Enforce a memory limit on MappedMemoryManager

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 "gpu/command_buffer/client/cmd_buffer_helper.h"
 
 namespace gpu {
 
 MemoryChunk::MemoryChunk(
     int32 shm_id, gpu::Buffer shm, CommandBufferHelper* helper)
     : shm_id_(shm_id),
       shm_(shm),
       allocator_(shm.size, helper, shm.ptr) {
 }
 
 MappedMemoryManager::MappedMemoryManager(CommandBufferHelper* helper)
     : chunk_size_multiple_(1),
-      helper_(helper) {
+      helper_(helper),
+      allocated_memory_(0),
+      memory_limit_(kNoLimit) {
+}
+
+MappedMemoryManager::MappedMemoryManager(CommandBufferHelper* helper,
+                                         size_t memory_limit)
+    : chunk_size_multiple_(1),
+      helper_(helper),
+      allocated_memory_(0),
+      memory_limit_(memory_limit) {
 }
 
 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) {
   GPU_DCHECK(shm_id);
   GPU_DCHECK(shm_offset);
-  // See if any of the chucks can satisfy this request.
+  // 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();
     if (chunk->GetLargestFreeSizeWithoutWaiting() >= size) {
       void* mem = chunk->Alloc(size);
       GPU_DCHECK(mem);
       *shm_id = chunk->shm_id();
       *shm_offset = chunk->GetOffset(mem);
       return mem;
     }
   }
 
+  // If there is a memory limit being enforced and the allocated memory
+  // is above the limit, try existing chunks again with waiting.
+  if (memory_limit_ != kNoLimit && allocated_memory_ >= memory_limit_) {
+    for (size_t ii = 0; ii < chunks_.size(); ++ii) {
+      MemoryChunk* chunk = chunks_[ii];
+      chunk->FreeUnused();
+      if (chunk->GetLargestFreeSizeWithWaiting() >= size) {
+        void* mem = chunk->Alloc(size);
+        GPU_DCHECK(mem);
+        *shm_id = chunk->shm_id();
+        *shm_offset = chunk->GetOffset(mem);
+        return mem;
+      }
+    }

[piman, 2013/08/15 02:49:03]

So, if we get here, that means that we're not going to respect the limit anyway.
We should probably log something (and clarify that the limit is not strict).

[kaanb, 2013/08/16 22:50:44]

Done.

+  }
+
   // 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_);
+  allocated_memory_ += mc->GetSize();
   chunks_.push_back(mc);
   void* mem = mc->Alloc(size);
   GPU_DCHECK(mem);
   *shm_id = mc->shm_id();
   *shm_offset = mc->GetOffset(mem);
   return mem;
 }
 
 void MappedMemoryManager::Free(void* pointer) {
   for (size_t ii = 0; ii < chunks_.size(); ++ii) {
@@ skipping 18 matching lines @@
 }
 
 void MappedMemoryManager::FreeUnused() {
   CommandBuffer* cmd_buf = helper_->command_buffer();
   MemoryChunkVector::iterator iter = chunks_.begin();
   while (iter != chunks_.end()) {
     MemoryChunk* chunk = *iter;
     chunk->FreeUnused();
     if (!chunk->InUse()) {
       cmd_buf->DestroyTransferBuffer(chunk->shm_id());
+      allocated_memory_ -= chunk->GetSize();
       iter = chunks_.erase(iter);
     } else {
       ++iter;
     }
   }
 }
 
 }  // namespace gpu
-
-
-