#include <linux/jiffies.h>
#include <linux/utsname.h>
#include <linux/err.h>
+#include <linux/vmalloc.h>
+
#include "wrapper/uuid.h"
#include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
#include "wrapper/random.h"
#include "lttng-events.h"
#include "lttng-tracer.h"
#include "lttng-abi-old.h"
+#include "wrapper/vzalloc.h"
+#include "wrapper/ringbuffer/backend.h"
+#include "wrapper/ringbuffer/frontend.h"
#define METADATA_CACHE_DEFAULT_SIZE 4096
GFP_KERNEL);
if (!metadata_cache)
goto err_free_session;
- metadata_cache->data = kzalloc(METADATA_CACHE_DEFAULT_SIZE,
- GFP_KERNEL);
+ metadata_cache->data = lttng_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,
{
struct lttng_metadata_cache *cache =
container_of(kref, struct lttng_metadata_cache, refcount);
- kfree(cache->data);
+ vfree(cache->data);
kfree(cache);
}
chan->header_type = 2; /* large */
}
+ /* Clear each stream's quiescent state. */
+ list_for_each_entry(chan, &session->chan, list) {
+ if (chan->channel_type != METADATA_CHANNEL)
+ lib_ring_buffer_clear_quiescent_channel(chan->chan);
+ }
+
ACCESS_ONCE(session->active) = 1;
ACCESS_ONCE(session->been_active) = 1;
ret = _lttng_session_metadata_statedump(session);
int lttng_session_disable(struct lttng_session *session)
{
int ret = 0;
+ struct lttng_channel *chan;
mutex_lock(&sessions_mutex);
if (!session->active) {
goto end;
}
ACCESS_ONCE(session->active) = 0;
+
+ /* Set each stream's quiescent state. */
+ list_for_each_entry(chan, &session->chan, list) {
+ if (chan->channel_type != METADATA_CHANNEL)
+ lib_ring_buffer_set_quiescent_channel(chan->chan);
+ }
+
end:
mutex_unlock(&sessions_mutex);
return ret;
/*
* 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.
*/
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;
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, ...)
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;
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 = lttng_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;
}
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)
return 0;
err:
+ mutex_unlock(&session->metadata_cache->lock);
kfree(str);
return -ENOMEM;
}
projects / lttng-modules.git / blobdiff