implementation of object memory pool via class-specific operator new/delete

lib/include/srslte/adt/mem_pool.h

@@ -13,6 +13,7 @@
 #ifndef SRSLTE_MEM_POOL_H
 #define SRSLTE_MEM_POOL_H
 
+#include <cassert>
 #include <cstdint>
 #include <memory>
 #include <mutex>
@@ -135,28 +136,17 @@ private:
 };
 
 /**
- * Pool specialized for big objects. Created objects are of same time, and are not contiguous in memory.
- * Memory management of created objects is automatically handled. Relevant methods:
- * - ::make(...) - create an object whose memory is automatically managed by the pool. The object dtor returns the
- *                 allocated memory back to the pool
+ * Pool specialized for big objects. Created objects are not contiguous in memory.
+ * Relevant methods:
+ * - ::allocate_node(sz) - allocate memory of sizeof(T), or reuse memory already present in cache
+ * - ::deallocate_node(void* p) - return memory addressed by p back to the pool to be cached.
  * - ::reserve(N) - prereserve memory slots for faster object creation
- * @tparam T object type
+ * @tparam ObjSize object memory size
  * @tparam ThreadSafe if object pool is thread-safe or not
  */
 template <typename T, bool ThreadSafe = false>
-class obj_pool
+class big_obj_pool
 {
-  /// single-thread obj pool deleter
-  struct obj_deleter {
-    explicit obj_deleter(obj_pool<T, ThreadSafe>* pool_) : pool(pool_) {}
-    void operator()(void* block)
-    {
-      static_cast<T*>(block)->~T();
-      pool->stack.push(static_cast<uint8_t*>(block));
-    }
-    obj_pool<T, ThreadSafe>* pool;
-  };
-
   // memory stack type derivation (thread safe or not)
   using stack_type = typename std::conditional<ThreadSafe, mutexed_memblock_stack, memblock_stack>::type;
 
@@ -164,24 +154,25 @@ class obj_pool
   stack_type stack;
 
 public:
-  using obj_ptr = std::unique_ptr<T, obj_deleter>;
+  ~big_obj_pool() { clear(); }
 
-  ~obj_pool()
+  /// alloc new object space. If no memory is pre-reserved in the pool, malloc is called.
+  void* allocate_node(size_t sz)
   {
+    assert(sz == sizeof(T));
+    static const size_t blocksize = std::max(sizeof(T), memblock_stack::min_memblock_size());
     uint8_t*            block     = stack.try_pop();
-    while (block != nullptr) {
-      delete[] block;
-      block = stack.try_pop();
+    if (block == nullptr) {
+      block = new uint8_t[blocksize];
     }
+    return block;
   }
 
-  /// create new object with given arguments. If no memory is pre-reserved in the pool, malloc is called.
-  template <typename... Args>
-  obj_ptr make(Args&&... args)
+  void deallocate_node(void* p)
   {
-    uint8_t* block = allocate_node();
-    new (block) T(std::forward<Args>(args)...);
-    return obj_ptr(reinterpret_cast<T*>(block), obj_deleter(this));
+    if (p != nullptr) {
+      stack.push(static_cast<uint8_t*>(p));
+    }
   }
 
   /// Pre-reserve N memory chunks for future object allocations
@@ -195,24 +186,15 @@ public:
 
   size_t capacity() const { return stack.size(); }
 
-private:
-  uint8_t* allocate_node()
+  void clear()
   {
-    static const size_t blocksize = std::max(sizeof(T), memblock_stack::min_memblock_size());
     uint8_t* block = stack.try_pop();
-    if (block == nullptr) {
-      block = new uint8_t[blocksize];
+    while (block != nullptr) {
+      delete[] block;
+      block = stack.try_pop();
     }
-    return block;
   }
 };
-template <typename T>
-using mutexed_pool_obj = obj_pool<T, true>;
-
-template <typename T>
-using unique_pool_obj = typename obj_pool<T, false>::obj_ptr;
-template <typename T>
-using unique_mutexed_pool_obj = typename obj_pool<T, true>::obj_ptr;
 
 } // namespace srslte
 

lib/test/adt/mem_pool_test.cc

@@ -19,17 +19,31 @@ public:
   C() { default_ctor_counter++; }
   ~C() { dtor_counter++; }
 
+  void* operator new(size_t sz);
+  void  operator delete(void* ptr)noexcept;
+
   static int default_ctor_counter;
   static int dtor_counter;
 };
 int C::default_ctor_counter = 0;
 int C::dtor_counter         = 0;
 
+srslte::big_obj_pool<C> pool;
+
+void* C::operator new(size_t sz)
+{
+  return pool.allocate_node(sz);
+}
+
+void C::operator delete(void* ptr)noexcept
+{
+  pool.deallocate_node(ptr);
+}
+
 int test_nontrivial_obj_pool()
 {
   // No object creation on reservation
   {
-    srslte::obj_pool<C> pool;
     pool.reserve(10);
   }
   TESTASSERT(C::default_ctor_counter == 0);
@@ -37,10 +51,10 @@ int test_nontrivial_obj_pool()
 
   // default Ctor/Dtor are correctly called
   {
-    srslte::obj_pool<C> pool;
+    pool.clear();
     pool.reserve(10);
 
-    srslte::unique_pool_obj<C> c = pool.make();
+    std::unique_ptr<C> c(new C{});
   }
   TESTASSERT(C::default_ctor_counter == 1);
   TESTASSERT(C::dtor_counter == 1);
@@ -49,11 +63,11 @@ int test_nontrivial_obj_pool()
   C::default_ctor_counter = 0;
   C::dtor_counter         = 0;
   {
-    srslte::obj_pool<C> pool;
+    pool.clear();
     pool.reserve(10);
 
-    srslte::unique_pool_obj<C> c  = pool.make();
-    srslte::unique_pool_obj<C> c2 = std::move(c);
+    std::unique_ptr<C> c(new C{});
+    auto               c2 = std::move(c);
   }
   TESTASSERT(C::default_ctor_counter == 1);
   TESTASSERT(C::dtor_counter == 1);

srsenb/hdr/stack/rrc/rrc.h

@@ -150,7 +150,7 @@ private:
 
   // state
   std::unique_ptr<freq_res_common_list>          cell_res_list;
-  std::map<uint16_t, srslte::unique_pool_obj<ue> > users; // NOTE: has to have fixed addr
+  std::map<uint16_t, std::unique_ptr<ue> >       users; // NOTE: has to have fixed addr
   std::map<uint32_t, asn1::rrc::paging_record_s> pending_paging;
 
   void     process_release_complete(uint16_t rnti);
@@ -192,7 +192,7 @@ private:
 
   std::mutex paging_mutex;
 
-  srslte::obj_pool<ue, false> ue_pool;
+  static srslte::big_obj_pool<ue, false> ue_pool;
 };
 
 } // namespace srsenb

srsenb/hdr/stack/rrc/rrc_ue.h

@@ -94,6 +94,11 @@ public:
 
   bool is_csfb = false;
 
+  void* operator new(size_t sz);
+  void* operator new[](size_t sz) = delete;
+  void  operator delete(void* ptr)noexcept;
+  void  operator delete[](void* ptr) = delete;
+
 private:
   // args
   srslte::byte_buffer_pool*           pool = nullptr;

srsenb/src/stack/rrc/rrc.cc

@@ -151,9 +151,9 @@ void rrc::add_user(uint16_t rnti, const sched_interface::ue_cfg_t& sched_ue_cfg)
     bool rnti_added = true;
     if (rnti != SRSLTE_MRNTI) {
       // only non-eMBMS RNTIs are present in user map
-      auto p = users.insert(std::make_pair(rnti, ue_pool.make(this, rnti, sched_ue_cfg)));
+      auto p = users.insert(std::make_pair(rnti, std::unique_ptr<ue>{new ue(this, rnti, sched_ue_cfg)}));
       if (ue_pool.capacity() <= 4) {
-        task_sched.defer_task([this]() { ue_pool.reserve(16); });
+        task_sched.defer_task([]() { rrc::ue_pool.reserve(16); });
       }
       rnti_added = p.second and p.first->second->is_allocated();
     }
@@ -962,4 +962,7 @@ void rrc::tti_clock()
   }
 }
 
+// definition of rrc static member
+srslte::big_obj_pool<rrc::ue, false> rrc::ue_pool;
+
 } // namespace srsenb

srsenb/src/stack/rrc/rrc_ue.cc

@@ -14,6 +14,7 @@
 #include "srsenb/hdr/stack/rrc/mac_controller.h"
 #include "srsenb/hdr/stack/rrc/rrc_mobility.h"
 #include "srsenb/hdr/stack/rrc/ue_rr_cfg.h"
+#include "srslte/adt/mem_pool.h"
 #include "srslte/asn1/rrc_utils.h"
 #include "srslte/common/enb_events.h"
 #include "srslte/common/int_helpers.h"
@@ -56,6 +57,16 @@ rrc::ue::ue(rrc* outer_rrc, uint16_t rnti_, const sched_interface::ue_cfg_t& sch
 
 rrc::ue::~ue() {}
 
+void* rrc::ue::operator new(size_t sz)
+{
+  assert(sz == sizeof(ue));
+  return rrc::ue_pool.allocate_node(sz);
+}
+void rrc::ue::operator delete(void* ptr)noexcept
+{
+  rrc::ue_pool.deallocate_node(ptr);
+}
+
 rrc_state_t rrc::ue::get_state()
 {
   return state;