From 7fad9b39ca9e872aadd7df5bcb21db02fe46f70e Mon Sep 17 00:00:00 2001 From: Francis Deslauriers Date: Wed, 5 Feb 2020 14:46:08 -0500 Subject: [PATCH] Implement event notifier probes Signed-off-by: Francis Deslauriers Signed-off-by: Mathieu Desnoyers Change-Id: I807b344edb65ad8d1343187b987f693113029794 --- include/lttng/events.h | 2 + include/lttng/tracepoint-event-impl.h | 189 +++++++++++++++++++++++++- 2 files changed, 189 insertions(+), 2 deletions(-) diff --git a/include/lttng/events.h b/include/lttng/events.h index 4c94116e..37319ac9 100644 --- a/include/lttng/events.h +++ b/include/lttng/events.h @@ -170,6 +170,7 @@ struct lttng_perf_counter_field { struct lttng_probe_ctx { struct lttng_event *event; + struct lttng_event_notifier *event_notifier; // Not sure if we will ever need it. uint8_t interruptible; }; @@ -212,6 +213,7 @@ struct lttng_event_desc { const struct lttng_event_field *fields; /* event payload */ unsigned int nr_fields; struct module *owner; + void *event_notifier_callback; }; struct lttng_probe_desc { diff --git a/include/lttng/tracepoint-event-impl.h b/include/lttng/tracepoint-event-impl.h index f27a45c0..d6448f0b 100644 --- a/include/lttng/tracepoint-event-impl.h +++ b/include/lttng/tracepoint-event-impl.h @@ -172,6 +172,41 @@ void __event_template_proto___##_name(void); #include TRACE_INCLUDE(TRACE_INCLUDE_FILE) +/* + * Stage 1.2 of the trace event_notifier. + * + * Create dummy trace prototypes for each event class, and for each used + * template. This will allow checking whether the prototypes from the + * class and the instance using the class actually match. + */ + +#include /* Reset all macros within TRACE_EVENT */ + +#undef TP_PROTO +#define TP_PROTO(...) __VA_ARGS__ + +#undef TP_ARGS +#define TP_ARGS(...) __VA_ARGS__ + +#undef LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP +#define LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP(_template, _name, _map, _proto, _args) \ +void __event_notifier_template_proto___##_template(_proto); + +#undef LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP_NOARGS +#define LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP_NOARGS(_template, _name, _map) \ +void __event_notifier_template_proto___##_template(void); + +#undef LTTNG_TRACEPOINT_EVENT_CLASS_CODE +#define LTTNG_TRACEPOINT_EVENT_CLASS_CODE(_name, _proto, _args, _locvar, _code_pre, _fields, _code_post) \ +void __event_notifier_template_proto___##_name(_proto); + +#undef LTTNG_TRACEPOINT_EVENT_CLASS_CODE_NOARGS +#define LTTNG_TRACEPOINT_EVENT_CLASS_CODE_NOARGS(_name, _locvar, _code_pre, _fields, _code_post) \ +void __event_notifier_template_proto___##_name(void); + +#include TRACE_INCLUDE(TRACE_INCLUDE_FILE) + + /* * Stage 1.2 of tracepoint event generation * @@ -469,6 +504,28 @@ static void __event_probe__##_name(void *__data); #include TRACE_INCLUDE(TRACE_INCLUDE_FILE) +/* + * Stage 3.1 of the trace event_notifiers. + * + * Create event_notifier probe callback prototypes. + */ + +/* Reset all macros within TRACEPOINT_EVENT */ +#include + +#undef TP_PROTO +#define TP_PROTO(...) __VA_ARGS__ + +#undef LTTNG_TRACEPOINT_EVENT_CLASS_CODE +#define LTTNG_TRACEPOINT_EVENT_CLASS_CODE(_name, _proto, _args, _locvar, _code_pre, _fields, _code_post) \ +static void __event_notifier_probe__##_name(void *__data, _proto); + +#undef LTTNG_TRACEPOINT_EVENT_CLASS_CODE_NOARGS +#define LTTNG_TRACEPOINT_EVENT_CLASS_CODE_NOARGS(_name, _locvar, _code_pre, _fields, _code_post) \ +static void __event_notifier_probe__##_name(void *__data); + +#include TRACE_INCLUDE(TRACE_INCLUDE_FILE) + /* * Stage 4 of the trace events. * @@ -1131,8 +1188,9 @@ static void __event_probe__##_name(void *__data, _proto) \ { \ struct probe_local_vars { _locvar }; \ struct lttng_event *__event = __data; \ - struct lttng_probe_ctx __lttng_probe_ctx = { \ + struct lttng_probe_ctx __lttng_probe_ctx = { \ .event = __event, \ + .event_notifier = NULL, \ .interruptible = !irqs_disabled(), \ }; \ struct lttng_channel *__chan = __event->chan; \ @@ -1226,8 +1284,9 @@ static void __event_probe__##_name(void *__data) \ { \ struct probe_local_vars { _locvar }; \ struct lttng_event *__event = __data; \ - struct lttng_probe_ctx __lttng_probe_ctx = { \ + struct lttng_probe_ctx __lttng_probe_ctx = { \ .event = __event, \ + .event_notifier = NULL, \ .interruptible = !irqs_disabled(), \ }; \ struct lttng_channel *__chan = __event->chan; \ @@ -1319,6 +1378,127 @@ __post: \ #undef __get_dynamic_len +/* + * Stage 6.1 of tracepoint generation: generate event notifier probes + * + * Create the probe function. This function evaluates the filter bytecode and + * queue a notification to be sent to userspace. + */ + +#include /* Reset all macros within LTTNG_TRACEPOINT_EVENT */ + +#undef TP_PROTO +#define TP_PROTO(...) __VA_ARGS__ + +#undef TP_ARGS +#define TP_ARGS(...) __VA_ARGS__ + +#undef TP_FIELDS +#define TP_FIELDS(...) __VA_ARGS__ + +#undef TP_locvar +#define TP_locvar(...) __VA_ARGS__ + +#undef TP_code_pre +#define TP_code_pre(...) __VA_ARGS__ + +#undef TP_code_post +#define TP_code_post(...) __VA_ARGS__ + +/* + * Using twice size for filter stack data to hold size and pointer for + * each field (worse case). For integers, max size required is 64-bit. + * Same for double-precision floats. Those fit within + * 2*sizeof(unsigned long) for all supported architectures. + * Perform UNION (||) of filter runtime list. + */ +#undef LTTNG_TRACEPOINT_EVENT_CLASS_CODE +#define LTTNG_TRACEPOINT_EVENT_CLASS_CODE(_name, _proto, _args, _locvar, _code_pre, _fields, _code_post) \ +static void __event_notifier_probe__##_name(void *__data, _proto) \ +{ \ + struct probe_local_vars { _locvar }; \ + struct lttng_event_notifier *__event_notifier = __data; \ + struct lttng_probe_ctx __lttng_probe_ctx = { \ + .event = NULL, \ + .event_notifier = __event_notifier, \ + .interruptible = !irqs_disabled(), \ + }; \ + union { \ + size_t __dynamic_len_removed[ARRAY_SIZE(__event_fields___##_name)]; \ + char __filter_stack_data[2 * sizeof(unsigned long) * ARRAY_SIZE(__event_fields___##_name)]; \ + } __stackvar; \ + struct probe_local_vars __tp_locvar; \ + struct probe_local_vars *tp_locvar __attribute__((unused)) = \ + &__tp_locvar; \ + \ + if (unlikely(!READ_ONCE(__event_notifier->enabled))) \ + return; \ + _code_pre \ + if (unlikely(!list_empty(&__event_notifier->bytecode_runtime_head))) { \ + struct lttng_bytecode_runtime *bc_runtime; \ + int __filter_record = __event_notifier->has_enablers_without_bytecode; \ + \ + __event_prepare_filter_stack__##_name(__stackvar.__filter_stack_data, \ + tp_locvar, _args); \ + lttng_list_for_each_entry_rcu(bc_runtime, &__event_notifier->bytecode_runtime_head, node) { \ + if (unlikely(bc_runtime->filter(bc_runtime, &__lttng_probe_ctx, \ + __stackvar.__filter_stack_data) & LTTNG_FILTER_RECORD_FLAG)) \ + __filter_record = 1; \ + } \ + if (likely(!__filter_record)) \ + goto __post; \ + } \ + \ + __event_notifier->send_notification(__event_notifier); \ +__post: \ + _code_post \ + return; \ +} + +#undef LTTNG_TRACEPOINT_EVENT_CLASS_CODE_NOARGS +#define LTTNG_TRACEPOINT_EVENT_CLASS_CODE_NOARGS(_name, _locvar, _code_pre, _fields, _code_post) \ +static void __event_notifier_probe__##_name(void *__data) \ +{ \ + struct probe_local_vars { _locvar }; \ + struct lttng_event_notifier *__event_notifier = __data; \ + struct lttng_probe_ctx __lttng_probe_ctx = { \ + .event = NULL, \ + .event_notifier = __event_notifier, \ + .interruptible = !irqs_disabled(), \ + }; \ + union { \ + size_t __dynamic_len_removed[ARRAY_SIZE(__event_fields___##_name)]; \ + char __filter_stack_data[2 * sizeof(unsigned long) * ARRAY_SIZE(__event_fields___##_name)]; \ + } __stackvar; \ + struct probe_local_vars __tp_locvar; \ + struct probe_local_vars *tp_locvar __attribute__((unused)) = \ + &__tp_locvar; \ + \ + if (unlikely(!READ_ONCE(__event_notifier->enabled))) \ + return; \ + _code_pre \ + if (unlikely(!list_empty(&__event_notifier->bytecode_runtime_head))) { \ + struct lttng_bytecode_runtime *bc_runtime; \ + int __filter_record = __event_notifier->has_enablers_without_bytecode; \ + \ + __event_prepare_filter_stack__##_name(__stackvar.__filter_stack_data, \ + tp_locvar); \ + lttng_list_for_each_entry_rcu(bc_runtime, &__event_notifier->bytecode_runtime_head, node) { \ + if (unlikely(bc_runtime->filter(bc_runtime, &__lttng_probe_ctx, \ + __stackvar.__filter_stack_data) & LTTNG_FILTER_RECORD_FLAG)) \ + __filter_record = 1; \ + } \ + if (likely(!__filter_record)) \ + goto __post; \ + } \ + \ + __event_notifier->send_notification(__event_notifier); \ +__post: \ + _code_post \ + return; \ +} + +#include TRACE_INCLUDE(TRACE_INCLUDE_FILE) /* * Stage 7 of the trace events. * @@ -1333,6 +1513,10 @@ __post: \ #define TP_PROBE_CB(_template) &__event_probe__##_template #endif +#ifndef TP_EVENT_NOTIFIER_PROBE_CB +#define TP_EVENT_NOTIFIER_PROBE_CB(_template) &__event_notifier_probe__##_template +#endif + #undef LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP_NOARGS #define LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP_NOARGS(_template, _name, _map) \ static const struct lttng_event_desc __event_desc___##_map = { \ @@ -1342,6 +1526,7 @@ static const struct lttng_event_desc __event_desc___##_map = { \ .probe_callback = (void *) TP_PROBE_CB(_template), \ .nr_fields = ARRAY_SIZE(__event_fields___##_template), \ .owner = THIS_MODULE, \ + .event_notifier_callback = (void *) TP_EVENT_NOTIFIER_PROBE_CB(_template), \ }; #undef LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP -- 2.34.1