X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=liblttng-ust%2Flttng-probes.c;h=b1d5fe28558433209f70460119125ca81b433793;hb=4dcd7e8051161c3497af97e55f4866ea5ebeac11;hp=6b671da06c673ad0f6c59622062038439b46f138;hpb=48205d6057735bebb9e9fb87781bb17614782200;p=lttng-ust.git diff --git a/liblttng-ust/lttng-probes.c b/liblttng-ust/lttng-probes.c index 6b671da0..b1d5fe28 100644 --- a/liblttng-ust/lttng-probes.c +++ b/liblttng-ust/lttng-probes.c @@ -38,25 +38,23 @@ /* * probe list is protected by ust_lock()/ust_unlock(). */ -CDS_LIST_HEAD(probe_list); +static CDS_LIST_HEAD(_probe_list); -struct cds_list_head *lttng_get_probe_list_head(void) -{ - return &probe_list; -} - -static -const struct lttng_probe_desc *find_provider(const char *provider) -{ - struct lttng_probe_desc *iter; +/* + * List of probes registered by not yet processed. + */ +static CDS_LIST_HEAD(lazy_probe_init); - cds_list_for_each_entry(iter, &probe_list, head) { - if (!strcmp(iter->provider, provider)) - return iter; - } - return NULL; -} +/* + * lazy_nesting counter ensures we don't trigger lazy probe registration + * fixup while we are performing the fixup. It is protected by the ust + * mutex. + */ +static int lazy_nesting; +/* + * Called under ust lock. + */ static int check_event_provider(struct lttng_probe_desc *desc) { @@ -74,22 +72,16 @@ int check_event_provider(struct lttng_probe_desc *desc) return 1; } -int lttng_probe_register(struct lttng_probe_desc *desc) +/* + * Called under ust lock. + */ +static +void lttng_lazy_probe_register(struct lttng_probe_desc *desc) { struct lttng_probe_desc *iter; - int ret = 0; + struct cds_list_head *probe_list; int i; - ust_lock(); - - /* - * Check if the provider has already been registered. - */ - if (find_provider(desc->provider)) { - ret = -EEXIST; - goto end; - } - /* * Each provider enforce that every event name begins with the * provider name. Check this in an assertion for extra @@ -108,7 +100,8 @@ int lttng_probe_register(struct lttng_probe_desc *desc) * We sort the providers by struct lttng_probe_desc pointer * address. */ - cds_list_for_each_entry_reverse(iter, &probe_list, head) { + probe_list = &_probe_list; + cds_list_for_each_entry_reverse(iter, probe_list, head) { BUG_ON(iter == desc); /* Should never be in the list twice */ if (iter < desc) { /* We belong to the location right after iter. */ @@ -117,7 +110,7 @@ int lttng_probe_register(struct lttng_probe_desc *desc) } } /* We should be added at the head of the list */ - cds_list_add(&desc->head, &probe_list); + cds_list_add(&desc->head, probe_list); desc_added: DBG("just registered probe %s containing %u events", desc->provider, desc->nr_events); @@ -126,6 +119,7 @@ desc_added: */ for (i = 0; i < desc->nr_events; i++) { const struct lttng_event_desc *ed; + int ret; ed = desc->event_desc[i]; DBG("Registered event probe \"%s\" with signature \"%s\"", @@ -133,6 +127,74 @@ desc_added: ret = lttng_fix_pending_event_desc(ed); assert(!ret); } +} + +/* + * Called under ust lock. + */ +static +void fixup_lazy_probes(void) +{ + struct lttng_probe_desc *iter, *tmp; + + lazy_nesting++; + cds_list_for_each_entry_safe(iter, tmp, + &lazy_probe_init, lazy_init_head) { + lttng_lazy_probe_register(iter); + iter->lazy = 0; + cds_list_del(&iter->lazy_init_head); + } + lazy_nesting--; +} + +/* + * Called under ust lock. + */ +struct cds_list_head *lttng_get_probe_list_head(void) +{ + if (!lazy_nesting && !cds_list_empty(&lazy_probe_init)) + fixup_lazy_probes(); + return &_probe_list; +} + +static +const struct lttng_probe_desc *find_provider(const char *provider) +{ + struct lttng_probe_desc *iter; + struct cds_list_head *probe_list; + + probe_list = lttng_get_probe_list_head(); + cds_list_for_each_entry(iter, probe_list, head) { + if (!strcmp(iter->provider, provider)) + return iter; + } + return NULL; +} + +int lttng_probe_register(struct lttng_probe_desc *desc) +{ + int ret = 0; + + ust_lock(); + + /* + * Check if the provider has already been registered. + */ + if (find_provider(desc->provider)) { + ret = -EEXIST; + goto end; + } + cds_list_add(&desc->lazy_init_head, &lazy_probe_init); + desc->lazy = 1; + DBG("adding probe %s containing %u events to lazy registration list", + desc->provider, desc->nr_events); + /* + * If there is at least one active session, we need to register + * the probe immediately, since we cannot delay event + * registration because they are needed ASAP. + */ + if (lttng_session_active()) + fixup_lazy_probes(); end: ust_unlock(); return ret; @@ -147,7 +209,10 @@ int ltt_probe_register(struct lttng_probe_desc *desc) void lttng_probe_unregister(struct lttng_probe_desc *desc) { ust_lock(); - cds_list_del(&desc->head); + if (!desc->lazy) + cds_list_del(&desc->head); + else + cds_list_del(&desc->lazy_init_head); DBG("just unregistered probe %s", desc->provider); ust_unlock(); } @@ -175,9 +240,11 @@ int lttng_probes_get_event_list(struct lttng_ust_tracepoint_list *list) { struct lttng_probe_desc *probe_desc; int i; + struct cds_list_head *probe_list; + probe_list = lttng_get_probe_list_head(); CDS_INIT_LIST_HEAD(&list->head); - cds_list_for_each_entry(probe_desc, &probe_list, head) { + cds_list_for_each_entry(probe_desc, probe_list, head) { for (i = 0; i < probe_desc->nr_events; i++) { struct tp_list_entry *list_entry; @@ -245,9 +312,11 @@ int lttng_probes_get_field_list(struct lttng_ust_field_list *list) { struct lttng_probe_desc *probe_desc; int i; + struct cds_list_head *probe_list; + probe_list = lttng_get_probe_list_head(); CDS_INIT_LIST_HEAD(&list->head); - cds_list_for_each_entry(probe_desc, &probe_list, head) { + cds_list_for_each_entry(probe_desc, probe_list, head) { for (i = 0; i < probe_desc->nr_events; i++) { const struct lttng_event_desc *event_desc = probe_desc->event_desc[i];