From fea813ae3de5343a2bc91306fddf6dbd1832f93d Mon Sep 17 00:00:00 2001
From: Florin Coras <fcoras@cisco.com>
Date: Fri, 27 Dec 2019 10:26:56 -0800
Subject: svm: broadcast on raw dequeues and full rings

Type: fix

Change-Id: I0cac9001290e7ed4e2e318ae62c56e97ec75a3db
Signed-off-by: Florin Coras <fcoras@cisco.com>
---
 src/svm/message_queue.c |  6 ++++++
 src/svm/queue.c         | 28 +++++++++++++++++++++-------
 src/svm/queue.h         |  1 +
 3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/src/svm/message_queue.c b/src/svm/message_queue.c
index 10266a8039c..b381173c70b 100644
--- a/src/svm/message_queue.c
+++ b/src/svm/message_queue.c
@@ -170,6 +170,7 @@ void
 svm_msg_q_free_msg (svm_msg_q_t * mq, svm_msg_q_msg_t * msg)
 {
   svm_msg_q_ring_t *ring;
+  int need_signal;
 
   ASSERT (vec_len (mq->rings) > msg->ring_index);
   ring = &mq->rings[msg->ring_index];
@@ -183,7 +184,12 @@ svm_msg_q_free_msg (svm_msg_q_t * mq, svm_msg_q_msg_t * msg)
       /* for now, expect messages to be processed in order */
       ASSERT (0);
     }
+
+  need_signal = ring->cursize == ring->nitems;
   clib_atomic_fetch_sub (&ring->cursize, 1);
+
+  if (PREDICT_FALSE (need_signal))
+    svm_queue_send_signal (mq->q, 0);
 }
 
 static int
diff --git a/src/svm/queue.c b/src/svm/queue.c
index c9db454db1e..4d37a5f7810 100644
--- a/src/svm/queue.c
+++ b/src/svm/queue.c
@@ -112,7 +112,7 @@ svm_queue_is_full (svm_queue_t * q)
 }
 
 static inline void
-svm_queue_send_signal (svm_queue_t * q, u8 is_prod)
+svm_queue_send_signal_inline (svm_queue_t * q, u8 is_prod)
 {
   if (q->producer_evtfd == -1)
     {
@@ -125,9 +125,17 @@ svm_queue_send_signal (svm_queue_t * q, u8 is_prod)
       ASSERT (q->consumer_evtfd > 0 && q->producer_evtfd > 0);
       fd = is_prod ? q->producer_evtfd : q->consumer_evtfd;
       rv = write (fd, &data, sizeof (data));
+      if (PREDICT_FALSE (rv))
+	clib_unix_warning ("signal write returned %d", rv);
     }
 }
 
+void
+svm_queue_send_signal (svm_queue_t * q, u8 is_prod)
+{
+  svm_queue_send_signal_inline (q, is_prod);
+}
+
 static inline void
 svm_queue_wait_inline (svm_queue_t * q)
 {
@@ -212,7 +220,7 @@ svm_queue_add_nolock (svm_queue_t * q, u8 * elem)
     q->tail = 0;
 
   if (need_broadcast)
-    svm_queue_send_signal (q, 1);
+    svm_queue_send_signal_inline (q, 1);
   return 0;
 }
 
@@ -228,7 +236,7 @@ svm_queue_add_raw (svm_queue_t * q, u8 * elem)
   q->cursize++;
 
   if (q->cursize == 1)
-    svm_queue_send_signal (q, 1);
+    svm_queue_send_signal_inline (q, 1);
 }
 
 
@@ -275,7 +283,7 @@ svm_queue_add (svm_queue_t * q, u8 * elem, int nowait)
     q->tail = 0;
 
   if (need_broadcast)
-    svm_queue_send_signal (q, 1);
+    svm_queue_send_signal_inline (q, 1);
 
   svm_queue_unlock (q);
 
@@ -334,7 +342,7 @@ svm_queue_add2 (svm_queue_t * q, u8 * elem, u8 * elem2, int nowait)
     q->tail = 0;
 
   if (need_broadcast)
-    svm_queue_send_signal (q, 1);
+    svm_queue_send_signal_inline (q, 1);
 
   svm_queue_unlock (q);
 
@@ -402,7 +410,7 @@ svm_queue_sub (svm_queue_t * q, u8 * elem, svm_q_conditional_wait_t cond,
     q->head = 0;
 
   if (need_broadcast)
-    svm_queue_send_signal (q, 0);
+    svm_queue_send_signal_inline (q, 0);
 
   svm_queue_unlock (q);
 
@@ -434,7 +442,7 @@ svm_queue_sub2 (svm_queue_t * q, u8 * elem)
   svm_queue_unlock (q);
 
   if (need_broadcast)
-    svm_queue_send_signal (q, 0);
+    svm_queue_send_signal_inline (q, 0);
 
   return 0;
 }
@@ -442,6 +450,7 @@ svm_queue_sub2 (svm_queue_t * q, u8 * elem)
 int
 svm_queue_sub_raw (svm_queue_t * q, u8 * elem)
 {
+  int need_broadcast;
   i8 *headp;
 
   if (PREDICT_FALSE (q->cursize == 0))
@@ -453,9 +462,14 @@ svm_queue_sub_raw (svm_queue_t * q, u8 * elem)
   headp = (i8 *) (&q->data[0] + q->elsize * q->head);
   clib_memcpy_fast (elem, headp, q->elsize);
 
+  need_broadcast = q->cursize == q->maxsize;
+
   q->head = (q->head + 1) % q->maxsize;
   q->cursize--;
 
+  if (PREDICT_FALSE (need_broadcast))
+    svm_queue_send_signal_inline (q, 0);
+
   return 0;
 }
 
diff --git a/src/svm/queue.h b/src/svm/queue.h
index 2630f17a86c..9d21b24d7ea 100644
--- a/src/svm/queue.h
+++ b/src/svm/queue.h
@@ -77,6 +77,7 @@ int svm_queue_sub (svm_queue_t * q, u8 * elem, svm_q_conditional_wait_t cond,
 		   u32 time);
 int svm_queue_sub2 (svm_queue_t * q, u8 * elem);
 void svm_queue_lock (svm_queue_t * q);
+void svm_queue_send_signal (svm_queue_t * q, u8 is_prod);
 void svm_queue_unlock (svm_queue_t * q);
 int svm_queue_is_full (svm_queue_t * q);
 int svm_queue_add_nolock (svm_queue_t * q, u8 * elem);
-- 
cgit 1.2.3-korg