buffers: configurable buffer fault injector

[vpp.git] / src / vlib / buffer.c

diff --git a/src/vlib/buffer.c b/src/vlib/buffer.c
index c4c05bb..f5b8137 100644 (file)
--- a/src/vlib/buffer.c
+++ b/src/vlib/buffer.c
@@ -92,7 +92,7 @@ vlib_buffer_length_in_chain_slow_path (vlib_main_t * vm,
 }
 
 u8 *
-format_vlib_buffer (u8 * s, va_list * args)
+format_vlib_buffer_no_chain (u8 * s, va_list * args)
 {
   vlib_buffer_t *b = va_arg (*args, vlib_buffer_t *);
   u32 indent = format_get_indent (s);
@@ -118,9 +118,20 @@ format_vlib_buffer (u8 * s, va_list * args)
     s = format (s, "\n%U%v", format_white_space, indent, a);
   vec_free (a);
 
+  return s;
+}
+
+u8 *
+format_vlib_buffer (u8 * s, va_list * args)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  vlib_buffer_t *b = va_arg (*args, vlib_buffer_t *);
+  u32 indent = format_get_indent (s);
+
+  s = format (s, "%U", format_vlib_buffer_no_chain, b);
+
   while (b->flags & VLIB_BUFFER_NEXT_PRESENT)
     {
-      vlib_main_t *vm = vlib_get_main ();
       u32 next_buffer = b->next_buffer;
       b = vlib_get_buffer (vm, next_buffer);
 
@@ -552,9 +563,9 @@ vlib_buffer_pool_create (vlib_main_t * vm, char *name, u32 data_size,
   n_alloc_per_page = (1ULL << m->log2_page_size) / alloc_size;
 
   /* preallocate buffer indices memory */
-  vec_validate_aligned (bp->buffers, m->n_pages * n_alloc_per_page,
-                       CLIB_CACHE_LINE_BYTES);
-  vec_reset_length (bp->buffers);
+  bp->n_buffers = m->n_pages * n_alloc_per_page;
+  bp->buffers = clib_mem_alloc_aligned (bp->n_buffers * sizeof (u32),
+                                       CLIB_CACHE_LINE_BYTES);
 
   clib_spinlock_init (&bp->lock);
 
@@ -567,15 +578,23 @@ vlib_buffer_pool_create (vlib_main_t * vm, char *name, u32 data_size,
        p = m->base + (j << m->log2_page_size) + i * alloc_size;
        p += bm->ext_hdr_size;
 
+       /*
+        * Waste 1 buffer (maximum) so that 0 is never a valid buffer index.
+        * Allows various places to ASSERT (bi != 0). Much easier
+        * than debugging downstream crashes in successor nodes.
+        */
+       if (p == m->base)
+         continue;
+
        vlib_buffer_copy_template ((vlib_buffer_t *) p, &bp->buffer_template);
 
        bi = vlib_get_buffer_index (vm, (vlib_buffer_t *) p);
 
-       vec_add1_aligned (bp->buffers, bi, CLIB_CACHE_LINE_BYTES);
+       bp->buffers[bp->n_avail++] = bi;
+
        vlib_get_buffer (vm, bi);
       }
 
-  bp->n_buffers = vec_len (bp->buffers);
   return bp->index;
 }
 
@@ -594,14 +613,14 @@ format_vlib_buffer_pool (u8 * s, va_list * va)
 
   /* *INDENT-OFF* */
   vec_foreach (bpt, bp->threads)
-    cached += vec_len (bpt->cached_buffers);
+    cached += bpt->n_cached;
   /* *INDENT-ON* */
 
   s = format (s, "%-20s%=6d%=6d%=6u%=11u%=6u%=8u%=8u%=8u",
              bp->name, bp->index, bp->numa_node, bp->data_size +
              sizeof (vlib_buffer_t) + vm->buffer_main->ext_hdr_size,
-             bp->data_size, bp->n_buffers, vec_len (bp->buffers), cached,
-             bp->n_buffers - vec_len (bp->buffers) - cached);
+             bp->data_size, bp->n_buffers, bp->n_avail, cached,
+             bp->n_buffers - bp->n_avail - cached);
 
   return s;
 }
@@ -736,7 +755,7 @@ buffer_get_cached (vlib_buffer_pool_t * bp)
 
   /* *INDENT-OFF* */
   vec_foreach (bpt, bp->threads)
-    cached += vec_len (bpt->cached_buffers);
+    cached += bpt->n_cached;
   /* *INDENT-ON* */
 
   clib_spinlock_unlock (&bp->lock);
@@ -763,7 +782,7 @@ buffer_gauges_update_used_fn (stat_segment_directory_entry_t * e, u32 index)
   if (!bp)
     return;
 
-  e->value = bp->n_buffers - vec_len (bp->buffers) - buffer_get_cached (bp);
+  e->value = bp->n_buffers - bp->n_avail - buffer_get_cached (bp);
 }
 
 static void
@@ -775,7 +794,7 @@ buffer_gauges_update_available_fn (stat_segment_directory_entry_t * e,
   if (!bp)
     return;
 
-  e->value = vec_len (bp->buffers);
+  e->value = bp->n_avail;
 }
 
 static void
@@ -912,6 +931,24 @@ vlib_buffers_configure (vlib_main_t * vm, unformat_input_t * input)
 
 VLIB_EARLY_CONFIG_FUNCTION (vlib_buffers_configure, "buffers");
 
+#if VLIB_BUFFER_ALLOC_FAULT_INJECTOR > 0
+u32
+vlib_buffer_alloc_may_fail (vlib_main_t * vm, u32 n_buffers)
+{
+  f64 r;
+
+  r = random_f64 (&vm->buffer_alloc_success_seed);
+
+  /* Fail this request? */
+  if (r > vm->buffer_alloc_success_rate)
+    n_buffers--;
+  /* 5% chance of returning nothing at all */
+  if (r > vm->buffer_alloc_success_rate && r > 0.95)
+    n_buffers = 0;
+
+  return n_buffers;
+}
+#endif
 
 /** @endcond */
 /*