session/svm: add want_tx_event flag to fifo

[vpp.git] / src / svm / svm_fifo.h

diff --git a/src/svm/svm_fifo.h b/src/svm/svm_fifo.h
index a83cd85..1ac5b63 100644 (file)
--- a/src/svm/svm_fifo.h
+++ b/src/svm/svm_fifo.h
@@ -62,6 +62,7 @@ typedef struct _svm_fifo
   u32 segment_manager;
     CLIB_CACHE_LINE_ALIGN_MARK (end_shared);
   u32 head;
+  volatile u32 want_tx_evt;    /**< producer wants nudge */
     CLIB_CACHE_LINE_ALIGN_MARK (end_consumer);
 
   /* producer */
@@ -75,9 +76,22 @@ typedef struct _svm_fifo
 #if SVM_FIFO_TRACE
   svm_fifo_trace_elem_t *trace;
 #endif
+  u32 freelist_index;          /**< aka log2(allocated_size) - const. */
+  i8 refcnt;                   /**< reference count  */
     CLIB_CACHE_LINE_ALIGN_MARK (data);
 } svm_fifo_t;
 
+typedef enum
+{
+  SVM_FIFO_FULL = -2,
+} svm_fifo_err_t;
+
+typedef struct svm_fifo_segment_
+{
+  u8 *data;
+  u32 len;
+} svm_fifo_segment_t;
+
 #if SVM_FIFO_TRACE
 #define svm_fifo_trace_add(_f, _s, _l, _t)             \
 {                                                      \
@@ -100,12 +114,30 @@ svm_fifo_max_dequeue (svm_fifo_t * f)
   return f->cursize;
 }
 
+static inline int
+svm_fifo_is_full (svm_fifo_t * f)
+{
+  return (f->cursize == f->nitems);
+}
+
+static inline int
+svm_fifo_is_empty (svm_fifo_t * f)
+{
+  return (f->cursize == 0);
+}
+
 static inline u32
 svm_fifo_max_enqueue (svm_fifo_t * f)
 {
   return f->nitems - svm_fifo_max_dequeue (f);
 }
 
+static inline int
+svm_fifo_has_event (svm_fifo_t * f)
+{
+  return f->has_event;
+}
+
 static inline u8
 svm_fifo_has_ooo_data (svm_fifo_t * f)
 {
@@ -115,39 +147,59 @@ svm_fifo_has_ooo_data (svm_fifo_t * f)
 /**
  * Sets fifo event flag.
  *
+ * Also acts as a release barrier.
+ *
  * @return 1 if flag was not set.
  */
 always_inline u8
 svm_fifo_set_event (svm_fifo_t * f)
 {
-  /* Probably doesn't need to be atomic. Still, better avoid surprises */
-  return __sync_lock_test_and_set (&f->has_event, 1) == 0;
+  /* return __sync_lock_test_and_set (&f->has_event, 1) == 0;
+     return __sync_bool_compare_and_swap (&f->has_event, 0, 1); */
+  return !__atomic_exchange_n (&f->has_event, 1, __ATOMIC_RELEASE);
 }
 
 /**
  * Unsets fifo event flag.
+ *
+ * Also acts as a release barrier.
  */
 always_inline void
 svm_fifo_unset_event (svm_fifo_t * f)
 {
-  /* Probably doesn't need to be atomic. Still, better avoid surprises */
   __sync_lock_release (&f->has_event);
 }
 
+static inline void
+svm_fifo_set_want_tx_evt (svm_fifo_t * f, u8 want_evt)
+{
+  f->want_tx_evt = want_evt;
+}
+
+static inline u8
+svm_fifo_want_tx_evt (svm_fifo_t * f)
+{
+  return f->want_tx_evt;
+}
+
 svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);
 void svm_fifo_free (svm_fifo_t * f);
 
 int svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes,
-                            u8 * copy_from_here);
+                            const u8 * copy_from_here);
 int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset,
                                  u32 required_bytes, u8 * copy_from_here);
 int svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here);
 
 int svm_fifo_peek (svm_fifo_t * f, u32 offset, u32 max_bytes, u8 * copy_here);
 int svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes);
+void svm_fifo_dequeue_drop_all (svm_fifo_t * f);
+int svm_fifo_segments (svm_fifo_t * f, svm_fifo_segment_t * fs);
+void svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_segment_t * fs);
 u32 svm_fifo_number_ooo_segments (svm_fifo_t * f);
 ooo_segment_t *svm_fifo_first_ooo_segment (svm_fifo_t * f);
 void svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer);
+void svm_fifo_overwrite_head (svm_fifo_t * f, u8 * data, u32 len);
 
 format_function_t format_svm_fifo;
 
@@ -165,6 +217,49 @@ svm_fifo_newest_ooo_segment_reset (svm_fifo_t * f)
   f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
 }
 
+/**
+ * Max contiguous chunk of data that can be read
+ */
+always_inline u32
+svm_fifo_max_read_chunk (svm_fifo_t * f)
+{
+  return ((f->tail > f->head) ? (f->tail - f->head) : (f->nitems - f->head));
+}
+
+/**
+ * Max contiguous chunk of data that can be written
+ */
+always_inline u32
+svm_fifo_max_write_chunk (svm_fifo_t * f)
+{
+  return ((f->tail >= f->head) ? (f->nitems - f->tail) : (f->head - f->tail));
+}
+
+/**
+ * Advance tail pointer
+ *
+ * Useful for moving tail pointer after external enqueue.
+ */
+always_inline void
+svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 bytes)
+{
+  ASSERT (bytes <= svm_fifo_max_enqueue (f));
+  f->tail = (f->tail + bytes) % f->nitems;
+  f->cursize += bytes;
+}
+
+always_inline u8 *
+svm_fifo_head (svm_fifo_t * f)
+{
+  return (f->data + f->head);
+}
+
+always_inline u8 *
+svm_fifo_tail (svm_fifo_t * f)
+{
+  return (f->data + f->tail);
+}
+
 always_inline u32
 ooo_segment_distance_from_tail (svm_fifo_t * f, u32 pos)
 {