X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=libust%2Ftracepoint.c;h=1a18463667d3bdac31c67855a99c28b79c0c3ccd;hb=c1ef86f0812ff62354175f4c7136930814b8f850;hp=1c4669b535890a444bacbd0805a509fb05c5f38f;hpb=b979b3468dc6a9329288f53ce568815617780d9c;p=lttng-ust.git diff --git a/libust/tracepoint.c b/libust/tracepoint.c index 1c4669b5..1a184636 100644 --- a/libust/tracepoint.c +++ b/libust/tracepoint.c @@ -1,11 +1,11 @@ /* - * Copyright (C) 2008 Mathieu Desnoyers + * Copyright (C) 2008-2011 Mathieu Desnoyers * Copyright (C) 2009 Pierre-Marc Fournier * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2.1 of the License, or (at your option) any later version. + * License as published by the Free Software Foundation; + * version 2.1 of the License. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of @@ -19,30 +19,34 @@ * Ported to userspace by Pierre-Marc Fournier. */ +#define _LGPL_SOURCE #include #include +#include #include #include -#include "usterr_signal_safe.h" - -#define _LGPL_SOURCE #include #include +#include -//extern struct tracepoint __start___tracepoints[] __attribute__((visibility("hidden"))); -//extern struct tracepoint __stop___tracepoints[] __attribute__((visibility("hidden"))); +#include +#include "ltt-tracer-core.h" /* Set to 1 to enable tracepoint debug output */ static const int tracepoint_debug; +static int initialized; +static void (*new_tracepoint_cb)(struct tracepoint *); /* libraries that contain tracepoints (struct tracepoint_lib) */ static CDS_LIST_HEAD(libs); /* - * tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the - * builtin and module tracepoints and the hash table. + * 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 DEFINE_MUTEX(tracepoints_mutex); /* * Tracepoint hash table, containing the active tracepoints. @@ -52,6 +56,9 @@ static DEFINE_MUTEX(tracepoints_mutex); #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) static struct cds_hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; +static CDS_LIST_HEAD(old_probes); +static int need_update; + /* * Note about RCU : * It is used to to delay the free of multiple probes array until a quiescent @@ -67,7 +74,6 @@ struct tracepoint_entry { struct tp_probes { union { -//ust// struct rcu_head rcu; struct cds_list_head list; } u; struct tracepoint_probe probes[0]; @@ -80,17 +86,11 @@ static inline void *allocate_probes(int count) return p == NULL ? NULL : p->probes; } -//ust// static void rcu_free_old_probes(struct rcu_head *head) -//ust// { -//ust// kfree(container_of(head, struct tp_probes, u.rcu)); -//ust// } - static inline void release_probes(void *old) { if (old) { struct tp_probes *tp_probes = _ust_container_of(old, struct tp_probes, probes[0]); -//ust// call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes); synchronize_rcu(); free(tp_probes); } @@ -241,7 +241,7 @@ static struct tracepoint_entry *add_tracepoint(const char *name) /* * 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) { @@ -287,13 +287,13 @@ static void disable_tracepoint(struct tracepoint *elem) * * Updates the probe callback corresponding to a range of tracepoints. */ +static void tracepoint_update_probe_range(struct tracepoint * const *begin, struct tracepoint * const *end) { struct tracepoint * const *iter; struct tracepoint_entry *mark_entry; - pthread_mutex_lock(&tracepoints_mutex); for (iter = begin; iter < end; iter++) { if (!*iter) continue; /* skip dummy */ @@ -309,18 +309,16 @@ void tracepoint_update_probe_range(struct tracepoint * const *begin, disable_tracepoint(*iter); } } - pthread_mutex_unlock(&tracepoints_mutex); } static void lib_update_tracepoints(void) { struct tracepoint_lib *lib; -//ust// pthread_mutex_lock(&module_mutex); - cds_list_for_each_entry(lib, &libs, list) + cds_list_for_each_entry(lib, &libs, list) { tracepoint_update_probe_range(lib->tracepoints_start, lib->tracepoints_start + lib->tracepoints_count); -//ust// pthread_mutex_unlock(&module_mutex); + } } /* @@ -328,10 +326,7 @@ static void lib_update_tracepoints(void) */ static void tracepoint_update_probes(void) { - /* Core kernel tracepoints */ -//ust// tracepoint_update_probe_range(__start___tracepoints, -//ust// __stop___tracepoints); - /* tracepoints in modules. */ + /* tracepoints registered from libraries and executable. */ lib_update_tracepoints(); } @@ -354,20 +349,19 @@ tracepoint_add_probe(const char *name, void *probe, void *data) } /** - * tracepoint_probe_register - Connect a probe to a tracepoint + * __tracepoint_probe_register - Connect a probe to a tracepoint * @name: tracepoint name * @probe: probe handler * * 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) +int __tracepoint_probe_register(const char *name, void *probe, void *data) { void *old; - pthread_mutex_lock(&tracepoints_mutex); old = tracepoint_add_probe(name, probe, data); - pthread_mutex_unlock(&tracepoints_mutex); if (IS_ERR(old)) return PTR_ERR(old); @@ -375,7 +369,6 @@ int tracepoint_probe_register(const char *name, void *probe, void *data) release_probes(old); return 0; } -//ust// EXPORT_SYMBOL_GPL(tracepoint_probe_register); static void *tracepoint_remove_probe(const char *name, void *probe, void *data) { @@ -399,18 +392,13 @@ static void *tracepoint_remove_probe(const char *name, void *probe, void *data) * @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) +int __tracepoint_probe_unregister(const char *name, void *probe, void *data) { void *old; - pthread_mutex_lock(&tracepoints_mutex); old = tracepoint_remove_probe(name, probe, data); - pthread_mutex_unlock(&tracepoints_mutex); if (IS_ERR(old)) return PTR_ERR(old); @@ -418,10 +406,6 @@ int tracepoint_probe_unregister(const char *name, void *probe, void *data) release_probes(old); return 0; } -//ust// EXPORT_SYMBOL_GPL(tracepoint_probe_unregister); - -static CDS_LIST_HEAD(old_probes); -static int need_update; static void tracepoint_add_old_probes(void *old) { @@ -439,23 +423,20 @@ static void tracepoint_add_old_probes(void *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; - pthread_mutex_lock(&tracepoints_mutex); old = tracepoint_add_probe(name, probe, data); if (IS_ERR(old)) { - pthread_mutex_unlock(&tracepoints_mutex); return PTR_ERR(old); } tracepoint_add_old_probes(old); - pthread_mutex_unlock(&tracepoints_mutex); return 0; } -//ust// EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate); /** * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect @@ -463,62 +444,56 @@ int tracepoint_probe_register_noupdate(const char *name, void *probe, * @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; - pthread_mutex_lock(&tracepoints_mutex); old = tracepoint_remove_probe(name, probe, data); if (IS_ERR(old)) { - pthread_mutex_unlock(&tracepoints_mutex); return PTR_ERR(old); } tracepoint_add_old_probes(old); - pthread_mutex_unlock(&tracepoints_mutex); return 0; } -//ust// EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate); /** * 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; - pthread_mutex_lock(&tracepoints_mutex); if (!need_update) { - pthread_mutex_unlock(&tracepoints_mutex); return; } if (!cds_list_empty(&old_probes)) cds_list_replace_init(&old_probes, &release_probes); need_update = 0; - pthread_mutex_unlock(&tracepoints_mutex); tracepoint_update_probes(); cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { cds_list_del(&pos->u.list); -//ust// call_rcu_sched(&pos->u.rcu, rcu_free_old_probes); synchronize_rcu(); free(pos); } } -//ust// EXPORT_SYMBOL_GPL(tracepoint_probe_update_all); /* * Returns 0 if current not found. * Returns 1 if current found. + * + * Called with tracepoint mutex held */ int lib_get_iter_tracepoints(struct tracepoint_iter *iter) { struct tracepoint_lib *iter_lib; int found = 0; -//ust// pthread_mutex_lock(&module_mutex); cds_list_for_each_entry(iter_lib, &libs, list) { if (iter_lib < iter->lib) continue; @@ -532,7 +507,6 @@ int lib_get_iter_tracepoints(struct tracepoint_iter *iter) break; } } -//ust// pthread_mutex_unlock(&module_mutex); return found; } @@ -545,6 +519,7 @@ int lib_get_iter_tracepoints(struct tracepoint_iter *iter) * Returns whether a next tracepoint has been found (1) or not (0). * Will return the first tracepoint in the range if the input tracepoint is * NULL. + * Called with tracepoint mutex held. */ int tracepoint_get_iter_range(struct tracepoint * const **tracepoint, struct tracepoint * const *begin, struct tracepoint * const *end) @@ -559,32 +534,31 @@ int tracepoint_get_iter_range(struct tracepoint * const **tracepoint, } return 0; } -//ust// EXPORT_SYMBOL_GPL(tracepoint_get_iter_range); +/* + * Called with tracepoint mutex held. + */ static void tracepoint_get_iter(struct tracepoint_iter *iter) { int found = 0; -//ust// /* Core kernel tracepoints */ -//ust// if (!iter->module) { -//ust// found = tracepoint_get_iter_range(&iter->tracepoint, -//ust// __start___tracepoints, __stop___tracepoints); -//ust// if (found) -//ust// goto end; -//ust// } /* tracepoints in libs. */ found = lib_get_iter_tracepoints(iter); -//ust// end: if (!found) tracepoint_iter_reset(iter); } +/* + * Called with UST lock held. + */ void tracepoint_iter_start(struct tracepoint_iter *iter) { tracepoint_get_iter(iter); } -//ust// EXPORT_SYMBOL_GPL(tracepoint_iter_start); +/* + * Called with UST lock held. + */ void tracepoint_iter_next(struct tracepoint_iter *iter) { iter->tracepoint++; @@ -595,54 +569,18 @@ void tracepoint_iter_next(struct tracepoint_iter *iter) */ tracepoint_get_iter(iter); } -//ust// EXPORT_SYMBOL_GPL(tracepoint_iter_next); +/* + * Called with UST lock held. + */ void tracepoint_iter_stop(struct tracepoint_iter *iter) { } -//ust// EXPORT_SYMBOL_GPL(tracepoint_iter_stop); void tracepoint_iter_reset(struct tracepoint_iter *iter) { -//ust// iter->module = NULL; iter->tracepoint = NULL; } -//ust// EXPORT_SYMBOL_GPL(tracepoint_iter_reset); - -//ust// #ifdef CONFIG_MODULES - -//ust// int tracepoint_module_notify(struct notifier_block *self, -//ust// unsigned long val, void *data) -//ust// { -//ust// struct module *mod = data; -//ust// -//ust// switch (val) { -//ust// case MODULE_STATE_COMING: -//ust// tracepoint_update_probe_range(mod->tracepoints, -//ust// mod->tracepoints + mod->num_tracepoints); -//ust// break; -//ust// case MODULE_STATE_GOING: -//ust// tracepoint_update_probe_range(mod->tracepoints, -//ust// mod->tracepoints + mod->num_tracepoints); -//ust// break; -//ust// } -//ust// return 0; -//ust// } - -//ust// struct notifier_block tracepoint_module_nb = { -//ust// .notifier_call = tracepoint_module_notify, -//ust// .priority = 0, -//ust// }; - -//ust// static int init_tracepoints(void) -//ust// { -//ust// return register_module_notifier(&tracepoint_module_nb); -//ust// } -//ust// __initcall(init_tracepoints); - -//ust// #endif /* CONFIG_MODULES */ - -static void (*new_tracepoint_cb)(struct tracepoint *) = NULL; void tracepoint_set_new_tracepoint_cb(void (*cb)(struct tracepoint *)) { @@ -654,24 +592,26 @@ static void new_tracepoints(struct tracepoint * const *start, struct tracepoint if (new_tracepoint_cb) { struct tracepoint * const *t; - for(t = start; t < end; t++) { + for (t = start; t < end; t++) { if (*t) new_tracepoint_cb(*t); } } } -int tracepoint_register_lib(struct tracepoint * const *tracepoints_start, int tracepoints_count) +int tracepoint_register_lib(struct tracepoint * const *tracepoints_start, + int tracepoints_count) { struct tracepoint_lib *pl, *iter; + init_tracepoint(); + pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib)); pl->tracepoints_start = tracepoints_start; pl->tracepoints_count = tracepoints_count; - /* FIXME: maybe protect this with its own mutex? */ - pthread_mutex_lock(&tracepoints_mutex); + ust_lock(); /* * We sort the libs by struct lib pointer address. */ @@ -686,15 +626,14 @@ int tracepoint_register_lib(struct tracepoint * const *tracepoints_start, int tr /* We should be added at the head of the list */ cds_list_add(&pl->list, &libs); lib_added: - pthread_mutex_unlock(&tracepoints_mutex); - new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count); - /* FIXME: update just the loaded lib */ + /* TODO: update just the loaded lib */ lib_update_tracepoints(); + ust_unlock(); - /* tracepoints_count - 1: skip dummy */ - DBG("just registered a tracepoints section from %p and having %d tracepoints (minus dummy tracepoints)", tracepoints_start, tracepoints_count); + DBG("just registered a tracepoints section from %p and having %d tracepoints", + tracepoints_start, tracepoints_count); return 0; } @@ -703,8 +642,7 @@ int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start) { struct tracepoint_lib *lib; - pthread_mutex_lock(&tracepoints_mutex); - + ust_lock(); cds_list_for_each_entry(lib, &libs, list) { if (lib->tracepoints_start == tracepoints_start) { struct tracepoint_lib *lib2free = lib; @@ -713,8 +651,19 @@ int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start) break; } } - - pthread_mutex_unlock(&tracepoints_mutex); + ust_unlock(); return 0; } + +void init_tracepoint(void) +{ + if (uatomic_xchg(&initialized, 1) == 1) + return; + init_usterr(); +} + +void exit_tracepoint(void) +{ + initialized = 0; +}