svm: Add support for thresh dequeue notification

Add the ability to set a threshold on the fifo that will
be used to notify caller when de-queue from the fifo reached
a value that is less than or equal to the threshold.

Type: feature

Change-Id: I70ba1a05f783ce5247409e9beebe4e336b7c1eb5
Signed-off-by: Michal Kalderon <mkalderon@marvell.com>
Signed-off-by: Yuval Caduri <cyuval@marvell.com>

diff --git a/src/svm/fifo_types.h b/src/svm/fifo_types.h
index 3787e5d..742351b 100644 (file)
--- a/src/svm/fifo_types.h
+++ b/src/svm/fifo_types.h
@@ -78,6 +78,7 @@ typedef struct svm_fifo_shr_
   u32 head;                    /**< fifo head position/byte */
   volatile u32 want_deq_ntf;   /**< producer wants nudge */
   volatile u32 has_deq_ntf;
+  u32 deq_thresh; /**< fifo threshold used for notifications */
 
   CLIB_CACHE_LINE_ALIGN_MARK (producer);
   u32 tail;                    /**< fifo tail position/byte */

diff --git a/src/svm/svm_fifo.h b/src/svm/svm_fifo.h
index aed8770..42efb5a 100644 (file)
--- a/src/svm/svm_fifo.h
+++ b/src/svm/svm_fifo.h
@@ -34,7 +34,9 @@ typedef enum svm_fifo_deq_ntf_
   SVM_FIFO_NO_DEQ_NOTIF = 0,           /**< No notification requested */
   SVM_FIFO_WANT_DEQ_NOTIF = 1,         /**< Notify on dequeue */
   SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL = 2, /**< Notify on transition from full */
-  SVM_FIFO_WANT_DEQ_NOTIF_IF_EMPTY = 4,        /**< Notify on transition to empty */
+  SVM_FIFO_WANT_DEQ_NOTIF_IF_EMPTY = 4, /**< Notify on transition to empty */
+  SVM_FIFO_WANT_DEQ_NOTIF_IF_LEQ_THRESH = 5, /**< Notify on transition to less
+                                              than or equal threshold */
 } svm_fifo_deq_ntf_t;
 
 typedef enum svm_fifo_flag_
@@ -793,7 +795,8 @@ svm_fifo_clear_deq_ntf (svm_fifo_t * f)
   /* Set the flag if want_notif_if_full was the only ntf requested */
   f->shr->has_deq_ntf =
     f->shr->want_deq_ntf == SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL;
-  svm_fifo_del_want_deq_ntf (f, SVM_FIFO_WANT_DEQ_NOTIF);
+  svm_fifo_del_want_deq_ntf (f, SVM_FIFO_WANT_DEQ_NOTIF |
+                                 SVM_FIFO_WANT_DEQ_NOTIF_IF_LEQ_THRESH);
 }
 
 /**
@@ -843,9 +846,27 @@ svm_fifo_needs_deq_ntf (svm_fifo_t * f, u32 n_last_deq)
       if (!f->shr->has_deq_ntf && svm_fifo_is_empty (f))
        return 1;
     }
+  if (want_ntf & SVM_FIFO_WANT_DEQ_NOTIF_IF_LEQ_THRESH)
+    {
+      if (!f->shr->has_deq_ntf &&
+         (svm_fifo_max_dequeue (f) <= f->shr->deq_thresh))
+       return 1;
+    }
   return 0;
 }
 
+/**
+ * Set the fifo dequeue threshold which will be used for notifications.
+ *
+ * Note: If not set, by default threshold is zero, equivalent to
+ * empty.
+ */
+static inline void
+svm_fifo_set_deq_thresh (svm_fifo_t *f, u32 thresh)
+{
+  f->shr->deq_thresh = thresh;
+}
+
 #endif /* __included_ssvm_fifo_h__ */
 
 /*