Rename Metadata into MemoryBlock::Desc

paddle/fluid/memory/detail/CMakeLists.txt

-cc_library(memory_block SRCS memory_block.cc meta_data.cc meta_cache.cc)
+cc_library(memory_block SRCS memory_block.cc memory_block_desc.cc meta_cache.cc)
 
 if(${WITH_GPU})
   nv_library(system_allocator SRCS system_allocator.cc DEPS gflags cpu_info gpu_info)

paddle/fluid/memory/detail/memory_block.cc

@@ -21,7 +21,8 @@ namespace detail {
 
 void MemoryBlock::init(MetadataCache* cache, Type t, size_t index, size_t size,
                        void* left_buddy, void* right_buddy) {
-  cache->save(this, Metadata(t, index, size - sizeof(Metadata), size,
+  cache->save(
+      this, MemoryBlock::Desc(t, index, size - sizeof(MemoryBlock::Desc), size,
                               static_cast<MemoryBlock*>(left_buddy),
                               static_cast<MemoryBlock*>(right_buddy)));
 }
@@ -63,7 +64,7 @@ void MemoryBlock::split(MetadataCache* cache, size_t size) {
   PADDLE_ASSERT(total_size(*cache) >= size);
 
   // bail out if there is no room for another partition
-  if (total_size(*cache) - size <= sizeof(Metadata)) {
+  if (total_size(*cache) - size <= sizeof(MemoryBlock::Desc)) {
     return;
   }
 
@@ -78,13 +79,13 @@ void MemoryBlock::split(MetadataCache* cache, size_t size) {
   // Write the metadata for the new block
   auto new_block_right_buddy = metadata.right_buddy;
 
-  cache->save(
-      static_cast<MemoryBlock*>(right_partition),
-      Metadata(FREE_CHUNK, index(*cache), remaining_size - sizeof(Metadata),
+  cache->save(static_cast<MemoryBlock*>(right_partition),
+              MemoryBlock::Desc(FREE_CHUNK, index(*cache),
+                                remaining_size - sizeof(MemoryBlock::Desc),
                                 remaining_size, this, new_block_right_buddy));
 
   metadata.right_buddy = static_cast<MemoryBlock*>(right_partition);
-  metadata.size = size - sizeof(Metadata);
+  metadata.size = size - sizeof(MemoryBlock::Desc);
   metadata.total_size = size;
 
   cache->save(this, metadata);
@@ -122,7 +123,8 @@ void MemoryBlock::merge(MetadataCache* cache, MemoryBlock* right_buddy) {
   metadata.total_size += right_buddy->total_size(*cache);
 
   cache->save(this, metadata);
-  cache->save(right_buddy, Metadata(INVALID_CHUNK, 0, 0, 0, nullptr, nullptr));
+  cache->save(right_buddy,
+              MemoryBlock::Desc(INVALID_CHUNK, 0, 0, 0, nullptr, nullptr));
 }
 
 void MemoryBlock::mark_as_free(MetadataCache* cache) {
@@ -139,12 +141,14 @@ void MemoryBlock::set_type(MetadataCache* cache, Type t) {
 }
 
 void* MemoryBlock::data() const {
-  return const_cast<Metadata*>(reinterpret_cast<const Metadata*>(this)) + 1;
+  return const_cast<MemoryBlock::Desc*>(
+             reinterpret_cast<const MemoryBlock::Desc*>(this)) +
+         1;
 }
 
 MemoryBlock* MemoryBlock::metadata() const {
   return const_cast<MemoryBlock*>(reinterpret_cast<const MemoryBlock*>(
-      reinterpret_cast<const Metadata*>(this) - 1));
+      reinterpret_cast<const MemoryBlock::Desc*>(this) - 1));
 }
 
 }  // namespace detail

paddle/fluid/memory/detail/memory_block.h

@@ -23,9 +23,8 @@ namespace detail {
 class MetadataCache;
 
 // MemoryBlock represents Each allocated memory block, which contains
-// Metadata and the payload.
-class MemoryBlock {
- public:
+// MemoryBlock::Desc and the payload.
+struct MemoryBlock {
   enum Type {
     FREE_CHUNK,    // memory is free and idle
     ARENA_CHUNK,   // memory is being occupied
@@ -33,17 +32,17 @@ class MemoryBlock {
     INVALID_CHUNK  // memory is invalid
   };
 
-  // init saves the Metadata of the memory block in a MetadataCache.
+  // init saves the MemoryBlock::Desc of the memory block in a MetadataCache.
   // If it is a CPU memory block, the MetadataCache writes the
-  // Metadata to the beginning of the block; or, if it is a GPU memory
+  // MemoryBlock::Desc to the beginning of the block; or, if it is a GPU memory
   // block, the MetadataCache writes the Meatadata to a std::map in
   // the CPU.
-  void init(MetadataCache* cache, Type t, size_t index, size_t size,
+  void init(MemoryBlock::DescCache* cache, Type t, size_t index, size_t size,
             void* left_buddy, void* right_buddy);
 
-  // All these accessors returns fields in the Metadata of the memory
+  // All these accessors returns fields in the MemoryBlock::Desc of the memory
   // block.  They all need a MetadataCache instance as their first
-  // parameter because they read the Metadata from the cache.
+  // parameter because they read the MemoryBlock::Desc from the cache.
   Type type(const MetadataCache& cache) const;
   size_t size(const MetadataCache& cache) const;
   size_t index(const MetadataCache& cache) const;
@@ -68,12 +67,11 @@ class MemoryBlock {
   void* data() const;
   MemoryBlock* metadata() const;
 
- private:
-  // Metadata describes a MemoryBlock.
-  struct Metadata {
-    Metadata(MemoryBlock::Type t, size_t i, size_t s, size_t ts, MemoryBlock* l,
+  // MemoryBlock::Desc describes a MemoryBlock.
+  struct Desc {
+    Desc(MemoryBlock::Type t, size_t i, size_t s, size_t ts, MemoryBlock* l,
          MemoryBlock* r);
-    Metadata();
+    Desc();
 
     // Updates guard_begin and guard_end by hashes of the Metadata object.
     void update_guards();
@@ -94,9 +92,10 @@ class MemoryBlock {
 };
 
 // A cache for accessing memory block meta-data that may be expensive
-// to access directly.  This class exists to unify the metadata format
-// between GPU and CPU allocations. It should be removed when the CPU
-// can access all GPU allocations directly via UVM.
+// to access directly.  This class exists to unify the
+// MemoryBlock::Desc format between GPU and CPU allocations. It should
+// be removed when the CPU can access all GPU allocations directly via
+// UVM.
 class MetadataCache {
  public:
   explicit MetadataCache(bool uses_gpu);
@@ -105,22 +104,22 @@ class MetadataCache {
   MetadataCache(const MetadataCache&) = delete;
   MetadataCache& operator=(const MetadataCache&) = delete;
 
-  // Returns the Metadata for a memory block.  When MetadataCache is
-  // used to manage CPU memory, the Metadata resides at the beginning
+  // Returns the MemoryBlock::Desc for a memory block.  When MetadataCache is
+  // used to manage CPU memory, the MemoryBlock::Desc resides at the beginning
   // of the memory block; when used to manage GPU memory, the
   // Meatadata resides in CPU memory indexed by cache_.
-  Metadata load(const MemoryBlock* memory_block) const;
+  MemoryBlock::Desc load(const MemoryBlock* memory_block) const;
 
-  // Saves the Metadata of a memory block into the cache.  For CPU
-  // memory block, writes the Metadata to the beginning of the memory
+  // Saves the MemoryBlock::Desc of a memory block into the cache.  For CPU
+  // memory block, writes the MemoryBlock::Desc to the beginning of the memory
   // block; whereas for GPU memory, writes it to cache_.
-  void save(MemoryBlock* memory_block, const Metadata& meta_data);
+  void save(MemoryBlock* memory_block, const MemoryBlock::Desc& meta_data);
 
-  // For GPU memory block, erases its Metadata from cache_.
+  // For GPU memory block, erases its MemoryBlock::Desc from cache_.
   void invalidate(MemoryBlock* memory_block);
 
  private:
-  typedef std::unordered_map<const MemoryBlock*, Metadata> MetadataMap;
+  typedef std::unordered_map<const MemoryBlock*, MemoryBlock::Desc> MetadataMap;
   MetadataMap cache_;
   bool uses_gpu_;
 };

paddle/fluid/memory/detail/meta_data.cc → paddle/fluid/memory/detail/memory_block_desc.cc

@@ -20,7 +20,7 @@ namespace paddle {
 namespace memory {
 namespace detail {
 
-Metadata::Metadata(MemoryBlock::Type t, size_t i, size_t s, size_t ts,
+MemoryBlock::Desc::Desc(MemoryBlock::Type t, size_t i, size_t s, size_t ts,
                         MemoryBlock* l, MemoryBlock* r)
     : type(t),
       index(i),
@@ -29,7 +29,7 @@ Metadata::Metadata(MemoryBlock::Type t, size_t i, size_t s, size_t ts,
       left_buddy(l),
       right_buddy(r) {}
 
-Metadata::Metadata()
+MemoryBlock::Desc::Desc()
     : type(MemoryBlock::INVALID_CHUNK),
       index(0),
       size(0),
@@ -45,7 +45,7 @@ inline void hash_combine(std::size_t* seed, const T& v) {
   (*seed) ^= hasher(v) + 0x9e3779b9 + ((*seed) << 6) + ((*seed) >> 2);
 }
 
-inline size_t hash(const Metadata& metadata, size_t initial_seed) {
+inline size_t hash(const MemoryBlock::Desc& metadata, size_t initial_seed) {
   size_t seed = initial_seed;
 
   hash_combine(&seed, static_cast<size_t>(metadata.type));
@@ -60,12 +60,12 @@ inline size_t hash(const Metadata& metadata, size_t initial_seed) {
 
 }  // namespace
 
-void Metadata::update_guards() {
+void MemoryBlock::Desc::update_guards() {
   guard_begin = hash(this, 1);
   guard_end = hash(this, 2);
 }
 
-bool Metadata::check_guards() const {
+bool MemoryBlock::Desc::check_guards() const {
   return guard_begin == hash(this, 1) && guard_end == hash(this, 2);
 }