Enforce a memory limit on MappedMemoryManager

gpu/command_buffer/client/mapped_memory.cc

Index: gpu/command_buffer/client/mapped_memory.cc
diff --git a/gpu/command_buffer/client/mapped_memory.cc b/gpu/command_buffer/client/mapped_memory.cc
index 82829d48ec1cda6fd7534f596b95acbce03b8522..8747fe5cb2951d5c2d4eec2c30ba8340ffc3aa8d 100644
--- a/gpu/command_buffer/client/mapped_memory.cc
+++ b/gpu/command_buffer/client/mapped_memory.cc
@@ -7,6 +7,10 @@
 #include <algorithm>
 #include <functional>
 
+#if defined(OS_ANDROID)
+#include "base/android/sys_utils.h"
+#endif
+
 #include "gpu/command_buffer/client/cmd_buffer_helper.h"
 
 namespace gpu {
@@ -20,7 +24,14 @@ MemoryChunk::MemoryChunk(
 
 MappedMemoryManager::MappedMemoryManager(CommandBufferHelper* helper)
     : chunk_size_multiple_(1),
-      helper_(helper) {
+      helper_(helper),
+      allocated_memory_(0),
+      memory_limit_(kNoLimit) {
+#if defined(OS_ANDROID)

[no sievers, 2013/08/14 02:05:52]

can we avoid ifdefs? Can't we just pass in the limit like we do it for the
transfer buffer?

can you add a unit test?

+  if (base::android::SysUtils::IsLowEndDevice()) {
+    memory_limit_ = kAndroidLowEndLimit;
+  }
+#endif
 }
 
 MappedMemoryManager::~MappedMemoryManager() {
@@ -36,7 +47,7 @@ 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();
@@ -49,6 +60,22 @@ void* MappedMemoryManager::Alloc(
     }
   }
 
+  // If there is a memory limit being enforced and allocation of
+  // a new chunk would exceed the limit, try again with waiting.
+  if (memory_limit_ != kNoLimit && (allocated_memory_ + size) > 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;
+      }
+    }
+  }
+
   // Make a new chunk to satisfy the request.
   CommandBuffer* cmd_buf = helper_->command_buffer();
   unsigned int chunk_size =
@@ -59,6 +86,7 @@ void* MappedMemoryManager::Alloc(
   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);
@@ -97,6 +125,7 @@ void MappedMemoryManager::FreeUnused() {
     chunk->FreeUnused();
     if (!chunk->InUse()) {
       cmd_buf->DestroyTransferBuffer(chunk->shm_id());
+      allocated_memory_ -= chunk->GetSize();
       iter = chunks_.erase(iter);
     } else {
       ++iter;