Make GLES2Implementation use a larger chunk size for mapping functions.

This will make it allocate less shared memory blocks resulting
in less file descriptors.

BUG=none
TEST=unit tests


Review URL: http://codereview.chromium.org/8340003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@107544 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 49 insertions, 2 deletions

diff --git a/gpu/command_buffer/client/gles2_implementation.cc b/gpu/command_buffer/client/gles2_implementation.cc
index 9a9cd85..12238da 100644
--- a/gpu/command_buffer/client/gles2_implementation.cc
+++ b/gpu/command_buffer/client/gles2_implementation.cc
@@ -562,6 +562,7 @@ GLES2Implementation::GLES2Implementation(
   memset(&reserved_ids_, 0, sizeof(reserved_ids_));
 
   mapped_memory_.reset(new MappedMemoryManager(helper_));
+  SetSharedMemoryChunkSizeMultiple(1024 * 1024 * 2);
 
   if (share_resources) {
     if (!bind_generates_resource) {
@@ -641,6 +642,11 @@ GLES2Implementation::~GLES2Implementation() {
 #endif
 }
 
+void GLES2Implementation::SetSharedMemoryChunkSizeMultiple(
+    unsigned int multiple) {
+  mapped_memory_->set_chunk_size_multiple(multiple);
+}
+
 void GLES2Implementation::FreeUnusedSharedMemory() {
   mapped_memory_->FreeUnused();
 }
diff --git a/gpu/command_buffer/client/gles2_implementation.h b/gpu/command_buffer/client/gles2_implementation.h
index 43cb2ad..81f0145 100644
--- a/gpu/command_buffer/client/gles2_implementation.h
+++ b/gpu/command_buffer/client/gles2_implementation.h
@@ -197,6 +197,8 @@ class GLES2Implementation {
     texture_id_handler_->FreeIds(1, &id);
   }
 
+  void SetSharedMemoryChunkSizeMultiple(unsigned int multiple);
+
   void FreeUnusedSharedMemory();
 
  private:
diff --git a/gpu/command_buffer/client/mapped_memory.cc b/gpu/command_buffer/client/mapped_memory.cc
index 461343e..c8d400e 100644
--- a/gpu/command_buffer/client/mapped_memory.cc
+++ b/gpu/command_buffer/client/mapped_memory.cc
@@ -23,7 +23,8 @@ MemoryChunk::MemoryChunk(
 }
 
 MappedMemoryManager::MappedMemoryManager(CommandBufferHelper* helper)
-    : helper_(helper) {
+    : chunk_size_multiple_(1),
+      helper_(helper) {
 }
 
 MappedMemoryManager::~MappedMemoryManager() {
@@ -52,7 +53,10 @@ void* MappedMemoryManager::Alloc(
 
   // Make a new chunk to satisfy the request.
   CommandBuffer* cmd_buf = helper_->command_buffer();
-  int32 id = cmd_buf->CreateTransferBuffer(size, -1);
+  unsigned int chunk_size =
+      ((size + chunk_size_multiple_ - 1) / chunk_size_multiple_) *
+      chunk_size_multiple_;
+  int32 id = cmd_buf->CreateTransferBuffer(chunk_size, -1);
   if (id == -1) {
     return NULL;
   }
diff --git a/gpu/command_buffer/client/mapped_memory.h b/gpu/command_buffer/client/mapped_memory.h
index ed66664..f38470f 100644
--- a/gpu/command_buffer/client/mapped_memory.h
+++ b/gpu/command_buffer/client/mapped_memory.h
@@ -110,6 +110,14 @@ class MappedMemoryManager {
 
   ~MappedMemoryManager();
 
+  unsigned int chunk_size_multiple() const {
+    return chunk_size_multiple_;
+  }
+
+  void set_chunk_size_multiple(unsigned int multiple) {
+    chunk_size_multiple_ = multiple;
+  }
+
   // Allocates a block of memory
   // Parameters:
   //   size: size of memory to allocate.
@@ -145,6 +153,8 @@ class MappedMemoryManager {
  private:
   typedef std::vector<MemoryChunk*> MemoryChunkVector;
 
+  // size a chunk is rounded up to.
+  unsigned int chunk_size_multiple_;
   CommandBufferHelper* helper_;
   MemoryChunkVector chunks_;
 
diff --git a/gpu/command_buffer/client/mapped_memory_unittest.cc b/gpu/command_buffer/client/mapped_memory_unittest.cc
index 0b60897..6ca8c14 100644
--- a/gpu/command_buffer/client/mapped_memory_unittest.cc
+++ b/gpu/command_buffer/client/mapped_memory_unittest.cc
@@ -273,6 +273,31 @@ TEST_F(MappedMemoryManagerTest, FreeUnused) {
   EXPECT_EQ(0u, manager_->num_chunks());
 }
 
+TEST_F(MappedMemoryManagerTest, ChunkSizeMultiple) {
+  const unsigned int kSize = 1024;
+  manager_->set_chunk_size_multiple(kSize *  2);
+  // Check if we allocate less than the chunk size multiple we get
+  // chunks arounded up.
+  int32 id1 = -1;
+  unsigned int offset1 = 0xFFFFFFFFU;
+  void* mem1 = manager_->Alloc(kSize, &id1, &offset1);
+  int32 id2 = -1;
+  unsigned int offset2 = 0xFFFFFFFFU;
+  void* mem2 = manager_->Alloc(kSize, &id2, &offset2);
+  int32 id3 = -1;
+  unsigned int offset3 = 0xFFFFFFFFU;
+  void* mem3 = manager_->Alloc(kSize, &id3, &offset3);
+  ASSERT_TRUE(mem1);
+  ASSERT_TRUE(mem2);
+  ASSERT_TRUE(mem3);
+  EXPECT_NE(-1, id1);
+  EXPECT_EQ(id1, id2);
+  EXPECT_NE(id2, id3);
+  EXPECT_EQ(0u, offset1);
+  EXPECT_EQ(kSize, offset2);
+  EXPECT_EQ(0u, offset3);
+}
+
 }  // namespace gpu