X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Ftracepoint.c;h=5fd1126aa42d3b03c5709994aaad61c4ddaa11ae;hb=d037c38da67d7955ab65d994a6d718697a1e7182;hp=013f9b2a6091a69e4e07f8d9365ac695c39cc84f;hpb=3469bbbe391e22739245dc35091d944b50429179;p=lttng-ust.git diff --git a/liblttng-ust/tracepoint.c b/liblttng-ust/tracepoint.c index 013f9b2a..5fd1126a 100644 --- a/liblttng-ust/tracepoint.c +++ b/liblttng-ust/tracepoint.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include /* for LTTNG_UST_SYM_NAME_LEN */ @@ -45,7 +46,7 @@ /* Set to 1 to enable tracepoint debug output */ static const int tracepoint_debug; static int initialized; -static void (*new_tracepoint_cb)(struct tracepoint *); +static void (*new_tracepoint_cb)(struct lttng_ust_tracepoint *); /* * tracepoint_mutex nests inside UST mutex. @@ -93,8 +94,9 @@ static int need_update; */ struct tracepoint_entry { struct cds_hlist_node hlist; - struct tracepoint_probe *probes; + struct lttng_ust_tracepoint_probe *probes; int refcount; /* Number of times armed. 0 if disarmed. */ + int callsite_refcount; /* how many libs use this tracepoint */ const char *signature; char name[0]; }; @@ -105,7 +107,7 @@ struct tp_probes { /* Field below only used for call_rcu scheme */ /* struct rcu_head head; */ } u; - struct tracepoint_probe probes[0]; + struct lttng_ust_tracepoint_probe probes[0]; }; /* @@ -119,16 +121,19 @@ static struct cds_hlist_head callsite_table[CALLSITE_TABLE_SIZE]; struct callsite_entry { struct cds_hlist_node hlist; /* hash table node */ struct cds_list_head node; /* lib list of callsites node */ - struct tracepoint *tp; + struct lttng_ust_tracepoint *tp; }; +/* coverity[+alloc] */ static void *allocate_probes(int count) { - struct tp_probes *p = zmalloc(count * sizeof(struct tracepoint_probe) - + sizeof(struct tp_probes)); + struct tp_probes *p = + zmalloc(count * sizeof(struct lttng_ust_tracepoint_probe) + + sizeof(struct tp_probes)); return p == NULL ? NULL : p->probes; } +/* coverity[+free : arg-0] */ static void release_probes(void *old) { if (old) { @@ -155,7 +160,7 @@ tracepoint_entry_add_probe(struct tracepoint_entry *entry, void (*probe)(void), void *data) { int nr_probes = 0; - struct tracepoint_probe *old, *new; + struct lttng_ust_tracepoint_probe *old, *new; if (!probe) { WARN_ON(1); @@ -175,7 +180,8 @@ tracepoint_entry_add_probe(struct tracepoint_entry *entry, if (new == NULL) return ERR_PTR(-ENOMEM); if (old) - memcpy(new, old, nr_probes * sizeof(struct tracepoint_probe)); + memcpy(new, old, + nr_probes * sizeof(struct lttng_ust_tracepoint_probe)); new[nr_probes].func = probe; new[nr_probes].data = data; new[nr_probes + 1].func = NULL; @@ -190,7 +196,7 @@ tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void (*probe)(void), void *data) { int nr_probes = 0, nr_del = 0, i; - struct tracepoint_probe *old, *new; + struct lttng_ust_tracepoint_probe *old, *new; old = entry->probes; @@ -293,6 +299,7 @@ static struct tracepoint_entry *add_tracepoint(const char *name, e->name[name_len] = '\0'; e->probes = NULL; e->refcount = 0; + e->callsite_refcount = 0; e->signature = signature; cds_hlist_add_head(&e->hlist, head); return e; @@ -308,46 +315,11 @@ static void remove_tracepoint(struct tracepoint_entry *e) free(e); } -/* - * Add the callsite to the callsite hash table. Must be called with - * tracepoint mutex held. - */ -static void add_callsite(struct tracepoint *tp) -{ - struct cds_hlist_head *head; - struct callsite_entry *e; - const char *name = tp->name; - size_t name_len = strlen(name); - uint32_t hash; - - if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { - WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); - name_len = LTTNG_UST_SYM_NAME_LEN - 1; - } - hash = jhash(name, name_len, 0); - head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; - e = zmalloc(sizeof(struct callsite_entry)); - assert(e); - cds_hlist_add_head(&e->hlist, head); - e->tp = tp; -} - -/* - * Remove the callsite from the callsite hash table and from lib - * callsite list. Must be called with tracepoint mutex held. - */ -static void remove_callsite(struct callsite_entry *e) -{ - cds_hlist_del(&e->hlist); - cds_list_del(&e->node); - free(e); -} - /* * Sets the probe callback corresponding to one tracepoint. */ static void set_tracepoint(struct tracepoint_entry **entry, - struct tracepoint *elem, int active) + struct lttng_ust_tracepoint *elem, int active) { WARN_ON(strncmp((*entry)->name, elem->name, LTTNG_UST_SYM_NAME_LEN - 1) != 0); /* @@ -376,7 +348,7 @@ static void set_tracepoint(struct tracepoint_entry **entry, * is used. */ rcu_assign_pointer(elem->probes, (*entry)->probes); - elem->state = active; + CMM_STORE_SHARED(elem->state, active); } /* @@ -385,12 +357,65 @@ static void set_tracepoint(struct tracepoint_entry **entry, * function insures that the original callback is not used anymore. This insured * by preempt_disable around the call site. */ -static void disable_tracepoint(struct tracepoint *elem) +static void disable_tracepoint(struct lttng_ust_tracepoint *elem) { - elem->state = 0; + CMM_STORE_SHARED(elem->state, 0); rcu_assign_pointer(elem->probes, NULL); } +/* + * Add the callsite to the callsite hash table. Must be called with + * tracepoint mutex held. + */ +static void add_callsite(struct tracepoint_lib * lib, struct lttng_ust_tracepoint *tp) +{ + struct cds_hlist_head *head; + struct callsite_entry *e; + const char *name = tp->name; + size_t name_len = strlen(name); + uint32_t hash; + struct tracepoint_entry *tp_entry; + + if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { + WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); + name_len = LTTNG_UST_SYM_NAME_LEN - 1; + } + hash = jhash(name, name_len, 0); + head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; + e = zmalloc(sizeof(struct callsite_entry)); + if (!e) { + PERROR("Unable to add callsite for tracepoint \"%s\"", name); + return; + } + cds_hlist_add_head(&e->hlist, head); + e->tp = tp; + cds_list_add(&e->node, &lib->callsites); + + tp_entry = get_tracepoint(name); + if (!tp_entry) + return; + tp_entry->callsite_refcount++; +} + +/* + * Remove the callsite from the callsite hash table and from lib + * callsite list. Must be called with tracepoint mutex held. + */ +static void remove_callsite(struct callsite_entry *e) +{ + struct tracepoint_entry *tp_entry; + + tp_entry = get_tracepoint(e->tp->name); + if (tp_entry) { + tp_entry->callsite_refcount--; + if (tp_entry->callsite_refcount == 0) + disable_tracepoint(e->tp); + } + cds_hlist_del(&e->hlist); + cds_list_del(&e->node); + free(e); +} + /* * Enable/disable all callsites based on the state of a specific * tracepoint entry. @@ -413,7 +438,7 @@ static void tracepoint_sync_callsites(const char *name) hash = jhash(name, name_len, 0); head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; cds_hlist_for_each_entry(e, node, head, hlist) { - struct tracepoint *tp = e->tp; + struct lttng_ust_tracepoint *tp = e->tp; if (strncmp(name, tp->name, LTTNG_UST_SYM_NAME_LEN - 1)) continue; @@ -434,10 +459,10 @@ static void tracepoint_sync_callsites(const char *name) * Updates the probe callback corresponding to a range of tracepoints. */ static -void tracepoint_update_probe_range(struct tracepoint * const *begin, - struct tracepoint * const *end) +void tracepoint_update_probe_range(struct lttng_ust_tracepoint * const *begin, + struct lttng_ust_tracepoint * const *end) { - struct tracepoint * const *iter; + struct lttng_ust_tracepoint * const *iter; struct tracepoint_entry *mark_entry; for (iter = begin; iter < end; iter++) { @@ -465,9 +490,9 @@ static void lib_update_tracepoints(struct tracepoint_lib *lib) static void lib_register_callsites(struct tracepoint_lib *lib) { - struct tracepoint * const *begin; - struct tracepoint * const *end; - struct tracepoint * const *iter; + struct lttng_ust_tracepoint * const *begin; + struct lttng_ust_tracepoint * const *end; + struct lttng_ust_tracepoint * const *iter; begin = lib->tracepoints_start; end = lib->tracepoints_start + lib->tracepoints_count; @@ -478,7 +503,7 @@ static void lib_register_callsites(struct tracepoint_lib *lib) if (!(*iter)->name) { continue; } - add_callsite(*iter); + add_callsite(lib, *iter); } } @@ -502,18 +527,18 @@ static void tracepoint_update_probes(void) lib_update_tracepoints(lib); } -static struct tracepoint_probe * +static struct lttng_ust_tracepoint_probe * tracepoint_add_probe(const char *name, void (*probe)(void), void *data, const char *signature) { struct tracepoint_entry *entry; - struct tracepoint_probe *old; + struct lttng_ust_tracepoint_probe *old; entry = get_tracepoint(name); if (!entry) { entry = add_tracepoint(name, signature); if (IS_ERR(entry)) - return (struct tracepoint_probe *)entry; + return (struct lttng_ust_tracepoint_probe *)entry; } old = tracepoint_entry_add_probe(entry, probe, data); if (IS_ERR(old) && !entry->refcount) @@ -685,15 +710,16 @@ end: pthread_mutex_unlock(&tracepoint_mutex); } -void tracepoint_set_new_tracepoint_cb(void (*cb)(struct tracepoint *)) +void tracepoint_set_new_tracepoint_cb(void (*cb)(struct lttng_ust_tracepoint *)) { new_tracepoint_cb = cb; } -static void new_tracepoints(struct tracepoint * const *start, struct tracepoint * const *end) +static void new_tracepoints(struct lttng_ust_tracepoint * const *start, + struct lttng_ust_tracepoint * const *end) { if (new_tracepoint_cb) { - struct tracepoint * const *t; + struct lttng_ust_tracepoint * const *t; for (t = start; t < end; t++) { if (*t) @@ -702,25 +728,7 @@ static void new_tracepoints(struct tracepoint * const *start, struct tracepoint } } -static -void lib_disable_tracepoints(struct tracepoint_lib *lib) -{ - struct tracepoint * const *begin; - struct tracepoint * const *end; - struct tracepoint * const *iter; - - begin = lib->tracepoints_start; - end = lib->tracepoints_start + lib->tracepoints_count; - - for (iter = begin; iter < end; iter++) { - if (!*iter) - continue; /* skip dummy */ - disable_tracepoint(*iter); - } - -} - -int tracepoint_register_lib(struct tracepoint * const *tracepoints_start, +int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start, int tracepoints_count) { struct tracepoint_lib *pl, *iter; @@ -728,7 +736,10 @@ int tracepoint_register_lib(struct tracepoint * const *tracepoints_start, init_tracepoint(); pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib)); - + if (!pl) { + PERROR("Unable to register tracepoint lib"); + return -1; + } pl->tracepoints_start = tracepoints_start; pl->tracepoints_count = tracepoints_count; CDS_INIT_LIST_HEAD(&pl->callsites); @@ -766,7 +777,7 @@ lib_added: return 0; } -int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start) +int tracepoint_unregister_lib(struct lttng_ust_tracepoint * const *tracepoints_start) { struct tracepoint_lib *lib; @@ -777,13 +788,11 @@ int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start) cds_list_del(&lib->list); /* - * Force tracepoint disarm for all tracepoints of this lib. - * This takes care of destructor of library that would leave a - * LD_PRELOAD wrapper override function enabled for tracing, but - * the session teardown would not be able to reach the - * tracepoint anymore to disable it. + * Unregistering a callsite also decreases the + * callsite reference count of the corresponding + * tracepoint, and disables the tracepoint if + * the reference count drops to zero. */ - lib_disable_tracepoints(lib); lib_unregister_callsites(lib); DBG("just unregistered a tracepoints section from %p", lib->tracepoints_start);