X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fsvm%2Fsvm_fifo.h;h=4a119341d8b3cb3a519e360c4ab6c56331e86e26;hb=c5df8c71c;hp=d7852a79b32aea3c7bb23b05aa34a578a14f8ee2;hpb=326b81e30e63a8296df51d85e6514356cd737225;p=vpp.git

diff --git a/src/svm/svm_fifo.h b/src/svm/svm_fifo.h
index d7852a79b32..4a119341d8b 100644
--- a/src/svm/svm_fifo.h
+++ b/src/svm/svm_fifo.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Copyright (c) 2016-2019 Cisco and/or its affiliates.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
@@ -39,6 +39,15 @@ format_function_t format_ooo_list;
 #define SVM_FIFO_TRACE 			(0)
 #define OOO_SEGMENT_INVALID_INDEX 	((u32)~0)
 #define SVM_FIFO_INVALID_SESSION_INDEX 	((u32)~0)
+#define SVM_FIFO_INVALID_INDEX		((u32)~0)
+#define SVM_FIFO_MAX_EVT_SUBSCRIBERS	8
+
+enum
+{
+  SVM_FIFO_NO_TX_NOTIF = 0,
+  SVM_FIFO_WANT_TX_NOTIF = 1,
+  SVM_FIFO_WANT_TX_NOTIF_IF_FULL = 2,
+};
 
 typedef struct
 {
@@ -49,25 +58,29 @@ typedef struct
 
 typedef struct _svm_fifo
 {
+  CLIB_CACHE_LINE_ALIGN_MARK (shared_first);
   volatile u32 cursize;		/**< current fifo size */
   u32 nitems;
-    CLIB_CACHE_LINE_ALIGN_MARK (end_cursize);
 
+    CLIB_CACHE_LINE_ALIGN_MARK (shared_second);
   volatile u32 has_event;	/**< non-zero if deq event exists */
 
-  /* Backpointers */
   u32 master_session_index;
   u32 client_session_index;
   u8 master_thread_index;
   u8 client_thread_index;
   u32 segment_manager;
+  u32 segment_index;
   u32 ct_session_index;		/**< Local session index for vpp */
-    CLIB_CACHE_LINE_ALIGN_MARK (end_shared);
+  u32 freelist_index;		/**< aka log2(allocated_size) - const. */
+  i8 refcnt;			/**< reference count  */
+
+    CLIB_CACHE_LINE_ALIGN_MARK (consumer);
   u32 head;
-  volatile u32 want_tx_evt;	/**< producer wants nudge */
-    CLIB_CACHE_LINE_ALIGN_MARK (end_consumer);
+  volatile u32 want_tx_ntf;	/**< producer wants nudge */
+  volatile u32 has_tx_ntf;
 
-  /* producer */
+    CLIB_CACHE_LINE_ALIGN_MARK (producer);
   u32 tail;
 
   ooo_segment_t *ooo_segments;	/**< Pool of ooo segments */
@@ -75,11 +88,13 @@ typedef struct _svm_fifo
   u32 ooos_newest;		/**< Last segment to have been updated */
   struct _svm_fifo *next;	/**< next in freelist/active chain */
   struct _svm_fifo *prev;	/**< prev in active chain */
+  volatile u8 n_subscribers;
+  u8 subscribers[SVM_FIFO_MAX_EVT_SUBSCRIBERS];
+
 #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;
 
@@ -113,19 +128,19 @@ u8 *svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose);
 static inline u32
 svm_fifo_max_dequeue (svm_fifo_t * f)
 {
-  return f->cursize;
+  return clib_atomic_load_acq_n (&f->cursize);
 }
 
 static inline int
 svm_fifo_is_full (svm_fifo_t * f)
 {
-  return (f->cursize == f->nitems);
+  return (clib_atomic_load_acq_n (&f->cursize) == f->nitems);
 }
 
 static inline int
 svm_fifo_is_empty (svm_fifo_t * f)
 {
-  return (f->cursize == 0);
+  return (clib_atomic_load_acq_n (&f->cursize) == 0);
 }
 
 static inline u32
@@ -158,30 +173,18 @@ svm_fifo_set_event (svm_fifo_t * f)
 {
   /* 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);
+  return !clib_atomic_swap_rel_n (&f->has_event, 1);
 }
 
 /**
  * Unsets fifo event flag.
  *
- * Also acts as a release barrier.
+ * Also acts as an acquire barrier.
  */
 always_inline void
 svm_fifo_unset_event (svm_fifo_t * f)
 {
-  __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;
+  clib_atomic_swap_acq_n (&f->has_event, 0);
 }
 
 svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);
@@ -198,27 +201,12 @@ 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);
-
+void svm_fifo_add_subscriber (svm_fifo_t * f, u8 subscriber);
+void svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber);
 format_function_t format_svm_fifo;
 
-always_inline ooo_segment_t *
-svm_fifo_newest_ooo_segment (svm_fifo_t * f)
-{
-  if (f->ooos_newest == OOO_SEGMENT_INVALID_INDEX)
-    return 0;
-  return pool_elt_at_index (f->ooo_segments, f->ooos_newest);
-}
-
-always_inline void
-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
  */
@@ -247,7 +235,7 @@ 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;
+  clib_atomic_fetch_add_rel (&f->cursize, bytes);
 }
 
 always_inline u8 *
@@ -262,6 +250,83 @@ svm_fifo_tail (svm_fifo_t * f)
   return (f->data + f->tail);
 }
 
+always_inline u32
+svm_fifo_nitems (svm_fifo_t * f)
+{
+  return f->nitems;
+}
+
+static inline void
+svm_fifo_add_want_tx_ntf (svm_fifo_t * f, u8 ntf_type)
+{
+  f->want_tx_ntf |= ntf_type;
+}
+
+static inline void
+svm_fifo_del_want_tx_ntf (svm_fifo_t * f, u8 ntf_type)
+{
+  f->want_tx_ntf &= ~ntf_type;
+}
+
+static inline void
+svm_fifo_clear_tx_ntf (svm_fifo_t * f)
+{
+  /* Set the flag if want_tx_notif_if_full was the only ntf requested */
+  f->has_tx_ntf = f->want_tx_ntf == SVM_FIFO_WANT_TX_NOTIF_IF_FULL;
+  svm_fifo_del_want_tx_ntf (f, SVM_FIFO_WANT_TX_NOTIF);
+}
+
+static inline void
+svm_fifo_reset_tx_ntf (svm_fifo_t * f)
+{
+  f->has_tx_ntf = 0;
+}
+
+static inline u8
+svm_fifo_needs_tx_ntf (svm_fifo_t * f, u32 n_last_deq)
+{
+  u8 want_ntf = f->want_tx_ntf;
+
+  if (PREDICT_TRUE (want_ntf == SVM_FIFO_NO_TX_NOTIF))
+    return 0;
+  else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF)
+    return 1;
+  else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF_IF_FULL)
+    {
+      u32 max_deq = svm_fifo_max_dequeue (f);
+      u32 nitems = svm_fifo_nitems (f);
+      if (!f->has_tx_ntf && max_deq < nitems
+	  && max_deq + n_last_deq >= nitems)
+	return 1;
+
+      return 0;
+    }
+  return 0;
+}
+
+always_inline u8
+svm_fifo_n_subscribers (svm_fifo_t * f)
+{
+  return f->n_subscribers;
+}
+
+u32 svm_fifo_number_ooo_segments (svm_fifo_t * f);
+ooo_segment_t *svm_fifo_first_ooo_segment (svm_fifo_t * f);
+
+always_inline ooo_segment_t *
+svm_fifo_newest_ooo_segment (svm_fifo_t * f)
+{
+  if (f->ooos_newest == OOO_SEGMENT_INVALID_INDEX)
+    return 0;
+  return pool_elt_at_index (f->ooo_segments, f->ooos_newest);
+}
+
+always_inline void
+svm_fifo_newest_ooo_segment_reset (svm_fifo_t * f)
+{
+  f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
+}
+
 always_inline u32
 ooo_segment_distance_from_tail (svm_fifo_t * f, u32 pos)
 {