Support snapshot max-size limitation

[lttng-tools.git] / src / bin / lttng-sessiond / kernel.c

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index 6f2604c607d2c1bc5fe4c24a53a2cf0458a4053d..ddf01044c816f179b668525c5463c60a6f3483c2 100644 (file)
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -822,12 +822,13 @@ void kernel_destroy_channel(struct ltt_kernel_channel *kchan)
  * Return 0 on success or else a negative value.
  */
 int kernel_snapshot_record(struct ltt_kernel_session *ksess,
-               struct snapshot_output *output, int wait)
+               struct snapshot_output *output, int wait, unsigned int nb_streams)
 {
        int ret, saved_metadata_fd;
        struct consumer_socket *socket;
        struct lttng_ht_iter iter;
        struct ltt_kernel_metadata *saved_metadata;
+       uint64_t max_size_per_stream = 0;
 
        assert(ksess);
        assert(ksess->consumer);
@@ -853,6 +854,10 @@ int kernel_snapshot_record(struct ltt_kernel_session *ksess,
                goto error_open_stream;
        }
 
+       if (output->max_size > 0 && nb_streams > 0) {
+               max_size_per_stream = output->max_size / nb_streams;
+       }
+
        /* Send metadata to consumer and snapshot everything. */
        cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
                        socket, node.node) {
@@ -881,9 +886,20 @@ int kernel_snapshot_record(struct ltt_kernel_session *ksess,
 
                /* For each channel, ask the consumer to snapshot it. */
                cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
+                       if (max_size_per_stream &&
+                                       chan->channel->attr.subbuf_size > max_size_per_stream) {
+                               ret = LTTNG_ERR_INVALID;
+                               DBG3("Kernel snapshot record maximum stream size %" PRIu64
+                                               " is smaller than subbuffer size of %" PRIu64,
+                                               max_size_per_stream, chan->channel->attr.subbuf_size);
+                               goto error_consumer;
+                       }
+
                        pthread_mutex_lock(socket->lock);
                        ret = consumer_snapshot_channel(socket, chan->fd, output, 0,
-                                       ksess->uid, ksess->gid, DEFAULT_KERNEL_TRACE_DIR, wait);
+                                       ksess->uid, ksess->gid,
+                                       DEFAULT_KERNEL_TRACE_DIR, wait,
+                                       max_size_per_stream);
                        pthread_mutex_unlock(socket->lock);
                        if (ret < 0) {
                                ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
@@ -894,7 +910,8 @@ int kernel_snapshot_record(struct ltt_kernel_session *ksess,
                /* Snapshot metadata, */
                pthread_mutex_lock(socket->lock);
                ret = consumer_snapshot_channel(socket, ksess->metadata->fd, output,
-                               1, ksess->uid, ksess->gid, DEFAULT_KERNEL_TRACE_DIR, wait);
+                               1, ksess->uid, ksess->gid,
+                               DEFAULT_KERNEL_TRACE_DIR, wait, max_size_per_stream);
                pthread_mutex_unlock(socket->lock);
                if (ret < 0) {
                        ret = LTTNG_ERR_KERN_CONSUMER_FAIL;