X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=lttng-events.c;h=b49851b548fa357d1ff249d732596bc11e415a16;hb=5594698f9c8ad13e0964c67946d1867df7757dae;hp=7eec04c0f269682a1aed08bbc501a9a992a127ea;hpb=8c6e7f13c778701dec2d6549f1e2ca98970907a0;p=lttng-modules.git diff --git a/lttng-events.c b/lttng-events.c index 7eec04c0..b49851b5 100644 --- a/lttng-events.c +++ b/lttng-events.c @@ -39,6 +39,7 @@ #include "wrapper/file.h" #include #include +#include #include "wrapper/uuid.h" #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */ @@ -132,12 +133,12 @@ struct lttng_session *lttng_session_create(void) GFP_KERNEL); if (!metadata_cache) goto err_free_session; - metadata_cache->data = kzalloc(METADATA_CACHE_DEFAULT_SIZE, - GFP_KERNEL); + metadata_cache->data = vzalloc(METADATA_CACHE_DEFAULT_SIZE); if (!metadata_cache->data) goto err_free_cache; metadata_cache->cache_alloc = METADATA_CACHE_DEFAULT_SIZE; kref_init(&metadata_cache->refcount); + mutex_init(&metadata_cache->lock); session->metadata_cache = metadata_cache; INIT_LIST_HEAD(&metadata_cache->metadata_stream); memcpy(&metadata_cache->uuid, &session->uuid, @@ -162,7 +163,7 @@ void metadata_cache_destroy(struct kref *kref) { struct lttng_metadata_cache *cache = container_of(kref, struct lttng_metadata_cache, refcount); - kfree(cache->data); + vfree(cache->data); kfree(cache); } @@ -1439,10 +1440,12 @@ void lttng_session_lazy_sync_enablers(struct lttng_session *session) /* * 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. + * We grab the metadata cache mutex to get exclusive access to our metadata + * buffer and to the metadata cache. Exclusive access to the metadata buffer + * allows us to do racy operations such as looking for remaining space left in + * packet and write, since mutual exclusion protects us from concurrent writes. + * Mutual exclusion on the metadata cache allow us to read the cache content + * without racing against reallocation of the cache by updates. * Returns the number of bytes written in the channel, 0 if no data * was written and a negative value on error. */ @@ -1454,13 +1457,15 @@ int lttng_metadata_output_channel(struct lttng_metadata_stream *stream, size_t len, reserve_len; /* - * Ensure we support mutiple get_next / put sequences followed - * by put_next. The metadata stream lock internally protects - * reading the metadata cache. It can indeed be read - * concurrently by "get_next_subbuf" and "flush" operations on - * the buffer invoked by different processes. + * Ensure we support mutiple get_next / put sequences followed by + * put_next. The metadata cache lock protects reading the metadata + * cache. It can indeed be read concurrently by "get_next_subbuf" and + * "flush" operations on the buffer invoked by different processes. + * Moreover, since the metadata cache memory can be reallocated, we + * need to have exclusive access against updates even though we only + * read it. */ - mutex_lock(&stream->lock); + mutex_lock(&stream->metadata_cache->lock); WARN_ON(stream->metadata_in < stream->metadata_out); if (stream->metadata_in != stream->metadata_out) goto end; @@ -1490,13 +1495,15 @@ int lttng_metadata_output_channel(struct lttng_metadata_stream *stream, ret = reserve_len; end: - mutex_unlock(&stream->lock); + mutex_unlock(&stream->metadata_cache->lock); return ret; } /* * Write the metadata to the metadata cache. * Must be called with sessions_mutex held. + * The metadata cache lock protects us from concurrent read access from + * thread outputting metadata content to ring buffer. */ int lttng_metadata_printf(struct lttng_session *session, const char *fmt, ...) @@ -1515,6 +1522,7 @@ int lttng_metadata_printf(struct lttng_session *session, return -ENOMEM; len = strlen(str); + mutex_lock(&session->metadata_cache->lock); if (session->metadata_cache->metadata_written + len > session->metadata_cache->cache_alloc) { char *tmp_cache_realloc; @@ -1523,10 +1531,16 @@ int lttng_metadata_printf(struct lttng_session *session, 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); + tmp_cache_realloc = vzalloc(tmp_cache_alloc_size); if (!tmp_cache_realloc) goto err; + if (session->metadata_cache->data) { + memcpy(tmp_cache_realloc, + session->metadata_cache->data, + session->metadata_cache->cache_alloc); + vfree(session->metadata_cache->data); + } + session->metadata_cache->cache_alloc = tmp_cache_alloc_size; session->metadata_cache->data = tmp_cache_realloc; } @@ -1534,6 +1548,7 @@ int lttng_metadata_printf(struct lttng_session *session, session->metadata_cache->metadata_written, str, len); session->metadata_cache->metadata_written += len; + mutex_unlock(&session->metadata_cache->lock); kfree(str); list_for_each_entry(stream, &session->metadata_cache->metadata_stream, list) @@ -1542,6 +1557,7 @@ int lttng_metadata_printf(struct lttng_session *session, return 0; err: + mutex_unlock(&session->metadata_cache->lock); kfree(str); return -ENOMEM; } @@ -1836,6 +1852,7 @@ int _lttng_stream_packet_context_declare(struct lttng_session *session) " uint64_clock_monotonic_t timestamp_end;\n" " uint64_t content_size;\n" " uint64_t packet_size;\n" + " uint64_t packet_seq_num;\n" " unsigned long events_discarded;\n" " uint32_t cpu_id;\n" "};\n\n" @@ -1957,6 +1974,7 @@ int _lttng_session_metadata_statedump(struct lttng_session *session) " uint32_t magic;\n" " uint8_t uuid[16];\n" " uint32_t stream_id;\n" + " uint64_t stream_instance_id;\n" " };\n" "};\n\n", lttng_alignof(uint8_t) * CHAR_BIT,