gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/client/mapped_memory.cc

 // Copyright (c) 2011 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.
 
 #include "gpu/command_buffer/client/mapped_memory.h"
 
 #include <algorithm>
 #include <functional>
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "gpu/command_buffer/client/cmd_buffer_helper.h"
 
 namespace gpu {
 
-MemoryChunk::MemoryChunk(
-    int32 shm_id, gpu::Buffer shm, CommandBufferHelper* helper)
+MemoryChunk::MemoryChunk(int32 shm_id,
+                         gpu::Buffer shm,
+                         bool aggressive_reuse,
+                         CommandBufferHelper* helper)
     : shm_id_(shm_id),
       shm_(shm),
-      allocator_(shm.size, helper, shm.ptr) {
+      allocator_(shm.size, aggressive_reuse, helper, shm.ptr) {
 }
 
 MappedMemoryManager::MappedMemoryManager(CommandBufferHelper* helper,
-                                         size_t unused_memory_reclaim_limit)
+                                         MappedMemoryManagerSettings settings)
     : chunk_size_multiple_(1),
       helper_(helper),
       allocated_memory_(0),
-      max_free_bytes_(unused_memory_reclaim_limit) {
+      max_free_bytes_(settings.unused_memory_reclaim_limit),
+      aggressive_reuse_(settings.aggressive_reuse) {
 }
 
 MappedMemoryManager::~MappedMemoryManager() {
   CommandBuffer* cmd_buf = helper_->command_buffer();
   for (MemoryChunkVector::iterator iter = chunks_.begin();
        iter != chunks_.end(); ++iter) {
     MemoryChunk* chunk = *iter;
     cmd_buf->DestroyTransferBuffer(chunk->shm_id());
   }
 }
 
 void* MappedMemoryManager::Alloc(
     unsigned int size, int32* shm_id, unsigned int* shm_offset) {
   DCHECK(shm_id);
   DCHECK(shm_offset);
   if (size <= allocated_memory_) {
     size_t total_bytes_in_use = 0;
     // See if any of the chunks can satisfy this request.
     for (size_t ii = 0; ii < chunks_.size(); ++ii) {
       MemoryChunk* chunk = chunks_[ii];
       chunk->FreeUnused();
       total_bytes_in_use += chunk->bytes_in_use();
-      if (chunk->GetLargestFreeSizeWithoutWaiting() >= size) {
+      unsigned int largest_size =
+          aggressive_reuse_ ? chunk->GetLargestFreeSizeWithWaiting()
+                            : chunk->GetLargestFreeSizeWithoutWaiting();
+      if (largest_size >= size) {
         void* mem = chunk->Alloc(size);
         DCHECK(mem);
         *shm_id = chunk->shm_id();
         *shm_offset = chunk->GetOffset(mem);
         return mem;
       }
     }
 
     // If there is a memory limit being enforced and total free
     // memory (allocated_memory_ - total_bytes_in_use) is larger than
     // the limit try waiting.
-    if (max_free_bytes_ != kNoLimit &&
+    if (!aggressive_reuse_ && max_free_bytes_ != kNoLimit &&
         (allocated_memory_ - total_bytes_in_use) >= max_free_bytes_) {
       TRACE_EVENT0("gpu", "MappedMemoryManager::Alloc::wait");
       for (size_t ii = 0; ii < chunks_.size(); ++ii) {
         MemoryChunk* chunk = chunks_[ii];
         if (chunk->GetLargestFreeSizeWithWaiting() >= size) {
           void* mem = chunk->Alloc(size);
           DCHECK(mem);
           *shm_id = chunk->shm_id();
           *shm_offset = chunk->GetOffset(mem);
           return mem;
         }
       }
     }
   }
 
   // Make a new chunk to satisfy the request.
   CommandBuffer* cmd_buf = helper_->command_buffer();
   unsigned int chunk_size =
       ((size + chunk_size_multiple_ - 1) / chunk_size_multiple_) *
       chunk_size_multiple_;
   int32 id = -1;
   gpu::Buffer shm = cmd_buf->CreateTransferBuffer(chunk_size, &id);
   if (id  < 0)
     return NULL;
-  MemoryChunk* mc = new MemoryChunk(id, shm, helper_);
+  MemoryChunk* mc = new MemoryChunk(id, shm, aggressive_reuse_, helper_);
   allocated_memory_ += mc->GetSize();
   chunks_.push_back(mc);
   void* mem = mc->Alloc(size);
   DCHECK(mem);
   *shm_id = mc->shm_id();
   *shm_offset = mc->GetOffset(mem);
   return mem;
 }
 
 void MappedMemoryManager::Free(void* pointer) {
@@ skipping 28 matching lines @@
       cmd_buf->DestroyTransferBuffer(chunk->shm_id());
       allocated_memory_ -= chunk->GetSize();
       iter = chunks_.erase(iter);
     } else {
       ++iter;
     }
   }
 }
 
 }  // namespace gpu