Merge pull request #51 from AntelopeIO/reclaimable_memory

expose amount of memory in `chainbase_node_allocator`'s free list
AntelopeIO · Aug 13, 2024 · 60757ff · 60757ff
2 parents 5275ccc + ce64753
commit 60757ff
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Showing 3 changed files with 24 additions and 2 deletions.
diff --git a/include/chainbase/chainbase.hpp b/include/chainbase/chainbase.hpp
@@ -163,6 +163,7 @@ namespace chainbase {
          virtual void    undo_all()const = 0;
          virtual uint32_t type_id()const  = 0;
          virtual uint64_t row_count()const = 0;
+         virtual size_t freelist_memory_usage()const = 0;
          virtual const std::string& type_name()const = 0;
          virtual std::pair<uint64_t, uint64_t> undo_stack_revision_range()const = 0;
 
@@ -190,6 +191,7 @@ namespace chainbase {
          virtual void     undo_all() const override {_base.undo_all(); }
          virtual uint32_t type_id()const override { return BaseIndex::value_type::type_id; }
          virtual uint64_t row_count()const override { return _base.indices().size(); }
+         virtual size_t freelist_memory_usage() const override { return _base.freelist_memory_usage(); }
          virtual const std::string& type_name() const override { return BaseIndex_name; }
          virtual std::pair<uint64_t, uint64_t> undo_stack_revision_range()const override { return _base.undo_stack_revision_range(); }
 
@@ -398,6 +400,16 @@ namespace chainbase {
             return _db_file.get_segment_manager()->get_free_memory();
          }
 
+         size_t get_reclaimable_memory() const {
+            size_t ret = 0;
+            for(const unique_ptr<abstract_index>& ai_ptr : _index_map) {
+               if(!ai_ptr)
+                  continue;
+               ret += ai_ptr->freelist_memory_usage();
+            }
+            return ret;
+         }
+
          template<typename MultiIndexType>
          const generic_index<MultiIndexType>& get_index()const
          {

diff --git a/include/chainbase/chainbase_node_allocator.hpp b/include/chainbase/chainbase_node_allocator.hpp
@@ -26,6 +26,7 @@ namespace chainbase {
             list_item* result = &*_freelist;
             _freelist = _freelist->_next;
             result->~list_item();
+            --_freelist_size;
             return pointer{(T*)result};
          } else {
             return pointer{(T*)_manager->allocate(num*sizeof(T))};
@@ -34,22 +35,26 @@ namespace chainbase {
       void deallocate(const pointer& p, std::size_t num) {
          if (num == 1) {
             _freelist = new (&*p) list_item{_freelist};
+            ++_freelist_size;
          } else {
             _manager->deallocate(&*p);
          }
       }
       bool operator==(const chainbase_node_allocator& other) const { return this == &other; }
       bool operator!=(const chainbase_node_allocator& other) const { return this != &other; }
       segment_manager* get_segment_manager() const { return _manager.get(); }
+      size_t freelist_memory_usage() const { return _freelist_size * sizeof(T); }
     private:
       template<typename T2, typename S2>
       friend class chainbase_node_allocator;
       void get_some() {
          static_assert(sizeof(T) >= sizeof(list_item), "Too small for free list");
          static_assert(sizeof(T) % alignof(list_item) == 0, "Bad alignment for free list");
-         char* result = (char*)_manager->allocate(sizeof(T) * 64);
+         const unsigned allocation_batch_size = 64;
+         char* result = (char*)_manager->allocate(sizeof(T) * allocation_batch_size);
+         _freelist_size += allocation_batch_size;
          _freelist = bip::offset_ptr<list_item>{(list_item*)result};
-         for(int i = 0; i < 63; ++i) {
+         for(int i = 0; i < allocation_batch_size-1; ++i) {
             char* next = result + sizeof(T);
             new(result) list_item{bip::offset_ptr<list_item>{(list_item*)next}};
             result = next;
@@ -59,6 +64,7 @@ namespace chainbase {
       struct list_item { bip::offset_ptr<list_item> _next; };
       bip::offset_ptr<segment_manager> _manager;
       bip::offset_ptr<list_item> _freelist{};
+      size_t _freelist_size = 0;
    };
 
 }  // namepsace chainbase
diff --git a/include/chainbase/undo_index.hpp b/include/chainbase/undo_index.hpp
@@ -642,6 +642,10 @@ namespace chainbase {
          compress_impl(_undo_stack.back());
       }
 
+      size_t freelist_memory_usage() const {
+         return _allocator.freelist_memory_usage() + _old_values_allocator.freelist_memory_usage();
+      }
+
     private:
 
       // Removes elements of the last undo session that would be redundant