X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=lib%2Fringbuffer%2Fring_buffer_frontend.c;h=4ab474aadfe06dbefd1bc146b41a356e59d6347c;hb=49c50022873702bca7c7589e82c1addee410690c;hp=1931414b067a4c8836b1cece70be5c5ad45ad8a7;hpb=64c796d8aec1efa5d6f0d5850d2a0095cb7842e3;p=lttng-modules.git

diff --git a/lib/ringbuffer/ring_buffer_frontend.c b/lib/ringbuffer/ring_buffer_frontend.c
index 1931414b..4ab474aa 100644
--- a/lib/ringbuffer/ring_buffer_frontend.c
+++ b/lib/ringbuffer/ring_buffer_frontend.c
@@ -164,7 +164,6 @@ int lib_ring_buffer_create(struct lib_ring_buffer *buf,
 	const struct lib_ring_buffer_config *config = chanb->config;
 	struct channel *chan = container_of(chanb, struct channel, backend);
 	void *priv = chanb->priv;
-	unsigned int num_subbuf;
 	size_t subbuf_header_size;
 	u64 tsc;
 	int ret;
@@ -203,8 +202,8 @@ int lib_ring_buffer_create(struct lib_ring_buffer *buf,
 		goto free_commit;
 	}
 
-	num_subbuf = chan->backend.num_subbuf;
 	init_waitqueue_head(&buf->read_wait);
+	init_waitqueue_head(&buf->write_wait);
 	raw_spin_lock_init(&buf->raw_tick_nohz_spinlock);
 
 	/*
@@ -410,6 +409,7 @@ int __cpuinit lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb,
 	case CPU_DOWN_FAILED_FROZEN:
 	case CPU_ONLINE:
 	case CPU_ONLINE_FROZEN:
+		wake_up_interruptible(&chan->hp_wait);
 		lib_ring_buffer_start_switch_timer(buf);
 		lib_ring_buffer_start_read_timer(buf);
 		return NOTIFY_OK;
@@ -626,6 +626,7 @@ struct channel *channel_create(const struct lib_ring_buffer_config *config,
 	chan->read_timer_interval = usecs_to_jiffies(read_timer_interval);
 	kref_init(&chan->ref);
 	init_waitqueue_head(&chan->read_wait);
+	init_waitqueue_head(&chan->hp_wait);
 
 	if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
 #if defined(CONFIG_NO_HZ) && defined(CONFIG_LIB_RING_BUFFER)
@@ -698,11 +699,11 @@ void channel_release(struct kref *kref)
  * @chan: channel to destroy
  *
  * Holds cpu hotplug.
- * Call "destroy" callback, finalize channels, wait for readers to release their
- * reference, then destroy ring buffer data. Note that when readers have
- * completed data consumption of finalized channels, get_subbuf() will return
- * -ENODATA. They should release their handle at that point.
- * Returns the private data pointer.
+ * Call "destroy" callback, finalize channels, and then decrement the
+ * channel reference count.  Note that when readers have completed data
+ * consumption of finalized channels, get_subbuf() will return -ENODATA.
+ * They should release their handle at that point.  Returns the private
+ * data pointer.
  */
 void *channel_destroy(struct channel *chan)
 {
@@ -748,9 +749,11 @@ void *channel_destroy(struct channel *chan)
 		ACCESS_ONCE(buf->finalized) = 1;
 		wake_up_interruptible(&buf->read_wait);
 	}
+	ACCESS_ONCE(chan->finalized) = 1;
+	wake_up_interruptible(&chan->hp_wait);
 	wake_up_interruptible(&chan->read_wait);
-	kref_put(&chan->ref, channel_release);
 	priv = chan->backend.priv;
+	kref_put(&chan->ref, channel_release);
 	return priv;
 }
 EXPORT_SYMBOL_GPL(channel_destroy);
@@ -865,6 +868,8 @@ EXPORT_SYMBOL_GPL(lib_ring_buffer_snapshot);
 
 /**
  * lib_ring_buffer_put_snapshot - move consumed counter forward
+ *
+ * Should only be called from consumer context.
  * @buf: ring buffer
  * @consumed_new: new consumed count value
  */
@@ -886,6 +891,8 @@ void lib_ring_buffer_move_consumer(struct lib_ring_buffer *buf,
 	while ((long) consumed - (long) consumed_new < 0)
 		consumed = atomic_long_cmpxchg(&buf->consumed, consumed,
 					       consumed_new);
+	/* Wake-up the metadata producer */
+	wake_up_interruptible(&buf->write_wait);
 }
 EXPORT_SYMBOL_GPL(lib_ring_buffer_move_consumer);
 
@@ -1695,3 +1702,20 @@ int lib_ring_buffer_reserve_slow(struct lib_ring_buffer_ctx *ctx)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(lib_ring_buffer_reserve_slow);
+
+int __init init_lib_ring_buffer_frontend(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		spin_lock_init(&per_cpu(ring_buffer_nohz_lock, cpu));
+	return 0;
+}
+
+module_init(init_lib_ring_buffer_frontend);
+
+void __exit exit_lib_ring_buffer_frontend(void)
+{
+}
+
+module_exit(exit_lib_ring_buffer_frontend);