misc: add callback hooks and refactor pmc

Callbacks for monitoring and performance measurement:
- Add new callback list type, with context
- Add callbacks for API, CLI, and barrier sync
- Modify node dispatch callback to pass plugin-specific context
- Modify perfmon plugin to keep PMC samples local to the plugin
- Include process nodes in dispatch callback
- Pass dispatch function return value to callback

Type: refactor

Signed-off-by: Tom Seidenberg <tseidenb@cisco.com>
Change-Id: I28b06c58490611e08d76ff5b01b2347ba2109b22

3 files changed, 319 insertions, 4 deletions

diff --git a/src/vppinfra/CMakeLists.txt b/src/vppinfra/CMakeLists.txt
index a10f335dd52..8648275e0da 100644
--- a/src/vppinfra/CMakeLists.txt
+++ b/src/vppinfra/CMakeLists.txt
@@ -102,6 +102,7 @@ set(VPPINFRA_HEADERS
   byte_order.h
   cache.h
   callback.h
+  callback_data.h
   clib_error.h
   clib.h
   cpu.h
diff --git a/src/vppinfra/callback.h b/src/vppinfra/callback.h
index 595d69d72ab..a938ea326c9 100644
--- a/src/vppinfra/callback.h
+++ b/src/vppinfra/callback.h
@@ -70,12 +70,11 @@ do {                                                    \
    * Note: fp exists to shut up gcc-6, which            \
    * produces a warning not seen with gcc-7 or 8        \
    */                                                   \
-  void (*fp)(void *a1, ...);                            \
+  typeof (h) h_ = (h);                                  \
   int i;                                                \
-  for (i = 0; i < vec_len (h); i++)                     \
+  for (i = 0; i < vec_len (h_); i++)                    \
     {                                                   \
-      fp = (void *)(h[i]);                              \
-      (*fp) (__VA_ARGS__);                              \
+      (h_[i]) (__VA_ARGS__);                            \
     }                                                   \
  } while (0);
 
diff --git a/src/vppinfra/callback_data.h b/src/vppinfra/callback_data.h
new file mode 100644
index 00000000000..9a1ad0a9778
--- /dev/null
+++ b/src/vppinfra/callback_data.h
@@ -0,0 +1,315 @@
+/*
+ * Copyright (c) 2020 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/** @file
+ * @brief Callback multiplex scheme
+ */
+
+#ifndef included_callback_data_h
+#define included_callback_data_h
+#include <vppinfra/clib.h>
+
+/** @brief Declare and define a callback set type
+ * @param set_t_ The set type to define
+ * @param cb_t_ The callback type to use
+ */
+#define clib_callback_data_typedef(set_t_, cb_t_)   \
+typedef struct set_t_                               \
+{                                                   \
+  cb_t_* curr;                                      \
+  cb_t_* volatile next;                             \
+  cb_t_* spare;                                     \
+  clib_spinlock_t* lock;                            \
+} set_t_
+
+/** @brief Initialize a callback set
+ * @param set_ The callback set to initialize
+ * @param lock_ The lock to use, if any
+ */
+#define clib_callback_data_init(set_,lock_)  \
+do {                                         \
+  (set_)->lock = (lock_);                    \
+  (set_)->curr = 0;                          \
+  (set_)->next = 0;                          \
+  (set_)->spare = 0;                         \
+} while (0)
+
+/** @brief Add a callback to the specified callback set
+ * @param set_ The callback set
+ * @param value_ The value_ to assign the callback
+ *
+ * Add a callback from the indicated callback set.  If the set is
+ * currently being iterated, then the change will be applied after the
+ * current full iteration, and prior to the next full iteration.
+ */
+#define clib_callback_data_add(set_,value_)          \
+do {                                                 \
+  clib_spinlock_lock_if_init ((set_)->lock);         \
+  typeof ((set_)->next) next_ = (set_)->next;        \
+  if (PREDICT_TRUE (next_ == 0))                     \
+    {                                                \
+      next_ = (set_)->spare;                         \
+      (set_)->spare = 0;                             \
+      vec_append (next_, (set_)->curr);              \
+    }                                                \
+  u32 sz_ = vec_len (next_);                         \
+  vec_validate (next_, sz_);                         \
+  next_[sz_] = (value_);                             \
+  (set_)->next = next_;                              \
+  clib_spinlock_unlock_if_init ((set_)->lock);       \
+} while (0)
+
+/** @brief Remove a callback from the specified callback set
+ * @param set_ The callback set
+ * @param fp_ The current callback function
+ * @return 1 if the function was removed, 0 if not
+ *
+ * Remove a callback from the indicated callback set.  Idempotent.  If
+ * the set is currently being iterated, then the change will be applied
+ * after the current full iteration, and prior to the next full
+ * iteration.
+ */
+#define clib_callback_data_remove(set_,fp_)          \
+({                                                   \
+  int found_ = 0;                                    \
+  clib_spinlock_lock_if_init ((set_)->lock);         \
+  typeof ((set_)->next) next_ = (set_)->next;        \
+  if (PREDICT_TRUE (next_ == 0))                     \
+    {                                                \
+      next_ = (set_)->spare;                         \
+      (set_)->spare = 0;                             \
+      vec_append (next_, (set_)->curr);              \
+    }                                                \
+  u32 sz_ = vec_len (next_);                         \
+  u32 i_;                                            \
+  for (i_ = 0; i_ < sz_; i_++)                       \
+    if (next_[i_].fp == (fp_))                       \
+      {                                              \
+        vec_delete (next_, 1, i_);                   \
+        found_ = 1;                                  \
+        break;                                       \
+      }                                              \
+  (set_)->next = next_;                              \
+  clib_spinlock_unlock_if_init ((set_)->lock);       \
+  found_;                                            \
+})
+
+/** @brief Swap a callback in the specified callback set
+ * @param set_ The callback set
+ * @param fp_ The current callback function
+ * @param value_ The value_ to assign the callback
+ * @return 1 if the function was swapped, 0 if not
+ *
+ * Swap a callback in the indicated callback set.  If the callback is
+ * not found, then nothing is done.  If the set is currently being
+ * iterated, then the change will be applied after the current full
+ * iteration, and prior to the next full iteration.
+ */
+#define clib_callback_data_swap(set_,fp_,value_)     \
+({                                                   \
+  int found_ = 0;                                    \
+  clib_spinlock_lock_if_init ((set_)->lock);         \
+  typeof ((set_)->next) next_ = (set_)->next;        \
+  if (PREDICT_TRUE (next_ == 0))                     \
+    {                                                \
+      next_ = (set_)->spare;                         \
+      (set_)->spare = 0;                             \
+      vec_append (next_, (set_)->curr);              \
+    }                                                \
+  u32 sz_ = vec_len (next_);                         \
+  u32 i_;                                            \
+  for (i_ = 0; i_ < sz_; i_++)                       \
+    if (next_[i_].fp == (fp_))                       \
+      {                                              \
+        next_[i_] = (value_);                        \
+        found_ = 1;                                  \
+        break;                                       \
+      }                                              \
+  (set_)->next = next_;                              \
+  clib_spinlock_unlock_if_init ((set_)->lock);       \
+  found_;                                            \
+})
+
+/** @brief Ensure a callback is in the specified callback set
+ * @param set_ The callback set
+ * @param value_ The value_ to assign the callback
+ * @return 1 if the function was swapped, 0 if not
+ *
+ * Add or swap a callback in the indicated callback set.  If the
+ * callback is already in the set, it is replaced.  If the callback is
+ * not found, then it is added.  If the set is currently being
+ * iterated, then the change will be applied after the current full
+ * iteration, and prior to the next full iteration.
+ */
+#define clib_callback_data_ensure(set_,value_)       \
+do {                                                 \
+  int found_ = 0;                                    \
+  clib_spinlock_lock_if_init ((set_)->lock);         \
+  typeof ((set_)->next) next_ = (set_)->next;        \
+  if (PREDICT_TRUE (next_ == 0))                     \
+    {                                                \
+      next_ = (set_)->spare;                         \
+      (set_)->spare = 0;                             \
+      vec_append (next_, (set_)->curr);              \
+    }                                                \
+  u32 sz_ = vec_len (next_);                         \
+  u32 i_;                                            \
+  for (i_ = 0; i_ < sz_; i_++)                       \
+    if (next_[i_].fp == (value_).fp)                 \
+      {                                              \
+        found_ = 1;                                  \
+        break;                                       \
+      }                                              \
+  if (!found_)                                       \
+    vec_validate (next_, i_);                        \
+  next_[i_] = (value_);                              \
+  (set_)->next = next_;                              \
+  clib_spinlock_unlock_if_init ((set_)->lock);       \
+} while(0)
+
+/** @brief Enable/Disable the specified callback
+ * @param set_ The callback set
+ * @param fp_ The callback function
+ * @param ena_ 1 to enable, 0 to disable
+ *
+ * Enable or disable a callback function, with no data.
+ */
+#define clib_callback_data_enable_disable(set_,fp_,ena_)   \
+do {                                                       \
+  if (ena_)                                                \
+    {                                                      \
+      typeof ((set_)->next[0]) data_ = { .fp = (fp_) };    \
+      clib_callback_data_add ((set_), data_);              \
+    }                                                      \
+  else                                                     \
+    clib_callback_data_remove ((set_), (fp_));             \
+} while (0)
+
+/** @brief Get the value of a callback, if set.
+ * @param set_ The callback set
+ * @param fp_ The callback function
+ * @param v_ Set to the callback's current value
+ * @return 1 if the function is in the set, 0 if not
+ */
+#define clib_callback_data_get_value(set_,fp_,v_)    \
+({                                                   \
+  int found_ = 0;                                    \
+  clib_spinlock_lock_if_init ((set_)->lock);         \
+  typeof ((set_)->next) search_ = (set_)->next;      \
+  if (PREDICT_TRUE (search_ == 0))                   \
+    search_ = (set_)->curr;                          \
+  u32 sz_ = vec_len (search_);                       \
+  u32 i_;                                            \
+  for (i_ = 0; i_ < sz_; i_++)                       \
+    if (search_[i_].fp == (fp_))                     \
+      {                                              \
+        (v_) = search_[i];                           \
+        found_ = 1;                                  \
+        break;                                       \
+      }                                              \
+  clib_spinlock_unlock_if_init ((set_)->lock);       \
+  found_;                                            \
+})
+
+/** @brief Check if callback is set
+ * @param set_ The callback set
+ * @param fp_ The callback function
+ * @return 1 if the function is in the set, 0 if not
+ */
+#define clib_callback_data_is_set(set_,fp_)          \
+({                                                   \
+  int found_ = 0;                                    \
+  clib_spinlock_lock_if_init ((set_)->lock);         \
+  typeof ((set_)->next) search_ = (set_)->next;      \
+  if (PREDICT_TRUE (search_ == 0))                   \
+    search_ = (set_)->curr;                          \
+  u32 sz_ = vec_len (search_);                       \
+  u32 i_;                                            \
+  for (i_ = 0; i_ < sz_; i_++)                       \
+    if (search_[i_].fp == (fp_))                     \
+      {                                              \
+        found_ = 1;                                  \
+        break;                                       \
+      }                                              \
+  clib_spinlock_unlock_if_init ((set_)->lock);       \
+  found_;                                            \
+})
+
+/** @brief Check for and get current callback set
+ * @param set_ the callback set
+ * @param varargs additional callback parameters
+ */
+#define clib_callback_data_check_and_get(set_)       \
+({                                                   \
+  typeof ((set_)->curr) curr_ = (set_)->curr;        \
+  if (PREDICT_FALSE ((set_)->next != 0))             \
+    {                                                \
+      clib_spinlock_lock_if_init ((set_)->lock);     \
+      vec_reset_length (curr_);                      \
+      (set_)->spare = curr_;                         \
+      curr_ = (set_)->next;                          \
+      (set_)->next = 0;                              \
+      if (PREDICT_FALSE (0 == vec_len (curr_)))      \
+        vec_free (curr_);                            \
+      (set_)->curr = curr_;                          \
+      clib_spinlock_unlock_if_init ((set_)->lock);   \
+    }                                                \
+  curr_;                                             \
+})
+
+/** @brief Iterate and call a callback vector
+ * @param vec_ the callback vector
+ * @param varargs additional callback parameters
+ */
+#define clib_callback_data_call_vec(vec_, ...)                     \
+do {                                                               \
+  u32 sz_ = vec_len (vec_);                                        \
+  u32 i_;                                                          \
+  for (i_ = 0; i_ < sz_; i_++)                                     \
+    {                                                              \
+      CLIB_PREFETCH (&vec_[i_+1], CLIB_CACHE_LINE_BYTES, STORE);   \
+      (vec_[i_].fp) (&vec_[i_], __VA_ARGS__);                      \
+    }                                                              \
+} while (0)
+
+/** @brief Call the specified callback set
+ * @param set_ the callback set
+ * @param varargs additional callback parameters
+ */
+#define clib_callback_data_call(set_, ...)                           \
+do {                                                                 \
+  typeof ((set_)->curr) v_ = clib_callback_data_check_and_get(set_); \
+  clib_callback_data_iterate (v_, __VA_ARGS__);                      \
+} while (0)
+
+/** @brief prefetch the callback set
+ * @param set_ The callback set
+ */
+#define clib_callback_data_prefetch(set_)                        \
+do {                                                             \
+  if (PREDICT_FALSE ((set_)->curr))                              \
+    CLIB_PREFETCH ((set_)->curr, CLIB_CACHE_LINE_BYTES, STORE);  \
+} while (0)
+
+
+#endif /* included_callback_data_h */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */