/*
* The sessions mutex is the centralized mutex across UST tracing
- * control and probe registration.
+ * control and probe registration. All operations within this file are
+ * called by the communication thread, under ust_lock protection.
*/
static DEFINE_MUTEX(sessions_mutex);
-void lock_ust(void)
+void ust_lock(void)
{
pthread_mutex_lock(&sessions_mutex);
}
-void unlock_ust(void)
+void ust_unlock(void)
{
pthread_mutex_unlock(&sessions_mutex);
}
session = zmalloc(sizeof(struct ltt_session));
if (!session)
return NULL;
- pthread_mutex_lock(&sessions_mutex);
CDS_INIT_LIST_HEAD(&session->chan);
CDS_INIT_LIST_HEAD(&session->events);
uuid_generate(session->uuid);
cds_list_add(&session->list, &sessions);
- pthread_mutex_unlock(&sessions_mutex);
return session;
}
struct ltt_event *event, *tmpevent;
int ret;
- pthread_mutex_lock(&sessions_mutex);
CMM_ACCESS_ONCE(session->active) = 0;
cds_list_for_each_entry(event, &session->events, list) {
ret = _ltt_event_unregister(event);
cds_list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
_ltt_channel_destroy(chan);
cds_list_del(&session->list);
- pthread_mutex_unlock(&sessions_mutex);
free(session);
}
int ret = 0;
struct ltt_channel *chan;
- pthread_mutex_lock(&sessions_mutex);
if (session->active) {
ret = -EBUSY;
goto end;
if (ret)
CMM_ACCESS_ONCE(session->active) = 0;
end:
- pthread_mutex_unlock(&sessions_mutex);
return ret;
}
{
int ret = 0;
- pthread_mutex_lock(&sessions_mutex);
if (!session->active) {
ret = -EBUSY;
goto end;
}
CMM_ACCESS_ONCE(session->active) = 0;
end:
- pthread_mutex_unlock(&sessions_mutex);
return ret;
}
struct ltt_channel *chan;
struct ltt_transport *transport;
- pthread_mutex_lock(&sessions_mutex);
if (session->been_active)
goto active; /* Refuse to add channel to active session */
transport = ltt_transport_find(transport_name);
chan->enabled = 1;
chan->ops = &transport->ops;
cds_list_add(&chan->list, &session->chan);
- pthread_mutex_unlock(&sessions_mutex);
return chan;
create_error:
nomem:
notransport:
active:
- pthread_mutex_unlock(&sessions_mutex);
return NULL;
}
struct ltt_event *event;
int ret;
- pthread_mutex_lock(&sessions_mutex);
if (chan->used_event_id == -1UL)
goto full;
/*
goto statedump_error;
}
cds_list_add(&event->list, &chan->session->events);
- pthread_mutex_unlock(&sessions_mutex);
return event;
statedump_error:
cache_error:
exist:
full:
- pthread_mutex_unlock(&sessions_mutex);
return NULL;
}
/*
* We have exclusive access to our metadata buffer (protected by the
- * sessions_mutex), so we can do racy operations such as looking for
+ * ust_lock), so we can do racy operations such as looking for
* remaining space left in packet and write, since mutual exclusion
* protects us from concurrent writes.
*/
* @transport: transport structure
*
* Registers a transport which can be used as output to extract the data out of
- * LTTng.
+ * LTTng. Called with ust_lock held.
*/
void ltt_transport_register(struct ltt_transport *transport)
{
- pthread_mutex_lock(&sessions_mutex);
cds_list_add_tail(&transport->node, <t_transport_list);
- pthread_mutex_unlock(&sessions_mutex);
}
/**
* ltt_transport_unregister - LTT transport unregistration
* @transport: transport structure
+ * Called with ust_lock held.
*/
void ltt_transport_unregister(struct ltt_transport *transport)
{
- pthread_mutex_lock(&sessions_mutex);
cds_list_del(&transport->node);
- pthread_mutex_unlock(&sessions_mutex);
}
void ltt_events_exit(void)
#include "ltt-tracer-core.h"
/*
- * probe list is protected by lock_ust()/unlock_ust().
+ * probe list is protected by ust_lock()/ust_unlock().
*/
static CDS_LIST_HEAD(probe_list);
int ret = 0;
int i;
- lock_ust();
+ ust_lock();
/*
* TODO: This is O(N^2). Turn into a hash table when probe registration
* overhead becomes an issue.
assert(!ret);
}
end:
- unlock_ust();
+ ust_unlock();
return ret;
}
void ltt_probe_unregister(struct lttng_probe_desc *desc)
{
- lock_ust();
+ ust_lock();
cds_list_del(&desc->head);
- unlock_ust();
+ ust_unlock();
}
/*
struct ltt_channel;
struct ltt_event;
-void lock_ust(void);
-void unlock_ust(void);
+void ust_lock(void);
+void ust_unlock(void);
#endif /* _LTT_TRACER_CORE_H */
ops->release(i);
}
free(objd_table.array);
+ objd_table.freelist_head = -1;
}
/*
static int initialized;
/*
- * communication thread mutex. Held when handling a command, also held
- * by fork() to deal with removal of threads, and by exit path.
+ * The ust_lock/ust_unlock lock is used as a communication thread mutex.
+ * Held when handling a command, also held by fork() to deal with
+ * removal of threads, and by exit path.
*/
-static pthread_mutex_t lttng_ust_comm_mutex = PTHREAD_MUTEX_INITIALIZER;
/* Should the ust comm thread quit ? */
static int lttng_ust_comm_should_quit;
const struct objd_ops *ops;
struct lttcomm_ust_reply lur;
- pthread_mutex_lock(<tng_ust_comm_mutex);
+ ust_lock();
memset(&lur, 0, sizeof(lur));
}
ret = send_reply(sock, &lur);
- pthread_mutex_unlock(<tng_ust_comm_mutex);
+ ust_unlock();
return ret;
}
/* Restart trying to connect to the session daemon */
restart:
- pthread_mutex_lock(<tng_ust_comm_mutex);
+ ust_lock();
if (lttng_ust_comm_should_quit) {
- pthread_mutex_unlock(<tng_ust_comm_mutex);
+ ust_unlock();
goto quit;
}
*/
ret = handle_register_done(sock_info);
assert(!ret);
- pthread_mutex_unlock(<tng_ust_comm_mutex);
+ ust_unlock();
sleep(5);
goto restart;
}
ret = lttng_abi_create_root_handle();
if (ret) {
ERR("Error creating root handle");
- pthread_mutex_unlock(<tng_ust_comm_mutex);
+ ust_unlock();
goto quit;
}
sock_info->root_handle = ret;
*/
ret = handle_register_done(sock_info);
assert(!ret);
- pthread_mutex_unlock(<tng_ust_comm_mutex);
+ ust_unlock();
sleep(5);
goto restart;
}
- pthread_mutex_unlock(<tng_ust_comm_mutex);
+ ust_unlock();
for (;;) {
ssize_t len;
}
}
+static
+void lttng_ust_cleanup(int exiting)
+{
+ cleanup_sock_info(&global_apps);
+ if (local_apps.allowed) {
+ cleanup_sock_info(&local_apps);
+ }
+ lttng_ust_abi_exit();
+ ltt_events_exit();
+ ltt_ring_buffer_client_discard_exit();
+ ltt_ring_buffer_client_overwrite_exit();
+ ltt_ring_buffer_metadata_client_exit();
+ exit_tracepoint();
+ if (!exiting) {
+ /* Reinitialize values for fork */
+ sem_count = 2;
+ lttng_ust_comm_should_quit = 0;
+ initialized = 0;
+ }
+}
+
void __attribute__((destructor)) lttng_ust_exit(void)
{
int ret;
* mutexes to ensure it is not in a mutex critical section when
* pthread_cancel is later called.
*/
- pthread_mutex_lock(<tng_ust_comm_mutex);
+ ust_lock();
lttng_ust_comm_should_quit = 1;
- pthread_mutex_unlock(<tng_ust_comm_mutex);
+ ust_unlock();
ret = pthread_cancel(global_apps.ust_listener);
if (ret) {
ERR("Error cancelling global ust listener thread");
}
-
- cleanup_sock_info(&global_apps);
-
if (local_apps.allowed) {
ret = pthread_cancel(local_apps.ust_listener);
if (ret) {
ERR("Error cancelling local ust listener thread");
}
-
- cleanup_sock_info(&local_apps);
}
-
- lttng_ust_abi_exit();
- ltt_events_exit();
- ltt_ring_buffer_client_discard_exit();
- ltt_ring_buffer_client_overwrite_exit();
- ltt_ring_buffer_metadata_client_exit();
- exit_tracepoint();
+ lttng_ust_cleanup(1);
}
/*
if (ret == -1) {
PERROR("sigprocmask");
}
- pthread_mutex_lock(<tng_ust_comm_mutex);
+ ust_lock();
rcu_bp_before_fork();
}
{
int ret;
- pthread_mutex_unlock(<tng_ust_comm_mutex);
+ DBG("process %d", getpid());
+ ust_unlock();
/* Restore signals */
ret = sigprocmask(SIG_SETMASK, &fork_info->orig_sigs, NULL);
if (ret == -1) {
void ust_after_fork_parent(ust_fork_info_t *fork_info)
{
+ DBG("process %d", getpid());
rcu_bp_after_fork_parent();
/* Release mutexes and reenable signals */
ust_after_fork_common(fork_info);
}
+/*
+ * After fork, in the child, we need to cleanup all the leftover state,
+ * except the worker thread which already magically disappeared thanks
+ * to the weird Linux fork semantics. After tyding up, we call
+ * lttng_ust_init() again to start over as a new PID.
+ *
+ * This is meant for forks() that have tracing in the child between the
+ * fork and following exec call (if there is any).
+ */
void ust_after_fork_child(ust_fork_info_t *fork_info)
{
+ DBG("process %d", getpid());
/* Release urcu mutexes */
rcu_bp_after_fork_child();
+ lttng_ust_cleanup(0);
+ lttng_ust_init();
/* Release mutexes and reenable signals */
ust_after_fork_common(fork_info);
}
static CDS_LIST_HEAD(libs);
/*
- * Allow nested mutex for mutex listing and nested enable.
+ * The UST lock protects the library tracepoints, the hash table, and
+ * the library list.
+ * All calls to the tracepoint API must be protected by the UST lock,
+ * excepts calls to tracepoint_register_lib and
+ * tracepoint_unregister_lib, which take the UST lock themselves.
*/
-static __thread int nested_mutex;
-
-/*
- * Tracepoints mutex protects the library tracepoints, the hash table,
- * and the library list.
- */
-static pthread_mutex_t tracepoints_mutex;
-
-static
-void lock_tracepoints(void)
-{
- if (!(nested_mutex++))
- pthread_mutex_lock(&tracepoints_mutex);
-}
-
-static
-void unlock_tracepoints(void)
-{
- if (!(--nested_mutex))
- pthread_mutex_unlock(&tracepoints_mutex);
-}
/*
* Tracepoint hash table, containing the active tracepoints.
/*
* Remove the tracepoint from the tracepoint hash table. Must be called with
- * mutex_lock held.
+ * ust_lock held.
*/
static inline void remove_tracepoint(struct tracepoint_entry *e)
{
{
struct tracepoint_lib *lib;
- lock_tracepoints();
cds_list_for_each_entry(lib, &libs, list) {
tracepoint_update_probe_range(lib->tracepoints_start,
lib->tracepoints_start + lib->tracepoints_count);
}
- unlock_tracepoints();
}
/*
*
* Returns 0 if ok, error value on error.
* The probe address must at least be aligned on the architecture pointer size.
+ * Called with the UST lock held.
*/
int __tracepoint_probe_register(const char *name, void *probe, void *data)
{
void *old;
- lock_tracepoints();
old = tracepoint_add_probe(name, probe, data);
- unlock_tracepoints();
if (IS_ERR(old))
return PTR_ERR(old);
* @probe: probe function pointer
* @probe: probe data pointer
*
- * We do not need to call a synchronize_sched to make sure the probes have
- * finished running before doing a module unload, because the module unload
- * itself uses stop_machine(), which insures that every preempt disabled section
- * have finished.
+ * Called with the UST lock held.
*/
int __tracepoint_probe_unregister(const char *name, void *probe, void *data)
{
void *old;
- lock_tracepoints();
old = tracepoint_remove_probe(name, probe, data);
- unlock_tracepoints();
if (IS_ERR(old))
return PTR_ERR(old);
* @probe: probe handler
*
* caller must call tracepoint_probe_update_all()
+ * Called with the UST lock held.
*/
int tracepoint_probe_register_noupdate(const char *name, void *probe,
void *data)
{
void *old;
- lock_tracepoints();
old = tracepoint_add_probe(name, probe, data);
if (IS_ERR(old)) {
- unlock_tracepoints();
return PTR_ERR(old);
}
tracepoint_add_old_probes(old);
- unlock_tracepoints();
return 0;
}
* @probe: probe function pointer
*
* caller must call tracepoint_probe_update_all()
+ * Called with the UST lock held.
*/
int tracepoint_probe_unregister_noupdate(const char *name, void *probe,
void *data)
{
void *old;
- lock_tracepoints();
old = tracepoint_remove_probe(name, probe, data);
if (IS_ERR(old)) {
- unlock_tracepoints();
return PTR_ERR(old);
}
tracepoint_add_old_probes(old);
- unlock_tracepoints();
return 0;
}
/**
* tracepoint_probe_update_all - update tracepoints
+ * Called with the UST lock held.
*/
void tracepoint_probe_update_all(void)
{
CDS_LIST_HEAD(release_probes);
struct tp_probes *pos, *next;
- lock_tracepoints();
if (!need_update) {
- unlock_tracepoints();
return;
}
if (!cds_list_empty(&old_probes))
cds_list_replace_init(&old_probes, &release_probes);
need_update = 0;
- unlock_tracepoints();
tracepoint_update_probes();
cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) {
tracepoint_iter_reset(iter);
}
+/*
+ * Called with UST lock held.
+ */
void tracepoint_iter_start(struct tracepoint_iter *iter)
{
- lock_tracepoints();
tracepoint_get_iter(iter);
}
/*
- * Called with tracepoint mutex held.
+ * Called with UST lock held.
*/
void tracepoint_iter_next(struct tracepoint_iter *iter)
{
tracepoint_get_iter(iter);
}
+/*
+ * Called with UST lock held.
+ */
void tracepoint_iter_stop(struct tracepoint_iter *iter)
{
- unlock_tracepoints();
}
void tracepoint_iter_reset(struct tracepoint_iter *iter)
pl->tracepoints_start = tracepoints_start;
pl->tracepoints_count = tracepoints_count;
- lock_tracepoints();
+ ust_lock();
/*
* We sort the libs by struct lib pointer address.
*/
/* We should be added at the head of the list */
cds_list_add(&pl->list, &libs);
lib_added:
- unlock_tracepoints();
-
new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count);
/* TODO: update just the loaded lib */
lib_update_tracepoints();
+ ust_unlock();
DBG("just registered a tracepoints section from %p and having %d tracepoints",
tracepoints_start, tracepoints_count);
{
struct tracepoint_lib *lib;
- lock_tracepoints();
+ ust_lock();
cds_list_for_each_entry(lib, &libs, list) {
if (lib->tracepoints_start == tracepoints_start) {
struct tracepoint_lib *lib2free = lib;
break;
}
}
- unlock_tracepoints();
+ ust_unlock();
return 0;
}
void exit_tracepoint(void)
{
+ initialized = 0;
}
projects / ust.git / commitdiff
