X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=libringbuffer%2Ffrontend_internal.h;h=4ad921ec0ec8263086cddbf1c11044110dc672f6;hb=beca55a1aa4ff272188d7c37c19eb0540f811c8b;hp=c973e6b25f88c1cc905bedfb28463f7cc5499316;hpb=16ec84c8bd34ce34dd59a9052e7a24eaa0f427f5;p=lttng-ust.git

diff --git a/libringbuffer/frontend_internal.h b/libringbuffer/frontend_internal.h
index c973e6b2..4ad921ec 100644
--- a/libringbuffer/frontend_internal.h
+++ b/libringbuffer/frontend_internal.h
@@ -158,7 +158,8 @@ int last_tsc_overflow(const struct lttng_ust_lib_ring_buffer_config *config,
 #endif
 
 extern
-int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx);
+int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx,
+		void *client_ctx);
 
 extern
 void lib_ring_buffer_switch_slow(struct lttng_ust_lib_ring_buffer *buf,
@@ -204,6 +205,32 @@ void lib_ring_buffer_reserve_push_reader(struct lttng_ust_lib_ring_buffer *buf,
 					      consumed_new) != consumed_old));
 }
 
+static inline
+void lib_ring_buffer_clear_reader(struct lttng_ust_lib_ring_buffer *buf,
+				  struct lttng_ust_shm_handle *handle)
+{
+	struct channel *chan;
+	const struct lttng_ust_lib_ring_buffer_config *config;
+	unsigned long offset, consumed_old, consumed_new;
+
+	chan = shmp(handle, buf->backend.chan);
+	if (!chan)
+		return;
+	config = &chan->backend.config;
+
+	do {
+		offset = v_read(config, &buf->offset);
+		consumed_old = uatomic_read(&buf->consumed);
+		if (caa_unlikely(subbuf_trunc(offset, chan)
+			      - subbuf_trunc(consumed_old, chan)
+			     > 0))
+			consumed_new = subbuf_trunc(offset, chan);
+		else
+			return;
+	} while (caa_unlikely(uatomic_cmpxchg(&buf->consumed, consumed_old,
+					      consumed_new) != consumed_old));
+}
+
 static inline
 int lib_ring_buffer_pending_data(const struct lttng_ust_lib_ring_buffer_config *config,
 				 struct lttng_ust_lib_ring_buffer *buf,
@@ -233,10 +260,14 @@ int lib_ring_buffer_reserve_committed(const struct lttng_ust_lib_ring_buffer_con
 				      struct lttng_ust_shm_handle *handle)
 {
 	unsigned long offset, idx, commit_count;
+	struct commit_counters_hot *cc_hot = shmp_index(handle, buf->commit_hot, idx);
 
 	CHAN_WARN_ON(chan, config->alloc != RING_BUFFER_ALLOC_PER_CPU);
 	CHAN_WARN_ON(chan, config->sync != RING_BUFFER_SYNC_PER_CPU);
 
+	if (caa_unlikely(!cc_hot))
+		return 0;
+
 	/*
 	 * Read offset and commit count in a loop so they are both read
 	 * atomically wrt interrupts. By deal with interrupt concurrency by
@@ -248,7 +279,7 @@ int lib_ring_buffer_reserve_committed(const struct lttng_ust_lib_ring_buffer_con
 	do {
 		offset = v_read(config, &buf->offset);
 		idx = subbuf_index(offset, chan);
-		commit_count = v_read(config, &shmp_index(handle, buf->commit_hot, idx)->cc);
+		commit_count = v_read(config, &cc_hot->cc);
 	} while (offset != v_read(config, &buf->offset));
 
 	return ((buf_trunc(offset, chan) >> chan->backend.num_subbuf_order)
@@ -294,10 +325,10 @@ static inline
 void lib_ring_buffer_write_commit_counter(const struct lttng_ust_lib_ring_buffer_config *config,
 					  struct lttng_ust_lib_ring_buffer *buf,
 				          struct channel *chan,
-				          unsigned long idx,
 				          unsigned long buf_offset,
 				          unsigned long commit_count,
-					  struct lttng_ust_shm_handle *handle)
+					  struct lttng_ust_shm_handle *handle,
+					  struct commit_counters_hot *cc_hot)
 {
 	unsigned long commit_seq_old;
 
@@ -313,10 +344,9 @@ void lib_ring_buffer_write_commit_counter(const struct lttng_ust_lib_ring_buffer
 	if (caa_unlikely(subbuf_offset(buf_offset - commit_count, chan)))
 		return;
 
-	commit_seq_old = v_read(config, &shmp_index(handle, buf->commit_hot, idx)->seq);
+	commit_seq_old = v_read(config, &cc_hot->seq);
 	if (caa_likely((long) (commit_seq_old - commit_count) < 0))
-		v_set(config, &shmp_index(handle, buf->commit_hot, idx)->seq,
-			commit_count);
+		v_set(config, &cc_hot->seq, commit_count);
 }
 
 extern int lib_ring_buffer_create(struct lttng_ust_lib_ring_buffer *buf,