Add GenericSharedMemoryId and use w/ GpuMemoryBuffer

content/browser/gpu/browser_gpu_memory_buffer_manager.cc

Index: content/browser/gpu/browser_gpu_memory_buffer_manager.cc
diff --git a/content/browser/gpu/browser_gpu_memory_buffer_manager.cc b/content/browser/gpu/browser_gpu_memory_buffer_manager.cc
index a1d54b7b365c2f4485e71dfe0bd38a63402556d5..01bc6807b101b66df045b4a6720de377ad11a40a 100644
--- a/content/browser/gpu/browser_gpu_memory_buffer_manager.cc
+++ b/content/browser/gpu/browser_gpu_memory_buffer_manager.cc
@@ -14,6 +14,7 @@
 #include "base/trace_event/trace_event.h"
 #include "content/browser/gpu/gpu_process_host.h"
 #include "content/common/child_process_host_impl.h"
+#include "content/common/generic_shared_memory_id_generator.h"
 #include "content/common/gpu/client/gpu_memory_buffer_impl.h"
 #include "content/common/gpu/client/gpu_memory_buffer_impl_shared_memory.h"
 #include "content/common/gpu/gpu_memory_buffer_factory_shared_memory.h"
@@ -120,9 +121,6 @@ GetSupportedGpuMemoryBufferConfigurations(gfx::GpuMemoryBufferType type) {
 
 BrowserGpuMemoryBufferManager* g_gpu_memory_buffer_manager = nullptr;
 
-// Global atomic to generate gpu memory buffer unique IDs.
-base::StaticAtomicSequenceNumber g_next_gpu_memory_buffer_id;
-
 }  // namespace
 
 struct BrowserGpuMemoryBufferManager::AllocateGpuMemoryBufferRequest {
@@ -213,6 +211,7 @@ BrowserGpuMemoryBufferManager::AllocateGpuMemoryBufferForScanout(
 }
 
 void BrowserGpuMemoryBufferManager::AllocateGpuMemoryBufferForChildProcess(
+    gfx::GpuMemoryBufferId id,
     const gfx::Size& size,
     gfx::BufferFormat format,
     gfx::BufferUsage usage,
@@ -221,11 +220,9 @@ void BrowserGpuMemoryBufferManager::AllocateGpuMemoryBufferForChildProcess(
     const AllocationCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  gfx::GpuMemoryBufferId new_id = g_next_gpu_memory_buffer_id.GetNext();
-
   // Use service side allocation if this is a supported configuration.
   if (IsGpuMemoryBufferConfigurationSupported(format, usage)) {
-    AllocateGpuMemoryBufferOnIO(new_id, size, format, usage, child_client_id, 0,
+    AllocateGpuMemoryBufferOnIO(id, size, format, usage, child_client_id, 0,
                                 false, callback);
     return;
   }
@@ -239,13 +236,12 @@ void BrowserGpuMemoryBufferManager::AllocateGpuMemoryBufferForChildProcess(
   }
 
   BufferMap& buffers = clients_[child_client_id];
-  DCHECK(buffers.find(new_id) == buffers.end());
+  DCHECK(buffers.find(id) == buffers.end());

[reveman, 2015/08/06 04:25:06]

We need to change this now that the child process controls the ID. This needs to
check if the id already exists and fail in that case. It can't crash as that
allows a child process to crash the browser process.

[ericrk, 2015/08/06 18:28:08]

Done.

 
   // Allocate shared memory buffer as fallback.
-  buffers[new_id] =
-      BufferInfo(size, gfx::SHARED_MEMORY_BUFFER, format, usage, 0);
+  buffers[id] = BufferInfo(size, gfx::SHARED_MEMORY_BUFFER, format, usage, 0);
   callback.Run(GpuMemoryBufferImplSharedMemory::AllocateForChildProcess(
-      new_id, size, format, child_process_handle));
+      id, size, format, child_process_handle));
 }
 
 gfx::GpuMemoryBuffer*
@@ -302,6 +298,22 @@ bool BrowserGpuMemoryBufferManager::OnMemoryDump(
                                                 buffer_id);
       pmd->CreateSharedGlobalAllocatorDump(shared_buffer_guid);
       pmd->AddOwnershipEdge(dump->guid(), shared_buffer_guid);
+
+      // Create an additional shared ownership edge with the

[reveman, 2015/08/06 04:25:06]

Ideally we'd instead add the generic shared memory node on the GPU process side
in the case of GPU process side allocated buffers or ask the
GpuMemoryBufferImplSharedMemory code to create it in case of shared memory.

[ericrk, 2015/08/06 18:28:08]

This isn't necessarily ideal, but might be fine as it only applies to
SHARED_MEMORY_BUFFER - could also register each GpuMemoryBufferImplSharedMemory,
but that seems inefficient? Could also just inline code here... let me know what
you think.

+      // GenericSharedMemoryId for the shared memory which backs this
+      // GpuMemoryBuffer.
+      base::trace_event::MemoryAllocatorDumpGuid shared_memory_guid =
+          base::memory::GetGenericSharedMemoryGUIDForTracing(
+              client_tracing_process_id, buffer_id);
+      pmd->CreateSharedGlobalAllocatorDump(shared_memory_guid);
+
+      // The link from the shared memory guid to the gpu memory buffer guid is
+      // higher than the link from the shared memory guid to the various low
+      // level memory dumps. This ensures that memory is tracked on the gpu
+      // memory buffer.
+      const int kImportance = 2;
+      pmd->AddOwnershipEdge(shared_buffer_guid, shared_memory_guid,
+                            kImportance);
     }
   }
 
@@ -382,7 +394,7 @@ void BrowserGpuMemoryBufferManager::AllocateGpuMemoryBufferForSurfaceOnIO(
     AllocateGpuMemoryBufferRequest* request) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  gfx::GpuMemoryBufferId new_id = g_next_gpu_memory_buffer_id.GetNext();
+  gfx::GpuMemoryBufferId new_id = content::GetNextGenericSharedMemoryId();
 
   // Use service side allocation if this is a supported configuration.
   if (IsGpuMemoryBufferConfigurationSupported(request->format,