session: use msg queue for events

Change-Id: I3c58367eec2243fe19b75be78a175c5261863e9e
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 153 insertions, 4 deletions

diff --git a/src/svm/message_queue.h b/src/svm/message_queue.h
index 5ec8547016e..708a03d716e 100644
--- a/src/svm/message_queue.h
+++ b/src/svm/message_queue.h
@@ -21,14 +21,15 @@
 #define SRC_SVM_MESSAGE_QUEUE_H_
 
 #include <vppinfra/clib.h>
+#include <vppinfra/error.h>
 #include <svm/queue.h>
 
 typedef struct svm_msg_q_ring_
 {
   volatile u32 cursize;			/**< current size of the ring */
   u32 nitems;				/**< max size of the ring */
-  u32 head;				/**< current head (for dequeue) */
-  u32 tail;				/**< current tail (for enqueue) */
+  volatile u32 head;			/**< current head (for dequeue) */
+  volatile u32 tail;			/**< current tail (for enqueue) */
   u32 elsize;				/**< size of an element */
   u8 *data;				/**< chunk of memory for msg data */
 } svm_msg_q_ring_t;
@@ -64,6 +65,7 @@ typedef union
   u64 as_u64;
 } svm_msg_q_msg_t;
 
+#define SVM_MQ_INVALID_MSG { .as_u64 = ~0 }
 /**
  * Allocate message queue
  *
@@ -98,6 +100,36 @@ void svm_msg_q_free (svm_msg_q_t * mq);
 svm_msg_q_msg_t svm_msg_q_alloc_msg (svm_msg_q_t * mq, u32 nbytes);
 
 /**
+ * Allocate message buffer on ring
+ *
+ * Message is allocated, on requested ring. The caller MUST check that
+ * the ring is not full.
+ *
+ * @param mq		message queue
+ * @param ring_index	ring on which the allocation should occur
+ * @return		message structure pointing to the ring and position
+ * 			allocated
+ */
+svm_msg_q_msg_t svm_msg_q_alloc_msg_w_ring (svm_msg_q_t * mq, u32 ring_index);
+
+/**
+ * Lock message queue and allocate message buffer on ring
+ *
+ * This should be used when multiple writers/readers are expected to
+ * compete for the rings/queue. Message should be enqueued by calling
+ * @ref svm_msg_q_add_w_lock and the caller MUST unlock the queue once
+ * the message in enqueued.
+ *
+ * @param mq		message queue
+ * @param ring_index	ring on which the allocation should occur
+ * @param noblock	flag that indicates if request should block
+ * @param msg		pointer to message to be filled in
+ * @return		0 on success, negative number otherwise
+ */
+int svm_msg_q_lock_and_alloc_msg_w_ring (svm_msg_q_t * mq, u32 ring_index,
+					 u8 noblock, svm_msg_q_msg_t * msg);
+
+/**
  * Free message buffer
  *
  * Marks message buffer on ring as free.
@@ -106,6 +138,7 @@ svm_msg_q_msg_t svm_msg_q_alloc_msg (svm_msg_q_t * mq, u32 nbytes);
  * @param msg		message to be freed
  */
 void svm_msg_q_free_msg (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
+
 /**
  * Producer enqueue one message to queue
  *
@@ -117,7 +150,20 @@ void svm_msg_q_free_msg (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
  * @param nowait	flag to indicate if request is blocking or not
  * @return		success status
  */
-int svm_msg_q_add (svm_msg_q_t * mq, svm_msg_q_msg_t msg, int nowait);
+int svm_msg_q_add (svm_msg_q_t * mq, svm_msg_q_msg_t * msg, int nowait);
+
+/**
+ * Producer enqueue one message to queue with mutex held
+ *
+ * Prior to calling this, the producer should've obtained a message buffer
+ * from one of the rings by calling @ref svm_msg_q_alloc_msg. It assumes
+ * the queue mutex is held.
+ *
+ * @param mq		message queue
+ * @param msg		message (pointer to ring position) to be enqueued
+ * @return		success status
+ */
+void svm_msg_q_add_w_lock (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
 
 /**
  * Consumer dequeue one message from queue
@@ -129,13 +175,28 @@ int svm_msg_q_add (svm_msg_q_t * mq, svm_msg_q_msg_t msg, int nowait);
  * @param mq		message queue
  * @param msg		pointer to structure where message is to be received
  * @param cond		flag that indicates if request should block or not
+ * @param time		time to wait if condition it SVM_Q_TIMEDWAIT
  * @return		success status
  */
 int svm_msg_q_sub (svm_msg_q_t * mq, svm_msg_q_msg_t * msg,
 		   svm_q_conditional_wait_t cond, u32 time);
 
 /**
- * Get data for message in queu
+ * Consumer dequeue one message from queue with mutex held
+ *
+ * Returns the message pointing to the data in the message rings under the
+ * assumption that the message queue lock is already held. The consumer is
+ * expected to call @ref svm_msg_q_free_msg once it finishes
+ * processing/copies the message data.
+ *
+ * @param mq		message queue
+ * @param msg		pointer to structure where message is to be received
+ * @return		success status
+ */
+void svm_msg_q_sub_w_lock (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
+
+/**
+ * Get data for message in queue
  *
  * @param mq		message queue
  * @param msg		message for which the data is requested
@@ -143,6 +204,94 @@ int svm_msg_q_sub (svm_msg_q_t * mq, svm_msg_q_msg_t * msg,
  */
 void *svm_msg_q_msg_data (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
 
+/**
+ * Get message queue ring
+ *
+ * @param mq		message queue
+ * @param ring_index	index of ring
+ * @return		pointer to ring
+ */
+svm_msg_q_ring_t *svm_msg_q_ring (svm_msg_q_t * mq, u32 ring_index);
+
+/**
+ * Check if message queue is full
+ */
+static inline u8
+svm_msg_q_is_full (svm_msg_q_t * mq)
+{
+  return (mq->q->cursize == mq->q->maxsize);
+}
+
+static inline u8
+svm_msg_q_ring_is_full (svm_msg_q_t * mq, u32 ring_index)
+{
+  ASSERT (ring_index < vec_len (mq->rings));
+  return (mq->rings[ring_index].cursize == mq->rings[ring_index].nitems);
+}
+
+/**
+ * Check if message queue is empty
+ */
+static inline u8
+svm_msg_q_is_empty (svm_msg_q_t * mq)
+{
+  return (mq->q->cursize == 0);
+}
+
+/**
+ * Check length of message queue
+ */
+static inline u32
+svm_msg_q_size (svm_msg_q_t * mq)
+{
+  return mq->q->cursize;
+}
+
+/**
+ * Check if message is invalid
+ */
+static inline u8
+svm_msg_q_msg_is_invalid (svm_msg_q_msg_t * msg)
+{
+  return (msg->as_u64 == (u64) ~ 0);
+}
+
+/**
+ * Try locking message queue
+ */
+static inline int
+svm_msg_q_try_lock (svm_msg_q_t * mq)
+{
+  return pthread_mutex_trylock (&mq->q->mutex);
+}
+
+/**
+ * Lock, or block trying, the message queue
+ */
+static inline int
+svm_msg_q_lock (svm_msg_q_t * mq)
+{
+  return pthread_mutex_lock (&mq->q->mutex);
+}
+
+static inline void
+svm_msg_q_wait (svm_msg_q_t * mq)
+{
+  pthread_cond_wait (&mq->q->condvar, &mq->q->mutex);
+}
+
+/**
+ * Unlock message queue
+ */
+static inline void
+svm_msg_q_unlock (svm_msg_q_t * mq)
+{
+  /* The other side of the connection is not polling */
+  if (mq->q->cursize < (mq->q->maxsize / 8))
+    (void) pthread_cond_broadcast (&mq->q->condvar);
+  pthread_mutex_unlock (&mq->q->mutex);
+}
+
 #endif /* SRC_SVM_MESSAGE_QUEUE_H_ */
 
 /*