+               desc_name = desc->event_name;
                switch (enabler->format_type) {
                case LTTNG_ENABLER_FORMAT_STAR_GLOB:
                        return lttng_match_enabler_star_glob(desc_name, enabler_name);
@@ -1904,8 +1843,8 @@ int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
                }
                break;
 
-       case LTTNG_KERNEL_SYSCALL:
-               desc_name = desc->name;
+       case LTTNG_KERNEL_ABI_SYSCALL:
+               desc_name = desc->event_name;
                if (!strncmp(desc_name, "compat_", strlen("compat_"))) {
                        desc_name += strlen("compat_");
                        compat = true;
@@ -1922,13 +1861,13 @@ int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
                        return -EINVAL;
                }
                switch (enabler->event_param.u.syscall.entryexit) {
-               case LTTNG_KERNEL_SYSCALL_ENTRYEXIT:
+               case LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT:
                        break;
-               case LTTNG_KERNEL_SYSCALL_ENTRY:
+               case LTTNG_KERNEL_ABI_SYSCALL_ENTRY:
                        if (!entry)
                                return 0;
                        break;
-               case LTTNG_KERNEL_SYSCALL_EXIT:
+               case LTTNG_KERNEL_ABI_SYSCALL_EXIT:
                        if (entry)
                                return 0;
                        break;
@@ -1936,13 +1875,13 @@ int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
                        return -EINVAL;
                }
                switch (enabler->event_param.u.syscall.abi) {
-               case LTTNG_KERNEL_SYSCALL_ABI_ALL:
+               case LTTNG_KERNEL_ABI_SYSCALL_ABI_ALL:
                        break;
-               case LTTNG_KERNEL_SYSCALL_ABI_NATIVE:
+               case LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE:
                        if (compat)
                                return 0;
                        break;
-               case LTTNG_KERNEL_SYSCALL_ABI_COMPAT:
+               case LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT:
                        if (!compat)
                                return 0;
                        break;
@@ -1950,7 +1889,7 @@ int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
                        return -EINVAL;
                }
                switch (enabler->event_param.u.syscall.match) {
-               case LTTNG_KERNEL_SYSCALL_MATCH_NAME:
+               case LTTNG_KERNEL_ABI_SYSCALL_MATCH_NAME:
                        switch (enabler->format_type) {
                        case LTTNG_ENABLER_FORMAT_STAR_GLOB:
                                return lttng_match_enabler_star_glob(desc_name, enabler_name);
@@ -1960,7 +1899,7 @@ int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
                                return -EINVAL;
                        }
                        break;
-               case LTTNG_KERNEL_SYSCALL_MATCH_NR:
+               case LTTNG_KERNEL_ABI_SYSCALL_MATCH_NR:
                        return -EINVAL; /* Not implemented. */
                default:
                        return -EINVAL;
@@ -1973,43 +1912,144 @@ int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
        }
 }
 
-static
-int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
-               struct lttng_event *event)
+bool lttng_desc_match_enabler(const struct lttng_kernel_event_desc *desc,
+               struct lttng_event_enabler_common *enabler)
 {
-       struct lttng_enabler *base_enabler = lttng_event_enabler_as_enabler(
-               event_enabler);
+       int ret;
 
-       if (base_enabler->event_param.instrumentation != event->instrumentation)
-               return 0;
-       if (lttng_desc_match_enabler(event->desc, base_enabler)
-                       && event->chan == event_enabler->chan)
-               return 1;
-       else
-               return 0;
+       ret = lttng_desc_match_enabler_check(desc, enabler);
+       if (ret < 0) {
+               WARN_ON_ONCE(1);
+               return false;
+       }
+       return ret;
 }
 
-static
-int lttng_event_notifier_enabler_match_event_notifier(struct lttng_event_notifier_enabler *event_notifier_enabler,
-               struct lttng_event_notifier *event_notifier)
+bool lttng_event_enabler_match_event(struct lttng_event_enabler_common *event_enabler,
+               struct lttng_kernel_event_common *event)
 {
-       struct lttng_enabler *base_enabler = lttng_event_notifier_enabler_as_enabler(
-               event_notifier_enabler);
+       if (event_enabler->event_param.instrumentation != event->priv->instrumentation)
+               return false;
 
-       if (base_enabler->event_param.instrumentation != event_notifier->instrumentation)
-               return 0;
-       if (lttng_desc_match_enabler(event_notifier->desc, base_enabler)
-                       && event_notifier->group == event_notifier_enabler->group
-                       && event_notifier->user_token == event_notifier_enabler->base.user_token)
-               return 1;
-       else
-               return 0;
+       switch (event_enabler->enabler_type) {
+       case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
+       {
+               struct lttng_event_recorder_enabler *event_recorder_enabler =
+                       container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
+               struct lttng_kernel_event_recorder *event_recorder =
+                       container_of(event, struct lttng_kernel_event_recorder, parent);
+
+               if (lttng_desc_match_enabler(event->priv->desc, event_enabler)
+                               && event_recorder->chan == event_recorder_enabler->chan)
+                       return true;
+               else
+                       return false;
+       }
+       case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
+       {
+               struct lttng_event_notifier_enabler *event_notifier_enabler =
+                       container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
+               struct lttng_kernel_event_notifier *event_notifier =
+                       container_of(event, struct lttng_kernel_event_notifier, parent);
+
+               if (lttng_desc_match_enabler(event->priv->desc, event_enabler)
+                               && event_notifier->priv->group == event_notifier_enabler->group
+                               && event->priv->user_token == event_enabler->user_token)
+                       return true;
+               else
+                       return false;
+       }
+       default:
+               WARN_ON_ONCE(1);
+               return false;
+       }
+}
+
+bool lttng_event_enabler_desc_match_event(struct lttng_event_enabler_common *event_enabler,
+               const struct lttng_kernel_event_desc *desc,
+               struct lttng_kernel_event_common *event)
+{
+       if (event_enabler->event_param.instrumentation != event->priv->instrumentation)
+               return false;
+
+       switch (event_enabler->enabler_type) {
+       case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
+       {
+               struct lttng_event_recorder_enabler *event_recorder_enabler =
+                       container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
+               struct lttng_kernel_event_recorder *event_recorder =
+                       container_of(event, struct lttng_kernel_event_recorder, parent);
+
+               if (event->priv->desc == desc && event_recorder->chan == event_recorder_enabler->chan)
+                       return true;
+               else
+                       return false;
+       }
+       case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
+       {
+               struct lttng_event_notifier_enabler *event_notifier_enabler =
+                       container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
+               struct lttng_kernel_event_notifier *event_notifier =
+                       container_of(event, struct lttng_kernel_event_notifier, parent);
+
+               if (event->priv->desc == desc
+                               && event_notifier->priv->group == event_notifier_enabler->group
+                               && event->priv->user_token == event_enabler->user_token)
+                       return true;
+               else
+                       return false;
+       }
+       default:
+               WARN_ON_ONCE(1);
+               return false;
+       }
+}
+
+bool lttng_event_enabler_event_name_match_event(struct lttng_event_enabler_common *event_enabler,
+               const char *event_name,
+               struct lttng_kernel_event_common *event)
+{
+       if (event_enabler->event_param.instrumentation != event->priv->instrumentation)
+               return false;
+
+       switch (event_enabler->enabler_type) {
+       case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
+       {
+               struct lttng_event_recorder_enabler *event_recorder_enabler =
+                       container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
+               struct lttng_kernel_event_recorder *event_recorder =
+                       container_of(event, struct lttng_kernel_event_recorder, parent);
+
+               if (!strncmp(event->priv->desc->event_name, event_name, LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1)
+                               && event_recorder->chan == event_recorder_enabler->chan)
+                       return true;
+               else
+                       return false;
+       }
+       case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
+       {
+               struct lttng_event_notifier_enabler *event_notifier_enabler =
+                       container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
+               struct lttng_kernel_event_notifier *event_notifier =
+                       container_of(event, struct lttng_kernel_event_notifier, parent);
+
+               if (!strncmp(event->priv->desc->event_name, event_name, LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1)
+                               && event_notifier->priv->group == event_notifier_enabler->group
+                               && event->priv->user_token == event_enabler->user_token)
+                       return true;
+               else
+                       return false;
+       }
+       default:
+               WARN_ON_ONCE(1);
+               return false;
+       }
 }
 
 static
 struct lttng_enabler_ref *lttng_enabler_ref(
                struct list_head *enablers_ref_list,
-               struct lttng_enabler *enabler)
+               struct lttng_event_enabler_common *enabler)
 {
        struct lttng_enabler_ref *enabler_ref;
 
@@ -2021,151 +2061,73 @@ struct lttng_enabler_ref *lttng_enabler_ref(
 }
 
 static
-void lttng_create_tracepoint_event_if_missing(struct lttng_event_enabler *event_enabler)
+void lttng_event_enabler_create_tracepoint_events_if_missing(struct lttng_event_enabler_common *event_enabler)
 {
-       struct lttng_session *session = event_enabler->chan->session;
-       struct lttng_probe_desc *probe_desc;
-       const struct lttng_event_desc *desc;
-       int i;
+       struct lttng_event_ht *events_ht = lttng_get_event_ht_from_enabler(event_enabler);
+       struct lttng_kernel_probe_desc *probe_desc;
+       const struct lttng_kernel_event_desc *desc;
        struct list_head *probe_list;
-
-       probe_list = lttng_get_probe_list_head();
-       /*
-        * For each probe event, if we find that a probe event matches
-        * our enabler, create an associated lttng_event if not
-        * already present.
-        */
-       list_for_each_entry(probe_desc, probe_list, head) {
-               for (i = 0; i < probe_desc->nr_events; i++) {
-                       int found = 0;
-                       struct hlist_head *head;
-                       struct lttng_event *event;
-
-                       desc = probe_desc->event_desc[i];
-                       if (!lttng_desc_match_enabler(desc,
-                                       lttng_event_enabler_as_enabler(event_enabler)))
-                               continue;
-
-                       /*
-                        * Check if already created.
-                        */
-                       head = utils_borrow_hash_table_bucket(
-                               session->events_ht.table, LTTNG_EVENT_HT_SIZE,
-                               desc->name);
-                       lttng_hlist_for_each_entry(event, head, hlist) {
-                               if (event->desc == desc
-                                               && event->chan == event_enabler->chan)
-                                       found = 1;
-                       }
-                       if (found)
-                               continue;
-
-                       /*
-                        * We need to create an event for this
-                        * event probe.
-                        */
-                       event = _lttng_event_create(event_enabler->chan,
-                                       NULL, NULL, desc,
-                                       LTTNG_KERNEL_TRACEPOINT);
-                       if (!event) {
-                               printk(KERN_INFO "LTTng: Unable to create event %s\n",
-                                       probe_desc->event_desc[i]->name);
-                       }
-               }
-       }
-}
-
-static
-void lttng_create_tracepoint_event_notifier_if_missing(struct lttng_event_notifier_enabler *event_notifier_enabler)
-{
-       struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
-       struct lttng_probe_desc *probe_desc;
-       const struct lttng_event_desc *desc;
        int i;
-       struct list_head *probe_list;
 
        probe_list = lttng_get_probe_list_head();
        /*
         * For each probe event, if we find that a probe event matches
-        * our enabler, create an associated lttng_event_notifier if not
+        * our enabler, create an associated lttng_event if not
         * already present.
         */
        list_for_each_entry(probe_desc, probe_list, head) {
                for (i = 0; i < probe_desc->nr_events; i++) {
-                       int found = 0;
+                       bool found = false;
                        struct hlist_head *head;
-                       struct lttng_event_notifier *event_notifier;
+                       struct lttng_kernel_event_common *event;
+                       struct lttng_kernel_event_common_private *event_priv;
 
                        desc = probe_desc->event_desc[i];
-                       if (!lttng_desc_match_enabler(desc,
-                                       lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
+                       if (!lttng_desc_match_enabler(desc, event_enabler))
                                continue;
 
                        /*
                         * Check if already created.
                         */
-                       head = utils_borrow_hash_table_bucket(
-                               event_notifier_group->event_notifiers_ht.table,
-                               LTTNG_EVENT_NOTIFIER_HT_SIZE, desc->name);
-                       lttng_hlist_for_each_entry(event_notifier, head, hlist) {
-                               if (event_notifier->desc == desc
-                                               && event_notifier->user_token == event_notifier_enabler->base.user_token)
-                                       found = 1;
-                       }
-                       if (found)
-                               continue;
-
-                       /*
-                        * We need to create a event_notifier for this event probe.
-                        */
-                       event_notifier = _lttng_event_notifier_create(desc,
-                               event_notifier_enabler->base.user_token,
-                               event_notifier_enabler->error_counter_index,
-                               event_notifier_group, NULL, NULL,
-                               LTTNG_KERNEL_TRACEPOINT);
-                       if (IS_ERR(event_notifier)) {
-                               printk(KERN_INFO "Unable to create event_notifier %s\n",
-                                       probe_desc->event_desc[i]->name);
-                       }
-               }
-       }
-}
-
-static
-void lttng_create_syscall_event_if_missing(struct lttng_event_enabler *event_enabler)
-{
-       int ret;
-
-       ret = lttng_syscalls_register_event(event_enabler, NULL);
-       WARN_ON_ONCE(ret);
-}
-
-static
-void lttng_create_syscall_event_notifier_if_missing(struct lttng_event_notifier_enabler *event_notifier_enabler)
-{
-       int ret;
+                       head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, desc->event_name);
+                       lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
+                               if (lttng_event_enabler_desc_match_event(event_enabler, desc, event_priv->pub)) {
+                                       found = true;
+                                       break;
+                               }
+                       }
+                       if (found)
+                               continue;
 
-       ret = lttng_syscalls_register_event_notifier(event_notifier_enabler, NULL);
-       WARN_ON_ONCE(ret);
-       ret = lttng_syscals_create_matching_event_notifiers(event_notifier_enabler, NULL);
-       WARN_ON_ONCE(ret);
+                       /*
+                        * We need to create an event for this event probe.
+                        */
+                       event = _lttng_kernel_event_create(event_enabler, desc);
+                       if (IS_ERR(event)) {
+                               printk(KERN_INFO "LTTng: Unable to create event %s\n",
+                                       probe_desc->event_desc[i]->event_name);
+                       }
+               }
+       }
 }
 
 /*
- * Create struct lttng_event if it is missing and present in the list of
- * tracepoint probes.
+ * Create event if it is missing and present in the list of tracepoint probes.
  * Should be called with sessions mutex held.
  */
 static
-void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
+void lttng_event_enabler_create_events_if_missing(struct lttng_event_enabler_common *event_enabler)
 {
-       switch (event_enabler->base.event_param.instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               lttng_create_tracepoint_event_if_missing(event_enabler);
+       int ret;
+
+       switch (event_enabler->event_param.instrumentation) {
+       case LTTNG_KERNEL_ABI_TRACEPOINT:
+               lttng_event_enabler_create_tracepoint_events_if_missing(event_enabler);
                break;
 
-       case LTTNG_KERNEL_SYSCALL:
-               lttng_create_syscall_event_if_missing(event_enabler);
+       case LTTNG_KERNEL_ABI_SYSCALL:
+               ret = lttng_event_enabler_create_syscall_events_if_missing(event_enabler);
+               WARN_ON_ONCE(ret);
                break;
 
        default:
@@ -2174,132 +2136,66 @@ void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
        }
 }
 
-/*
- * Create events associated with an event_enabler (if not already present),
- * and add backward reference from the event to the enabler.
- * Should be called with sessions mutex held.
- */
 static
-int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
+void lttng_event_enabler_init_event_filter(struct lttng_event_enabler_common *event_enabler,
+               struct lttng_kernel_event_common *event)
 {
-       struct lttng_channel *chan = event_enabler->chan;
-       struct lttng_session *session = event_enabler->chan->session;
-       struct lttng_enabler *base_enabler = lttng_event_enabler_as_enabler(event_enabler);
-       struct lttng_event *event;
-
-       if (base_enabler->event_param.instrumentation == LTTNG_KERNEL_SYSCALL &&
-                       base_enabler->event_param.u.syscall.abi == LTTNG_KERNEL_SYSCALL_ABI_ALL &&
-                       base_enabler->event_param.u.syscall.match == LTTNG_KERNEL_SYSCALL_MATCH_NAME &&
-                       !strcmp(base_enabler->event_param.name, "*")) {
-               int enabled = base_enabler->enabled;
-               enum lttng_kernel_syscall_entryexit entryexit = base_enabler->event_param.u.syscall.entryexit;
-
-               if (entryexit == LTTNG_KERNEL_SYSCALL_ENTRY || entryexit == LTTNG_KERNEL_SYSCALL_ENTRYEXIT)
-                       WRITE_ONCE(chan->syscall_all_entry, enabled);
-
-               if (entryexit == LTTNG_KERNEL_SYSCALL_EXIT || entryexit == LTTNG_KERNEL_SYSCALL_ENTRYEXIT)
-                       WRITE_ONCE(chan->syscall_all_exit, enabled);
-       }
-
-       /* First ensure that probe events are created for this enabler. */
-       lttng_create_event_if_missing(event_enabler);
-
-       /* For each event matching event_enabler in session event list. */
-       list_for_each_entry(event, &session->events, list) {
-               struct lttng_enabler_ref *enabler_ref;
-
-               if (!lttng_event_enabler_match_event(event_enabler, event))
-                       continue;
-               enabler_ref = lttng_enabler_ref(&event->enablers_ref_head,
-                       lttng_event_enabler_as_enabler(event_enabler));
-               if (!enabler_ref) {
-                       /*
-                        * If no backward ref, create it.
-                        * Add backward ref from event to event_enabler.
-                        */
-                       enabler_ref = kzalloc(sizeof(*enabler_ref), GFP_KERNEL);
-                       if (!enabler_ref)
-                               return -ENOMEM;
-                       enabler_ref->ref = lttng_event_enabler_as_enabler(event_enabler);
-                       list_add(&enabler_ref->node,
-                               &event->enablers_ref_head);
-               }
-
-               /*
-                * Link filter bytecodes if not linked yet.
-                */
-               lttng_enabler_link_bytecode(event->desc,
-                       lttng_static_ctx,
-                       &event->filter_bytecode_runtime_head,
-                       &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
-
-               /* TODO: merge event context. */
-       }
-       return 0;
+       /* Link filter bytecodes if not linked yet. */
+       lttng_enabler_link_bytecode(event->priv->desc, lttng_static_ctx,
+               &event->priv->filter_bytecode_runtime_head, &event_enabler->filter_bytecode_head);
 }
 
-/*
- * Create struct lttng_event_notifier if it is missing and present in the list of
- * tracepoint probes.
- * Should be called with sessions mutex held.
- */
 static
-void lttng_create_event_notifier_if_missing(struct lttng_event_notifier_enabler *event_notifier_enabler)
+void lttng_event_enabler_init_event_capture(struct lttng_event_enabler_common *event_enabler,
+               struct lttng_kernel_event_common *event)
 {
-       switch (event_notifier_enabler->base.event_param.instrumentation) {
-       case LTTNG_KERNEL_TRACEPOINT:
-               lttng_create_tracepoint_event_notifier_if_missing(event_notifier_enabler);
+       switch (event_enabler->enabler_type) {
+       case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
                break;
+       case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
+       {
+               struct lttng_event_notifier_enabler *event_notifier_enabler =
+                       container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
+               struct lttng_kernel_event_notifier *event_notifier =
+                       container_of(event, struct lttng_kernel_event_notifier, parent);
 
-       case LTTNG_KERNEL_SYSCALL:
-               lttng_create_syscall_event_notifier_if_missing(event_notifier_enabler);
+               /* Link capture bytecodes if not linked yet. */
+               lttng_enabler_link_bytecode(event->priv->desc,
+                       lttng_static_ctx, &event_notifier->priv->capture_bytecode_runtime_head,
+                       &event_notifier_enabler->capture_bytecode_head);
+               event_notifier->priv->num_captures = event_notifier_enabler->num_captures;
                break;
-
+       }
        default:
                WARN_ON_ONCE(1);
-               break;
        }
 }
 
 /*
- * Create event_notifiers associated with a event_notifier enabler (if not already present).
+ * Create events associated with an event_enabler (if not already present),
+ * and add backward reference from the event to the enabler.
+ * Should be called with sessions mutex held.
  */
 static
-int lttng_event_notifier_enabler_ref_event_notifiers(
-               struct lttng_event_notifier_enabler *event_notifier_enabler)
+int lttng_event_enabler_ref_events(struct lttng_event_enabler_common *event_enabler)
 {
-       struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
-       struct lttng_enabler *base_enabler = lttng_event_notifier_enabler_as_enabler(event_notifier_enabler);
-       struct lttng_event_notifier *event_notifier;
-
-       if (base_enabler->event_param.instrumentation == LTTNG_KERNEL_SYSCALL &&
-                       base_enabler->event_param.u.syscall.abi == LTTNG_KERNEL_SYSCALL_ABI_ALL &&
-                       base_enabler->event_param.u.syscall.match == LTTNG_KERNEL_SYSCALL_MATCH_NAME &&
-                       !strcmp(base_enabler->event_param.name, "*")) {
-
-               int enabled = base_enabler->enabled;
-               enum lttng_kernel_syscall_entryexit entryexit = base_enabler->event_param.u.syscall.entryexit;
-
-               if (entryexit == LTTNG_KERNEL_SYSCALL_ENTRY || entryexit == LTTNG_KERNEL_SYSCALL_ENTRYEXIT)
-                       WRITE_ONCE(event_notifier_group->syscall_all_entry, enabled);
+       struct list_head *event_list_head = lttng_get_event_list_head_from_enabler(event_enabler);
+       struct lttng_kernel_event_common_private *event_priv;
 
-               if (entryexit == LTTNG_KERNEL_SYSCALL_EXIT || entryexit == LTTNG_KERNEL_SYSCALL_ENTRYEXIT)
-                       WRITE_ONCE(event_notifier_group->syscall_all_exit, enabled);
+       lttng_syscall_table_set_wildcard_all(event_enabler);
 
-       }
-
-       /* First ensure that probe event_notifiers are created for this enabler. */
-       lttng_create_event_notifier_if_missing(event_notifier_enabler);
+       /* First ensure that probe events are created for this enabler. */
+       lttng_event_enabler_create_events_if_missing(event_enabler);
 
-       /* Link the created event_notifier with its associated enabler. */
-       list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, list) {
+       /* Link the created event with its associated enabler. */
+       list_for_each_entry(event_priv, event_list_head, node) {
+               struct lttng_kernel_event_common *event = event_priv->pub;
                struct lttng_enabler_ref *enabler_ref;
 
-               if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier))
+               if (!lttng_event_enabler_match_event(event_enabler, event))
                        continue;
 
-               enabler_ref = lttng_enabler_ref(&event_notifier->enablers_ref_head,
-                       lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
+               enabler_ref = lttng_enabler_ref(&event_priv->enablers_ref_head, event_enabler);
                if (!enabler_ref) {
                        /*
                         * If no backward ref, create it.
@@ -2309,25 +2205,12 @@ int lttng_event_notifier_enabler_ref_event_notifiers(
                        if (!enabler_ref)
                                return -ENOMEM;
 
-                       enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
-                               event_notifier_enabler);
-                       list_add(&enabler_ref->node,
-                               &event_notifier->enablers_ref_head);
+                       enabler_ref->ref = event_enabler;
+                       list_add(&enabler_ref->node, &event_priv->enablers_ref_head);
                }
 
-               /*
-                * Link filter bytecodes if not linked yet.
-                */
-               lttng_enabler_link_bytecode(event_notifier->desc,
-                       lttng_static_ctx, &event_notifier->filter_bytecode_runtime_head,
-                       &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
-
-               /* Link capture bytecodes if not linked yet. */
-               lttng_enabler_link_bytecode(event_notifier->desc,
-                       lttng_static_ctx, &event_notifier->capture_bytecode_runtime_head,
-                       &event_notifier_enabler->capture_bytecode_head);
-
-               event_notifier->num_captures = event_notifier_enabler->num_captures;
+               lttng_event_enabler_init_event_filter(event_enabler, event);
+               lttng_event_enabler_init_event_capture(event_enabler, event);
        }
        return 0;
 }
@@ -2339,21 +2222,20 @@ int lttng_event_notifier_enabler_ref_event_notifiers(
  */
 int lttng_fix_pending_events(void)
 {
-       struct lttng_session *session;
+       struct lttng_kernel_session_private *session_priv;
 
-       list_for_each_entry(session, &sessions, list)
-               lttng_session_lazy_sync_event_enablers(session);
+       list_for_each_entry(session_priv, &sessions, list)
+               lttng_session_lazy_sync_event_enablers(session_priv->pub);
        return 0;
 }
 
 static bool lttng_event_notifier_group_has_active_event_notifiers(
                struct lttng_event_notifier_group *event_notifier_group)
 {
-       struct lttng_event_notifier_enabler *event_notifier_enabler;
+       struct lttng_event_enabler_common *event_enabler;
 
-       list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head,
-                       node) {
-               if (event_notifier_enabler->base.enabled)
+       list_for_each_entry(event_enabler, &event_notifier_group->enablers_head, node) {
+               if (event_enabler->enabled)
                        return true;
        }
        return false;
@@ -2379,54 +2261,60 @@ int lttng_fix_pending_event_notifiers(void)
        return 0;
 }
 
-struct lttng_event_enabler *lttng_event_enabler_create(
+struct lttng_event_recorder_enabler *lttng_event_recorder_enabler_create(
                enum lttng_enabler_format_type format_type,
-               struct lttng_kernel_event *event_param,
-               struct lttng_channel *chan)
+               struct lttng_kernel_abi_event *event_param,
+               struct lttng_kernel_channel_buffer *chan)
 {
-       struct lttng_event_enabler *event_enabler;
+       struct lttng_event_recorder_enabler *event_enabler;
 
        event_enabler = kzalloc(sizeof(*event_enabler), GFP_KERNEL);
        if (!event_enabler)
                return NULL;
-       event_enabler->base.format_type = format_type;
-       INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
-       memcpy(&event_enabler->base.event_param, event_param,
-               sizeof(event_enabler->base.event_param));
+       event_enabler->parent.enabler_type = LTTNG_EVENT_ENABLER_TYPE_RECORDER;
+       event_enabler->parent.format_type = format_type;
+       INIT_LIST_HEAD(&event_enabler->parent.filter_bytecode_head);
+       memcpy(&event_enabler->parent.event_param, event_param,
+               sizeof(event_enabler->parent.event_param));
        event_enabler->chan = chan;
        /* ctx left NULL */
-       event_enabler->base.enabled = 0;
-       event_enabler->base.evtype = LTTNG_TYPE_ENABLER;
+       event_enabler->parent.enabled = 0;
+       return event_enabler;
+}
+
+void lttng_event_enabler_session_add(struct lttng_kernel_session *session,
+               struct lttng_event_recorder_enabler *event_enabler)
+{
        mutex_lock(&sessions_mutex);
-       list_add(&event_enabler->node, &event_enabler->chan->session->enablers_head);
-       lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
+       list_add(&event_enabler->parent.node, &session->priv->enablers_head);
+       event_enabler->parent.published = true;
+       lttng_session_lazy_sync_event_enablers(session);
        mutex_unlock(&sessions_mutex);
-       return event_enabler;
 }
 
-int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
+int lttng_event_enabler_enable(struct lttng_event_enabler_common *event_enabler)
 {
        mutex_lock(&sessions_mutex);
-       lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
-       lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
+       event_enabler->enabled = 1;
+       lttng_event_enabler_sync(event_enabler);
        mutex_unlock(&sessions_mutex);
        return 0;
 }
 
-int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
+int lttng_event_enabler_disable(struct lttng_event_enabler_common *event_enabler)
 {
        mutex_lock(&sessions_mutex);
-       lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
-       lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
+       event_enabler->enabled = 0;
+       lttng_event_enabler_sync(event_enabler);
        mutex_unlock(&sessions_mutex);
        return 0;
 }
 
 static
-int lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
-               struct lttng_kernel_filter_bytecode __user *bytecode)
+int lttng_enabler_attach_filter_bytecode(struct lttng_event_enabler_common *enabler,
+               struct lttng_kernel_abi_filter_bytecode __user *bytecode)
 {
-       struct lttng_bytecode_node *bytecode_node;
+       struct lttng_kernel_bytecode_node *bytecode_node;
        uint32_t bytecode_len;
        int ret;
 
@@ -2442,7 +2330,7 @@ int lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
        if (ret)
                goto error_free;
 
-       bytecode_node->type = LTTNG_BYTECODE_NODE_TYPE_FILTER;
+       bytecode_node->type = LTTNG_KERNEL_BYTECODE_TYPE_FILTER;
        bytecode_node->enabler = enabler;
        /* Enforce length based on allocated size */
        bytecode_node->bc.len = bytecode_len;
@@ -2455,44 +2343,36 @@ error_free:
        return ret;
 }
 
-int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
-               struct lttng_kernel_filter_bytecode __user *bytecode)
+int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler_common *event_enabler,
+               struct lttng_kernel_abi_filter_bytecode __user *bytecode)
 {
        int ret;
-       ret = lttng_enabler_attach_filter_bytecode(
-               lttng_event_enabler_as_enabler(event_enabler), bytecode);
+       ret = lttng_enabler_attach_filter_bytecode(event_enabler, bytecode);
        if (ret)
                goto error;
-
-       lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
+       lttng_event_enabler_sync(event_enabler);
        return 0;
 
 error:
        return ret;
 }
 
-int lttng_event_add_callsite(struct lttng_event *event,
-               struct lttng_kernel_event_callsite __user *callsite)
+int lttng_event_add_callsite(struct lttng_kernel_event_common *event,
+               struct lttng_kernel_abi_event_callsite __user *callsite)
 {
 
-       switch (event->instrumentation) {
-       case LTTNG_KERNEL_UPROBE:
+       switch (event->priv->instrumentation) {
+       case LTTNG_KERNEL_ABI_UPROBE:
                return lttng_uprobes_event_add_callsite(event, callsite);
        default:
                return -EINVAL;
        }
 }
 
-int lttng_event_enabler_attach_context(struct lttng_event_enabler *event_enabler,
-               struct lttng_kernel_context *context_param)
-{
-       return -ENOSYS;
-}
-
 static
-void lttng_enabler_destroy(struct lttng_enabler *enabler)
+void lttng_enabler_destroy(struct lttng_event_enabler_common *enabler)
 {
-       struct lttng_bytecode_node *filter_node, *tmp_filter_node;
+       struct lttng_kernel_bytecode_node *filter_node, *tmp_filter_node;
 
        /* Destroy filter bytecode */
        list_for_each_entry_safe(filter_node, tmp_filter_node,
@@ -2501,22 +2381,38 @@ void lttng_enabler_destroy(struct lttng_enabler *enabler)
        }
 }
 
-static
-void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
+void lttng_event_enabler_destroy(struct lttng_event_enabler_common *event_enabler)
 {
-       lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
+       lttng_enabler_destroy(event_enabler);
+       if (event_enabler->published)
+               list_del(&event_enabler->node);
+
+       switch (event_enabler->enabler_type) {
+       case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
+       {
+               struct lttng_event_recorder_enabler *event_recorder_enabler =
+                       container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
 
-       /* Destroy contexts */
-       lttng_destroy_context(event_enabler->ctx);
+               kfree(event_recorder_enabler);
+               break;
+       }
+       case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
+       {
+               struct lttng_event_notifier_enabler *event_notifier_enabler =
+                       container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
 
-       list_del(&event_enabler->node);
-       kfree(event_enabler);
+               kfree(event_notifier_enabler);
+               break;
+       }
+       default:
+               WARN_ON_ONCE(1);
+       }
 }
 
 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
-               struct lttng_event_notifier_group *event_notifier_group,
                enum lttng_enabler_format_type format_type,
-               struct lttng_kernel_event_notifier *event_notifier_param)
+               struct lttng_kernel_abi_event_notifier *event_notifier_param,
+               struct lttng_event_notifier_group *event_notifier_group)
 {
        struct lttng_event_notifier_enabler *event_notifier_enabler;
 
@@ -2524,28 +2420,31 @@ struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
        if (!event_notifier_enabler)
                return NULL;
 
-       event_notifier_enabler->base.format_type = format_type;
-       INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
+       event_notifier_enabler->parent.enabler_type = LTTNG_EVENT_ENABLER_TYPE_NOTIFIER;
+       event_notifier_enabler->parent.format_type = format_type;
+       INIT_LIST_HEAD(&event_notifier_enabler->parent.filter_bytecode_head);
        INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
 
        event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
        event_notifier_enabler->num_captures = 0;
 
-       memcpy(&event_notifier_enabler->base.event_param, &event_notifier_param->event,
-               sizeof(event_notifier_enabler->base.event_param));
-       event_notifier_enabler->base.evtype = LTTNG_TYPE_ENABLER;
+       memcpy(&event_notifier_enabler->parent.event_param, &event_notifier_param->event,
+               sizeof(event_notifier_enabler->parent.event_param));
 
-       event_notifier_enabler->base.enabled = 0;
-       event_notifier_enabler->base.user_token = event_notifier_param->event.token;
+       event_notifier_enabler->parent.enabled = 0;
+       event_notifier_enabler->parent.user_token = event_notifier_param->event.token;
        event_notifier_enabler->group = event_notifier_group;
+       return event_notifier_enabler;
+}
 
+void lttng_event_notifier_enabler_group_add(struct lttng_event_notifier_group *event_notifier_group,
+               struct lttng_event_notifier_enabler *event_notifier_enabler)
+{
        mutex_lock(&sessions_mutex);
-       list_add(&event_notifier_enabler->node, &event_notifier_enabler->group->enablers_head);
+       list_add(&event_notifier_enabler->parent.node, &event_notifier_enabler->group->enablers_head);
+       event_notifier_enabler->parent.published = true;
        lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
-
        mutex_unlock(&sessions_mutex);
-
-       return event_notifier_enabler;
 }
 
 int lttng_event_notifier_enabler_enable(
@@ -2568,31 +2467,12 @@ int lttng_event_notifier_enabler_disable(
        return 0;
 }
 
-int lttng_event_notifier_enabler_attach_filter_bytecode(
-               struct lttng_event_notifier_enabler *event_notifier_enabler,
-               struct lttng_kernel_filter_bytecode __user *bytecode)
-{
-       int ret;
-
-       ret = lttng_enabler_attach_filter_bytecode(
-               lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
-               bytecode);
-       if (ret)
-               goto error;
-
-       lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
-       return 0;
-
-error:
-       return ret;
-}
-
 int lttng_event_notifier_enabler_attach_capture_bytecode(
                struct lttng_event_notifier_enabler *event_notifier_enabler,
-               struct lttng_kernel_capture_bytecode __user *bytecode)
+               struct lttng_kernel_abi_capture_bytecode __user *bytecode)
 {
-       struct lttng_bytecode_node *bytecode_node;
-       struct lttng_enabler *enabler =
+       struct lttng_kernel_bytecode_node *bytecode_node;
+       struct lttng_event_enabler_common *enabler =
                        lttng_event_notifier_enabler_as_enabler(event_notifier_enabler);
        uint32_t bytecode_len;
        int ret;
@@ -2611,7 +2491,7 @@ int lttng_event_notifier_enabler_attach_capture_bytecode(
        if (ret)
                goto error_free;
 
-       bytecode_node->type = LTTNG_BYTECODE_NODE_TYPE_CAPTURE;
+       bytecode_node->type = LTTNG_KERNEL_BYTECODE_TYPE_CAPTURE;
        bytecode_node->enabler = enabler;
 
        /* Enforce length based on allocated size */
@@ -2629,117 +2509,169 @@ end:
        return ret;
 }
 
-int lttng_event_notifier_add_callsite(struct lttng_event_notifier *event_notifier,
-               struct lttng_kernel_event_callsite __user *callsite)
+static
+void lttng_event_sync_filter_state(struct lttng_kernel_event_common *event)
 {
+       int has_enablers_without_filter_bytecode = 0, nr_filters = 0;
+       struct lttng_kernel_bytecode_runtime *runtime;
+       struct lttng_enabler_ref *enabler_ref;
 
-       switch (event_notifier->instrumentation) {
-       case LTTNG_KERNEL_UPROBE:
-               return lttng_uprobes_event_notifier_add_callsite(event_notifier,
-                               callsite);
-       default:
-               return -EINVAL;
+       /* Check if has enablers without bytecode enabled */
+       list_for_each_entry(enabler_ref, &event->priv->enablers_ref_head, node) {
+               if (enabler_ref->ref->enabled
+                               && list_empty(&enabler_ref->ref->filter_bytecode_head)) {
+                       has_enablers_without_filter_bytecode = 1;
+                       break;
+               }
+       }
+       event->priv->has_enablers_without_filter_bytecode = has_enablers_without_filter_bytecode;
+
+       /* Enable filters */
+       list_for_each_entry(runtime, &event->priv->filter_bytecode_runtime_head, node) {
+               lttng_bytecode_sync_state(runtime);
+               nr_filters++;
        }
+       WRITE_ONCE(event->eval_filter, !(has_enablers_without_filter_bytecode || !nr_filters));
 }
 
-int lttng_event_notifier_enabler_attach_context(
-               struct lttng_event_notifier_enabler *event_notifier_enabler,
-               struct lttng_kernel_context *context_param)
+static
+void lttng_event_sync_capture_state(struct lttng_kernel_event_common *event)
 {
-       return -ENOSYS;
+       switch (event->type) {
+       case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+               break;
+       case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
+       {
+               struct lttng_kernel_event_notifier *event_notifier =
+                       container_of(event, struct lttng_kernel_event_notifier, parent);
+               struct lttng_kernel_bytecode_runtime *runtime;
+               int nr_captures = 0;
+
+               /* Enable captures */
+               list_for_each_entry(runtime, &event_notifier->priv->capture_bytecode_runtime_head, node) {
+                       lttng_bytecode_sync_state(runtime);
+                       nr_captures++;
+               }
+               WRITE_ONCE(event_notifier->eval_capture, !!nr_captures);
+               break;
+       }
+       default:
+               WARN_ON_ONCE(1);
+       }
 }
 
 static
-void lttng_event_notifier_enabler_destroy(
-               struct lttng_event_notifier_enabler *event_notifier_enabler)
+bool lttng_get_event_enabled_state(struct lttng_kernel_event_common *event)
 {
-       if (!event_notifier_enabler) {
-               return;
+       struct lttng_enabler_ref *enabler_ref;
+       bool enabled = false;
+
+       switch (event->priv->instrumentation) {
+       case LTTNG_KERNEL_ABI_TRACEPOINT:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_SYSCALL:
+               /* Enable events */
+               list_for_each_entry(enabler_ref, &event->priv->enablers_ref_head, node) {
+                       if (enabler_ref->ref->enabled) {
+                               enabled = true;
+                               break;
+                       }
+               }
+               break;
+       default:
+               WARN_ON_ONCE(1);
+               return false;
+       }
+
+       switch (event->type) {
+       case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+       {
+               struct lttng_kernel_event_recorder *event_recorder =
+                       container_of(event, struct lttng_kernel_event_recorder, parent);
+
+               /*
+                * Enabled state is based on union of enablers, with
+                * intersection of session and channel transient enable
+                * states.
+                */
+               return enabled && event_recorder->chan->parent.session->priv->tstate && event_recorder->chan->priv->parent.tstate;
+       }
+       case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
+               return enabled;
+       default:
+               WARN_ON_ONCE(1);
+               return false;
        }
+}
 
-       list_del(&event_notifier_enabler->node);
+static
+bool lttng_event_is_lazy_sync(struct lttng_kernel_event_common *event)
+{
+       switch (event->priv->instrumentation) {
+       case LTTNG_KERNEL_ABI_TRACEPOINT:
+               lttng_fallthrough;
+       case LTTNG_KERNEL_ABI_SYSCALL:
+               return true;
 
-       lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
-       kfree(event_notifier_enabler);
+       default:
+               /* Not handled with lazy sync. */
+               return false;
+       }
 }
 
 /*
- * lttng_session_sync_event_enablers should be called just before starting a
- * session.
  * Should be called with sessions mutex held.
  */
 static
-void lttng_session_sync_event_enablers(struct lttng_session *session)
+void lttng_sync_event_list(struct list_head *event_enabler_list,
+               struct list_head *event_list)
 {
-       struct lttng_event_enabler *event_enabler;
-       struct lttng_event *event;
+       struct lttng_kernel_event_common_private *event_priv;
+       struct lttng_event_enabler_common *event_enabler;
 
-       list_for_each_entry(event_enabler, &session->enablers_head, node)
+       list_for_each_entry(event_enabler, event_enabler_list, node)
                lttng_event_enabler_ref_events(event_enabler);
+
        /*
         * For each event, if at least one of its enablers is enabled,
         * and its channel and session transient states are enabled, we
         * enable the event, else we disable it.
         */
-       list_for_each_entry(event, &session->events, list) {
-               struct lttng_enabler_ref *enabler_ref;
-               struct lttng_bytecode_runtime *runtime;
-               int enabled = 0, has_enablers_without_bytecode = 0;
-
-               switch (event->instrumentation) {
-               case LTTNG_KERNEL_TRACEPOINT:   /* Fall-through */
-               case LTTNG_KERNEL_SYSCALL:
-                       /* Enable events */
-                       list_for_each_entry(enabler_ref,
-                                       &event->enablers_ref_head, node) {
-                               if (enabler_ref->ref->enabled) {
-                                       enabled = 1;
-                                       break;
-                               }
-                       }
-                       break;
+       list_for_each_entry(event_priv, event_list, node) {
+               struct lttng_kernel_event_common *event = event_priv->pub;
+               bool enabled;
 
-               default:
-                       /* Not handled with lazy sync. */
+               if (!lttng_event_is_lazy_sync(event))
                        continue;
-               }
-               /*
-                * Enabled state is based on union of enablers, with
-                * intesection of session and channel transient enable
-                * states.
-                */
-               enabled = enabled && session->tstate && event->chan->tstate;
 
+               enabled = lttng_get_event_enabled_state(event);
                WRITE_ONCE(event->enabled, enabled);
                /*
-                * Sync tracepoint registration with event enabled
-                * state.
+                * Sync tracepoint registration with event enabled state.
                 */
                if (enabled) {
-                       register_event(event);
+                       if (!event_priv->registered)
+                               register_event(event);
                } else {
-                       _lttng_event_unregister(event);
-               }
-
-               /* Check if has enablers without bytecode enabled */
-               list_for_each_entry(enabler_ref,
-                               &event->enablers_ref_head, node) {
-                       if (enabler_ref->ref->enabled
-                                       && list_empty(&enabler_ref->ref->filter_bytecode_head)) {
-                               has_enablers_without_bytecode = 1;
-                               break;
-                       }
+                       if (event_priv->registered)
+                               unregister_event(event);
                }
-               event->has_enablers_without_bytecode =
-                       has_enablers_without_bytecode;
 
-               /* Enable filters */
-               list_for_each_entry(runtime,
-                               &event->filter_bytecode_runtime_head, node)
-                       lttng_bytecode_filter_sync_state(runtime);
+               lttng_event_sync_filter_state(event);
+               lttng_event_sync_capture_state(event);
        }
 }
 
+/*
+ * lttng_session_sync_event_enablers should be called just before starting a
+ * session.
+ */
+static
+void lttng_session_sync_event_enablers(struct lttng_kernel_session *session)
+{
+       lttng_sync_event_list(&session->priv->enablers_head, &session->priv->events);
+}
+
 /*
  * Apply enablers to session events, adding events to session if need
  * be. It is required after each modification applied to an active
@@ -2748,7 +2680,7 @@ void lttng_session_sync_event_enablers(struct lttng_session *session)
  * Should be called with sessions mutex held.
  */
 static
-void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
+void lttng_session_lazy_sync_event_enablers(struct lttng_kernel_session *session)
 {
        /* We can skip if session is not active */
        if (!session->active)
@@ -2759,75 +2691,29 @@ void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
 static
 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
 {
-       struct lttng_event_notifier_enabler *event_notifier_enabler;
-       struct lttng_event_notifier *event_notifier;
-
-       list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
-               lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
-
-       /*
-        * For each event_notifier, if at least one of its enablers is enabled,
-        * we enable the event_notifier, else we disable it.
-        */
-       list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, list) {
-               struct lttng_enabler_ref *enabler_ref;
-               struct lttng_bytecode_runtime *runtime;
-               int enabled = 0, has_enablers_without_bytecode = 0;
-
-               switch (event_notifier->instrumentation) {
-               case LTTNG_KERNEL_TRACEPOINT:   /* Fall-through */
-               case LTTNG_KERNEL_SYSCALL:
-                       /* Enable event_notifiers */
-                       list_for_each_entry(enabler_ref,
-                                       &event_notifier->enablers_ref_head, node) {
-                               if (enabler_ref->ref->enabled) {
-                                       enabled = 1;
-                                       break;
-                               }
-                       }
-                       break;
-
-               default:
-                       /* Not handled with sync. */
-                       continue;
-               }
-
-               WRITE_ONCE(event_notifier->enabled, enabled);
-               /*
-                * Sync tracepoint registration with event_notifier enabled
-                * state.
-                */
-               if (enabled) {
-                       if (!event_notifier->registered)
-                               register_event_notifier(event_notifier);
-               } else {
-                       if (event_notifier->registered)
-                               _lttng_event_notifier_unregister(event_notifier);
-               }
-
-               /* Check if has enablers without bytecode enabled */
-               list_for_each_entry(enabler_ref,
-                               &event_notifier->enablers_ref_head, node) {
-                       if (enabler_ref->ref->enabled
-                                       && list_empty(&enabler_ref->ref->filter_bytecode_head)) {
-                               has_enablers_without_bytecode = 1;
-                               break;
-                       }
-               }
-               event_notifier->has_enablers_without_bytecode =
-                       has_enablers_without_bytecode;
-
-               /* Enable filters */
-               list_for_each_entry(runtime,
-                               &event_notifier->filter_bytecode_runtime_head, node)
-                       lttng_bytecode_filter_sync_state(runtime);
-
-               /* Enable captures */
-               list_for_each_entry(runtime,
-                               &event_notifier->capture_bytecode_runtime_head, node)
-                       lttng_bytecode_capture_sync_state(runtime);
+       lttng_sync_event_list(&event_notifier_group->enablers_head, &event_notifier_group->event_notifiers_head);
+}
 
-               WRITE_ONCE(event_notifier->eval_capture, !!event_notifier->num_captures);
+static
+void lttng_event_enabler_sync(struct lttng_event_enabler_common *event_enabler)
+{
+       switch (event_enabler->enabler_type) {
+       case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
+       {
+               struct lttng_event_recorder_enabler *event_recorder_enabler =
+                       container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
+               lttng_session_lazy_sync_event_enablers(event_recorder_enabler->chan->parent.session);
+               break;
+       }
+       case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
+       {
+               struct lttng_event_notifier_enabler *event_notifier_enabler =
+                       container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
+               lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
+               break;
+       }
+       default:
+               WARN_ON_ONCE(1);
        }
 }
 
@@ -2844,9 +2730,9 @@ void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group
  * was written and a negative value on error.
  */
 int lttng_metadata_output_channel(struct lttng_metadata_stream *stream,
-               struct channel *chan, bool *coherent)
+               struct lttng_kernel_ring_buffer_channel *chan, bool *coherent)
 {
-       struct lib_ring_buffer_ctx ctx;
+       struct lttng_kernel_ring_buffer_ctx ctx;
        int ret = 0;
        size_t len, reserve_len;
 
@@ -2873,14 +2759,14 @@ int lttng_metadata_output_channel(struct lttng_metadata_stream *stream,
        if (!len)
                goto end;
        reserve_len = min_t(size_t,
-                       stream->transport->ops.packet_avail_size(chan),
+                       stream->transport->ops.priv->packet_avail_size(chan),
                        len);
-       lib_ring_buffer_ctx_init(&ctx, chan, NULL, reserve_len,
-                       sizeof(char), -1);
+       lib_ring_buffer_ctx_init(&ctx, chan, reserve_len,
+                       sizeof(char), NULL);
        /*
         * If reservation failed, return an error to the caller.
         */
-       ret = stream->transport->ops.event_reserve(&ctx, 0);
+       ret = stream->transport->ops.event_reserve(&ctx);
        if (ret != 0) {
                printk(KERN_WARNING "LTTng: Metadata event reservation failed\n");
                stream->coherent = false;
@@ -2888,7 +2774,7 @@ int lttng_metadata_output_channel(struct lttng_metadata_stream *stream,
        }
        stream->transport->ops.event_write(&ctx,
                        stream->metadata_cache->data + stream->metadata_in,
-                       reserve_len);
+                       reserve_len, 1);
        stream->transport->ops.event_commit(&ctx);
        stream->metadata_in += reserve_len;
        if (reserve_len < len)
@@ -2905,22 +2791,22 @@ end:
 }
 
 static
-void lttng_metadata_begin(struct lttng_session *session)
+void lttng_metadata_begin(struct lttng_kernel_session *session)
 {
-       if (atomic_inc_return(&session->metadata_cache->producing) == 1)
-               mutex_lock(&session->metadata_cache->lock);
+       if (atomic_inc_return(&session->priv->metadata_cache->producing) == 1)
+               mutex_lock(&session->priv->metadata_cache->lock);
 }
 
 static
-void lttng_metadata_end(struct lttng_session *session)
+void lttng_metadata_end(struct lttng_kernel_session *session)
 {
-       WARN_ON_ONCE(!atomic_read(&session->metadata_cache->producing));
-       if (atomic_dec_return(&session->metadata_cache->producing) == 0) {
+       WARN_ON_ONCE(!atomic_read(&session->priv->metadata_cache->producing));
+       if (atomic_dec_return(&session->priv->metadata_cache->producing) == 0) {
                struct lttng_metadata_stream *stream;
 
-               list_for_each_entry(stream, &session->metadata_cache->metadata_stream, list)
+               list_for_each_entry(stream, &session->priv->metadata_cache->metadata_stream, list)
                        wake_up_interruptible(&stream->read_wait);
-               mutex_unlock(&session->metadata_cache->lock);
+               mutex_unlock(&session->priv->metadata_cache->lock);
        }
 }
 
@@ -2932,7 +2818,7 @@ void lttng_metadata_end(struct lttng_session *session)
  * The content of the printf is printed as a single atomic metadata
  * transaction.
  */
-int lttng_metadata_printf(struct lttng_session *session,
+int lttng_metadata_printf(struct lttng_kernel_session *session,
                          const char *fmt, ...)
 {
        char *str;
@@ -2948,32 +2834,32 @@ int lttng_metadata_printf(struct lttng_session *session,
                return -ENOMEM;
 
        len = strlen(str);
-       WARN_ON_ONCE(!atomic_read(&session->metadata_cache->producing));
-       if (session->metadata_cache->metadata_written + len >
-                       session->metadata_cache->cache_alloc) {
+       WARN_ON_ONCE(!atomic_read(&session->priv->metadata_cache->producing));
+       if (session->priv->metadata_cache->metadata_written + len >
+                       session->priv->metadata_cache->cache_alloc) {
                char *tmp_cache_realloc;
                unsigned int tmp_cache_alloc_size;
 
                tmp_cache_alloc_size = max_t(unsigned int,
-                               session->metadata_cache->cache_alloc + len,
-                               session->metadata_cache->cache_alloc << 1);
+                               session->priv->metadata_cache->cache_alloc + len,
+                               session->priv->metadata_cache->cache_alloc << 1);
                tmp_cache_realloc = vzalloc(tmp_cache_alloc_size);
                if (!tmp_cache_realloc)
                        goto err;
-               if (session->metadata_cache->data) {
+               if (session->priv->metadata_cache->data) {
                        memcpy(tmp_cache_realloc,
-                               session->metadata_cache->data,
-                               session->metadata_cache->cache_alloc);
-                       vfree(session->metadata_cache->data);
+                               session->priv->metadata_cache->data,
+                               session->priv->metadata_cache->cache_alloc);
+                       vfree(session->priv->metadata_cache->data);
                }
 
-               session->metadata_cache->cache_alloc = tmp_cache_alloc_size;
-               session->metadata_cache->data = tmp_cache_realloc;
+               session->priv->metadata_cache->cache_alloc = tmp_cache_alloc_size;
+               session->priv->metadata_cache->data = tmp_cache_realloc;
        }
-       memcpy(session->metadata_cache->data +
-                       session->metadata_cache->metadata_written,
+       memcpy(session->priv->metadata_cache->data +
+                       session->priv->metadata_cache->metadata_written,
                        str, len);
-       session->metadata_cache->metadata_written += len;
+       session->priv->metadata_cache->metadata_written += len;
        kfree(str);
 
        return 0;
@@ -2984,7 +2870,7 @@ err:
 }
 
 static
-int print_tabs(struct lttng_session *session, size_t nesting)
+int print_tabs(struct lttng_kernel_session *session, size_t nesting)
 {
        size_t i;
 
@@ -3000,39 +2886,39 @@ int print_tabs(struct lttng_session *session, size_t nesting)
 }
 
 static
-int lttng_field_name_statedump(struct lttng_session *session,
-               const struct lttng_event_field *field,
+int lttng_field_name_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_event_field *field,
                size_t nesting)
 {
        return lttng_metadata_printf(session, " _%s;\n", field->name);
 }
 
 static
-int _lttng_integer_type_statedump(struct lttng_session *session,
-               const struct lttng_type *type,
+int _lttng_integer_type_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_type_integer *type,
+               enum lttng_kernel_string_encoding parent_encoding,
                size_t nesting)
 {
        int ret;
 
-       WARN_ON_ONCE(type->type != lttng_kernel_type_integer);
        ret = print_tabs(session, nesting);
        if (ret)
                return ret;
        ret = lttng_metadata_printf(session,
                "integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s }",
-               type->u.integer.size,
-               type->u.integer.alignment,
-               type->u.integer.signedness,
-               (type->u.integer.encoding == lttng_kernel_string_encoding_none)
+               type->size,
+               type->alignment,
+               type->signedness,
+               (parent_encoding == lttng_kernel_string_encoding_none)
                        ? "none"
-                       : (type->u.integer.encoding == lttng_kernel_string_encoding_UTF8)
+                       : (parent_encoding == lttng_kernel_string_encoding_UTF8)
                                ? "UTF8"
                                : "ASCII",
-               type->u.integer.base,
+               type->base,
 #if __BYTE_ORDER == __BIG_ENDIAN
-               type->u.integer.reverse_byte_order ? " byte_order = le;" : ""
+               type->reverse_byte_order ? " byte_order = le;" : ""
 #else
-               type->u.integer.reverse_byte_order ? " byte_order = be;" : ""
+               type->reverse_byte_order ? " byte_order = be;" : ""
 #endif
        );
        return ret;
@@ -3042,16 +2928,15 @@ int _lttng_integer_type_statedump(struct lttng_session *session,
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_struct_type_statedump(struct lttng_session *session,
-               const struct lttng_type *type,
+int _lttng_struct_type_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_type_struct *type,
                size_t nesting)
 {
+       const char *prev_field_name = NULL;
        int ret;
        uint32_t i, nr_fields;
        unsigned int alignment;
 
-       WARN_ON_ONCE(type->type != lttng_kernel_type_struct_nestable);
-
        ret = print_tabs(session, nesting);
        if (ret)
                return ret;
@@ -3059,19 +2944,19 @@ int _lttng_struct_type_statedump(struct lttng_session *session,
                "struct {\n");
        if (ret)
                return ret;
-       nr_fields = type->u.struct_nestable.nr_fields;
+       nr_fields = type->nr_fields;
        for (i = 0; i < nr_fields; i++) {
-               const struct lttng_event_field *iter_field;
+               const struct lttng_kernel_event_field *iter_field;
 
-               iter_field = &type->u.struct_nestable.fields[i];
-               ret = _lttng_field_statedump(session, iter_field, nesting + 1);
+               iter_field = type->fields[i];
+               ret = _lttng_field_statedump(session, iter_field, nesting + 1, &prev_field_name);
                if (ret)
                        return ret;
        }
        ret = print_tabs(session, nesting);
        if (ret)
                return ret;
-       alignment = type->u.struct_nestable.alignment;
+       alignment = type->alignment;
        if (alignment) {
                ret = lttng_metadata_printf(session,
                        "} align(%u)",
@@ -3087,14 +2972,14 @@ int _lttng_struct_type_statedump(struct lttng_session *session,
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_struct_field_statedump(struct lttng_session *session,
-               const struct lttng_event_field *field,
+int _lttng_struct_field_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_event_field *field,
                size_t nesting)
 {
        int ret;
 
        ret = _lttng_struct_type_statedump(session,
-                       &field->type, nesting);
+                       lttng_kernel_get_type_struct(field->type), nesting);
        if (ret)
                return ret;
        return lttng_field_name_statedump(session, field, nesting);
@@ -3104,33 +2989,39 @@ int _lttng_struct_field_statedump(struct lttng_session *session,
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_variant_type_statedump(struct lttng_session *session,
-               const struct lttng_type *type,
-               size_t nesting)
+int _lttng_variant_type_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_type_variant *type,
+               size_t nesting,
+               const char *prev_field_name)
 {
+       const char *tag_name;
        int ret;
        uint32_t i, nr_choices;
 
-       WARN_ON_ONCE(type->type != lttng_kernel_type_variant_nestable);
+       tag_name = type->tag_name;
+       if (!tag_name)
+               tag_name = prev_field_name;
+       if (!tag_name)
+               return -EINVAL;
        /*
         * CTF 1.8 does not allow expressing nonzero variant alignment in a nestable way.
         */
-       if (type->u.variant_nestable.alignment != 0)
+       if (type->alignment != 0)
                return -EINVAL;
        ret = print_tabs(session, nesting);
        if (ret)
                return ret;
        ret = lttng_metadata_printf(session,
                "variant <_%s> {\n",
-               type->u.variant_nestable.tag_name);
+               tag_name);
        if (ret)
                return ret;
-       nr_choices = type->u.variant_nestable.nr_choices;
+       nr_choices = type->nr_choices;
        for (i = 0; i < nr_choices; i++) {
-               const struct lttng_event_field *iter_field;
+               const struct lttng_kernel_event_field *iter_field;
 
-               iter_field = &type->u.variant_nestable.choices[i];
-               ret = _lttng_field_statedump(session, iter_field, nesting + 1);
+               iter_field = type->choices[i];
+               ret = _lttng_field_statedump(session, iter_field, nesting + 1, NULL);
                if (ret)
                        return ret;
        }
@@ -3146,14 +3037,16 @@ int _lttng_variant_type_statedump(struct lttng_session *session,
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_variant_field_statedump(struct lttng_session *session,
-               const struct lttng_event_field *field,
-               size_t nesting)
+int _lttng_variant_field_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_event_field *field,
+               size_t nesting,
+               const char *prev_field_name)
 {
        int ret;
 
        ret = _lttng_variant_type_statedump(session,
-                       &field->type, nesting);
+                       lttng_kernel_get_type_variant(field->type), nesting,
+                       prev_field_name);
        if (ret)
                return ret;
        return lttng_field_name_statedump(session, field, nesting);
@@ -3163,22 +3056,24 @@ int _lttng_variant_field_statedump(struct lttng_session *session,
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_array_field_statedump(struct lttng_session *session,
-               const struct lttng_event_field *field,
+int _lttng_array_field_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_event_field *field,
                size_t nesting)
 {
        int ret;
-       const struct lttng_type *elem_type;
+       const struct lttng_kernel_type_array *array_type;
+       const struct lttng_kernel_type_common *elem_type;
 
-       WARN_ON_ONCE(field->type.type != lttng_kernel_type_array_nestable);
+       array_type = lttng_kernel_get_type_array(field->type);
+       WARN_ON_ONCE(!array_type);
 
-       if (field->type.u.array_nestable.alignment) {
+       if (array_type->alignment) {
                ret = print_tabs(session, nesting);
                if (ret)
                        return ret;
                ret = lttng_metadata_printf(session,
                "struct { } align(%u) _%s_padding;\n",
-                               field->type.u.array_nestable.alignment * CHAR_BIT,
+                               array_type->alignment * CHAR_BIT,
                                field->name);
                if (ret)
                        return ret;
@@ -3187,12 +3082,13 @@ int _lttng_array_field_statedump(struct lttng_session *session,
         * Nested compound types: Only array of structures and variants are
         * currently supported.
         */
-       elem_type = field->type.u.array_nestable.elem_type;
+       elem_type = array_type->elem_type;
        switch (elem_type->type) {
        case lttng_kernel_type_integer:
-       case lttng_kernel_type_struct_nestable:
-       case lttng_kernel_type_variant_nestable:
-               ret = _lttng_type_statedump(session, elem_type, nesting);
+       case lttng_kernel_type_struct:
+       case lttng_kernel_type_variant:
+               ret = _lttng_type_statedump(session, elem_type,
+                               array_type->encoding, nesting);
                if (ret)
                        return ret;
                break;
@@ -3203,7 +3099,7 @@ int _lttng_array_field_statedump(struct lttng_session *session,
        ret = lttng_metadata_printf(session,
                " _%s[%u];\n",
                field->name,
-               field->type.u.array_nestable.length);
+               array_type->length);
        return ret;
 }
 
@@ -3211,25 +3107,32 @@ int _lttng_array_field_statedump(struct lttng_session *session,
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_sequence_field_statedump(struct lttng_session *session,
-               const struct lttng_event_field *field,
-               size_t nesting)
+int _lttng_sequence_field_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_event_field *field,
+               size_t nesting,
+               const char *prev_field_name)
 {
        int ret;
        const char *length_name;
-       const struct lttng_type *elem_type;
+       const struct lttng_kernel_type_sequence *sequence_type;
+       const struct lttng_kernel_type_common *elem_type;
 
-       WARN_ON_ONCE(field->type.type != lttng_kernel_type_sequence_nestable);
+       sequence_type = lttng_kernel_get_type_sequence(field->type);
+       WARN_ON_ONCE(!sequence_type);
 
-       length_name = field->type.u.sequence_nestable.length_name;
+       length_name = sequence_type->length_name;
+       if (!length_name)
+               length_name = prev_field_name;
+       if (!length_name)
+               return -EINVAL;
 
-       if (field->type.u.sequence_nestable.alignment) {
+       if (sequence_type->alignment) {
                ret = print_tabs(session, nesting);
                if (ret)
                        return ret;
                ret = lttng_metadata_printf(session,
                "struct { } align(%u) _%s_padding;\n",
-                               field->type.u.sequence_nestable.alignment * CHAR_BIT,
+                               sequence_type->alignment * CHAR_BIT,
                                field->name);
                if (ret)
                        return ret;
@@ -3239,12 +3142,13 @@ int _lttng_sequence_field_statedump(struct lttng_session *session,
         * Nested compound types: Only array of structures and variants are
         * currently supported.
         */
-       elem_type = field->type.u.sequence_nestable.elem_type;
+       elem_type = sequence_type->elem_type;
        switch (elem_type->type) {
        case lttng_kernel_type_integer:
-       case lttng_kernel_type_struct_nestable:
-       case lttng_kernel_type_variant_nestable:
-               ret = _lttng_type_statedump(session, elem_type, nesting);
+       case lttng_kernel_type_struct:
+       case lttng_kernel_type_variant:
+               ret = _lttng_type_statedump(session, elem_type,
+                               sequence_type->encoding, nesting);
                if (ret)
                        return ret;
                break;
@@ -3255,7 +3159,7 @@ int _lttng_sequence_field_statedump(struct lttng_session *session,
        ret = lttng_metadata_printf(session,
                " _%s[ _%s ];\n",
                field->name,
-               field->type.u.sequence_nestable.length_name);
+               length_name);
        return ret;
 }
 
@@ -3263,21 +3167,21 @@ int _lttng_sequence_field_statedump(struct lttng_session *session,
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_enum_type_statedump(struct lttng_session *session,
-               const struct lttng_type *type,
+int _lttng_enum_type_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_type_enum *type,
                size_t nesting)
 {
-       const struct lttng_enum_desc *enum_desc;
-       const struct lttng_type *container_type;
+       const struct lttng_kernel_enum_desc *enum_desc;
+       const struct lttng_kernel_type_common *container_type;
        int ret;
        unsigned int i, nr_entries;
 
-       container_type = type->u.enum_nestable.container_type;
+       container_type = type->container_type;
        if (container_type->type != lttng_kernel_type_integer) {
                ret = -EINVAL;
                goto end;
        }
-       enum_desc = type->u.enum_nestable.desc;
+       enum_desc = type->desc;
        nr_entries = enum_desc->nr_entries;
 
        ret = print_tabs(session, nesting);
@@ -3286,7 +3190,8 @@ int _lttng_enum_type_statedump(struct lttng_session *session,
        ret = lttng_metadata_printf(session, "enum : ");
        if (ret)
                goto end;
-       ret = _lttng_integer_type_statedump(session, container_type, 0);
+       ret = _lttng_integer_type_statedump(session, lttng_kernel_get_type_integer(container_type),
+                       lttng_kernel_string_encoding_none, 0);
        if (ret)
                goto end;
        ret = lttng_metadata_printf(session, " {\n");
@@ -3294,7 +3199,7 @@ int _lttng_enum_type_statedump(struct lttng_session *session,
                goto end;
        /* Dump all entries */
        for (i = 0; i < nr_entries; i++) {
-               const struct lttng_kernel_enum_entry *entry = &enum_desc->entries[i];
+               const struct lttng_kernel_enum_entry *entry = enum_desc->entries[i];
                int j, len;
 
                ret = print_tabs(session, nesting + 1);
@@ -3379,59 +3284,64 @@ end:
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_enum_field_statedump(struct lttng_session *session,
-               const struct lttng_event_field *field,
+int _lttng_enum_field_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_event_field *field,
                size_t nesting)
 {
        int ret;
+       const struct lttng_kernel_type_enum *enum_type;
 
-       ret = _lttng_enum_type_statedump(session, &field->type, nesting);
+       enum_type = lttng_kernel_get_type_enum(field->type);
+       WARN_ON_ONCE(!enum_type);
+       ret = _lttng_enum_type_statedump(session, enum_type, nesting);
        if (ret)
                return ret;
        return lttng_field_name_statedump(session, field, nesting);
 }
 
 static
-int _lttng_integer_field_statedump(struct lttng_session *session,
-               const struct lttng_event_field *field,
+int _lttng_integer_field_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_event_field *field,
                size_t nesting)
 {
        int ret;
 
-       ret = _lttng_integer_type_statedump(session, &field->type, nesting);
+       ret = _lttng_integer_type_statedump(session, lttng_kernel_get_type_integer(field->type),
+                       lttng_kernel_string_encoding_none, nesting);
        if (ret)
                return ret;
        return lttng_field_name_statedump(session, field, nesting);
 }
 
 static
-int _lttng_string_type_statedump(struct lttng_session *session,
-               const struct lttng_type *type,
+int _lttng_string_type_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_type_string *type,
                size_t nesting)
 {
        int ret;
 
-       WARN_ON_ONCE(type->type != lttng_kernel_type_string);
        /* Default encoding is UTF8 */
        ret = print_tabs(session, nesting);
        if (ret)
                return ret;
        ret = lttng_metadata_printf(session,
                "string%s",
-               type->u.string.encoding == lttng_kernel_string_encoding_ASCII ?
+               type->encoding == lttng_kernel_string_encoding_ASCII ?
                        " { encoding = ASCII; }" : "");
        return ret;
 }
 
 static
-int _lttng_string_field_statedump(struct lttng_session *session,
-               const struct lttng_event_field *field,
+int _lttng_string_field_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_event_field *field,
                size_t nesting)
 {
+       const struct lttng_kernel_type_string *string_type;
        int ret;
 
-       WARN_ON_ONCE(field->type.type != lttng_kernel_type_string);
-       ret = _lttng_string_type_statedump(session, &field->type, nesting);
+       string_type = lttng_kernel_get_type_string(field->type);
+       WARN_ON_ONCE(!string_type);
+       ret = _lttng_string_type_statedump(session, string_type, nesting);
        if (ret)
                return ret;
        return lttng_field_name_statedump(session, field, nesting);
@@ -3441,32 +3351,43 @@ int _lttng_string_field_statedump(struct lttng_session *session,
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_type_statedump(struct lttng_session *session,
-               const struct lttng_type *type,
+int _lttng_type_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_type_common *type,
+               enum lttng_kernel_string_encoding parent_encoding,
                size_t nesting)
 {
        int ret = 0;
 
        switch (type->type) {
        case lttng_kernel_type_integer:
-               ret = _lttng_integer_type_statedump(session, type, nesting);
+               ret = _lttng_integer_type_statedump(session,
+                               lttng_kernel_get_type_integer(type),
+                               parent_encoding, nesting);
                break;
-       case lttng_kernel_type_enum_nestable:
-               ret = _lttng_enum_type_statedump(session, type, nesting);
+       case lttng_kernel_type_enum:
+               ret = _lttng_enum_type_statedump(session,
+                               lttng_kernel_get_type_enum(type),
+                               nesting);
                break;
        case lttng_kernel_type_string:
-               ret = _lttng_string_type_statedump(session, type, nesting);
+               ret = _lttng_string_type_statedump(session,
+                               lttng_kernel_get_type_string(type),
+                               nesting);
                break;
-       case lttng_kernel_type_struct_nestable:
-               ret = _lttng_struct_type_statedump(session, type, nesting);
+       case lttng_kernel_type_struct:
+               ret = _lttng_struct_type_statedump(session,
+                               lttng_kernel_get_type_struct(type),
+                               nesting);
                break;
-       case lttng_kernel_type_variant_nestable:
-               ret = _lttng_variant_type_statedump(session, type, nesting);
+       case lttng_kernel_type_variant:
+               ret = _lttng_variant_type_statedump(session,
+                               lttng_kernel_get_type_variant(type),
+                               nesting, NULL);
                break;
 
        /* Nested arrays and sequences are not supported yet. */
-       case lttng_kernel_type_array_nestable:
-       case lttng_kernel_type_sequence_nestable:
+       case lttng_kernel_type_array:
+       case lttng_kernel_type_sequence:
        default:
                WARN_ON_ONCE(1);
                return -EINVAL;
@@ -3478,55 +3399,62 @@ int _lttng_type_statedump(struct lttng_session *session,
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_field_statedump(struct lttng_session *session,
-               const struct lttng_event_field *field,
-               size_t nesting)
+int _lttng_field_statedump(struct lttng_kernel_session *session,
+               const struct lttng_kernel_event_field *field,
+               size_t nesting,
+               const char **prev_field_name_p)
 {
+       const char *prev_field_name = NULL;
        int ret = 0;
 
-       switch (field->type.type) {
+       if (prev_field_name_p)
+               prev_field_name = *prev_field_name_p;
+       switch (field->type->type) {
        case lttng_kernel_type_integer:
                ret = _lttng_integer_field_statedump(session, field, nesting);
                break;
-       case lttng_kernel_type_enum_nestable:
+       case lttng_kernel_type_enum:
                ret = _lttng_enum_field_statedump(session, field, nesting);
                break;
        case lttng_kernel_type_string:
                ret = _lttng_string_field_statedump(session, field, nesting);
                break;
-       case lttng_kernel_type_struct_nestable:
+       case lttng_kernel_type_struct:
                ret = _lttng_struct_field_statedump(session, field, nesting);
                break;
-       case lttng_kernel_type_array_nestable:
+       case lttng_kernel_type_array:
                ret = _lttng_array_field_statedump(session, field, nesting);
                break;
-       case lttng_kernel_type_sequence_nestable:
-               ret = _lttng_sequence_field_statedump(session, field, nesting);
+       case lttng_kernel_type_sequence:
+               ret = _lttng_sequence_field_statedump(session, field, nesting, prev_field_name);
                break;
-       case lttng_kernel_type_variant_nestable:
-               ret = _lttng_variant_field_statedump(session, field, nesting);
+       case lttng_kernel_type_variant:
+               ret = _lttng_variant_field_statedump(session, field, nesting, prev_field_name);
                break;
 
        default:
                WARN_ON_ONCE(1);
                return -EINVAL;
        }
+       if (prev_field_name_p)
+               *prev_field_name_p = field->name;
        return ret;
 }
 
 static
-int _lttng_context_metadata_statedump(struct lttng_session *session,
-                                   struct lttng_ctx *ctx)
+int _lttng_context_metadata_statedump(struct lttng_kernel_session *session,
+                                   struct lttng_kernel_ctx *ctx)
 {
+       const char *prev_field_name = NULL;
        int ret = 0;
        int i;
 
        if (!ctx)
                return 0;
        for (i = 0; i < ctx->nr_fields; i++) {
-               const struct lttng_ctx_field *field = &ctx->fields[i];
+               const struct lttng_kernel_ctx_field *field = &ctx->fields[i];
 
-               ret = _lttng_field_statedump(session, &field->event_field, 2);
+               ret = _lttng_field_statedump(session, field->event_field, 2, &prev_field_name);
                if (ret)
                        return ret;
        }
@@ -3534,17 +3462,18 @@ int _lttng_context_metadata_statedump(struct lttng_session *session,
 }
 
 static
-int _lttng_fields_metadata_statedump(struct lttng_session *session,
-                                  struct lttng_event *event)
+int _lttng_fields_metadata_statedump(struct lttng_kernel_session *session,
+                                  struct lttng_kernel_event_recorder *event_recorder)
 {
-       const struct lttng_event_desc *desc = event->desc;
+       const char *prev_field_name = NULL;
+       const struct lttng_kernel_event_desc *desc = event_recorder->priv->parent.desc;
        int ret = 0;
        int i;
 
-       for (i = 0; i < desc->nr_fields; i++) {
-               const struct lttng_event_field *field = &desc->fields[i];
+       for (i = 0; i < desc->tp_class->nr_fields; i++) {
+               const struct lttng_kernel_event_field *field = desc->tp_class->fields[i];
 
-               ret = _lttng_field_statedump(session, field, 2);
+               ret = _lttng_field_statedump(session, field, 2, &prev_field_name);
                if (ret)
                        return ret;
        }
@@ -3557,15 +3486,22 @@ int _lttng_fields_metadata_statedump(struct lttng_session *session,
  * transaction.
  */
 static
-int _lttng_event_metadata_statedump(struct lttng_session *session,
-                                 struct lttng_channel *chan,
-                                 struct lttng_event *event)
+int _lttng_event_recorder_metadata_statedump(struct lttng_kernel_event_common *event)
 {
+       struct lttng_kernel_event_recorder *event_recorder;
+       struct lttng_kernel_channel_buffer *chan;
+       struct lttng_kernel_session *session;
        int ret = 0;
 
-       if (event->metadata_dumped || !LTTNG_READ_ONCE(session->active))
+       if (event->type != LTTNG_KERNEL_EVENT_TYPE_RECORDER)
+               return 0;
+       event_recorder = container_of(event, struct lttng_kernel_event_recorder, parent);
+       chan = event_recorder->chan;
+       session = chan->parent.session;
+
+       if (event_recorder->priv->metadata_dumped || !LTTNG_READ_ONCE(session->active))
                return 0;
-       if (chan->channel_type == METADATA_CHANNEL)
+       if (chan->priv->channel_type == METADATA_CHANNEL)
                return 0;
 
        lttng_metadata_begin(session);
@@ -3575,27 +3511,11 @@ int _lttng_event_metadata_statedump(struct lttng_session *session,
                "       name = \"%s\";\n"
                "       id = %u;\n"
                "       stream_id = %u;\n",
-               event->desc->name,
-               event->id,
-               event->chan->id);
-       if (ret)
-               goto end;
-
-       if (event->ctx) {
-               ret = lttng_metadata_printf(session,
-                       "       context := struct {\n");
-               if (ret)
-                       goto end;
-       }
-       ret = _lttng_context_metadata_statedump(session, event->ctx);
+               event_recorder->priv->parent.desc->event_name,
+               event_recorder->priv->id,
+               event_recorder->chan->priv->id);
        if (ret)
                goto end;
-       if (event->ctx) {
-               ret = lttng_metadata_printf(session,
-                       "       };\n");
-               if (ret)
-                       goto end;
-       }
 
        ret = lttng_metadata_printf(session,
                "       fields := struct {\n"
@@ -3603,7 +3523,7 @@ int _lttng_event_metadata_statedump(struct lttng_session *session,
        if (ret)
                goto end;
 
-       ret = _lttng_fields_metadata_statedump(session, event);
+       ret = _lttng_fields_metadata_statedump(session, event_recorder);
        if (ret)
                goto end;
 
@@ -3617,7 +3537,7 @@ int _lttng_event_metadata_statedump(struct lttng_session *session,
        if (ret)
                goto end;
 
-       event->metadata_dumped = 1;
+       event_recorder->priv->metadata_dumped = 1;
 end:
        lttng_metadata_end(session);
        return ret;
@@ -3630,41 +3550,41 @@ end:
  * transaction.
  */
 static
-int _lttng_channel_metadata_statedump(struct lttng_session *session,
-                                   struct lttng_channel *chan)
+int _lttng_channel_metadata_statedump(struct lttng_kernel_session *session,
+                                   struct lttng_kernel_channel_buffer *chan)
 {
        int ret = 0;
 
-       if (chan->metadata_dumped || !LTTNG_READ_ONCE(session->active))
+       if (chan->priv->metadata_dumped || !LTTNG_READ_ONCE(session->active))
                return 0;
 
-       if (chan->channel_type == METADATA_CHANNEL)
+       if (chan->priv->channel_type == METADATA_CHANNEL)
                return 0;
 
        lttng_metadata_begin(session);
 
-       WARN_ON_ONCE(!chan->header_type);
+       WARN_ON_ONCE(!chan->priv->header_type);
        ret = lttng_metadata_printf(session,
                "stream {\n"
                "       id = %u;\n"
                "       event.header := %s;\n"
                "       packet.context := struct packet_context;\n",
-               chan->id,
-               chan->header_type == 1 ? "struct event_header_compact" :
+               chan->priv->id,
+               chan->priv->header_type == 1 ? "struct event_header_compact" :
                        "struct event_header_large");
        if (ret)
                goto end;
 
-       if (chan->ctx) {
+       if (chan->priv->ctx) {
                ret = lttng_metadata_printf(session,
                        "       event.context := struct {\n");
                if (ret)
                        goto end;
        }
-       ret = _lttng_context_metadata_statedump(session, chan->ctx);
+       ret = _lttng_context_metadata_statedump(session, chan->priv->ctx);
        if (ret)
                goto end;
-       if (chan->ctx) {
+       if (chan->priv->ctx) {
                ret = lttng_metadata_printf(session,
                        "       };\n");
                if (ret)
@@ -3674,7 +3594,7 @@ int _lttng_channel_metadata_statedump(struct lttng_session *session,
        ret = lttng_metadata_printf(session,
                "};\n\n");
 
-       chan->metadata_dumped = 1;
+       chan->priv->metadata_dumped = 1;
 end:
        lttng_metadata_end(session);
        return ret;
@@ -3684,7 +3604,7 @@ end:
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_stream_packet_context_declare(struct lttng_session *session)
+int _lttng_stream_packet_context_declare(struct lttng_kernel_session *session)
 {
        return lttng_metadata_printf(session,
                "struct packet_context {\n"
@@ -3711,7 +3631,7 @@ int _lttng_stream_packet_context_declare(struct lttng_session *session)
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_event_header_declare(struct lttng_session *session)
+int _lttng_event_header_declare(struct lttng_kernel_session *session)
 {
        return lttng_metadata_printf(session,
        "struct event_header_compact {\n"
@@ -3762,20 +3682,12 @@ int64_t measure_clock_offset(void)
        uint64_t tcf = trace_clock_freq();
        int64_t offset;
        unsigned long flags;
-#ifdef LTTNG_KERNEL_HAS_TIMESPEC64
        struct timespec64 rts = { 0, 0 };
-#else
-       struct timespec rts = { 0, 0 };
-#endif
 
        /* Disable interrupts to increase correlation precision. */
        local_irq_save(flags);
        monotonic[0] = trace_clock_read64();
-#ifdef LTTNG_KERNEL_HAS_TIMESPEC64
        ktime_get_real_ts64(&rts);
-#else
-       getnstimeofday(&rts);
-#endif
        monotonic[1] = trace_clock_read64();
        local_irq_restore(flags);
 
@@ -3794,7 +3706,7 @@ int64_t measure_clock_offset(void)
 }
 
 static
-int print_escaped_ctf_string(struct lttng_session *session, const char *string)
+int print_escaped_ctf_string(struct lttng_kernel_session *session, const char *string)
 {
        int ret = 0;
        size_t i;
@@ -3813,7 +3725,7 @@ int print_escaped_ctf_string(struct lttng_session *session, const char *string)
                        if (ret)
                                goto error;
                        /* We still print the current char */
-                       /* Fallthrough */
+                       lttng_fallthrough;
                default:
                        ret = lttng_metadata_printf(session, "%c", cur);
                        break;
@@ -3829,7 +3741,7 @@ error:
 }
 
 static
-int print_metadata_escaped_field(struct lttng_session *session, const char *field,
+int print_metadata_escaped_field(struct lttng_kernel_session *session, const char *field,
                const char *field_value)
 {
        int ret;
@@ -3853,13 +3765,13 @@ error:
  * Must be called with sessions_mutex held.
  */
 static
-int _lttng_session_metadata_statedump(struct lttng_session *session)
+int _lttng_session_metadata_statedump(struct lttng_kernel_session *session)
 {
-       unsigned char *uuid_c = session->uuid.b;
+       unsigned char *uuid_c = session->priv->uuid.b;
        unsigned char uuid_s[37], clock_uuid_s[BOOT_ID_LEN];
        const char *product_uuid;
-       struct lttng_channel *chan;
-       struct lttng_event *event;
+       struct lttng_kernel_channel_buffer_private *chan_priv;
+       struct lttng_kernel_event_recorder_private *event_recorder_priv;
        int ret = 0;
 
        if (!LTTNG_READ_ONCE(session->active))
@@ -3867,7 +3779,7 @@ int _lttng_session_metadata_statedump(struct lttng_session *session)
 
        lttng_metadata_begin(session);
 
-       if (session->metadata_dumped)
+       if (session->priv->metadata_dumped)
                goto skip_session;
 
        snprintf(uuid_s, sizeof(uuid_s),
@@ -3939,11 +3851,11 @@ int _lttng_session_metadata_statedump(struct lttng_session *session)
        if (ret)
                goto end;
 
-       ret = print_metadata_escaped_field(session, "trace_name", session->name);
+       ret = print_metadata_escaped_field(session, "trace_name", session->priv->name);
        if (ret)
                goto end;
        ret = print_metadata_escaped_field(session, "trace_creation_datetime",
-                       session->creation_time);
+                       session->priv->creation_time);
        if (ret)
                goto end;
 
@@ -4026,18 +3938,18 @@ int _lttng_session_metadata_statedump(struct lttng_session *session)
                goto end;
 
 skip_session:
-       list_for_each_entry(chan, &session->chan, list) {
-               ret = _lttng_channel_metadata_statedump(session, chan);
+       list_for_each_entry(chan_priv, &session->priv->chan, node) {
+               ret = _lttng_channel_metadata_statedump(session, chan_priv->pub);
                if (ret)
                        goto end;
        }
 
-       list_for_each_entry(event, &session->events, list) {
-               ret = _lttng_event_metadata_statedump(session, event->chan, event);
+       list_for_each_entry(event_recorder_priv, &session->priv->events, parent.node) {
+               ret = _lttng_event_recorder_metadata_statedump(&event_recorder_priv->pub->parent);
                if (ret)
                        goto end;
        }
-       session->metadata_dumped = 1;
+       session->priv->metadata_dumped = 1;
 end:
        lttng_metadata_end(session);
        return ret;
@@ -4231,18 +4143,11 @@ static void lttng_exit_cpu_hotplug(void)
 }
 #endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
 
-
 static int __init lttng_events_init(void)
 {
        int ret;
 
-       ret = wrapper_lttng_fixup_sig(THIS_MODULE);
-       if (ret)
-               return ret;
        ret = wrapper_get_pfnblock_flags_mask_init();
-       if (ret)
-               return ret;
-       ret = wrapper_get_pageblock_flags_mask_init();
        if (ret)
                return ret;
        ret = lttng_probes_init();
@@ -4254,16 +4159,26 @@ static int __init lttng_events_init(void)
        ret = lttng_tracepoint_init();
        if (ret)
                goto error_tp;
-       event_cache = KMEM_CACHE(lttng_event, 0);
-       if (!event_cache) {
+       event_recorder_cache = KMEM_CACHE(lttng_kernel_event_recorder, 0);
+       if (!event_recorder_cache) {
                ret = -ENOMEM;
-               goto error_kmem_event;
+               goto error_kmem_event_recorder;
        }
-       event_notifier_cache = KMEM_CACHE(lttng_event_notifier, 0);
+       event_recorder_private_cache = KMEM_CACHE(lttng_kernel_event_recorder_private, 0);
+       if (!event_recorder_private_cache) {
+               ret = -ENOMEM;
+               goto error_kmem_event_recorder_private;
+       }
+       event_notifier_cache = KMEM_CACHE(lttng_kernel_event_notifier, 0);
        if (!event_notifier_cache) {
                ret = -ENOMEM;
                goto error_kmem_event_notifier;
        }
+       event_notifier_private_cache = KMEM_CACHE(lttng_kernel_event_notifier_private, 0);
+       if (!event_notifier_private_cache) {
+               ret = -ENOMEM;
+               goto error_kmem_event_notifier_private;
+       }
        ret = lttng_abi_init();
        if (ret)
                goto error_abi;
@@ -4289,6 +4204,9 @@ static int __init lttng_events_init(void)
 #else
                "");
 #endif
+#ifdef CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM
+       printk(KERN_NOTICE "LTTng: Experimental bitwise enum enabled.\n");
+#endif /* CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM */
        return 0;
 
 error_hotplug:
@@ -4296,10 +4214,14 @@ error_hotplug:
 error_logger:
        lttng_abi_exit();
 error_abi:
+       kmem_cache_destroy(event_notifier_private_cache);
+error_kmem_event_notifier_private:
        kmem_cache_destroy(event_notifier_cache);
 error_kmem_event_notifier:
-       kmem_cache_destroy(event_cache);
-error_kmem_event:
+       kmem_cache_destroy(event_recorder_private_cache);
+error_kmem_event_recorder_private:
+       kmem_cache_destroy(event_recorder_cache);
+error_kmem_event_recorder:
        lttng_tracepoint_exit();
 error_tp:
        lttng_context_exit();
@@ -4326,15 +4248,17 @@ module_init(lttng_events_init);
 
 static void __exit lttng_events_exit(void)
 {
-       struct lttng_session *session, *tmpsession;
+       struct lttng_kernel_session_private *session_priv, *tmpsession_priv;
 
        lttng_exit_cpu_hotplug();
        lttng_logger_exit();
        lttng_abi_exit();
-       list_for_each_entry_safe(session, tmpsession, &sessions, list)
-               lttng_session_destroy(session);
-       kmem_cache_destroy(event_cache);
+       list_for_each_entry_safe(session_priv, tmpsession_priv, &sessions, list)
+               lttng_session_destroy(session_priv->pub);
+       kmem_cache_destroy(event_recorder_cache);
+       kmem_cache_destroy(event_recorder_private_cache);
        kmem_cache_destroy(event_notifier_cache);
+       kmem_cache_destroy(event_notifier_private_cache);
        lttng_tracepoint_exit();
        lttng_context_exit();
        printk(KERN_NOTICE "LTTng: Unloaded modules v%s.%s.%s%s (%s)%s%s\n",
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