bufmon: add buffer monitoring plugin

This plugin allow to keep track of buffer usage in VPP graph nodes. The
main use is to detect buffer leakages.

Type: feature

Change-Id: Iadcf4ab98207fab6e2fa375060879bc2a25b711e
Signed-off-by: Benoît Ganne <bganne@cisco.com>

3 files changed, 55 insertions, 24 deletions

diff --git a/src/vlib/buffer.c b/src/vlib/buffer.c
index adaafa36f5d..71f84d377af 100644
--- a/src/vlib/buffer.c
+++ b/src/vlib/buffer.c
@@ -615,20 +615,26 @@ format_vlib_buffer_pool (u8 * s, va_list * va)
   return s;
 }
 
-static clib_error_t *
-show_buffers (vlib_main_t * vm,
-	      unformat_input_t * input, vlib_cli_command_t * cmd)
+u8 *
+format_vlib_buffer_pool_all (u8 *s, va_list *va)
 {
+  vlib_main_t *vm = va_arg (*va, vlib_main_t *);
   vlib_buffer_main_t *bm = vm->buffer_main;
   vlib_buffer_pool_t *bp;
 
-  vlib_cli_output (vm, "%U", format_vlib_buffer_pool, vm, 0);
+  s = format (s, "%U", format_vlib_buffer_pool, vm, 0);
 
-  /* *INDENT-OFF* */
   vec_foreach (bp, bm->buffer_pools)
-    vlib_cli_output (vm, "%U", format_vlib_buffer_pool, vm, bp);
-  /* *INDENT-ON* */
+    s = format (s, "\n%U", format_vlib_buffer_pool, vm, bp);
+
+  return s;
+}
 
+static clib_error_t *
+show_buffers (vlib_main_t *vm, unformat_input_t *input,
+	      vlib_cli_command_t *cmd)
+{
+  vlib_cli_output (vm, "%U", format_vlib_buffer_pool_all, vm);
   return 0;
 }
 
@@ -971,6 +977,20 @@ vlib_buffer_alloc_may_fail (vlib_main_t * vm, u32 n_buffers)
 }
 #endif
 
+__clib_export int
+vlib_buffer_set_alloc_free_callback (
+  vlib_main_t *vm, vlib_buffer_alloc_free_callback_t *alloc_callback_fn,
+  vlib_buffer_alloc_free_callback_t *free_callback_fn)
+{
+  vlib_buffer_main_t *bm = vm->buffer_main;
+  if ((alloc_callback_fn && bm->alloc_callback_fn) ||
+      (free_callback_fn && bm->free_callback_fn))
+    return 1;
+  bm->alloc_callback_fn = alloc_callback_fn;
+  bm->free_callback_fn = free_callback_fn;
+  return 0;
+}
+
 /** @endcond */
 /*
  * fd.io coding-style-patch-verification: ON
diff --git a/src/vlib/buffer.h b/src/vlib/buffer.h
index 349b7324996..b548adf4be8 100644
--- a/src/vlib/buffer.h
+++ b/src/vlib/buffer.h
@@ -472,6 +472,10 @@ typedef struct
 
 #define VLIB_BUFFER_MAX_NUMA_NODES 32
 
+typedef u32 (vlib_buffer_alloc_free_callback_t) (struct vlib_main_t *vm,
+						 u8 buffer_pool_index,
+						 u32 *buffers, u32 n_buffers);
+
 typedef struct
 {
   CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
@@ -481,12 +485,9 @@ typedef struct
   uword buffer_mem_size;
   vlib_buffer_pool_t *buffer_pools;
 
-  /* Hash table mapping buffer index into number
-     0 => allocated but free, 1 => allocated and not-free.
-     If buffer index is not in hash table then this buffer
-     has never been allocated. */
-  uword *buffer_known_hash;
-  clib_spinlock_t buffer_known_hash_lockp;
+  vlib_buffer_alloc_free_callback_t *alloc_callback_fn;
+  vlib_buffer_alloc_free_callback_t *free_callback_fn;
+
   u8 default_buffer_pool_index_for_numa[VLIB_BUFFER_MAX_NUMA_NODES];
 
   /* config */
@@ -495,12 +496,25 @@ typedef struct
   u32 default_data_size;
   clib_mem_page_sz_t log2_page_size;
 
+  /* Hash table mapping buffer index into number
+     0 => allocated but free, 1 => allocated and not-free.
+     If buffer index is not in hash table then this buffer
+     has never been allocated. */
+  uword *buffer_known_hash;
+  clib_spinlock_t buffer_known_hash_lockp;
+
   /* logging */
   vlib_log_class_t log_default;
 } vlib_buffer_main_t;
 
 clib_error_t *vlib_buffer_main_init (struct vlib_main_t *vm);
 
+format_function_t format_vlib_buffer_pool_all;
+
+int vlib_buffer_set_alloc_free_callback (
+  struct vlib_main_t *vm, vlib_buffer_alloc_free_callback_t *alloc_callback_fn,
+  vlib_buffer_alloc_free_callback_t *free_callback_fn);
+
 extern u16 __vlib_buffer_external_hdr_size;
 #define VLIB_BUFFER_SET_EXT_HDR_SIZE(x) \
 static void __clib_constructor \
diff --git a/src/vlib/buffer_funcs.h b/src/vlib/buffer_funcs.h
index 89a765ee0d3..77964fde821 100644
--- a/src/vlib/buffer_funcs.h
+++ b/src/vlib/buffer_funcs.h
@@ -626,11 +626,7 @@ vlib_buffer_alloc_from_pool (vlib_main_t * vm, u32 * buffers, u32 n_buffers,
       src = bpt->cached_buffers + len - n_buffers;
       vlib_buffer_copy_indices (dst, src, n_buffers);
       bpt->n_cached -= n_buffers;
-
-      if (CLIB_DEBUG > 0)
-	vlib_buffer_validate_alloc_free (vm, buffers, n_buffers,
-					 VLIB_BUFFER_KNOWN_FREE);
-      return n_buffers;
+      goto done;
     }
 
   /* alloc bigger than cache - take buffers directly from main pool */
@@ -638,11 +634,7 @@ vlib_buffer_alloc_from_pool (vlib_main_t * vm, u32 * buffers, u32 n_buffers,
     {
       n_buffers = vlib_buffer_pool_get (vm, buffer_pool_index, buffers,
 					n_buffers);
-
-      if (CLIB_DEBUG > 0)
-	vlib_buffer_validate_alloc_free (vm, buffers, n_buffers,
-					 VLIB_BUFFER_KNOWN_FREE);
-      return n_buffers;
+      goto done;
     }
 
   /* take everything available in the cache */
@@ -670,11 +662,13 @@ vlib_buffer_alloc_from_pool (vlib_main_t * vm, u32 * buffers, u32 n_buffers,
 
   n_buffers -= n_left;
 
+done:
   /* Verify that buffers are known free. */
   if (CLIB_DEBUG > 0)
     vlib_buffer_validate_alloc_free (vm, buffers, n_buffers,
 				     VLIB_BUFFER_KNOWN_FREE);
-
+  if (PREDICT_FALSE (bm->alloc_callback_fn != 0))
+    bm->alloc_callback_fn (vm, buffer_pool_index, buffers, n_buffers);
   return n_buffers;
 }
 
@@ -776,6 +770,7 @@ static_always_inline void
 vlib_buffer_pool_put (vlib_main_t * vm, u8 buffer_pool_index,
 		      u32 * buffers, u32 n_buffers)
 {
+  vlib_buffer_main_t *bm = vm->buffer_main;
   vlib_buffer_pool_t *bp = vlib_get_buffer_pool (vm, buffer_pool_index);
   vlib_buffer_pool_thread_t *bpt = vec_elt_at_index (bp->threads,
 						     vm->thread_index);
@@ -784,6 +779,8 @@ vlib_buffer_pool_put (vlib_main_t * vm, u8 buffer_pool_index,
   if (CLIB_DEBUG > 0)
     vlib_buffer_validate_alloc_free (vm, buffers, n_buffers,
 				     VLIB_BUFFER_KNOWN_ALLOCATED);
+  if (PREDICT_FALSE (bm->free_callback_fn != 0))
+    bm->free_callback_fn (vm, buffer_pool_index, buffers, n_buffers);
 
   n_cached = bpt->n_cached;
   n_empty = VLIB_BUFFER_POOL_PER_THREAD_CACHE_SZ - n_cached;