X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=lttng-events.c;h=cfe2a3529de33efb0184409d4dbdbd105eb93b8a;hb=11441f8f17f7825f529e2f6c54d3605771709260;hp=8e8e65a576fc4434dcfb64d89283826d9a9ffdbc;hpb=8b7bb83e1100aa3c3e22148b27358b0d9a81786b;p=lttng-modules.git diff --git a/lttng-events.c b/lttng-events.c index 8e8e65a5..cfe2a352 100644 --- a/lttng-events.c +++ b/lttng-events.c @@ -30,7 +30,7 @@ #include #include -#include /* for wrapper_vmalloc_sync_all() */ +#include /* for wrapper_vmalloc_sync_mappings() */ #include #include #include @@ -1622,7 +1622,7 @@ void lttng_session_lazy_sync_enablers(struct lttng_session *session) * was written and a negative value on error. */ int lttng_metadata_output_channel(struct lttng_metadata_stream *stream, - struct channel *chan) + struct channel *chan, bool *coherent) { struct lib_ring_buffer_ctx ctx; int ret = 0; @@ -1661,6 +1661,7 @@ int lttng_metadata_output_channel(struct lttng_metadata_stream *stream, ret = stream->transport->ops.event_reserve(&ctx, 0); if (ret != 0) { printk(KERN_WARNING "LTTng: Metadata event reservation failed\n"); + stream->coherent = false; goto end; } stream->transport->ops.event_write(&ctx, @@ -1668,18 +1669,43 @@ int lttng_metadata_output_channel(struct lttng_metadata_stream *stream, reserve_len); stream->transport->ops.event_commit(&ctx); stream->metadata_in += reserve_len; + if (reserve_len < len || stream->metadata_cache->producing != 0) + stream->coherent = false; + else + stream->coherent = true; ret = reserve_len; end: + if (coherent) + *coherent = stream->coherent; mutex_unlock(&stream->metadata_cache->lock); return ret; } +static +void lttng_metadata_begin(struct lttng_session *session) +{ + mutex_lock(&session->metadata_cache->lock); + session->metadata_cache->producing++; + mutex_unlock(&session->metadata_cache->lock); +} + +static +void lttng_metadata_end(struct lttng_session *session) +{ + mutex_lock(&session->metadata_cache->lock); + WARN_ON_ONCE(!session->metadata_cache->producing); + session->metadata_cache->producing--; + mutex_unlock(&session->metadata_cache->lock); +} + /* * 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. + * The content of the printf is printed as a single atomic metadata + * transaction. */ int lttng_metadata_printf(struct lttng_session *session, const char *fmt, ...) @@ -1699,6 +1725,7 @@ int lttng_metadata_printf(struct lttng_session *session, len = strlen(str); mutex_lock(&session->metadata_cache->lock); + session->metadata_cache->producing++; if (session->metadata_cache->metadata_written + len > session->metadata_cache->cache_alloc) { char *tmp_cache_realloc; @@ -1724,6 +1751,7 @@ int lttng_metadata_printf(struct lttng_session *session, session->metadata_cache->metadata_written, str, len); session->metadata_cache->metadata_written += len; + session->metadata_cache->producing--; mutex_unlock(&session->metadata_cache->lock); kfree(str); @@ -1733,6 +1761,7 @@ int lttng_metadata_printf(struct lttng_session *session, return 0; err: + session->metadata_cache->producing--; mutex_unlock(&session->metadata_cache->lock); kfree(str); return -ENOMEM; @@ -2270,6 +2299,8 @@ int _lttng_fields_metadata_statedump(struct lttng_session *session, /* * Must be called with sessions_mutex held. + * The entire event metadata is printed as a single atomic metadata + * transaction. */ static int _lttng_event_metadata_statedump(struct lttng_session *session, @@ -2283,6 +2314,8 @@ int _lttng_event_metadata_statedump(struct lttng_session *session, if (chan->channel_type == METADATA_CHANNEL) return 0; + lttng_metadata_begin(session); + ret = lttng_metadata_printf(session, "event {\n" " name = \"%s\";\n" @@ -2332,12 +2365,15 @@ int _lttng_event_metadata_statedump(struct lttng_session *session, event->metadata_dumped = 1; end: + lttng_metadata_end(session); return ret; } /* * Must be called with sessions_mutex held. + * The entire channel metadata is printed as a single atomic metadata + * transaction. */ static int _lttng_channel_metadata_statedump(struct lttng_session *session, @@ -2351,6 +2387,8 @@ int _lttng_channel_metadata_statedump(struct lttng_session *session, if (chan->channel_type == METADATA_CHANNEL) return 0; + lttng_metadata_begin(session); + WARN_ON_ONCE(!chan->header_type); ret = lttng_metadata_printf(session, "stream {\n" @@ -2384,6 +2422,7 @@ int _lttng_channel_metadata_statedump(struct lttng_session *session, chan->metadata_dumped = 1; end: + lttng_metadata_end(session); return ret; } @@ -2571,6 +2610,9 @@ int _lttng_session_metadata_statedump(struct lttng_session *session) if (!READ_ONCE(session->active)) return 0; + + lttng_metadata_begin(session); + if (session->metadata_dumped) goto skip_session; @@ -2743,6 +2785,7 @@ skip_session: } session->metadata_dumped = 1; end: + lttng_metadata_end(session); return ret; } @@ -2753,9 +2796,9 @@ end: * Registers a transport which can be used as output to extract the data out of * LTTng. The module calling this registration function must ensure that no * trap-inducing code will be executed by the transport functions. E.g. - * vmalloc_sync_all() must be called between a vmalloc and the moment the memory + * vmalloc_sync_mappings() must be called between a vmalloc and the moment the memory * is made visible to the transport function. This registration acts as a - * vmalloc_sync_all. Therefore, only if the module allocates virtual memory + * vmalloc_sync_mappings. Therefore, only if the module allocates virtual memory * after its registration must it synchronize the TLBs. */ void lttng_transport_register(struct lttng_transport *transport) @@ -2763,9 +2806,9 @@ void lttng_transport_register(struct lttng_transport *transport) /* * Make sure no page fault can be triggered by the module about to be * registered. We deal with this here so we don't have to call - * vmalloc_sync_all() in each module's init. + * vmalloc_sync_mappings() in each module's init. */ - wrapper_vmalloc_sync_all(); + wrapper_vmalloc_sync_mappings(); mutex_lock(&sessions_mutex); list_add_tail(&transport->node, <tng_transport_list);