X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;ds=sidebyside;f=lib%2Fringbuffer%2Fring_buffer_frontend.c;h=3003dd8324458ee62c8e99460b295bc3ab8e481d;hb=5fee13fdbe001aacbdd61052f2ab0be57bfd6c5f;hp=5e633f438f32e57ad2793c4f4e89e56e5a0ce052;hpb=c099397a53087b8c616a7feaef0c26d939b9662f;p=lttng-modules.git

diff --git a/lib/ringbuffer/ring_buffer_frontend.c b/lib/ringbuffer/ring_buffer_frontend.c
index 5e633f43..3003dd83 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;
@@ -624,7 +624,9 @@ struct channel *channel_create(const struct lib_ring_buffer_config *config,
 	chan->commit_count_mask = (~0UL >> chan->backend.num_subbuf_order);
 	chan->switch_timer_interval = usecs_to_jiffies(switch_timer_interval);
 	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)
@@ -685,16 +687,23 @@ error:
 }
 EXPORT_SYMBOL_GPL(channel_create);
 
+static
+void channel_release(struct kref *kref)
+{
+	struct channel *chan = container_of(kref, struct channel, ref);
+	channel_free(chan);
+}
+
 /**
  * channel_destroy - Finalize, wait for q.s. and destroy channel.
  * @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)
 {
@@ -740,14 +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);
-
-	while (atomic_long_read(&chan->read_ref) > 0)
-		msleep(100);
-	/* Finish waiting for refcount before free */
-	smp_mb();
 	priv = chan->backend.priv;
-	channel_free(chan);
+	kref_put(&chan->ref, channel_release);
 	return priv;
 }
 EXPORT_SYMBOL_GPL(channel_destroy);
@@ -769,7 +775,7 @@ int lib_ring_buffer_open_read(struct lib_ring_buffer *buf)
 
 	if (!atomic_long_add_unless(&buf->active_readers, 1, 1))
 		return -EBUSY;
-	atomic_long_inc(&chan->read_ref);
+	kref_get(&chan->ref);
 	smp_mb__after_atomic_inc();
 	return 0;
 }
@@ -781,8 +787,8 @@ void lib_ring_buffer_release_read(struct lib_ring_buffer *buf)
 
 	CHAN_WARN_ON(chan, atomic_long_read(&buf->active_readers) != 1);
 	smp_mb__before_atomic_dec();
-	atomic_long_dec(&chan->read_ref);
 	atomic_long_dec(&buf->active_readers);
+	kref_put(&chan->ref, channel_release);
 }
 EXPORT_SYMBOL_GPL(lib_ring_buffer_release_read);
 
@@ -862,6 +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
  */
@@ -883,6 +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);
 
@@ -1507,16 +1517,15 @@ int lib_ring_buffer_try_reserve_slow(struct lib_ring_buffer *buf,
 		return -EIO;
 
 	if (last_tsc_overflow(config, buf, ctx->tsc))
-		ctx->rflags = RING_BUFFER_RFLAG_FULL_TSC;
+		ctx->rflags |= RING_BUFFER_RFLAG_FULL_TSC;
 
 	if (unlikely(subbuf_offset(offsets->begin, ctx->chan) == 0)) {
 		offsets->switch_new_start = 1;		/* For offsets->begin */
 	} else {
 		offsets->size = config->cb.record_header_size(config, chan,
 						offsets->begin,
-						ctx->data_size,
 						&offsets->pre_header_padding,
-						ctx->rflags, ctx);
+						ctx);
 		offsets->size +=
 			lib_ring_buffer_align(offsets->begin + offsets->size,
 					      ctx->largest_align)
@@ -1579,9 +1588,8 @@ int lib_ring_buffer_try_reserve_slow(struct lib_ring_buffer *buf,
 		offsets->size =
 			config->cb.record_header_size(config, chan,
 						offsets->begin,
-						ctx->data_size,
 						&offsets->pre_header_padding,
-						ctx->rflags, ctx);
+						ctx);
 		offsets->size +=
 			lib_ring_buffer_align(offsets->begin + offsets->size,
 					      ctx->largest_align)