vcl svm: provide apps access to fifo chunks

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

diff --git a/src/svm/svm_fifo.c b/src/svm/svm_fifo.c
index 1723cb4..2cce2bf 100644 (file)
--- a/src/svm/svm_fifo.c
+++ b/src/svm/svm_fifo.c
@@ -1024,6 +1024,10 @@ svm_fifo_dequeue (svm_fifo_t * f, u32 len, u8 * dst)
   svm_fifo_copy_from_chunk (f, f->head_chunk, head, dst, len, &f->head_chunk);
   head = head + len;
 
+  /* In order dequeues are not supported in combination with ooo peeking.
+   * Use svm_fifo_dequeue_drop instead. */
+  ASSERT (rb_tree_n_nodes (&f->ooo_deq_lookup) <= 1);
+
   if (f_pos_geq (head, f_chunk_end (f->start_chunk)))
     fsh_collect_chunks (f->fs_hdr, f->slice_index,
                        f_unlink_chunks (f, head, 0));
@@ -1132,9 +1136,11 @@ svm_fifo_fill_chunk_list (svm_fifo_t * f)
 }
 
 int
-svm_fifo_segments (svm_fifo_t * f, svm_fifo_seg_t * fs)
+svm_fifo_segments (svm_fifo_t * f, svm_fifo_seg_t * fs, u32 n_segs,
+                  u32 max_bytes)
 {
-  u32 cursize, head, tail, head_idx;
+  u32 cursize, to_read, head, tail, fs_index = 1, n_bytes, head_pos, len;
+  svm_fifo_chunk_t *c;
 
   f_load_head_tail_cons (f, &head, &tail);
 
@@ -1144,37 +1150,26 @@ svm_fifo_segments (svm_fifo_t * f, svm_fifo_seg_t * fs)
   if (PREDICT_FALSE (cursize == 0))
     return SVM_FIFO_EEMPTY;
 
-  head_idx = head;
+  to_read = clib_min (cursize, max_bytes);
 
-  if (tail < head)
-    {
-      fs[0].len = f->size - head_idx;
-      fs[0].data = f->head_chunk->data + head_idx;
-      fs[1].len = cursize - fs[0].len;
-      fs[1].data = f->head_chunk->data;
-    }
-  else
+  c = f->head_chunk;
+  head_pos = head - c->start_byte;
+  fs[0].data = c->data + head_pos;
+  fs[0].len = c->length - head_pos;
+  n_bytes = fs[0].len;
+  c = c->next;
+
+  while (n_bytes < to_read && fs_index < n_segs)
     {
-      fs[0].len = cursize;
-      fs[0].data = f->head_chunk->data + head_idx;
-      fs[1].len = 0;
-      fs[1].data = 0;
+      len = clib_min (c->length, to_read - n_bytes);
+      fs[fs_index].data = c->data;
+      fs[fs_index].len = len;
+      n_bytes += len;
+      c = c->next;
+      fs_index += 1;
     }
-  return cursize;
-}
-
-void
-svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_seg_t * fs)
-{
-  u32 head;
 
-  /* consumer owned index */
-  head = f->head;
-
-  ASSERT (fs[0].data == f->head_chunk->data + head);
-  head = (head + fs[0].len + fs[1].len);
-  /* store-rel: consumer owned index (paired with load-acq in producer) */
-  clib_atomic_store_rel_n (&f->head, head);
+  return n_bytes;
 }
 
 /**
@@ -1403,7 +1398,7 @@ svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose)
   u8 *data = 0;
   svm_fifo_trace_elem_t *trace;
   u32 offset;
-  svm_fifo_t *dummy_fifo;
+  svm_fifo_t *placeholder_fifo;
 
   if (!f)
     return s;
@@ -1416,7 +1411,7 @@ svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose)
   trace_len = 0;
 #endif
 
-  dummy_fifo = svm_fifo_alloc (f->size);
+  placeholder_fifo = svm_fifo_alloc (f->size);
   svm_fifo_init (f, f->size);
   clib_memset (f->head_chunk->data, 0xFF, f->size);
   vec_validate (data, f->size);
@@ -1431,26 +1426,26 @@ svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose)
          if (verbose)
            s = format (s, "adding [%u, %u]:", trace[i].offset,
                        (trace[i].offset + trace[i].len));
-         svm_fifo_enqueue_with_offset (dummy_fifo, trace[i].offset,
+         svm_fifo_enqueue_with_offset (placeholder_fifo, trace[i].offset,
                                        trace[i].len, &data[offset]);
        }
       else if (trace[i].action == 2)
        {
          if (verbose)
            s = format (s, "adding [%u, %u]:", 0, trace[i].len);
-         svm_fifo_enqueue (dummy_fifo, trace[i].len, &data[offset]);
+         svm_fifo_enqueue (placeholder_fifo, trace[i].len, &data[offset]);
        }
       else if (!no_read)
        {
          if (verbose)
            s = format (s, "read: %u", trace[i].len);
-         svm_fifo_dequeue_drop (dummy_fifo, trace[i].len);
+         svm_fifo_dequeue_drop (placeholder_fifo, trace[i].len);
        }
       if (verbose)
-       s = format (s, "%U", format_svm_fifo, dummy_fifo, 1);
+       s = format (s, "%U", format_svm_fifo, placeholder_fifo, 1);
     }
 
-  s = format (s, "result: %U", format_svm_fifo, dummy_fifo, 1);
+  s = format (s, "result: %U", format_svm_fifo, placeholder_fifo, 1);
 
   return s;
 }