buffers: make buffer data size configurable from startup config

Example:

buffers {
	default data-size 1536
}

Change-Id: I5b4436850ca18025c9fdcfc7ed648c2c2732d660
Signed-off-by: Damjan Marion <damarion@cisco.com>

4 files changed, 43 insertions, 29 deletions

diff --git a/src/vlib/buffer.c b/src/vlib/buffer.c
index 345cd5c564b..a45b9bf2fc7 100644
--- a/src/vlib/buffer.c
+++ b/src/vlib/buffer.c
@@ -192,9 +192,9 @@ vlib_validate_buffer_helper (vlib_main_t * vm,
   if ((signed) b->current_data < (signed) -VLIB_BUFFER_PRE_DATA_SIZE)
     return format (0, "current data %d before pre-data", b->current_data);
 
-  if (b->current_data + b->current_length > VLIB_BUFFER_DATA_SIZE)
+  if (b->current_data + b->current_length > vlib_bufer_get_default_size (vm))
     return format (0, "%d-%d beyond end of buffer %d", b->current_data,
-		   b->current_length, VLIB_BUFFER_DATA_SIZE);
+		   b->current_length, vlib_bufer_get_default_size (vm));
 
   if (follow_buffer_next && (b->flags & VLIB_BUFFER_NEXT_PRESENT))
     {
@@ -407,7 +407,7 @@ vlib_buffer_add_data (vlib_main_t * vm, u32 * buffer_index, void *data,
 
   d = data;
   n_left = n_data_bytes;
-  n_buffer_bytes = VLIB_BUFFER_DATA_SIZE;
+  n_buffer_bytes = vlib_bufer_get_default_size (vm);
 
   b = vlib_get_buffer (vm, bi);
   b->flags &= ~VLIB_BUFFER_TOTAL_LENGTH_VALID;
@@ -455,7 +455,7 @@ vlib_buffer_chain_append_data_with_alloc (vlib_main_t * vm,
 					  u16 data_len)
 {
   vlib_buffer_t *l = *last;
-  u32 n_buffer_bytes = VLIB_BUFFER_DATA_SIZE;
+  u32 n_buffer_bytes = vlib_bufer_get_default_size (vm);
   u16 copied = 0;
   ASSERT (n_buffer_bytes >= l->current_length + l->current_data);
   while (data_len)
@@ -655,7 +655,7 @@ vlib_buffer_main_init_numa_node (struct vlib_main_t *vm, u32 numa_node)
   u32 buffers_per_numa;
   u32 buffer_size = CLIB_CACHE_LINE_ROUND (bm->ext_hdr_size +
 					   sizeof (vlib_buffer_t) +
-					   VLIB_BUFFER_DATA_SIZE);
+					   vlib_bufer_get_default_size (vm));
   u8 *name;
 
   pagesize = clib_mem_get_default_hugepage_size ();
@@ -690,7 +690,21 @@ retry:
   name = format (name, "default-numa-%d%c", numa_node, 0);
 
   return vlib_buffer_pool_create (vm, numa_node, (char *) name,
-				  VLIB_BUFFER_DATA_SIZE, physmem_map_index);
+				  vlib_bufer_get_default_size (vm),
+				  physmem_map_index);
+}
+
+void
+vlib_buffer_main_alloc (vlib_main_t * vm)
+{
+  vlib_buffer_main_t *bm;
+
+  if (vm->buffer_main)
+    return;
+
+  vm->buffer_main = bm = clib_mem_alloc (sizeof (bm[0]));
+  clib_memset (vm->buffer_main, 0, sizeof (bm[0]));
+  bm->default_data_size = VLIB_BUFFER_DEFAULT_DATA_SIZE;
 }
 
 clib_error_t *
@@ -701,11 +715,7 @@ vlib_buffer_main_init (struct vlib_main_t *vm)
   clib_bitmap_t *bmp = 0;
   u32 numa_node;
 
-  if (vm->buffer_main == 0)
-    {
-      vm->buffer_main = clib_mem_alloc (sizeof (bm[0]));
-      clib_memset (vm->buffer_main, 0, sizeof (bm[0]));
-    }
+  vlib_buffer_main_alloc (vm);
 
   bm = vm->buffer_main;
   bm->log_default = vlib_log_register_class ("buffer", 0);
@@ -741,11 +751,7 @@ vlib_buffers_configure (vlib_main_t * vm, unformat_input_t * input)
 {
   vlib_buffer_main_t *bm;
 
-  if (vm->buffer_main == 0)
-    {
-      vm->buffer_main = clib_mem_alloc (sizeof (bm[0]));
-      clib_memset (vm->buffer_main, 0, sizeof (bm[0]));
-    }
+  vlib_buffer_main_alloc (vm);
 
   bm = vm->buffer_main;
 
@@ -753,6 +759,9 @@ vlib_buffers_configure (vlib_main_t * vm, unformat_input_t * input)
     {
       if (unformat (input, "buffers-per-numa %u", &bm->buffers_per_numa))
 	;
+      else if (unformat (input, "default data-size %u",
+			 &bm->default_data_size))
+	;
       else
 	return unformat_parse_error (input);
     }
diff --git a/src/vlib/buffer.h b/src/vlib/buffer.h
index 1adde73d4ee..31baf5fd21e 100644
--- a/src/vlib/buffer.h
+++ b/src/vlib/buffer.h
@@ -48,9 +48,10 @@
 #include <vlib/error.h>		/* for vlib_error_t */
 
 #include <vlib/config.h>	/* for __PRE_DATA_SIZE */
-#define VLIB_BUFFER_DATA_SIZE		(2048)
 #define VLIB_BUFFER_PRE_DATA_SIZE	__PRE_DATA_SIZE
 
+#define VLIB_BUFFER_DEFAULT_DATA_SIZE (2048)
+
 /* Minimum buffer chain segment size. Does not apply to last buffer in chain.
    Dataplane code can safely asume that specified amount of data is not split
    into 2 chained buffers */
@@ -413,6 +414,7 @@ typedef struct
   /* config */
   u32 buffers_per_numa;
   u16 ext_hdr_size;
+  u32 default_data_size;
 
   /* logging */
   vlib_log_class_t log_default;
diff --git a/src/vlib/buffer_funcs.h b/src/vlib/buffer_funcs.h
index 09ffd06428f..97b687b8cc6 100644
--- a/src/vlib/buffer_funcs.h
+++ b/src/vlib/buffer_funcs.h
@@ -56,16 +56,11 @@ vlib_buffer_validate (vlib_main_t * vm, vlib_buffer_t * b)
   /* reference count in allocated buffer always must be 1 or higher */
   ASSERT (b->ref_count > 0);
 
-  /* verify that buffer pointer is from buffer memory range */
-  ASSERT (pointer_to_uword (b) >= bm->buffer_mem_start);
-  ASSERT (pointer_to_uword (b) < bm->buffer_mem_start + bm->buffer_mem_size -
-	  VLIB_BUFFER_DATA_SIZE);
-
   /* verify that buffer pool index is valid */
   bp = vec_elt_at_index (bm->buffer_pools, b->buffer_pool_index);
   ASSERT (pointer_to_uword (b) >= bp->start);
   ASSERT (pointer_to_uword (b) < bp->start + bp->size -
-	  VLIB_BUFFER_DATA_SIZE);
+	  (bp->data_size + sizeof (vlib_buffer_t)));
 }
 
 always_inline void *
@@ -93,6 +88,12 @@ vlib_get_buffer (vlib_main_t * vm, u32 buffer_index)
   return b;
 }
 
+static_always_inline u32
+vlib_bufer_get_default_size (vlib_main_t * vm)
+{
+  return vm->buffer_main->default_data_size;
+}
+
 static_always_inline void
 vlib_buffer_copy_indices (u32 * dst, u32 * src, u32 n_indices)
 {
@@ -1161,7 +1162,7 @@ vlib_buffer_chain_append_data (vlib_main_t * vm,
 			       vlib_buffer_t * first,
 			       vlib_buffer_t * last, void *data, u16 data_len)
 {
-  u32 n_buffer_bytes = VLIB_BUFFER_DATA_SIZE;
+  u32 n_buffer_bytes = vlib_bufer_get_default_size (vm);
   ASSERT (n_buffer_bytes >= last->current_length + last->current_data);
   u16 len = clib_min (data_len,
 		      n_buffer_bytes - last->current_length -
@@ -1236,7 +1237,7 @@ vlib_buffer_chain_compress (vlib_main_t * vm,
     }
 
   u32 want_first_size = clib_min (VLIB_BUFFER_CLONE_HEAD_SIZE,
-				  VLIB_BUFFER_DATA_SIZE -
+				  vlib_bufer_get_default_size (vm) -
 				  first->current_data);
   do
     {
@@ -1283,7 +1284,7 @@ always_inline int
 vlib_buffer_chain_linearize (vlib_main_t * vm, vlib_buffer_t * first)
 {
   vlib_buffer_t *b = first;
-  u32 buf_len = VLIB_BUFFER_DATA_SIZE;
+  u32 buf_len = vlib_bufer_get_default_size (vm);
   // free buffer chain starting from the second buffer
   int free_count = (b->flags & VLIB_BUFFER_NEXT_PRESENT) != 0;
   u32 chain_to_free = b->next_buffer;
diff --git a/src/vlib/unix/mc_socket.c b/src/vlib/unix/mc_socket.c
index aaf73ae5e1e..d4f4a7fe7e3 100644
--- a/src/vlib/unix/mc_socket.c
+++ b/src/vlib/unix/mc_socket.c
@@ -165,7 +165,7 @@ recvmsg_helper (mc_socket_main_t * msm,
   vlib_main_t *vm = msm->mc_main.vlib_main;
   vlib_buffer_t *b;
   uword n_left, n_alloc, n_mtu, i, i_rx;
-  const uword buffer_size = VLIB_BUFFER_DATA_SIZE;
+  const uword buffer_size = vlib_bufer_get_default_size (vm);
   word n_bytes_left;
 
   /* Make sure we have at least a MTU worth of buffers. */
@@ -1011,8 +1011,10 @@ mc_socket_main_init (mc_socket_main_t * msm, char **intfc_probe_list,
   }
 
   msm->rx_mtu_n_bytes = mtu;
-  msm->rx_mtu_n_buffers = msm->rx_mtu_n_bytes / VLIB_BUFFER_DATA_SIZE;
-  msm->rx_mtu_n_buffers += (msm->rx_mtu_n_bytes % VLIB_BUFFER_DATA_SIZE) != 0;
+  msm->rx_mtu_n_buffers =
+    msm->rx_mtu_n_bytes / vlib_bufer_get_default_size (vm);
+  msm->rx_mtu_n_buffers +=
+    (msm->rx_mtu_n_bytes % vlib_bufer_get_default_size (vm)) != 0;
 
   error = socket_setup (msm);
   if (error)