X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;ds=sidebyside;f=libringbuffer%2Fring_buffer_frontend.c;h=8c8126025878ed72929bf6ecd8ebedf9b2806148;hb=3962118d1f08fd33ad6adfad10452962c3662bd9;hp=84c6726e97a2d66ec612bc083aaa4ca36ab6225a;hpb=019fbcb65ec7eec2c86019ad1afce8fa47dc1269;p=lttng-ust.git

diff --git a/libringbuffer/ring_buffer_frontend.c b/libringbuffer/ring_buffer_frontend.c
index 84c6726e..8c812602 100644
--- a/libringbuffer/ring_buffer_frontend.c
+++ b/libringbuffer/ring_buffer_frontend.c
@@ -107,7 +107,8 @@
 struct switch_offsets {
 	unsigned long begin, end, old;
 	size_t pre_header_padding, size;
-	unsigned int switch_new_start:1, switch_old_start:1, switch_old_end:1;
+	unsigned int switch_new_start:1, switch_new_end:1, switch_old_start:1,
+		     switch_old_end:1;
 };
 
 DEFINE_URCU_TLS(unsigned int, lib_ring_buffer_nesting);
@@ -1414,6 +1415,30 @@ void lib_ring_buffer_switch_new_start(struct lttng_ust_lib_ring_buffer *buf,
 					     handle);
 }
 
+/*
+ * lib_ring_buffer_switch_new_end: finish switching current subbuffer
+ *
+ * Calls subbuffer_set_data_size() to set the data size of the current
+ * sub-buffer. We do not need to perform check_deliver nor commit here,
+ * since this task will be done by the "commit" of the event for which
+ * we are currently doing the space reservation.
+ */
+static
+void lib_ring_buffer_switch_new_end(struct lttng_ust_lib_ring_buffer *buf,
+				    struct channel *chan,
+				    struct switch_offsets *offsets,
+				    uint64_t tsc,
+				    struct lttng_ust_shm_handle *handle)
+{
+	const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
+	unsigned long endidx, data_size;
+
+	endidx = subbuf_index(offsets->end - 1, chan);
+	data_size = subbuf_offset(offsets->end - 1, chan) + 1;
+	subbuffer_set_data_size(config, &buf->backend, endidx, data_size,
+				handle);
+}
+
 /*
  * Returns :
  * 0 if ok
@@ -1566,6 +1591,7 @@ int lib_ring_buffer_try_reserve_slow(struct lttng_ust_lib_ring_buffer *buf,
 	offsets->begin = v_read(config, &buf->offset);
 	offsets->old = offsets->begin;
 	offsets->switch_new_start = 0;
+	offsets->switch_new_end = 0;
 	offsets->switch_old_end = 0;
 	offsets->pre_header_padding = 0;
 
@@ -1697,6 +1723,14 @@ int lib_ring_buffer_try_reserve_slow(struct lttng_ust_lib_ring_buffer *buf,
 		 */
 	}
 	offsets->end = offsets->begin + offsets->size;
+
+	if (caa_unlikely(subbuf_offset(offsets->end, chan) == 0)) {
+		/*
+		 * The offset_end will fall at the very beginning of the next
+		 * subbuffer.
+		 */
+		offsets->switch_new_end = 1;	/* For offsets->begin */
+	}
 	return 0;
 }
 
@@ -1770,6 +1804,9 @@ int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 	if (caa_unlikely(offsets.switch_new_start))
 		lib_ring_buffer_switch_new_start(buf, chan, &offsets, ctx->tsc, handle);
 
+	if (caa_unlikely(offsets.switch_new_end))
+		lib_ring_buffer_switch_new_end(buf, chan, &offsets, ctx->tsc, handle);
+
 	ctx->slot_size = offsets.size;
 	ctx->pre_offset = offsets.begin;
 	ctx->buf_offset = offsets.begin + offsets.pre_header_padding;