re-dump metadata cache at the right place

[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 b32193451f2060c401ac9d7503f2e48574be3fe4..ef5733c66eb2b652e66cb6c508b52183fee37429 100644 (file)
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -33,9 +33,12 @@
 #include "kernel-consumer.h"
 #include "kern-modules.h"
 #include "utils.h"
+#include "rotation-thread.h"
 
 /*
  * Add context on a kernel channel.
+ *
+ * Assumes the ownership of ctx.
  */
 int kernel_add_channel_context(struct ltt_kernel_channel *chan,
                struct ltt_kernel_context *ctx)
@@ -63,12 +66,16 @@ int kernel_add_channel_context(struct ltt_kernel_channel *chan,
                        goto error;
                }
        }
+       ret = 0;
 
 end:
        cds_list_add_tail(&ctx->list, &chan->ctx_list);
-       return 0;
-
+       ctx->in_list = true;
+       ctx = NULL;
 error:
+       if (ctx) {
+               trace_kernel_destroy_context(ctx);
+       }
        return ret;
 }
 
@@ -1120,3 +1127,85 @@ int kernel_supports_ring_buffer_snapshot_sample_positions(int tracer_fd)
 error:
        return ret;
 }
+
+/*
+ * Rotate a kernel session.
+ *
+ * Return 0 on success or else return a LTTNG_ERR code.
+ */
+int kernel_rotate_session(struct ltt_session *session)
+{
+       int ret;
+       struct consumer_socket *socket;
+       struct lttng_ht_iter iter;
+       struct ltt_kernel_session *ksess = session->kernel_session;
+
+       assert(ksess);
+       assert(ksess->consumer);
+
+       DBG("Rotate kernel session started");
+
+       rcu_read_lock();
+
+       cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
+                       socket, node.node) {
+               struct ltt_kernel_channel *chan;
+
+               /*
+                * Account the metadata channel first to make sure the
+                * number of channels waiting for a rotation cannot
+                * reach 0 before we complete the iteration over all
+                * the channels.
+                */
+               ret = rotate_add_channel_pending(ksess->metadata->fd,
+                               LTTNG_DOMAIN_KERNEL, session);
+               if (ret < 0) {
+                       ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
+                       pthread_mutex_unlock(socket->lock);
+                       goto error;
+               }
+
+               /* For each channel, ask the consumer to rotate it. */
+               cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
+                       /* FIXME: is that lock necessary, we don't do it in UST ? */
+                       pthread_mutex_lock(socket->lock);
+                       ret = rotate_add_channel_pending(chan->fd,
+                                       LTTNG_DOMAIN_KERNEL, session);
+                       if (ret < 0) {
+                               ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
+                               pthread_mutex_unlock(socket->lock);
+                               goto error;
+                       }
+
+                       ret = consumer_rotate_channel(socket, chan->fd,
+                                       ksess->uid, ksess->gid, ksess->consumer,
+                                       "", 0);
+                       if (ret < 0) {
+                               ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
+                               pthread_mutex_unlock(socket->lock);
+                               goto error;
+                       }
+
+                       pthread_mutex_unlock(socket->lock);
+               }
+
+               /*
+                * Rotate the metadata channel.
+                */
+               pthread_mutex_lock(socket->lock);
+               ret = consumer_rotate_channel(socket, ksess->metadata->fd,
+                               ksess->uid, ksess->gid, ksess->consumer, "", 1);
+               if (ret < 0) {
+                       ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
+                       pthread_mutex_unlock(socket->lock);
+                       goto error;
+               }
+               pthread_mutex_unlock(socket->lock);
+       }
+
+       ret = LTTNG_OK;
+
+error:
+       rcu_read_unlock();
+       return ret;
+}