X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=lttng-events.c;h=e3a7324b84ab82ebb31761500d812c0c1c728f80;hb=ae7345475575f3b6610e29d81131d27beea1e3d1;hp=4f30904dc0c922d7c865369387a42c4d860a45c9;hpb=6dccd6c113eb0431a145b92abaf869b85ef7a92f;p=lttng-modules.git diff --git a/lttng-events.c b/lttng-events.c index 4f30904d..e3a7324b 100644 --- a/lttng-events.c +++ b/lttng-events.c @@ -31,12 +31,18 @@ #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */ #include "wrapper/random.h" #include "wrapper/tracepoint.h" +#include "lttng-kernel-version.h" #include "lttng-events.h" #include "lttng-tracer.h" #include "lttng-abi-old.h" +#define METADATA_CACHE_DEFAULT_SIZE 4096 + static LIST_HEAD(sessions); static LIST_HEAD(lttng_transport_list); +/* + * Protect the sessions and metadata caches. + */ static DEFINE_MUTEX(sessions_mutex); static struct kmem_cache *event_cache; @@ -49,35 +55,74 @@ int _lttng_event_metadata_statedump(struct lttng_session *session, struct lttng_event *event); static int _lttng_session_metadata_statedump(struct lttng_session *session); +static +void _lttng_metadata_channel_hangup(struct lttng_metadata_stream *stream); void synchronize_trace(void) { synchronize_sched(); +#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,4,0)) +#ifdef CONFIG_PREEMPT_RT_FULL + synchronize_rcu(); +#endif +#else /* (LINUX_VERSION_CODE >= KERNEL_VERSION(3,4,0)) */ #ifdef CONFIG_PREEMPT_RT synchronize_rcu(); #endif +#endif /* (LINUX_VERSION_CODE >= KERNEL_VERSION(3,4,0)) */ } struct lttng_session *lttng_session_create(void) { struct lttng_session *session; + struct lttng_metadata_cache *metadata_cache; mutex_lock(&sessions_mutex); session = kzalloc(sizeof(struct lttng_session), GFP_KERNEL); if (!session) - return NULL; + goto err; INIT_LIST_HEAD(&session->chan); INIT_LIST_HEAD(&session->events); uuid_le_gen(&session->uuid); + + metadata_cache = kzalloc(sizeof(struct lttng_metadata_cache), + GFP_KERNEL); + if (!metadata_cache) + goto err_free_session; + metadata_cache->data = kzalloc(METADATA_CACHE_DEFAULT_SIZE, + GFP_KERNEL); + if (!metadata_cache->data) + goto err_free_cache; + metadata_cache->cache_alloc = METADATA_CACHE_DEFAULT_SIZE; + kref_init(&metadata_cache->refcount); + session->metadata_cache = metadata_cache; + INIT_LIST_HEAD(&metadata_cache->metadata_stream); list_add(&session->list, &sessions); mutex_unlock(&sessions_mutex); return session; + +err_free_cache: + kfree(metadata_cache); +err_free_session: + kfree(session); +err: + mutex_unlock(&sessions_mutex); + return NULL; +} + +void metadata_cache_destroy(struct kref *kref) +{ + struct lttng_metadata_cache *cache = + container_of(kref, struct lttng_metadata_cache, refcount); + kfree(cache->data); + kfree(cache); } void lttng_session_destroy(struct lttng_session *session) { struct lttng_channel *chan, *tmpchan; struct lttng_event *event, *tmpevent; + struct lttng_metadata_stream *metadata_stream; int ret; mutex_lock(&sessions_mutex); @@ -93,8 +138,13 @@ void lttng_session_destroy(struct lttng_session *session) synchronize_trace(); /* Wait for in-flight events to complete */ list_for_each_entry_safe(event, tmpevent, &session->events, list) _lttng_event_destroy(event); - list_for_each_entry_safe(chan, tmpchan, &session->chan, list) + list_for_each_entry_safe(chan, tmpchan, &session->chan, list) { + BUG_ON(chan->channel_type == METADATA_CHANNEL); _lttng_channel_destroy(chan); + } + list_for_each_entry(metadata_stream, &session->metadata_cache->metadata_stream, list) + _lttng_metadata_channel_hangup(metadata_stream); + kref_put(&session->metadata_cache->refcount, metadata_cache_destroy); list_del(&session->list); mutex_unlock(&sessions_mutex); kfree(session); @@ -158,7 +208,7 @@ int lttng_channel_enable(struct lttng_channel *channel) { int old; - if (channel == channel->session->metadata) + if (channel->channel_type == METADATA_CHANNEL) return -EPERM; old = xchg(&channel->enabled, 1); if (old) @@ -170,7 +220,7 @@ int lttng_channel_disable(struct lttng_channel *channel) { int old; - if (channel == channel->session->metadata) + if (channel->channel_type == METADATA_CHANNEL) return -EPERM; old = xchg(&channel->enabled, 0); if (!old) @@ -182,7 +232,7 @@ int lttng_event_enable(struct lttng_event *event) { int old; - if (event->chan == event->chan->session->metadata) + if (event->chan->channel_type == METADATA_CHANNEL) return -EPERM; old = xchg(&event->enabled, 1); if (old) @@ -194,7 +244,7 @@ int lttng_event_disable(struct lttng_event *event) { int old; - if (event->chan == event->chan->session->metadata) + if (event->chan->channel_type == METADATA_CHANNEL) return -EPERM; old = xchg(&event->enabled, 0); if (!old) @@ -218,13 +268,14 @@ struct lttng_channel *lttng_channel_create(struct lttng_session *session, void *buf_addr, size_t subbuf_size, size_t num_subbuf, unsigned int switch_timer_interval, - unsigned int read_timer_interval) + unsigned int read_timer_interval, + enum channel_type channel_type) { struct lttng_channel *chan; struct lttng_transport *transport = NULL; mutex_lock(&sessions_mutex); - if (session->been_active) + if (session->been_active && channel_type != METADATA_CHANNEL) goto active; /* Refuse to add channel to active session */ transport = lttng_transport_find(transport_name); if (!transport) { @@ -241,6 +292,7 @@ struct lttng_channel *lttng_channel_create(struct lttng_session *session, goto nomem; chan->session = session; chan->id = session->free_chan_id++; + chan->ops = &transport->ops; /* * Note: the channel creation op already writes into the packet * headers. Therefore the "chan" information used as input @@ -252,8 +304,8 @@ struct lttng_channel *lttng_channel_create(struct lttng_session *session, if (!chan->chan) goto create_error; chan->enabled = 1; - chan->ops = &transport->ops; chan->transport = transport; + chan->channel_type = channel_type; list_add(&chan->list, &session->chan); mutex_unlock(&sessions_mutex); return chan; @@ -270,7 +322,9 @@ active: } /* - * Only used internally at session destruction. + * Only used internally at session destruction for per-cpu channels, and + * when metadata channel is released. + * Needs to be called with sessions mutex held. */ static void _lttng_channel_destroy(struct lttng_channel *chan) @@ -282,6 +336,24 @@ void _lttng_channel_destroy(struct lttng_channel *chan) kfree(chan); } +void lttng_metadata_channel_destroy(struct lttng_channel *chan) +{ + BUG_ON(chan->channel_type != METADATA_CHANNEL); + + /* Protect the metadata cache with the sessions_mutex. */ + mutex_lock(&sessions_mutex); + _lttng_channel_destroy(chan); + mutex_unlock(&sessions_mutex); +} +EXPORT_SYMBOL_GPL(lttng_metadata_channel_destroy); + +static +void _lttng_metadata_channel_hangup(struct lttng_metadata_stream *stream) +{ + stream->finalized = 1; + wake_up_interruptible(&stream->read_wait); +} + /* * Supports event creation while tracing session is active. */ @@ -394,6 +466,7 @@ struct lttng_event *lttng_event_create(struct lttng_channel *chan, break; default: WARN_ON_ONCE(1); + goto register_error; } ret = _lttng_event_metadata_statedump(chan->session, chan, event); if (ret) @@ -482,20 +555,69 @@ void _lttng_event_destroy(struct lttng_event *event) } /* + * Serialize at most one packet worth of metadata into a metadata + * channel. * We have exclusive access to our metadata buffer (protected by the * sessions_mutex), 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. + * Returns the number of bytes written in the channel, 0 if no data + * was written and a negative value on error. + */ +int lttng_metadata_output_channel(struct lttng_metadata_stream *stream, + struct channel *chan) +{ + struct lib_ring_buffer_ctx ctx; + int ret = 0; + size_t len, reserve_len; + + /* + * Ensure we support mutiple get_next / put sequences followed + * by put_next. + */ + WARN_ON(stream->metadata_in < stream->metadata_out); + if (stream->metadata_in != stream->metadata_out) + return 0; + + len = stream->metadata_cache->metadata_written - + stream->metadata_in; + if (!len) + return 0; + reserve_len = min_t(size_t, + stream->transport->ops.packet_avail_size(chan), + len); + lib_ring_buffer_ctx_init(&ctx, chan, NULL, reserve_len, + sizeof(char), -1); + /* + * If reservation failed, return an error to the caller. + */ + ret = stream->transport->ops.event_reserve(&ctx, 0); + if (ret != 0) { + printk(KERN_WARNING "LTTng: Metadata event reservation failed\n"); + goto end; + } + stream->transport->ops.event_write(&ctx, + stream->metadata_cache->data + stream->metadata_in, + reserve_len); + stream->transport->ops.event_commit(&ctx); + stream->metadata_in += reserve_len; + ret = reserve_len; + +end: + return ret; +} + +/* + * Write the metadata to the metadata cache. + * Must be called with sessions_mutex held. */ int lttng_metadata_printf(struct lttng_session *session, const char *fmt, ...) { - struct lib_ring_buffer_ctx ctx; - struct lttng_channel *chan = session->metadata; char *str; - int ret = 0, waitret; - size_t len, reserve_len, pos; + size_t len; va_list ap; + struct lttng_metadata_stream *stream; WARN_ON_ONCE(!ACCESS_ONCE(session->active)); @@ -506,42 +628,40 @@ int lttng_metadata_printf(struct lttng_session *session, return -ENOMEM; len = strlen(str); - pos = 0; - - for (pos = 0; pos < len; pos += reserve_len) { - reserve_len = min_t(size_t, - chan->ops->packet_avail_size(chan->chan), - len - pos); - lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, reserve_len, - sizeof(char), -1); - /* - * We don't care about metadata buffer's records lost - * count, because we always retry here. Report error if - * we need to bail out after timeout or being - * interrupted. - */ - waitret = wait_event_interruptible_timeout(*chan->ops->get_writer_buf_wait_queue(chan->chan, -1), - ({ - ret = chan->ops->event_reserve(&ctx, 0); - ret != -ENOBUFS || !ret; - }), - msecs_to_jiffies(LTTNG_METADATA_TIMEOUT_MSEC)); - if (!waitret || waitret == -ERESTARTSYS || ret) { - printk(KERN_WARNING "LTTng: Failure to write metadata to buffers (%s)\n", - waitret == -ERESTARTSYS ? "interrupted" : - (ret == -ENOBUFS ? "timeout" : "I/O error")); - if (waitret == -ERESTARTSYS) - ret = waitret; - goto end; - } - chan->ops->event_write(&ctx, &str[pos], reserve_len); - chan->ops->event_commit(&ctx); + if (session->metadata_cache->metadata_written + len > + session->metadata_cache->cache_alloc) { + char *tmp_cache_realloc; + unsigned int tmp_cache_alloc_size; + + tmp_cache_alloc_size = max_t(unsigned int, + session->metadata_cache->cache_alloc + len, + session->metadata_cache->cache_alloc << 1); + tmp_cache_realloc = krealloc(session->metadata_cache->data, + tmp_cache_alloc_size, GFP_KERNEL); + if (!tmp_cache_realloc) + goto err; + session->metadata_cache->cache_alloc = tmp_cache_alloc_size; + session->metadata_cache->data = tmp_cache_realloc; } -end: + memcpy(session->metadata_cache->data + + session->metadata_cache->metadata_written, + str, len); + session->metadata_cache->metadata_written += len; kfree(str); - return ret; + + list_for_each_entry(stream, &session->metadata_cache->metadata_stream, list) + wake_up_interruptible(&stream->read_wait); + + return 0; + +err: + kfree(str); + return -ENOMEM; } +/* + * Must be called with sessions_mutex held. + */ static int _lttng_field_statedump(struct lttng_session *session, const struct lttng_event_field *field) @@ -698,6 +818,9 @@ int _lttng_fields_metadata_statedump(struct lttng_session *session, return ret; } +/* + * Must be called with sessions_mutex held. + */ static int _lttng_event_metadata_statedump(struct lttng_session *session, struct lttng_channel *chan, @@ -707,12 +830,12 @@ int _lttng_event_metadata_statedump(struct lttng_session *session, if (event->metadata_dumped || !ACCESS_ONCE(session->active)) return 0; - if (chan == session->metadata) + if (chan->channel_type == METADATA_CHANNEL) return 0; ret = lttng_metadata_printf(session, "event {\n" - " name = %s;\n" + " name = \"%s\";\n" " id = %u;\n" " stream_id = %u;\n", event->desc->name, @@ -763,6 +886,9 @@ end: } +/* + * Must be called with sessions_mutex held. + */ static int _lttng_channel_metadata_statedump(struct lttng_session *session, struct lttng_channel *chan) @@ -771,7 +897,8 @@ int _lttng_channel_metadata_statedump(struct lttng_session *session, if (chan->metadata_dumped || !ACCESS_ONCE(session->active)) return 0; - if (chan == session->metadata) + + if (chan->channel_type == METADATA_CHANNEL) return 0; WARN_ON_ONCE(!chan->header_type); @@ -810,6 +937,9 @@ end: return ret; } +/* + * Must be called with sessions_mutex held. + */ static int _lttng_stream_packet_context_declare(struct lttng_session *session) { @@ -833,6 +963,8 @@ int _lttng_stream_packet_context_declare(struct lttng_session *session) * Large header: * id: range: 0 - 65534. * id 65535 is reserved to indicate an extended header. + * + * Must be called with sessions_mutex held. */ static int _lttng_event_header_declare(struct lttng_session *session) @@ -897,6 +1029,7 @@ uint64_t measure_clock_offset(void) /* * Output metadata into this session's metadata buffers. + * Must be called with sessions_mutex held. */ static int _lttng_session_metadata_statedump(struct lttng_session *session) @@ -911,10 +1044,6 @@ int _lttng_session_metadata_statedump(struct lttng_session *session) return 0; if (session->metadata_dumped) goto skip_session; - if (!session->metadata) { - printk(KERN_WARNING "LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n"); - return -EPERM; - } snprintf(uuid_s, sizeof(uuid_s), "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", @@ -1131,3 +1260,6 @@ module_exit(lttng_events_exit); MODULE_LICENSE("GPL and additional rights"); MODULE_AUTHOR("Mathieu Desnoyers "); MODULE_DESCRIPTION("LTTng Events"); +MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "." + __stringify(LTTNG_MODULES_MINOR_VERSION) "." + __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION));