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..de07d14447762e993d2bd055f8f1731617499582 100644
--- a/gpu/command_buffer/client/mapped_memory.cc
+++ b/gpu/command_buffer/client/mapped_memory.cc
@@ -18,9 +18,12 @@ MemoryChunk::MemoryChunk(
       allocator_(shm.size, helper, shm.ptr) {
 }
 
-MappedMemoryManager::MappedMemoryManager(CommandBufferHelper* helper)
+MappedMemoryManager::MappedMemoryManager(CommandBufferHelper* helper,
+                                         size_t memory_limit)
     : chunk_size_multiple_(1),
-      helper_(helper) {
+      helper_(helper),
+      allocated_memory_(0),
+      max_free_bytes_(memory_limit) {
 }
 
 MappedMemoryManager::~MappedMemoryManager() {
@@ -36,10 +39,12 @@ void* MappedMemoryManager::Alloc(
     unsigned int size, int32* shm_id, unsigned int* shm_offset) {
   GPU_DCHECK(shm_id);
   GPU_DCHECK(shm_offset);

[no sievers, 2013/08/20 15:59:17]

Can you put 'if (size <= allocated_memory_)' around line 42-75 now?

[kaanb, 2013/08/20 22:15:46]

Done.

-  // See if any of the chucks can satisfy this request.
+  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) {
       void* mem = chunk->Alloc(size);
       GPU_DCHECK(mem);
@@ -49,6 +54,25 @@ void* MappedMemoryManager::Alloc(
     }
   }
 
+  // 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 &&
+      (allocated_memory_ - total_bytes_in_use) >= max_free_bytes_) {

[epenner, 2013/08/20 18:02:03]

Please add a trace in this if statement.

[kaanb, 2013/08/20 22:15:46]

Done.

+    for (size_t ii = 0; ii < chunks_.size(); ++ii) {
+      MemoryChunk* chunk = chunks_[ii];
+      chunk->FreeUnused();

[no sievers, 2013/08/20 02:46:54]

Should we skip the call to FreeUnused() here since we already did it above?

[kaanb, 2013/08/20 22:15:46]

Done.

+      if (chunk->GetLargestFreeSizeWithWaiting() >= size) {
+        void* mem = chunk->Alloc(size);
+        GPU_DCHECK(mem);
+        *shm_id = chunk->shm_id();
+        *shm_offset = chunk->GetOffset(mem);
+        return mem;
+      }
+    }
+    LOG(INFO) << "Exceeding memory limit: " << max_free_bytes_;

[no sievers, 2013/08/20 02:46:54]

Hmm that might be spammy. How about a trace event in
FencedAllocator::WaitForTokenAndFreeBlock() instead?

[kaanb, 2013/08/20 22:15:46]

I put the trace event in this method.

+  }
+
   // Make a new chunk to satisfy the request.
   CommandBuffer* cmd_buf = helper_->command_buffer();
   unsigned int chunk_size =
@@ -59,6 +83,7 @@ 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 +122,7 @@ void MappedMemoryManager::FreeUnused() {
     chunk->FreeUnused();
     if (!chunk->InUse()) {
       cmd_buf->DestroyTransferBuffer(chunk->shm_id());
+      allocated_memory_ -= chunk->GetSize();
       iter = chunks_.erase(iter);
     } else {
       ++iter;
@@ -105,6 +131,3 @@ void MappedMemoryManager::FreeUnused() {
 }
 
 }  // namespace gpu
-
-
-