gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/client/fenced_allocator.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file contains the definition of the FencedAllocator class.
 
 #ifndef GPU_COMMAND_BUFFER_CLIENT_FENCED_ALLOCATOR_H_
 #define GPU_COMMAND_BUFFER_CLIENT_FENCED_ALLOCATOR_H_
 
 #include <vector>
@@ skipping 47 matching lines @@
   void Free(Offset offset);
 
   // Frees a block of memory, pending the passage of a token. That memory won't
   // be re-allocated until the token has passed through the command stream.
   //
   // Parameters:
   //   offset: the offset of the memory block to free.
   //   token: the token value to wait for before re-using the memory.
   void FreePendingToken(Offset offset, int32 token);
 
+  void FreePendingSerial(Offset offset, uint32 token);
+
   // Frees any blocks pending a token for which the token has been read.
   void FreeUnused();
 
   // Gets the size of the largest free block that is available without waiting.
   unsigned int GetLargestFreeSize();
 
   // Gets the size of the largest free block that can be allocated if the
   // caller can wait. Allocating a block of this size will succeed, but may
   // block.
   unsigned int GetLargestFreeOrPendingSize();
 
   // Checks for consistency inside the book-keeping structures. Used for
   // testing.
   bool CheckConsistency();
 
   // True if any memory is allocated.
   bool InUse();
 
   // Return bytes of memory that is IN_USE
   size_t bytes_in_use() const { return bytes_in_use_; }
 
  private:
   // Status of a block of memory, for book-keeping.
   enum State {
     IN_USE,
     FREE,
-    FREE_PENDING_TOKEN
+    FREE_PENDING_TOKEN,
+    FREE_PENDING_SERIAL
   };
 
   // Book-keeping sturcture that describes a block of memory.
   struct Block {
     State state;
     Offset offset;
     unsigned int size;
     int32 token;  // token to wait for in the FREE_PENDING_TOKEN case.
+    uint32 serial;
   };
 
   // Comparison functor for memory block sorting.
   class OffsetCmp {
    public:
     bool operator() (const Block &left, const Block &right) {
       return left.offset < right.offset;
     }
   };
 
   typedef std::vector<Block> Container;
   typedef unsigned int BlockIndex;
 
   static const int32 kUnusedToken = 0;
+  static const uint32 kUnusedSerial = 0;
 
   // Gets the index of a memory block, given its offset.
   BlockIndex GetBlockByOffset(Offset offset);
 
   // Collapse a free block with its neighbours if they are free. Returns the
   // index of the collapsed block.
   // NOTE: this will invalidate block indices.
   BlockIndex CollapseFreeBlock(BlockIndex index);
 
   // Waits for a FREE_PENDING_TOKEN block to be usable, and free it. Returns
@@ skipping 68 matching lines @@
   // be re-allocated until the token has passed through the command stream.
   //
   // Parameters:
   //   pointer: the pointer to the memory block to free.
   //   token: the token value to wait for before re-using the memory.
   void FreePendingToken(void *pointer, int32 token) {
     DCHECK(pointer);
     allocator_.FreePendingToken(GetOffset(pointer), token);
   }
 
+  void FreePendingSerial(void *pointer, uint32 serial) {
+    DCHECK(pointer);
+    allocator_.FreePendingSerial(GetOffset(pointer), serial);
+  }
+
   // Frees any blocks pending a token for which the token has been read.
   void FreeUnused() {
     allocator_.FreeUnused();
   }
 
   // Gets a pointer to a memory block given the base memory and the offset.
   // It translates FencedAllocator::kInvalidOffset to NULL.
   void *GetPointer(FencedAllocator::Offset offset) {
     return (offset == FencedAllocator::kInvalidOffset) ?
         NULL : static_cast<char *>(base_) + offset;
@@ skipping 36 matching lines @@
 
  private:
   FencedAllocator allocator_;
   void* base_;
   DISALLOW_IMPLICIT_CONSTRUCTORS(FencedAllocatorWrapper);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_CLIENT_FENCED_ALLOCATOR_H_