Adding GpuMemoryManager to track GpuCommandBufferStub visibility and last_used_time and dictate mem…

content/common/gpu/gpu_memory_manager.cc

Index: content/common/gpu/gpu_memory_manager.cc
diff --git a/content/common/gpu/gpu_memory_manager.cc b/content/common/gpu/gpu_memory_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..57d6f82d45124485a8e770f0a6f6aed771e4bc3e
--- /dev/null
+++ b/content/common/gpu/gpu_memory_manager.cc
@@ -0,0 +1,124 @@
+// Copyright (c) 2012 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 "content/common/gpu/gpu_memory_manager.h"
+
+#if defined(ENABLE_GPU)
+
+#include <set>
+#include <algorithm>
+
+#include "base/bind.h"
+#include "base/message_loop.h"
+
+////////////////////////////////////////////////////////////////////////////////
+// Constructors/Destructors
+
+GpuMemoryManager::GpuMemoryManager(GpuMemoryManagerClient* client)
+    : client_(client)
+    , manage_scheduled_(false) {

[jonathan.backer, 2012/01/31 18:13:58]

nit: sorry, but I think this is the WK way, not the Chromium way... (commas
trail not lead)

[mmocny, 2012/01/31 18:54:57]

Done.

+}
+
+GpuMemoryManager::~GpuMemoryManager() {
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+void GpuMemoryManager::ScheduleManage() {
+  if (manage_scheduled_)
+    return;
+  manage_scheduled_ = true;
+  MessageLoop::current()->PostTask(
+    FROM_HERE, base::Bind(&GpuMemoryManager::Manage, base::Unretained(this)));

[nduca, 2012/01/31 06:53:47]

Hmmm isn't this going to crash if the task is posted when the manager dies and
the message loop keeps spinning?

The trick here is weak references. Look at GpuChannel's weak_factory_ member and
its OnScheduled function and copy that. 

+}
+
+void GpuMemoryManager::Manage() {

[nduca, 2012/01/31 06:53:47]

I think you should take some of the comments from your allocation classes about
the actual 3 limits and also add some text that explains this algorithm.

"The current managing algorithm simply classifies tabs as "foreground",
"background" and "hibernated." For each of those three categories, there are
predefined limits. It proceeds in X steps, as follows....

+  manage_scheduled_ = false;
+
+  // Ask client for command buffer stubs
+  std::vector<GpuMemoryManageableCommandBufferStub*> stubs_with_surface;

[nduca, 2012/01/31 06:53:47]

this is where I was saying you should just get all the stubs, then build two
vectors from them inside this function. Its really not gonna be a big deal perf
wise.

[mmocny, 2012/01/31 18:54:57]

Done.

+  std::vector<GpuMemoryManageableCommandBufferStub*> stubs_without_surface;
+  client_->AppendAllCommandBufferStubs(stubs_with_surface,
+                                       stubs_without_surface);
+
+  // Sort stubs with surface into {visibility,last_used_time} order using
+  // custom comparator
+  std::sort(stubs_with_surface.begin(), stubs_with_surface.end(),
+      StubComparator());
+
+  // Create allocations

[nduca, 2012/01/31 06:53:47]

This comment isn't adding a lot of value. You're better doing something like
// Set up the three predefined allocation values

[mmocny, 2012/01/31 18:54:57]

Done.

+  GpuMemoryAllocation all_buffers_allocation;
+  all_buffers_allocation.gpuResourceSizeInBytes =
+      GpuMemoryAllocation::kResourceSizeForegroundTab;
+  all_buffers_allocation.hasFrontbuffer = true;
+  all_buffers_allocation.hasBackbuffer = true;
+
+  GpuMemoryAllocation front_buffers_allocation;
+  front_buffers_allocation.gpuResourceSizeInBytes =
+      GpuMemoryAllocation::kResourceSizeBackgroundTab;
+  front_buffers_allocation.hasFrontbuffer = true;
+  front_buffers_allocation.hasBackbuffer = false;
+
+  GpuMemoryAllocation no_buffers_allocation;
+  no_buffers_allocation.gpuResourceSizeInBytes =
+      GpuMemoryAllocation::kResourceSizeHibernatedTab;
+  no_buffers_allocation.hasFrontbuffer = false;
+  no_buffers_allocation.hasBackbuffer = false;
+

[jonathan.backer, 2012/01/31 18:13:58]

AFAICT, these never change. Define them as constants? Perhaps in an anon
namespace at the beginning of the file?

[mmocny, 2012/01/31 18:54:57]

Done.

+  // Separate stubs with surfaces into three sets and send memory allocation

[nduca, 2012/01/31 06:53:47]

This should really be put up in the overall comment for the manage function.

The three numbered bullets here are a bit information dense. Use a few more
lines and/or prose to make this clearer? Its good information. :)

+  //  1. all_buffers:   Front, Back, and RootLayerTiles [all visible surfaces]
+  //  2. front_buffers: Front only                      [based on #tab limit]
+  //  3. no_buffers:    None                            [the rest]
+  static const size_t kMaxSurfacesWithFrontBufferSoftLimit = 8;
+  std::set<int32> all_buffers, front_buffers, no_buffers;
+
+  for (size_t i = 0; i < stubs_with_surface.size(); ++i) {
+    GpuMemoryManageableCommandBufferStub* stub = stubs_with_surface[i];
+    if (stub->surface_state().visible) {
+      all_buffers.insert(stub->surface_state().surface_id);
+      stub->SendMemoryAllocation(all_buffers_allocation);

[jonathan.backer, 2012/01/31 18:13:58]

Is this necessary given the code below? Aren't we sending the allocation twice?

[mmocny, 2012/01/31 18:54:57]

The first loop is over stubs_with_surfaces, the second loop is over
stubs_without_surface.
Sorry, its more confusing than it needs to be.
I've updated the comment at the top of this function to explain whats going on
here.  I can separate this out into two helper functions to make it extra
explicit, but perhaps that is overkill.
On 2012/01/31 18:13:58, jonathan.backer wrote:

+    } else if (i < kMaxSurfacesWithFrontBufferSoftLimit) {
+      front_buffers.insert(stub->surface_state().surface_id);
+      stub->SendMemoryAllocation(front_buffers_allocation);
+    } else {
+      no_buffers.insert(stub->surface_state().surface_id);
+      stub->SendMemoryAllocation(no_buffers_allocation);
+    }
+  }
+
+  // Now, go through the stubs without surfaces and send memory allocations
+  // based on buckets we just divided.  Because there may be multiple affected
+  // surfaces, use the state of the most "important" affected surface.
+  for (std::vector<GpuMemoryManageableCommandBufferStub*>::const_iterator it =
+      stubs_without_surface.begin(); it != stubs_without_surface.end(); ++it) {
+    GpuMemoryManageableCommandBufferStub* stub = *it;
+    if (std::find_first_of(all_buffers.begin(),
+                           all_buffers.end(),
+                           stub->affected_surface_ids().begin(),
+                           stub->affected_surface_ids().end()) !=
+                               all_buffers.end()) {
+      stub->SendMemoryAllocation(all_buffers_allocation);
+    } else if (std::find_first_of(front_buffers.begin(),
+                                  front_buffers.end(),
+                                  stub->affected_surface_ids().begin(),
+                                  stub->affected_surface_ids().end()) !=
+                                      front_buffers.end()) {
+      stub->SendMemoryAllocation(front_buffers_allocation);
+    } else if (std::find_first_of(no_buffers.begin(),
+                                  no_buffers.end(),
+                                  stub->affected_surface_ids().begin(),
+                                  stub->affected_surface_ids().end()) !=
+                                      no_buffers.end()) {
+      stub->SendMemoryAllocation(no_buffers_allocation);
+    } else {
+      // TODO(mmocny): Either (a) no affected surfaces, or

[nduca, 2012/01/31 06:53:47]

Fix this so you put an if(affected_surface_ids().size() == 0) continue up top
and some sort of real failure here. DLOG(CRITICAL) << "OMGWTFBBQ" for example.

[mmocny, 2012/01/31 18:54:57]

Done.

+      //                      (b) your affected surfaces are incorrect
+      // (a) is fine, (b) is not
+    }
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+#endif