#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/jiffies.h>
#include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
#include "ltt-events.h"
+#include "ltt-tracer.h"
static LIST_HEAD(sessions);
static LIST_HEAD(ltt_transport_list);
static DEFINE_MUTEX(sessions_mutex);
static struct kmem_cache *event_cache;
-static void synchronize_trace(void)
+static
+int _ltt_event_metadata_statedump(struct ltt_session *session,
+ struct ltt_channel *chan,
+ struct ltt_event *event);
+static
+int _ltt_session_metadata_statedump(struct ltt_session *session);
+
+
+static
+void synchronize_trace(void)
{
synchronize_sched();
#ifdef CONFIG_PREEMPT_RT
int ltt_session_start(struct ltt_session *session)
{
int ret = 0;
+ struct ltt_channel *chan;
mutex_lock(&sessions_mutex);
if (session->active) {
ret = -EBUSY;
goto end;
}
+
+ /*
+ * Snapshot the number of events per channel to know the type of header
+ * we need to use.
+ */
+ list_for_each_entry(chan, &session->chan, list) {
+ if (chan->header_type)
+ continue; /* don't change it if session stop/restart */
+ if (chan->free_event_id < 31)
+ chan->header_type = 1; /* compact */
+ else
+ chan->header_type = 2; /* large */
+ }
+
ACCESS_ONCE(session->active) = 1;
synchronize_trace(); /* Wait for in-flight events to complete */
+ ret = _ltt_session_metadata_statedump(session);
+ if (ret) {
+ ACCESS_ONCE(session->active) = 0;
+ synchronize_trace(); /* Wait for in-flight events to complete */
+ }
end:
mutex_unlock(&sessions_mutex);
return ret;
read_timer_interval);
if (!chan->chan)
goto create_error;
+ chan->id = session->free_chan_id++;
chan->ops = &transport->ops;
list_add(&chan->list, &session->chan);
mutex_unlock(&sessions_mutex);
default:
WARN_ON_ONCE(1);
}
+ ret = _ltt_event_metadata_statedump(chan->session, chan, event);
+ if (ret)
+ goto statedump_error;
list_add(&event->list, &chan->session->events);
mutex_unlock(&sessions_mutex);
return event;
+statedump_error:
+ WARN_ON_ONCE(tracepoint_probe_unregister(name, event_desc->probe_callback,
+ event));
register_error:
kmem_cache_free(event_cache, event);
cache_error:
kmem_cache_free(event_cache, event);
}
+int lttng_metadata_printf(struct ltt_session *session,
+ const char *fmt, ...)
+{
+ struct lib_ring_buffer_ctx ctx;
+ struct ltt_channel *chan = session->metadata;
+ char *str;
+ int ret = 0, waitret;
+ size_t len;
+ va_list ap;
+
+ WARN_ON_ONCE(!ACCESS_ONCE(session->active));
+
+ va_start(ap, fmt);
+ str = kvasprintf(GFP_KERNEL, fmt, ap);
+ va_end(ap);
+ if (!str)
+ return -ENOMEM;
+
+ len = strlen(str) + 1;
+ lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, 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_reader_wait_queue(chan),
+ ({
+ ret = chan->ops->event_reserve(&ctx);
+ ret != -ENOBUFS || !ret;
+ }),
+ msecs_to_jiffies(LTTNG_METADATA_TIMEOUT_MSEC));
+ if (waitret || 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, len);
+ chan->ops->event_commit(&ctx);
+end:
+ kfree(str);
+ return ret;
+}
+
+static
+int _ltt_fields_metadata_statedump(struct ltt_session *session,
+ struct ltt_event *event)
+{
+ const struct lttng_event_desc *desc = event->desc;
+ int ret = 0;
+ int i;
+
+ for (i = 0; i < desc->nr_fields; i++) {
+ const struct lttng_event_field *field = &desc->fields[i];
+
+ switch (field->type.atype) {
+ case atype_integer:
+ ret = lttng_metadata_printf(session,
+ " integer { size = %u; align = %u; signed = %u;%s } %s;\n",
+ field->type.u.basic.integer.size,
+ field->type.u.basic.integer.alignment,
+ field->type.u.basic.integer.signedness,
+#ifdef __BIG_ENDIAN
+ field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
+#else
+ field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
+#endif
+ field->name);
+ break;
+ case atype_enum:
+ ret = lttng_metadata_printf(session,
+ " %s %s;\n",
+ field->type.u.basic.enumeration.name,
+ field->name);
+ break;
+ case atype_array:
+ break;
+ case atype_sequence:
+ break;
+
+ case atype_string:
+ ret = lttng_metadata_printf(session,
+ " string%s %s;\n",
+ field->type.u.basic.string.encoding == lttng_encode_ASCII ?
+ " { encoding = ASCII; }" : "",
+ field->name);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return -EINVAL;
+ }
+ }
+ return ret;
+}
+
+static
+int _ltt_event_metadata_statedump(struct ltt_session *session,
+ struct ltt_channel *chan,
+ struct ltt_event *event)
+{
+ int ret = 0;
+
+ if (event->metadata_dumped || !ACCESS_ONCE(session->active))
+ return 0;
+ if (chan == session->metadata)
+ return 0;
+
+ ret = lttng_metadata_printf(session,
+ "event {\n"
+ " name = %s;\n"
+ " id = %u;\n"
+ " stream_id = %u;\n"
+ " event.fields := struct {\n",
+ event->desc->name,
+ event->id,
+ event->chan->id);
+ if (ret)
+ goto end;
+
+ ret = _ltt_fields_metadata_statedump(session, event);
+ if (ret)
+ goto end;
+
+ /*
+ * LTTng space reservation can only reserve multiples of the
+ * byte size.
+ */
+ ret = lttng_metadata_printf(session,
+ " } aligned(%u);\n"
+ "};\n", ltt_get_header_alignment());
+ if (ret)
+ goto end;
+
+
+
+
+ event->metadata_dumped = 1;
+end:
+ return ret;
+
+}
+
+static
+int _ltt_channel_metadata_statedump(struct ltt_session *session,
+ struct ltt_channel *chan)
+{
+ int ret = 0;
+
+ if (chan->metadata_dumped || !ACCESS_ONCE(session->active))
+ return 0;
+ if (chan == session->metadata)
+ return 0;
+
+ WARN_ON_ONCE(!chan->header_type);
+ ret = lttng_metadata_printf(session,
+ "stream {\n"
+ " id = %u;\n"
+ " event.header := %s;\n",
+ "};\n",
+ chan->id,
+ chan->header_type == 1 ? "struct event_header_compact" :
+ "struct event_header_large");
+ if (ret)
+ goto end;
+
+ chan->metadata_dumped = 1;
+end:
+ return ret;
+}
+
+/*
+ * Output metadata into this session's metadata buffers.
+ */
+static
+int _ltt_session_metadata_statedump(struct ltt_session *session)
+{
+ struct ltt_channel *chan;
+ struct ltt_event *event;
+ int ret = 0;
+
+ if (!ACCESS_ONCE(session->active))
+ return 0;
+ if (session->metadata_dumped)
+ goto skip_session;
+
+
+
+
+skip_session:
+ list_for_each_entry(chan, &session->chan, list) {
+ ret = _ltt_channel_metadata_statedump(session, chan);
+ if (ret)
+ goto end;
+ }
+
+ list_for_each_entry(event, &session->events, list) {
+ ret = _ltt_event_metadata_statedump(session, chan, event);
+ if (ret)
+ goto end;
+ }
+ session->metadata_dumped = 1;
+end:
+ return ret;
+}
+
/**
* ltt_transport_register - LTT transport registration
* @transport: transport structure
}
EXPORT_SYMBOL_GPL(ltt_transport_unregister);
-
static int __init ltt_events_init(void)
{
int ret;
projects / lttng-modules.git / blobdiff