svm: fifo segment cleanup

- consolidate chunk freelist functions
- remove redundant functions

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: Idd7e6700e2cc98a0fb9cfe20a2b739218fd48043

1 files changed, 205 insertions, 341 deletions

diff --git a/src/svm/fifo_segment.c b/src/svm/fifo_segment.c
index a5ffd4af2ed..473cdf31b64 100644
--- a/src/svm/fifo_segment.c
+++ b/src/svm/fifo_segment.c
@@ -133,6 +133,70 @@ fsh_check_mem (fifo_segment_header_t * fsh)
   fsh_update_free_bytes (fsh);
 }
 
+static inline int
+fss_chunk_fl_index_is_valid (fifo_segment_slice_t * fss, u32 fl_index)
+{
+  return (fl_index < vec_len (fss->free_chunks));
+}
+
+static void
+fss_chunk_free_list_push (fifo_segment_slice_t * fss, u32 fl_index,
+			  svm_fifo_chunk_t * c)
+{
+  c->next = fss->free_chunks[fl_index];
+  fss->free_chunks[fl_index] = c;
+}
+
+static void
+fss_chunk_free_list_push_list (fifo_segment_slice_t * fss, u32 fl_index,
+			       svm_fifo_chunk_t * head,
+			       svm_fifo_chunk_t * tail)
+{
+  tail->next = fss->free_chunks[fl_index];
+  fss->free_chunks[fl_index] = head;
+}
+
+static svm_fifo_chunk_t *
+fss_chunk_free_list_pop (fifo_segment_slice_t * fss, u32 fl_index)
+{
+  svm_fifo_chunk_t *c;
+
+  ASSERT (fss_chunk_fl_index_is_valid (fss, fl_index));
+
+  if (!fss->free_chunks[fl_index])
+    return 0;
+
+  c = fss->free_chunks[fl_index];
+  fss->free_chunks[fl_index] = c->next;
+
+  return c;
+}
+
+static inline void
+fss_fifo_add_active_list (fifo_segment_slice_t * fss, svm_fifo_t * f)
+{
+  if (fss->fifos)
+    {
+      fss->fifos->prev = f;
+      f->next = fss->fifos;
+    }
+  fss->fifos = f;
+}
+
+static inline void
+fss_fifo_del_active_list (fifo_segment_slice_t * fss, svm_fifo_t * f)
+{
+  if (f->flags & SVM_FIFO_F_LL_TRACKED)
+    {
+      if (f->prev)
+	f->prev->next = f->next;
+      else
+	fss->fifos = f->next;
+      if (f->next)
+	f->next->prev = f->prev;
+    }
+}
+
 /**
  * Initialize fifo segment shared header
  */
@@ -318,30 +382,6 @@ fs_chunk_size_is_valid (fifo_segment_header_t * fsh, u32 size)
     && size <= (1ULL << fsh->max_log2_chunk_size);
 }
 
-static svm_fifo_t *
-fs_try_alloc_fifo_freelist (fifo_segment_slice_t * fss, u32 fl_index)
-{
-  svm_fifo_chunk_t *c;
-  svm_fifo_t *f;
-
-  f = fss->free_fifos;
-  c = fss->free_chunks[fl_index];
-
-  if (!f || !c)
-    return 0;
-
-  fss->free_fifos = f->next;
-  fss->free_chunks[fl_index] = c->next;
-  c->next = 0;
-  c->start_byte = 0;
-  memset (f, 0, sizeof (*f));
-  f->start_chunk = c;
-  f->end_chunk = c;
-
-  fss->n_fl_chunk_bytes -= fs_freelist_index_to_size (fl_index);
-  return f;
-}
-
 svm_fifo_chunk_t *
 fs_try_alloc_multi_chunk (fifo_segment_header_t * fsh,
 			  fifo_segment_slice_t * fss, u32 data_bytes)
@@ -357,10 +397,9 @@ fs_try_alloc_multi_chunk (fifo_segment_header_t * fsh,
 
   while (req_bytes)
     {
-      c = fss->free_chunks[fl_index];
+      c = fss_chunk_free_list_pop (fss, fl_index);
       if (c)
 	{
-	  fss->free_chunks[fl_index] = c->next;
 	  c->next = first;
 	  first = c;
 	  n_alloc += fl_size;
@@ -371,28 +410,29 @@ fs_try_alloc_multi_chunk (fifo_segment_header_t * fsh,
 	  /* Failed to allocate with smaller chunks */
 	  if (fl_index == 0)
 	    {
-	      /* free all chunks if any allocated */
+	      /* Free all chunks if any allocated */
 	      c = first;
 	      while (c)
 		{
 		  fl_index = fs_freelist_for_size (c->length);
-		  fl_size = fs_freelist_index_to_size (fl_index);
 		  next = c->next;
-		  c->next = fss->free_chunks[fl_index];
-		  fss->free_chunks[fl_index] = c;
-		  fss->n_fl_chunk_bytes += fl_size;
+		  fss_chunk_free_list_push (fss, fl_index, c);
 		  c = next;
 		}
 	      n_alloc = 0;
 	      first = 0;
-	      fl_index = fs_freelist_for_size (data_bytes);
-	      if (fss->free_chunks[fl_index + 1])
+	      /* As last attempt, try allocating a chunk larger than
+	       * the requested size, if possible */
+	      fl_index = fs_freelist_for_size (data_bytes) + 1;
+	      if (!fss_chunk_fl_index_is_valid (fss, fl_index))
+		return 0;
+	      first = fss_chunk_free_list_pop (fss, fl_index);
+	      if (first)
 		{
-		  fl_index += 1;
-		  fl_size = fs_freelist_index_to_size (fl_index);
-		  continue;
+		  first->next = 0;
+		  n_alloc = fs_freelist_index_to_size (fl_index);
+		  goto done;
 		}
-
 	      return 0;
 	    }
 	  fl_index -= 1;
@@ -400,100 +440,45 @@ fs_try_alloc_multi_chunk (fifo_segment_header_t * fsh,
 	}
     }
 
+done:
   fss->n_fl_chunk_bytes -= n_alloc;
   fsh_cached_bytes_sub (fsh, n_alloc);
   return first;
 }
 
-static svm_fifo_t *
-fs_try_alloc_fifo_freelist_multi_chunk (fifo_segment_header_t * fsh,
-					fifo_segment_slice_t * fss,
-					u32 data_bytes)
+static int
+fsh_try_alloc_fifo_hdr_batch (fifo_segment_header_t * fsh,
+			      fifo_segment_slice_t * fss, u32 batch_size)
 {
-  svm_fifo_chunk_t *c, *first = 0, *last = 0, *next;
-  u32 fl_index, fl_size, n_alloc = 0;
   svm_fifo_t *f;
+  void *oldheap;
+  uword size;
+  u8 *fmem;
+  int i;
 
-  f = fss->free_fifos;
-  if (!f)
-    {
-      if (PREDICT_FALSE (fsh_n_free_bytes (fsh) < sizeof (svm_fifo_t)))
-	return 0;
-
-      void *oldheap = ssvm_push_heap (fsh->ssvm_sh);
-      f = clib_mem_alloc_aligned_or_null (sizeof (*f), CLIB_CACHE_LINE_BYTES);
-      ssvm_pop_heap (oldheap);
-      if (!f)
-	return 0;
-      memset (f, 0, sizeof (*f));
-      fsh_free_bytes_sub (fsh, sizeof (*f));
-    }
-  else
-    {
-      fss->free_fifos = f->next;
-    }
+  size = (uword) sizeof (*f) * batch_size;
 
-  fl_index = fs_freelist_for_size (data_bytes);
-  if (fl_index > 0)
-    fl_index -= 1;
+  oldheap = ssvm_push_heap (fsh->ssvm_sh);
+  fmem = clib_mem_alloc_aligned_at_offset (size, CLIB_CACHE_LINE_BYTES,
+					   0 /* align_offset */ ,
+					   0 /* os_out_of_memory */ );
+  ssvm_pop_heap (oldheap);
 
-  fl_size = fs_freelist_index_to_size (fl_index);
+  /* Out of space.. */
+  if (fmem == 0)
+    return -1;
 
-  while (data_bytes)
+  /* Carve fifo hdr space */
+  for (i = 0; i < batch_size; i++)
     {
-      c = fss->free_chunks[fl_index];
-      if (c)
-	{
-	  fss->free_chunks[fl_index] = c->next;
-	  if (!last)
-	    last = c;
-	  c->next = first;
-	  first = c;
-	  n_alloc += fl_size;
-	  data_bytes -= clib_min (fl_size, data_bytes);
-	}
-      else
-	{
-	  /* Failed to allocate with smaller chunks */
-	  if (fl_index == 0)
-	    {
-	      /* free all chunks if any allocated */
-	      c = first;
-	      while (c)
-		{
-		  fl_index = fs_freelist_for_size (c->length);
-		  fl_size = fs_freelist_index_to_size (fl_index);
-		  next = c->next;
-		  c->next = fss->free_chunks[fl_index];
-		  fss->free_chunks[fl_index] = c;
-		  fss->n_fl_chunk_bytes += fl_size;
-		  n_alloc -= fl_size;
-		  data_bytes += fl_size;
-		  c = next;
-		}
-	      first = last = 0;
-	      fl_index = fs_freelist_for_size (data_bytes);
-	      if (fss->free_chunks[fl_index + 1])
-		{
-		  fl_index += 1;
-		  fl_size = fs_freelist_index_to_size (fl_index);
-		  continue;
-		}
-
-	      f->next = fss->free_fifos;
-	      fss->free_fifos = f;
-	      return 0;
-	    }
-	  fl_index -= 1;
-	  fl_size = fl_size >> 1;
-	}
+      f = (svm_fifo_t *) fmem;
+      memset (f, 0, sizeof (*f));
+      f->next = fss->free_fifos;
+      fss->free_fifos = f;
+      fmem += sizeof (*f);
     }
 
-  f->start_chunk = first;
-  f->end_chunk = last;
-  fss->n_fl_chunk_bytes -= n_alloc;
-  fsh_cached_bytes_sub (fsh, n_alloc);
-  return f;
+  return 0;
 }
 
 static int
@@ -502,7 +487,7 @@ fsh_try_alloc_chunk_batch (fifo_segment_header_t * fsh,
 			   u32 fl_index, u32 batch_size)
 {
   u32 rounded_data_size;
-  svm_fifo_chunk_t *c;
+  svm_fifo_chunk_t *c, *head = 0, *tail;
   void *oldheap;
   uword size;
   u8 *cmem;
@@ -522,18 +507,20 @@ fsh_try_alloc_chunk_batch (fifo_segment_header_t * fsh,
     return -1;
 
   /* Carve fifo + chunk space */
+  tail = c = (svm_fifo_chunk_t *) cmem;
   for (i = 0; i < batch_size; i++)
     {
-      c = (svm_fifo_chunk_t *) cmem;
       c->start_byte = 0;
       c->length = rounded_data_size;
       c->enq_rb_index = RBTREE_TNIL_INDEX;
       c->deq_rb_index = RBTREE_TNIL_INDEX;
-      c->next = fss->free_chunks[fl_index];
-      fss->free_chunks[fl_index] = c;
+      c->next = head;
+      head = c;
       cmem += sizeof (*c) + rounded_data_size;
+      c = (svm_fifo_chunk_t *) cmem;
     }
 
+  fss_chunk_free_list_push_list (fss, fl_index, head, tail);
   fss->num_chunks[fl_index] += batch_size;
   fss->n_fl_chunk_bytes += batch_size * rounded_data_size;
   fsh_cached_bytes_add (fsh, batch_size * rounded_data_size);
@@ -547,57 +534,93 @@ fs_try_alloc_fifo_batch (fifo_segment_header_t * fsh,
 			 fifo_segment_slice_t * fss,
 			 u32 fl_index, u32 batch_size)
 {
-  u32 hdrs, rounded_data_size;
-  svm_fifo_chunk_t *c;
+  if (fsh_try_alloc_fifo_hdr_batch (fsh, fss, batch_size))
+    return 0;
+  return fsh_try_alloc_chunk_batch (fsh, fss, fl_index, batch_size);
+}
+
+static svm_fifo_t *
+fsh_try_alloc_fifo_hdr (fifo_segment_header_t * fsh,
+			fifo_segment_slice_t * fss)
+{
   svm_fifo_t *f;
-  void *oldheap;
-  uword size;
-  u8 *fmem;
-  int i;
 
-  rounded_data_size = fs_freelist_index_to_size (fl_index);
-  hdrs = sizeof (*f) + sizeof (*c);
-  size = (uword) (hdrs + rounded_data_size) * batch_size;
+  if (!fss->free_fifos)
+    {
+      if (fsh_try_alloc_fifo_hdr_batch (fsh, fss,
+					FIFO_SEGMENT_ALLOC_BATCH_SIZE))
+	return 0;
+    }
 
-  oldheap = ssvm_push_heap (fsh->ssvm_sh);
-  fmem = clib_mem_alloc_aligned_at_offset (size, CLIB_CACHE_LINE_BYTES,
-					   0 /* align_offset */ ,
-					   0 /* os_out_of_memory */ );
-  ssvm_pop_heap (oldheap);
+  f = fss->free_fifos;
+  fss->free_fifos = f->next;
+  memset (f, 0, sizeof (*f));
+  return f;
+}
 
-  /* Out of space.. */
-  if (fmem == 0)
-    return -1;
+static svm_fifo_chunk_t *
+fsh_try_alloc_chunk (fifo_segment_header_t * fsh,
+		     fifo_segment_slice_t * fss, u32 data_bytes)
+{
+  svm_fifo_chunk_t *c;
+  u32 fl_index;
 
-  /* Carve fifo hdr space */
-  for (i = 0; i < batch_size; i++)
+  fl_index = fs_freelist_for_size (data_bytes);
+
+free_list:
+  c = fss_chunk_free_list_pop (fss, fl_index);
+  if (c)
     {
-      f = (svm_fifo_t *) fmem;
-      memset (f, 0, sizeof (*f));
-      f->next = fss->free_fifos;
-      fss->free_fifos = f;
-      fmem += sizeof (*f);
+      c->next = 0;
+      fss->n_fl_chunk_bytes -= fs_freelist_index_to_size (fl_index);
+      fsh_cached_bytes_sub (fsh, fs_freelist_index_to_size (fl_index));
     }
-
-  /* Carve chunk space */
-  for (i = 0; i < batch_size; i++)
+  else
     {
-      c = (svm_fifo_chunk_t *) fmem;
-      c->start_byte = 0;
-      c->length = rounded_data_size;
-      c->enq_rb_index = RBTREE_TNIL_INDEX;
-      c->deq_rb_index = RBTREE_TNIL_INDEX;
-      c->next = fss->free_chunks[fl_index];
-      fss->free_chunks[fl_index] = c;
-      fmem += sizeof (svm_fifo_chunk_t) + rounded_data_size;
+      u32 chunk_size, batch = FIFO_SEGMENT_ALLOC_BATCH_SIZE;
+      uword n_free;
+
+      chunk_size = fs_freelist_index_to_size (fl_index);
+      n_free = fsh_n_free_bytes (fsh);
+
+      if (chunk_size <= n_free)
+	{
+	  batch = chunk_size * batch <= n_free ? batch : 1;
+	  if (!fsh_try_alloc_chunk_batch (fsh, fss, fl_index, batch))
+	    goto free_list;
+	}
+      /* Failed to allocate larger chunk, try to allocate multi-chunk
+       * that is close to what was actually requested */
+      if (data_bytes <= fss->n_fl_chunk_bytes)
+	{
+	  c = fs_try_alloc_multi_chunk (fsh, fss, data_bytes);
+	  if (c)
+	    goto done;
+	  batch = n_free / FIFO_SEGMENT_MIN_FIFO_SIZE;
+	  if (!batch || fsh_try_alloc_chunk_batch (fsh, fss, 0, batch))
+	    {
+	      fsh_check_mem (fsh);
+	      goto done;
+	    }
+	}
+      if (data_bytes <= fss->n_fl_chunk_bytes + n_free)
+	{
+	  u32 min_size = FIFO_SEGMENT_MIN_FIFO_SIZE;
+
+	  batch = (data_bytes - fss->n_fl_chunk_bytes) / min_size;
+	  batch = clib_min (batch + 1, n_free / min_size);
+	  if (fsh_try_alloc_chunk_batch (fsh, fss, 0, batch))
+	    {
+	      fsh_check_mem (fsh);
+	      goto done;
+	    }
+	  c = fs_try_alloc_multi_chunk (fsh, fss, data_bytes);
+	}
     }
 
-  fss->num_chunks[fl_index] += batch_size;
-  fss->n_fl_chunk_bytes += batch_size * rounded_data_size;
-  fsh_cached_bytes_add (fsh, batch_size * rounded_data_size);
-  fsh_free_bytes_sub (fsh, size);
+done:
 
-  return 0;
+  return c;
 }
 
 /**
@@ -613,69 +636,37 @@ static svm_fifo_t *
 fs_try_alloc_fifo (fifo_segment_header_t * fsh, fifo_segment_slice_t * fss,
 		   u32 data_bytes)
 {
-  u32 fifo_sz, fl_index;
+  u32 fl_index;
+  svm_fifo_chunk_t *c;
   svm_fifo_t *f = 0;
-  uword n_free_bytes;
   u32 min_size;
 
   min_size = clib_max ((fsh->pct_first_alloc * data_bytes) / 100, 4096);
   fl_index = fs_freelist_for_size (min_size);
 
-  if (fl_index >= vec_len (fss->free_chunks))
+  if (!fss_chunk_fl_index_is_valid (fss, fl_index))
     return 0;
 
   clib_spinlock_lock (&fss->chunk_lock);
 
-  if (fss->free_fifos && fss->free_chunks[fl_index])
-    {
-      f = fs_try_alloc_fifo_freelist (fss, fl_index);
-      if (f)
-	{
-	  fsh_cached_bytes_sub (fsh, fs_freelist_index_to_size (fl_index));
-	  goto done;
-	}
-    }
-
-  fifo_sz = sizeof (svm_fifo_t) + sizeof (svm_fifo_chunk_t);
-  fifo_sz += 1 << max_log2 (min_size);
-  n_free_bytes = fsh_n_free_bytes (fsh);
+  f = fsh_try_alloc_fifo_hdr (fsh, fss);
+  if (!f)
+    goto done;
 
-  if (fifo_sz * FIFO_SEGMENT_ALLOC_BATCH_SIZE < n_free_bytes)
+  c = fsh_try_alloc_chunk (fsh, fss, min_size);
+  if (c)
     {
-      if (!fs_try_alloc_fifo_batch (fsh, fss, fl_index,
-				    FIFO_SEGMENT_ALLOC_BATCH_SIZE))
-	{
-	  f = fs_try_alloc_fifo_freelist (fss, fl_index);
-	  if (f)
-	    {
-	      fsh_cached_bytes_sub (fsh,
-				    fs_freelist_index_to_size (fl_index));
-	      goto done;
-	    }
-	}
-      else
-	{
-	  fsh_check_mem (fsh);
-	  n_free_bytes = fsh_n_free_bytes (fsh);
-	}
+      f->start_chunk = c;
+      while (c->next)
+	c = c->next;
+      f->end_chunk = c;
     }
-  if (fifo_sz <= n_free_bytes)
+  else
     {
-      void *oldheap = ssvm_push_heap (fsh->ssvm_sh);
-      f = svm_fifo_alloc (min_size);
-      ssvm_pop_heap (oldheap);
-      if (f)
-	{
-	  clib_atomic_fetch_add_rel (&fss->num_chunks[fl_index], 1);
-	  fsh_free_bytes_sub (fsh, fifo_sz);
-	  goto done;
-	}
-      fsh_check_mem (fsh);
+      f->next = fss->free_fifos;
+      fss->free_fifos = f;
+      f = 0;
     }
-  /* All failed, try to allocate min of data bytes and fifo sz */
-  fifo_sz = clib_min (fifo_sz, data_bytes);
-  if (fifo_sz <= fss->n_fl_chunk_bytes)
-    f = fs_try_alloc_fifo_freelist_multi_chunk (fsh, fss, fifo_sz);
 
 done:
   clib_spinlock_unlock (&fss->chunk_lock);
@@ -693,77 +684,11 @@ fsh_alloc_chunk (fifo_segment_header_t * fsh, u32 slice_index, u32 chunk_size)
 {
   fifo_segment_slice_t *fss;
   svm_fifo_chunk_t *c;
-  int fl_index;
 
-  fl_index = fs_freelist_for_size (chunk_size);
   fss = fsh_slice_get (fsh, slice_index);
 
   clib_spinlock_lock (&fss->chunk_lock);
-
-  ASSERT (vec_len (fss->free_chunks) > fl_index);
-  c = fss->free_chunks[fl_index];
-
-  if (c)
-    {
-      fss->free_chunks[fl_index] = c->next;
-      c->next = 0;
-      fss->n_fl_chunk_bytes -= fs_freelist_index_to_size (fl_index);
-      fsh_cached_bytes_sub (fsh, fs_freelist_index_to_size (fl_index));
-    }
-  else
-    {
-      void *oldheap;
-      uword n_free;
-      u32 batch;
-
-      chunk_size = fs_freelist_index_to_size (fl_index);
-      n_free = fsh_n_free_bytes (fsh);
-
-      if (chunk_size <= n_free)
-	{
-	  oldheap = ssvm_push_heap (fsh->ssvm_sh);
-	  c = svm_fifo_chunk_alloc (chunk_size);
-	  ssvm_pop_heap (oldheap);
-
-	  if (c)
-	    {
-	      clib_atomic_fetch_add_rel (&fss->num_chunks[fl_index], 1);
-	      fsh_free_bytes_sub (fsh, chunk_size + sizeof (*c));
-	      goto done;
-	    }
-
-	  fsh_check_mem (fsh);
-	  n_free = fsh_n_free_bytes (fsh);
-	}
-      if (chunk_size <= fss->n_fl_chunk_bytes)
-	{
-	  c = fs_try_alloc_multi_chunk (fsh, fss, chunk_size);
-	  if (c)
-	    goto done;
-	  batch = n_free / FIFO_SEGMENT_MIN_FIFO_SIZE;
-	  if (!batch || fsh_try_alloc_chunk_batch (fsh, fss, 0, batch))
-	    {
-	      fsh_check_mem (fsh);
-	      goto done;
-	    }
-	}
-      if (chunk_size <= fss->n_fl_chunk_bytes + n_free)
-	{
-	  u32 min_size = FIFO_SEGMENT_MIN_FIFO_SIZE;
-
-	  batch = (chunk_size - fss->n_fl_chunk_bytes) / min_size;
-	  batch = clib_min (batch + 1, n_free / min_size);
-	  if (fsh_try_alloc_chunk_batch (fsh, fss, 0, batch))
-	    {
-	      fsh_check_mem (fsh);
-	      goto done;
-	    }
-	  c = fs_try_alloc_multi_chunk (fsh, fss, chunk_size);
-	}
-    }
-
-done:
-
+  c = fsh_try_alloc_chunk (fsh, fss, chunk_size);
   clib_spinlock_unlock (&fss->chunk_lock);
 
   return c;
@@ -773,9 +698,8 @@ static void
 fsh_slice_collect_chunks (fifo_segment_header_t * fsh,
 			  fifo_segment_slice_t * fss, svm_fifo_chunk_t * c)
 {
+  u32 n_collect = 0, fl_index;
   svm_fifo_chunk_t *next;
-  int fl_index;
-  u32 n_collect = 0;
 
   clib_spinlock_lock (&fss->chunk_lock);
 
@@ -784,10 +708,9 @@ fsh_slice_collect_chunks (fifo_segment_header_t * fsh,
       CLIB_MEM_UNPOISON (c, sizeof (*c));
       next = c->next;
       fl_index = fs_freelist_for_size (c->length);
-      c->next = fss->free_chunks[fl_index];
       c->enq_rb_index = RBTREE_TNIL_INDEX;
       c->deq_rb_index = RBTREE_TNIL_INDEX;
-      fss->free_chunks[fl_index] = c;
+      fss_chunk_free_list_push (fss, fl_index, c);
       n_collect += fs_freelist_index_to_size (fl_index);
       c = next;
     }
@@ -807,31 +730,6 @@ fsh_collect_chunks (fifo_segment_header_t * fsh, u32 slice_index,
   fsh_slice_collect_chunks (fsh, fss, c);
 }
 
-static inline void
-fss_fifo_add_active_list (fifo_segment_slice_t * fss, svm_fifo_t * f)
-{
-  if (fss->fifos)
-    {
-      fss->fifos->prev = f;
-      f->next = fss->fifos;
-    }
-  fss->fifos = f;
-}
-
-static inline void
-fss_fifo_del_active_list (fifo_segment_slice_t * fss, svm_fifo_t * f)
-{
-  if (f->flags & SVM_FIFO_F_LL_TRACKED)
-    {
-      if (f->prev)
-	f->prev->next = f->next;
-      else
-	fss->fifos = f->next;
-      if (f->next)
-	f->next->prev = f->prev;
-    }
-}
-
 /**
  * Allocate fifo in fifo segment
  */
@@ -1014,13 +912,8 @@ fifo_segment_prealloc_fifo_chunks (fifo_segment_t * fs, u32 slice_index,
 				   u32 chunk_size, u32 batch_size)
 {
   fifo_segment_header_t *fsh = fs->h;
-  u32 rounded_data_size, fl_index;
   fifo_segment_slice_t *fss;
-  svm_fifo_chunk_t *c;
-  void *oldheap;
-  uword size;
-  u8 *cmem;
-  int i;
+  u32 fl_index;
 
   if (!fs_chunk_size_is_valid (fsh, chunk_size))
     {
@@ -1029,38 +922,9 @@ fifo_segment_prealloc_fifo_chunks (fifo_segment_t * fs, u32 slice_index,
     }
 
   fl_index = fs_freelist_for_size (chunk_size);
-  rounded_data_size = fs_freelist_index_to_size (fl_index);
-  size = (uword) (sizeof (*c) + rounded_data_size) * batch_size;
-
-  oldheap = ssvm_push_heap (fsh->ssvm_sh);
-  cmem = clib_mem_alloc_aligned_at_offset (size, CLIB_CACHE_LINE_BYTES,
-					   0 /* align_offset */ ,
-					   0 /* os_out_of_memory */ );
-  ssvm_pop_heap (oldheap);
-
-  /* Out of space.. */
-  if (cmem == 0)
-    return -1;
-
   fss = fsh_slice_get (fsh, slice_index);
 
-  /* Carve fifo + chunk space */
-  for (i = 0; i < batch_size; i++)
-    {
-      c = (svm_fifo_chunk_t *) cmem;
-      c->start_byte = 0;
-      c->length = rounded_data_size;
-      c->next = fss->free_chunks[fl_index];
-      fss->free_chunks[fl_index] = c;
-      cmem += sizeof (*c) + rounded_data_size;
-      fsh_cached_bytes_add (fsh, rounded_data_size);
-    }
-
-  fss->num_chunks[fl_index] += batch_size;
-  fss->n_fl_chunk_bytes += batch_size * rounded_data_size;
-  fsh_free_bytes_sub (fsh, size);
-
-  return 0;
+  return fsh_try_alloc_chunk_batch (fsh, fss, fl_index, batch_size);
 }
 
 /**