gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/client/mapped_memory_unittest.cc

Index: gpu/command_buffer/client/mapped_memory_unittest.cc
diff --git a/gpu/command_buffer/client/mapped_memory_unittest.cc b/gpu/command_buffer/client/mapped_memory_unittest.cc
index 90d1ce7666b8215377fc1facb915879b1291d193..53667f8685e1d1f35dc8730bf5c3488c0a32c79f 100644
--- a/gpu/command_buffer/client/mapped_memory_unittest.cc
+++ b/gpu/command_buffer/client/mapped_memory_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "gpu/command_buffer/client/mapped_memory.h"
 
+#include <list>
 #include "base/bind.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
@@ -85,6 +86,11 @@ class MappedMemoryTestBase : public testing::Test {
 const unsigned int MappedMemoryTestBase::kBufferSize;
 #endif
 
+namespace {
+void EmptyPoll() {
+}
+}
+
 // Test fixture for MemoryChunk test - Creates a MemoryChunk, using a
 // CommandBufferHelper with a mock AsyncAPIInterface for its interface (calling
 // it directly, not through the RPC mechanism), making sure Noops are ignored
@@ -98,7 +104,10 @@ class MemoryChunkTest : public MappedMemoryTestBase {
     gpu::Buffer buf;
     buf.size = kBufferSize;
     buf.ptr = buffer_.get();
-    chunk_.reset(new MemoryChunk(kShmId, buf, helper_.get()));
+    chunk_.reset(new MemoryChunk(kShmId,
+                                 buf,
+                                 helper_.get(),
+                                 base::Bind(&EmptyPoll)));
   }
 
   virtual void TearDown() {
@@ -146,11 +155,16 @@ TEST_F(MemoryChunkTest, Basic) {
 }
 
 class MappedMemoryManagerTest : public MappedMemoryTestBase {
+ public:
+  MappedMemoryManager* manager() const {
+    return manager_.get();
+  }
+
  protected:
   virtual void SetUp() {
     MappedMemoryTestBase::SetUp();
     manager_.reset(new MappedMemoryManager(
-        helper_.get(), MappedMemoryManager::kNoLimit));
+        helper_.get(), base::Bind(&EmptyPoll), MappedMemoryManager::kNoLimit));
   }
 
   virtual void TearDown() {
@@ -310,7 +324,8 @@ TEST_F(MappedMemoryManagerTest, ChunkSizeMultiple) {
 TEST_F(MappedMemoryManagerTest, UnusedMemoryLimit) {
   const unsigned int kChunkSize = 2048;
   // Reset the manager with a memory limit.
-  manager_.reset(new MappedMemoryManager(helper_.get(), kChunkSize));
+  manager_.reset(new MappedMemoryManager(
+      helper_.get(), base::Bind(&EmptyPoll), kChunkSize));
   manager_->set_chunk_size_multiple(kChunkSize);
 
   // Allocate one chunk worth of memory.
@@ -338,7 +353,8 @@ TEST_F(MappedMemoryManagerTest, UnusedMemoryLimit) {
 TEST_F(MappedMemoryManagerTest, MemoryLimitWithReuse) {
   const unsigned int kSize = 1024;
   // Reset the manager with a memory limit.
-  manager_.reset(new MappedMemoryManager(helper_.get(), kSize));
+  manager_.reset(new MappedMemoryManager(
+      helper_.get(), base::Bind(&EmptyPoll), kSize));
   const unsigned int kChunkSize = 2 * 1024;
   manager_->set_chunk_size_multiple(kChunkSize);
 
@@ -384,4 +400,55 @@ TEST_F(MappedMemoryManagerTest, MemoryLimitWithReuse) {
   EXPECT_EQ(1 * kChunkSize, manager_->allocated_memory());
 }
 
+namespace {
+void Poll(MappedMemoryManagerTest *test, std::list<void*>* list) {
+  std::list<void*>::iterator it = list->begin();
+  while (it != list->end()) {
+    void* address = *it;
+    test->manager()->Free(address);
+    it = list->erase(it);
+  }
+}
+}
+
+TEST_F(MappedMemoryManagerTest, Poll) {
+  std::list<void*> unmanaged_memory_list;
+
+  const unsigned int kSize = 1024;
+  // Reset the manager with a memory limit.
+  manager_.reset(new MappedMemoryManager(
+      helper_.get(),
+      base::Bind(&Poll, this, &unmanaged_memory_list),
+      kSize));
+
+  // Allocate kSize bytes. Don't add the address to
+  // the unmanaged memory list, so that it won't be free:ed just yet.
+  int32 id1;
+  unsigned int offset1;
+  void* mem1 = manager_->Alloc(kSize, &id1, &offset1);
+  EXPECT_EQ(manager_->bytes_in_use(), kSize);
+
+  // Allocate kSize more bytes, and make sure we grew.
+  int32 id2;
+  unsigned int offset2;
+  void* mem2 = manager_->Alloc(kSize, &id2, &offset2);
+  EXPECT_EQ(manager_->bytes_in_use(), kSize * 2);
+
+  // Make the unmanaged buffer be released next time FreeUnused() is called
+  // in MappedMemoryManager/FencedAllocator. This happens for example when
+  // allocating new memory.
+  unmanaged_memory_list.push_back(mem1);
+
+  // Allocate kSize more bytes. This should poll unmanaged memory, which now
+  // should free the previously allocated unmanaged memory.
+  int32 id3;
+  unsigned int offset3;
+  void* mem3 = manager_->Alloc(kSize, &id3, &offset3);
+  EXPECT_EQ(manager_->bytes_in_use(), kSize * 2);
+
+  manager_->Free(mem2);
+  manager_->Free(mem3);
+  EXPECT_EQ(manager_->bytes_in_use(), static_cast<size_t>(0));
+}
+
 }  // namespace gpu