gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/client/buffer_tracker.h

Index: gpu/command_buffer/client/buffer_tracker.h
diff --git a/gpu/command_buffer/client/buffer_tracker.h b/gpu/command_buffer/client/buffer_tracker.h
index 3e50364317d234bc9d7ed336c81de4fdbc26d5a4..810dbe9b9fc467006c229f92492fdda736bbd217 100644
--- a/gpu/command_buffer/client/buffer_tracker.h
+++ b/gpu/command_buffer/client/buffer_tracker.h
@@ -35,7 +35,8 @@ class GLES2_IMPL_EXPORT BufferTracker {
           shm_offset_(shm_offset),
           address_(address),
           mapped_(false),
-          transfer_ready_token_(0) {
+          last_usage_token_(0),
+          async_token_(0) {
     }
 
     GLenum id() const {
@@ -66,12 +67,20 @@ class GLES2_IMPL_EXPORT BufferTracker {
       return mapped_;
     }
 
-    void set_transfer_ready_token(int token) {
-      transfer_ready_token_ = token;
+    void set_last_usage_token(int token) {
+      last_usage_token_ = token;
     }
 
-    uint32 transfer_ready_token() const {
-      return transfer_ready_token_;
+    int last_usage_token() const {
+      return last_usage_token_;
+    }
+
+    void set_async_token(uint32 async_token) {
+      async_token_ = async_token;
+    }
+
+    GLuint async_token() const {
+      return async_token_;
     }
 
    private:
@@ -84,7 +93,8 @@ class GLES2_IMPL_EXPORT BufferTracker {
     uint32 shm_offset_;
     void* address_;
     bool mapped_;
-    int32 transfer_ready_token_;
+    int32 last_usage_token_;
+    GLuint async_token_;

[reveman, 2014/01/22 17:30:04]

GLuint? "int32 last_async_usage_token_;" instead?

[jadahl, 2014/01/23 10:24:06]

According to what I read in the code, negative tokens are used for reporting
errors. Async tokens does not deal with errors as it is now, and thus doesn't
need to be signed. It should be uint32 instead of GLuint though. GLuint is a
left-over from when |async_token_| was |async_query_id_|.

   };
 
   BufferTracker(MappedMemoryManager* manager);
@@ -96,7 +106,9 @@ class GLES2_IMPL_EXPORT BufferTracker {
 
   // Frees the block of memory associated with buffer, pending the passage
   // of a token.
-  void FreePendingToken(Buffer*, int32 token);
+  void FreePendingToken(Buffer* buffer, int32 token);
+  void FreePendingAsyncToken(Buffer* buffer, uint32 async_token);
+  void Free(Buffer* buffer);
 
  private:
   typedef base::hash_map<GLuint, Buffer*> BufferMap;