X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fsvm%2Fsvm_fifo.c;h=975a82026f7bb008051c4b51a389867ee7370c2f;hb=4339c36157c0579c60963cea4bafd3ce2521d207;hp=3d538293c70cad9f1afe2cb36381321da54a5da8;hpb=8eb3e07dea2c905ab46e0236bca9750224484ee8;p=vpp.git

diff --git a/src/svm/svm_fifo.c b/src/svm/svm_fifo.c
index 3d538293c70..975a82026f7 100644
--- a/src/svm/svm_fifo.c
+++ b/src/svm/svm_fifo.c
@@ -400,10 +400,35 @@ svm_fifo_init (svm_fifo_t * f, u32 size)
   f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX;
   f->segment_index = SVM_FIFO_INVALID_INDEX;
   f->refcnt = 1;
-  f->flags = 0;
+  f->head = f->tail = f->flags = 0;
   f->head_chunk = f->tail_chunk = f->ooo_enq = f->ooo_deq = f->start_chunk;
 }
 
+void
+svm_fifo_init_chunks (svm_fifo_t * f)
+{
+  svm_fifo_chunk_t *c, *prev;
+
+  if (f->start_chunk->next == f->start_chunk)
+    return;
+
+  f->flags |= SVM_FIFO_F_MULTI_CHUNK;
+  rb_tree_init (&f->chunk_lookup);
+  rb_tree_add2 (&f->chunk_lookup, 0, pointer_to_uword (f->start_chunk));
+
+  f->start_chunk->start_byte = 0;
+  prev = f->start_chunk;
+  c = prev->next;
+
+  while (c != f->start_chunk)
+    {
+      c->start_byte = prev->start_byte + prev->length;
+      rb_tree_add2 (&f->chunk_lookup, c->start_byte, pointer_to_uword (c));
+      prev = c;
+      c = c->next;
+    }
+}
+
 /**
  * Creates a fifo in the current heap. Fails vs blow up the process
  */
@@ -559,11 +584,101 @@ svm_fifo_add_chunk (svm_fifo_t * f, svm_fifo_chunk_t * c)
    * that this is called with the heap where the rbtree's pool is pushed. */
   if (!(f->flags & SVM_FIFO_F_MULTI_CHUNK))
     {
+      ASSERT (f->start_chunk->next == f->start_chunk);
       rb_tree_init (&f->chunk_lookup);
       rb_tree_add2 (&f->chunk_lookup, 0, pointer_to_uword (f->start_chunk));
       f->flags |= SVM_FIFO_F_MULTI_CHUNK;
     }
 
+  /* If fifo is not wrapped, update the size now */
+  if (!svm_fifo_is_wrapped (f))
+    {
+      /* Initialize chunks and add to lookup rbtree */
+      cur = c;
+      if (f->new_chunks)
+	{
+	  prev = f->new_chunks;
+	  while (prev->next)
+	    prev = prev->next;
+	  prev->next = c;
+	}
+      else
+	prev = f->end_chunk;
+
+      while (cur)
+	{
+	  cur->start_byte = prev->start_byte + prev->length;
+	  rb_tree_add2 (&f->chunk_lookup, cur->start_byte,
+			pointer_to_uword (cur));
+	  prev = cur;
+	  cur = cur->next;
+	}
+
+      ASSERT (!f->new_chunks);
+      svm_fifo_grow (f, c);
+      return;
+    }
+
+  /* Wrapped */
+  if (f->flags & SVM_FIFO_F_SINGLE_THREAD_OWNED)
+    {
+      ASSERT (f->master_thread_index == os_get_thread_index ());
+
+      if (!f->new_chunks && f->head_chunk != f->tail_chunk)
+	{
+	  u32 head = 0, tail = 0;
+	  f_load_head_tail_cons (f, &head, &tail);
+
+	  svm_fifo_chunk_t *tmp = f->tail_chunk->next;
+
+	  prev = f->tail_chunk;
+	  u32 add_bytes = 0;
+	  cur = prev->next;
+	  while (cur != f->start_chunk)
+	    {
+	      /* remove any existing rb_tree entry */
+	      rb_tree_del (&f->chunk_lookup, cur->start_byte);
+	      cur = cur->next;
+	    }
+
+	  /* insert new chunk after the tail_chunk */
+	  f->tail_chunk->next = c;
+	  while (c)
+	    {
+	      add_bytes += c->length;
+	      c->start_byte = prev->start_byte + prev->length;
+	      rb_tree_add2 (&f->chunk_lookup, c->start_byte,
+			    pointer_to_uword (c));
+
+	      prev = c;
+	      c = c->next;
+	    }
+	  prev->next = tmp;
+
+	  /* shift existing chunks along */
+	  cur = tmp;
+	  while (cur != f->start_chunk)
+	    {
+	      cur->start_byte = prev->start_byte + prev->length;
+	      rb_tree_add2 (&f->chunk_lookup, cur->start_byte,
+			    pointer_to_uword (cur));
+	      prev = cur;
+	      cur = cur->next;
+	    }
+
+	  f->size += add_bytes;
+	  f->nitems = f->size - 1;
+	  f->new_chunks = 0;
+	  head += add_bytes;
+
+	  clib_atomic_store_rel_n (&f->head, head);
+	  ASSERT (svm_fifo_is_sane (f));
+
+	  return;
+	}
+    }
+
+  /* Wrapped, and optimization of single-thread-owned fifo cannot be applied */
   /* Initialize chunks and add to lookup rbtree */
   cur = c;
   if (f->new_chunks)
@@ -585,14 +700,6 @@ svm_fifo_add_chunk (svm_fifo_t * f, svm_fifo_chunk_t * c)
       cur = cur->next;
     }
 
-  /* If fifo is not wrapped, update the size now */
-  if (!svm_fifo_is_wrapped (f))
-    {
-      ASSERT (!f->new_chunks);
-      svm_fifo_grow (f, c);
-      return;
-    }
-
   /* Postpone size update */
   if (!f->new_chunks)
     {
@@ -626,7 +733,7 @@ svm_fifo_collect_chunks (svm_fifo_t * f)
 void
 svm_fifo_try_shrink (svm_fifo_t * f, u32 head, u32 tail)
 {
-  u32 len_to_shrink = 0, tail_pos, len;
+  u32 len_to_shrink = 0, tail_pos, len, last_pos;
   svm_fifo_chunk_t *cur, *prev, *next, *start;
 
   tail_pos = tail;
@@ -649,13 +756,24 @@ svm_fifo_try_shrink (svm_fifo_t * f, u32 head, u32 tail)
    * - not wrapped
    * - last used byte less than start of last chunk
    */
-  if (tail_pos >= head && tail_pos <= f->end_chunk->start_byte)
+  if (tail_pos >= head && tail_pos < f->end_chunk->start_byte)
     {
       /* Lookup the last position not to be removed. Since size still needs
-       * to be nitems + 1, nitems must fall within the usable space */
-      tail_pos = tail_pos > 0 ? tail_pos - 1 : tail_pos;
-      prev = svm_fifo_find_chunk (f, clib_max (f->nitems, tail_pos));
+       * to be nitems + 1, nitems must fall within the usable space. Also,
+       * first segment is not removable, so tail_pos can be 0. */
+      last_pos = tail_pos > 0 ? tail_pos - 1 : tail_pos;
+      prev = svm_fifo_find_chunk (f, clib_max (f->nitems, last_pos));
       next = prev->next;
+      /* If tail_pos is first position in next, skip the chunk, otherwise,
+       * we must update the tail and, if fifo size is 0, even the head.
+       * We should not invalidate the tail for the caller and must not change
+       * consumer owned variables from code that's typically called by the
+       * producer */
+      if (next->start_byte == tail_pos)
+	{
+	  prev = next;
+	  next = next->next;
+	}
       while (next != f->start_chunk)
 	{
 	  cur = next;
@@ -790,7 +908,11 @@ svm_fifo_enqueue (svm_fifo_t * f, u32 len, const u8 * src)
 
   /* collect out-of-order segments */
   if (PREDICT_FALSE (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX))
-    len += ooo_segment_try_collect (f, len, &tail);
+    {
+      len += ooo_segment_try_collect (f, len, &tail);
+      if (!svm_fifo_chunk_includes_pos (f->tail_chunk, tail))
+	f->tail_chunk = svm_fifo_find_chunk (f, tail);
+    }
 
   /* store-rel: producer owned index (paired with load-acq in consumer) */
   clib_atomic_store_rel_n (&f->tail, tail);
@@ -847,6 +969,10 @@ svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 len)
   /* load-relaxed: producer owned index */
   tail = f->tail;
   tail = (tail + len) % f->size;
+
+  if (!svm_fifo_chunk_includes_pos (f->tail_chunk, tail))
+    f->tail_chunk = svm_fifo_find_chunk (f, tail);
+
   /* store-rel: producer owned index (paired with load-acq in consumer) */
   clib_atomic_store_rel_n (&f->tail, tail);
 }
@@ -919,6 +1045,12 @@ svm_fifo_dequeue_drop (svm_fifo_t * f, u32 len)
   /* move head */
   head = (head + total_drop_bytes) % f->size;
 
+  if (!svm_fifo_chunk_includes_pos (f->head_chunk, head))
+    f->head_chunk = svm_fifo_find_chunk (f, head);
+
+  if (PREDICT_FALSE (f->flags & SVM_FIFO_F_GROW))
+    svm_fifo_try_grow (f, head);
+
   /* store-rel: consumer owned index (paired with load-acq in producer) */
   clib_atomic_store_rel_n (&f->head, head);
 
@@ -930,6 +1062,13 @@ svm_fifo_dequeue_drop_all (svm_fifo_t * f)
 {
   /* consumer foreign index */
   u32 tail = clib_atomic_load_acq_n (&f->tail);
+
+  if (!svm_fifo_chunk_includes_pos (f->head_chunk, tail))
+    f->head_chunk = svm_fifo_find_chunk (f, tail);
+
+  if (PREDICT_FALSE (f->flags & SVM_FIFO_F_GROW))
+    svm_fifo_try_grow (f, tail);
+
   /* store-rel: consumer owned index (paired with load-acq in producer) */
   clib_atomic_store_rel_n (&f->head, tail);
 }
@@ -1055,6 +1194,64 @@ svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber)
     }
 }
 
+u8
+svm_fifo_is_sane (svm_fifo_t * f)
+{
+  if (f->size - 1 != f->nitems && !(f->flags & SVM_FIFO_F_SHRINK))
+    return 0;
+  if (!svm_fifo_chunk_includes_pos (f->head_chunk, f->head))
+    return 0;
+  if (!svm_fifo_chunk_includes_pos (f->tail_chunk, f->tail))
+    return 0;
+
+  if (f->start_chunk->next != f->start_chunk)
+    {
+      svm_fifo_chunk_t *c, *prev = 0, *tmp;
+      u32 size = 0;
+
+      if (!(f->flags & SVM_FIFO_F_MULTI_CHUNK))
+	return 0;
+
+      c = f->start_chunk;
+      do
+	{
+	  tmp = svm_fifo_find_chunk (f, c->start_byte);
+	  if (tmp != c)
+	    return 0;
+	  if (prev && (prev->start_byte + prev->length != c->start_byte))
+	    return 0;
+	  size += c->length;
+	  prev = c;
+	  c = c->next;
+	}
+      while (c != f->start_chunk);
+
+      if (size != f->size)
+	return 0;
+    }
+
+  return 1;
+}
+
+u8
+svm_fifo_set_single_thread_owned (svm_fifo_t * f)
+{
+  if (f->flags & SVM_FIFO_F_SINGLE_THREAD_OWNED)
+    {
+      if (f->master_thread_index == os_get_thread_index ())
+	{
+	  /* just a duplicate call */
+	  return 0;
+	}
+
+      /* already owned by another thread */
+      return 1;
+    }
+
+  f->flags |= SVM_FIFO_F_SINGLE_THREAD_OWNED;
+  return 0;
+}
+
 u8 *
 format_ooo_segment (u8 * s, va_list * args)
 {