gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index f913c4883d5ebdb892dd908c2d97842b026ba4fc..aeaad45ca608785ef6bcebd631aa07b0b56d20b1 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -15,6 +15,7 @@
 
 #include "base/at_exit.h"
 #include "base/bind.h"
+#include "base/callback_helpers.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/debug/trace_event_synthetic_delay.h"
@@ -10290,6 +10291,13 @@ bool GLES2DecoderImpl::ValidateAsyncTransfer(
   return true;
 }
 
+namespace {
+void UpdateAsyncUploadToken(AsyncUploadSync* sync, uint32 async_upload_token) {
+  base::subtle::MemoryBarrier();

[epennerAtGoogle, 2014/02/07 20:43:58]

See my other comment on MemoryBarriers. Wouldn't hurt to have a comment. And, do
we need a full barrier here since we are only writing to the value? I have to
admit I'm not completely familiar with what is required on either side.

+  sync->async_token = async_upload_token;
+}
+}
+
 error::Error GLES2DecoderImpl::HandleAsyncTexImage2DCHROMIUM(
     uint32 immediate_data_size, const cmds::AsyncTexImage2DCHROMIUM& c) {
   TRACE_EVENT0("gpu", "GLES2DecoderImpl::HandleAsyncTexImage2DCHROMIUM");
@@ -10306,6 +10314,21 @@ error::Error GLES2DecoderImpl::HandleAsyncTexImage2DCHROMIUM(
   uint32 pixels_shm_id = static_cast<uint32>(c.pixels_shm_id);
   uint32 pixels_shm_offset = static_cast<uint32>(c.pixels_shm_offset);
   uint32 pixels_size;
+  uint32 async_upload_token = static_cast<uint32>(c.async_upload_token);
+  uint32 sync_data_shm_id = static_cast<uint32>(c.sync_data_shm_id);
+  uint32 sync_data_shm_offset = static_cast<uint32>(c.sync_data_shm_offset);
+
+  base::ScopedClosureRunner scoped_completion_callback;
+  if (async_upload_token) {
+    AsyncUploadSync* sync = GetSharedMemoryAs<AsyncUploadSync*>(
+        sync_data_shm_id, sync_data_shm_offset, sizeof(*sync));

[piman, 2014/02/07 22:58:20]

The shared memory backing the AsyncUploadSync could be destroyed / unmapped
before the completion. For the transfer data, we dup the shm (for better or
worse), so we should do something similar or add some refcounting of the
transfer buffers, or something.

[jadahl, 2014/02/08 09:18:25]

As epenner replied elsewhere, SafeSharedMemoryPool handles this other places, so
I guess I should look into using that. And then it should be replaced with ref
counting and some layering. epenner, what bug number is that?

[epennerAtGoogle, 2014/02/10 23:12:06]

Bug for reference counting SharedMemory:
https://code.google.com/p/chromium/issues/detail?id=177063

+    scoped_completion_callback.Reset(base::Bind(
+            &AsyncPixelTransferManager::AsyncRun,
+            base::Unretained(GetAsyncPixelTransferManager()),
+            base::Bind(&UpdateAsyncUploadToken,
+                       sync,
+                       async_upload_token)));
+  }
 
   // TODO(epenner): Move this and copies of this memory validation
   // into ValidateTexImage2D step.
@@ -10400,6 +10423,21 @@ error::Error GLES2DecoderImpl::HandleAsyncTexSubImage2DCHROMIUM(
   GLsizei height = static_cast<GLsizei>(c.height);
   GLenum format = static_cast<GLenum>(c.format);
   GLenum type = static_cast<GLenum>(c.type);
+  uint32 async_upload_token = static_cast<uint32>(c.async_upload_token);
+  uint32 sync_data_shm_id = static_cast<uint32>(c.sync_data_shm_id);
+  uint32 sync_data_shm_offset = static_cast<uint32>(c.sync_data_shm_offset);
+
+  base::ScopedClosureRunner scoped_completion_callback;
+  if (async_upload_token) {
+    AsyncUploadSync* sync = GetSharedMemoryAs<AsyncUploadSync*>(
+        sync_data_shm_id, sync_data_shm_offset, sizeof(*sync));
+    scoped_completion_callback.Reset(base::Bind(
+            &AsyncPixelTransferManager::AsyncRun,
+            base::Unretained(GetAsyncPixelTransferManager()),
+            base::Bind(&UpdateAsyncUploadToken,
+                       sync,
+                       async_upload_token)));
+  }
 
   // TODO(epenner): Move this and copies of this memory validation
   // into ValidateTexSubImage2D step.