cc: Start using raster/eviction iterators in tile manager

cc/resources/tile_manager.cc

 // Copyright 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 "cc/resources/tile_manager.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 
@@ skipping 209 matching lines @@
   skia::RefPtr<SkPixelRef> pixel_ref_;
   int layer_id_;
   RenderingStatsInstrumentation* rendering_stats_;
   const base::Callback<void(bool was_canceled)> reply_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageDecodeTaskImpl);
 };
 
 const size_t kScheduledRasterTasksLimit = 32u;
 
-// Memory limit policy works by mapping some bin states to the NEVER bin.
-const ManagedTileBin kBinPolicyMap[NUM_TILE_MEMORY_LIMIT_POLICIES][NUM_BINS] = {
-    // [ALLOW_NOTHING]
-    {NEVER_BIN,  // [NOW_AND_READY_TO_DRAW_BIN]
-     NEVER_BIN,  // [NOW_BIN]
-     NEVER_BIN,  // [SOON_BIN]
-     NEVER_BIN,  // [EVENTUALLY_AND_ACTIVE_BIN]
-     NEVER_BIN,  // [EVENTUALLY_BIN]
-     NEVER_BIN,  // [AT_LAST_AND_ACTIVE_BIN]
-     NEVER_BIN,  // [AT_LAST_BIN]
-     NEVER_BIN   // [NEVER_BIN]
-    },
-    // [ALLOW_ABSOLUTE_MINIMUM]
-    {NOW_AND_READY_TO_DRAW_BIN,  // [NOW_AND_READY_TO_DRAW_BIN]
-     NOW_BIN,                    // [NOW_BIN]
-     NEVER_BIN,                  // [SOON_BIN]
-     NEVER_BIN,                  // [EVENTUALLY_AND_ACTIVE_BIN]
-     NEVER_BIN,                  // [EVENTUALLY_BIN]
-     NEVER_BIN,                  // [AT_LAST_AND_ACTIVE_BIN]
-     NEVER_BIN,                  // [AT_LAST_BIN]
-     NEVER_BIN                   // [NEVER_BIN]
-    },
-    // [ALLOW_PREPAINT_ONLY]
-    {NOW_AND_READY_TO_DRAW_BIN,  // [NOW_AND_READY_TO_DRAW_BIN]
-     NOW_BIN,                    // [NOW_BIN]
-     SOON_BIN,                   // [SOON_BIN]
-     NEVER_BIN,                  // [EVENTUALLY_AND_ACTIVE_BIN]
-     NEVER_BIN,                  // [EVENTUALLY_BIN]
-     NEVER_BIN,                  // [AT_LAST_AND_ACTIVE_BIN]
-     NEVER_BIN,                  // [AT_LAST_BIN]
-     NEVER_BIN                   // [NEVER_BIN]
-    },
-    // [ALLOW_ANYTHING]
-    {NOW_AND_READY_TO_DRAW_BIN,  // [NOW_AND_READY_TO_DRAW_BIN]
-     NOW_BIN,                    // [NOW_BIN]
-     SOON_BIN,                   // [SOON_BIN]
-     EVENTUALLY_AND_ACTIVE_BIN,  // [EVENTUALLY_AND_ACTIVE_BIN]
-     EVENTUALLY_BIN,             // [EVENTUALLY_BIN]
-     AT_LAST_AND_ACTIVE_BIN,     // [AT_LAST_AND_ACTIVE_BIN]
-     AT_LAST_BIN,                // [AT_LAST_BIN]
-     NEVER_BIN                   // [NEVER_BIN]
-    }};
-
-// Ready to draw works by mapping NOW_BIN to NOW_AND_READY_TO_DRAW_BIN.
-const ManagedTileBin kBinReadyToDrawMap[2][NUM_BINS] = {
-    // Not ready
-    {NOW_AND_READY_TO_DRAW_BIN,  // [NOW_AND_READY_TO_DRAW_BIN]
-     NOW_BIN,                    // [NOW_BIN]
-     SOON_BIN,                   // [SOON_BIN]
-     EVENTUALLY_AND_ACTIVE_BIN,  // [EVENTUALLY_AND_ACTIVE_BIN]
-     EVENTUALLY_BIN,             // [EVENTUALLY_BIN]
-     AT_LAST_AND_ACTIVE_BIN,     // [AT_LAST_AND_ACTIVE_BIN]
-     AT_LAST_BIN,                // [AT_LAST_BIN]
-     NEVER_BIN                   // [NEVER_BIN]
-    },
-    // Ready
-    {NOW_AND_READY_TO_DRAW_BIN,  // [NOW_AND_READY_TO_DRAW_BIN]
-     NOW_AND_READY_TO_DRAW_BIN,  // [NOW_BIN]
-     SOON_BIN,                   // [SOON_BIN]
-     EVENTUALLY_AND_ACTIVE_BIN,  // [EVENTUALLY_AND_ACTIVE_BIN]
-     EVENTUALLY_BIN,             // [EVENTUALLY_BIN]
-     AT_LAST_AND_ACTIVE_BIN,     // [AT_LAST_AND_ACTIVE_BIN]
-     AT_LAST_BIN,                // [AT_LAST_BIN]
-     NEVER_BIN                   // [NEVER_BIN]
-    }};
-
-// Active works by mapping some bin stats to equivalent _ACTIVE_BIN state.
-const ManagedTileBin kBinIsActiveMap[2][NUM_BINS] = {
-    // Inactive
-    {NOW_AND_READY_TO_DRAW_BIN,  // [NOW_AND_READY_TO_DRAW_BIN]
-     NOW_BIN,                    // [NOW_BIN]
-     SOON_BIN,                   // [SOON_BIN]
-     EVENTUALLY_AND_ACTIVE_BIN,  // [EVENTUALLY_AND_ACTIVE_BIN]
-     EVENTUALLY_BIN,             // [EVENTUALLY_BIN]
-     AT_LAST_AND_ACTIVE_BIN,     // [AT_LAST_AND_ACTIVE_BIN]
-     AT_LAST_BIN,                // [AT_LAST_BIN]
-     NEVER_BIN                   // [NEVER_BIN]
-    },
-    // Active
-    {NOW_AND_READY_TO_DRAW_BIN,  // [NOW_AND_READY_TO_DRAW_BIN]
-     NOW_BIN,                    // [NOW_BIN]
-     SOON_BIN,                   // [SOON_BIN]
-     EVENTUALLY_AND_ACTIVE_BIN,  // [EVENTUALLY_AND_ACTIVE_BIN]
-     EVENTUALLY_AND_ACTIVE_BIN,  // [EVENTUALLY_BIN]
-     AT_LAST_AND_ACTIVE_BIN,     // [AT_LAST_AND_ACTIVE_BIN]
-     AT_LAST_AND_ACTIVE_BIN,     // [AT_LAST_BIN]
-     NEVER_BIN                   // [NEVER_BIN]
-    }};
-
-// Determine bin based on three categories of tiles: things we need now,
-// things we need soon, and eventually.
-inline ManagedTileBin BinFromTilePriority(const TilePriority& prio) {
-  if (prio.priority_bin == TilePriority::NOW)
-    return NOW_BIN;
-
-  if (prio.priority_bin == TilePriority::SOON)
-    return SOON_BIN;
-
-  if (prio.distance_to_visible == std::numeric_limits<float>::infinity())
-    return NEVER_BIN;
-
-  return EVENTUALLY_BIN;
-}
-
 }  // namespace
 
 RasterTaskCompletionStats::RasterTaskCompletionStats()
     : completed_count(0u), canceled_count(0u) {}
 
 scoped_ptr<base::Value> RasterTaskCompletionStatsAsValue(
     const RasterTaskCompletionStats& stats) {
   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
   state->SetInteger("completed_count", stats.completed_count);
   state->SetInteger("canceled_count", stats.canceled_count);
@@ skipping 17 matching lines @@
 TileManager::TileManager(
     TileManagerClient* client,
     base::SequencedTaskRunner* task_runner,
     ResourcePool* resource_pool,
     Rasterizer* rasterizer,
     RenderingStatsInstrumentation* rendering_stats_instrumentation)
     : client_(client),
       task_runner_(task_runner),
       resource_pool_(resource_pool),
       rasterizer_(rasterizer),
-      prioritized_tiles_dirty_(false),
       all_tiles_that_need_to_be_rasterized_have_memory_(true),
-      all_tiles_required_for_activation_have_memory_(true),
-      memory_required_bytes_(0),
-      memory_nice_to_have_bytes_(0),
-      bytes_releasable_(0),
-      resources_releasable_(0),
       ever_exceeded_memory_budget_(false),
       rendering_stats_instrumentation_(rendering_stats_instrumentation),
       did_initialize_visible_tile_(false),
       did_check_for_completed_tasks_since_last_schedule_tasks_(true),
       ready_to_activate_check_notifier_(
           task_runner_,
           base::Bind(&TileManager::CheckIfReadyToActivate,
                      base::Unretained(this))) {
   rasterizer_->SetClient(this);
 }
 
 TileManager::~TileManager() {
   // Reset global state and manage. This should cause
   // our memory usage to drop to zero.
   global_state_ = GlobalStateThatImpactsTilePriority();
 
   CleanUpReleasedTiles();
   DCHECK_EQ(0u, tiles_.size());
 
   RasterTaskQueue empty;
   rasterizer_->ScheduleTasks(&empty);
   orphan_raster_tasks_.clear();
 
   // This should finish all pending tasks and release any uninitialized
   // resources.
   rasterizer_->Shutdown();
   rasterizer_->CheckForCompletedTasks();
-
-  DCHECK_EQ(0u, bytes_releasable_);
-  DCHECK_EQ(0u, resources_releasable_);
 }
 
 void TileManager::Release(Tile* tile) {
-  prioritized_tiles_dirty_ = true;
   released_tiles_.push_back(tile);
 }
 
-void TileManager::DidChangeTilePriority(Tile* tile) {
-  prioritized_tiles_dirty_ = true;
-}
-
 bool TileManager::ShouldForceTasksRequiredForActivationToComplete() const {
   return global_state_.tree_priority != SMOOTHNESS_TAKES_PRIORITY;
 }
 
 void TileManager::CleanUpReleasedTiles() {
   for (std::vector<Tile*>::iterator it = released_tiles_.begin();
        it != released_tiles_.end();
        ++it) {

[reveman, 2014/06/18 03:35:42]

Completely unrelated. How about we only release tiles without raster tasks? That
would allow us to remove orphan_raster_tasks_ which will be a nice cleanup and
possibly small performance improvement. Definitely for a follow up and not part
of this patch though.

[vmpstr, 2014/06/18 06:45:00]

That sounds good. Filed crbug.com/386039

[reveman, 2014/06/18 16:41:09]

Thanks!

     Tile* tile = *it;
     ManagedTileState& mts = tile->managed_state();
 
     for (int mode = 0; mode < NUM_RASTER_MODES; ++mode) {
       FreeResourceForTile(tile, static_cast<RasterMode>(mode));
       orphan_raster_tasks_.push_back(mts.tile_versions[mode].raster_task_);
     }
 
     DCHECK(tiles_.find(tile->id()) != tiles_.end());
     tiles_.erase(tile->id());
 
     LayerCountMap::iterator layer_it =
         used_layer_counts_.find(tile->layer_id());
     DCHECK_GT(layer_it->second, 0);
     if (--layer_it->second == 0) {
       used_layer_counts_.erase(layer_it);
       image_decode_tasks_.erase(tile->layer_id());
     }
 
     delete tile;
   }
 
   released_tiles_.clear();
 }
 
-void TileManager::UpdatePrioritizedTileSetIfNeeded() {
-  if (!prioritized_tiles_dirty_)
-    return;
-
-  CleanUpReleasedTiles();
-
-  prioritized_tiles_.Clear();
-  GetTilesWithAssignedBins(&prioritized_tiles_);
-  prioritized_tiles_dirty_ = false;
-}
-
 void TileManager::DidFinishRunningTasks() {
   TRACE_EVENT0("cc", "TileManager::DidFinishRunningTasks");
 
   bool memory_usage_above_limit = resource_pool_->total_memory_usage_bytes() >
                                   global_state_.soft_memory_limit_in_bytes;
 
   // When OOM, keep re-assigning memory until we reach a steady state
   // where top-priority tiles are initialized.
   if (all_tiles_that_need_to_be_rasterized_have_memory_ &&
       !memory_usage_above_limit)
     return;
 
   rasterizer_->CheckForCompletedTasks();
   did_check_for_completed_tasks_since_last_schedule_tasks_ = true;
 
   TileVector tiles_that_need_to_be_rasterized;
-  AssignGpuMemoryToTiles(&prioritized_tiles_,
-                         &tiles_that_need_to_be_rasterized);
+  AssignGpuMemoryToTiles(&tiles_that_need_to_be_rasterized);
 
   // |tiles_that_need_to_be_rasterized| will be empty when we reach a
   // steady memory state. Keep scheduling tasks until we reach this state.
   if (!tiles_that_need_to_be_rasterized.empty()) {
     ScheduleTasks(tiles_that_need_to_be_rasterized);
     return;
   }
 
   resource_pool_->ReduceResourceUsage();
 
@@ skipping 20 matching lines @@
       tile_version.set_rasterize_on_demand();
       client_->NotifyTileStateChanged(tile);
     }
   }
 
   DCHECK(IsReadyToActivate());
   ready_to_activate_check_notifier_.Schedule();
 }
 
 void TileManager::DidFinishRunningTasksRequiredForActivation() {
-  // This is only a true indication that all tiles required for
-  // activation are initialized when no tiles are OOM. We need to
-  // wait for DidFinishRunningTasks() to be called, try to re-assign
-  // memory and in worst case use on-demand raster when tiles
-  // required for activation are OOM.
-  if (!all_tiles_required_for_activation_have_memory_)
-    return;
-
   ready_to_activate_check_notifier_.Schedule();
 }
 
-void TileManager::GetTilesWithAssignedBins(PrioritizedTileSet* tiles) {
-  TRACE_EVENT0("cc", "TileManager::GetTilesWithAssignedBins");
-
-  // Compute new stats to be return by GetMemoryStats().
-  memory_required_bytes_ = 0;
-  memory_nice_to_have_bytes_ = 0;
-
-  const TileMemoryLimitPolicy memory_policy = global_state_.memory_limit_policy;
-  const TreePriority tree_priority = global_state_.tree_priority;
-
-  // For each tree, bin into different categories of tiles.
-  for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it) {
-    Tile* tile = it->second;
-    ManagedTileState& mts = tile->managed_state();
-
-    const ManagedTileState::TileVersion& tile_version =
-        tile->GetTileVersionForDrawing();
-    bool tile_is_ready_to_draw = tile_version.IsReadyToDraw();
-    bool tile_is_active = tile_is_ready_to_draw ||
-                          mts.tile_versions[mts.raster_mode].raster_task_;
-
-    // Get the active priority and bin.
-    TilePriority active_priority = tile->priority(ACTIVE_TREE);
-    ManagedTileBin active_bin = BinFromTilePriority(active_priority);
-
-    // Get the pending priority and bin.
-    TilePriority pending_priority = tile->priority(PENDING_TREE);
-    ManagedTileBin pending_bin = BinFromTilePriority(pending_priority);
-
-    bool pending_is_low_res = pending_priority.resolution == LOW_RESOLUTION;
-    bool pending_is_non_ideal =
-        pending_priority.resolution == NON_IDEAL_RESOLUTION;
-    bool active_is_non_ideal =
-        active_priority.resolution == NON_IDEAL_RESOLUTION;
-
-    // Adjust bin state based on if ready to draw.
-    active_bin = kBinReadyToDrawMap[tile_is_ready_to_draw][active_bin];
-    pending_bin = kBinReadyToDrawMap[tile_is_ready_to_draw][pending_bin];
-
-    // Adjust bin state based on if active.
-    active_bin = kBinIsActiveMap[tile_is_active][active_bin];
-    pending_bin = kBinIsActiveMap[tile_is_active][pending_bin];
-
-    // We never want to paint new non-ideal tiles, as we always have
-    // a high-res tile covering that content (paint that instead).
-    if (!tile_is_ready_to_draw && active_is_non_ideal)
-      active_bin = NEVER_BIN;
-    if (!tile_is_ready_to_draw && pending_is_non_ideal)
-      pending_bin = NEVER_BIN;
-
-    if (!tile_is_ready_to_draw || tile_version.requires_resource()) {
-      // The bin that the tile would have if the GPU memory manager had
-      // a maximally permissive policy, send to the GPU memory manager
-      // to determine policy.
-      ManagedTileBin gpu_memmgr_stats_bin = std::min(active_bin, pending_bin);
-      if ((gpu_memmgr_stats_bin == NOW_BIN) ||
-          (gpu_memmgr_stats_bin == NOW_AND_READY_TO_DRAW_BIN))
-        memory_required_bytes_ += BytesConsumedIfAllocated(tile);
-      if (gpu_memmgr_stats_bin != NEVER_BIN)
-        memory_nice_to_have_bytes_ += BytesConsumedIfAllocated(tile);
-    }
-
-    ManagedTileBin tree_bin[NUM_TREES];
-    tree_bin[ACTIVE_TREE] = kBinPolicyMap[memory_policy][active_bin];
-    tree_bin[PENDING_TREE] = kBinPolicyMap[memory_policy][pending_bin];
-
-    // Adjust pending bin state for low res tiles. This prevents pending tree
-    // low-res tiles from being initialized before high-res tiles.
-    if (pending_is_low_res)
-      tree_bin[PENDING_TREE] = std::max(tree_bin[PENDING_TREE], EVENTUALLY_BIN);
-
-    TilePriority tile_priority;
-    switch (tree_priority) {
-      case SAME_PRIORITY_FOR_BOTH_TREES:
-        mts.bin = std::min(tree_bin[ACTIVE_TREE], tree_bin[PENDING_TREE]);
-        tile_priority = tile->combined_priority();
-        break;
-      case SMOOTHNESS_TAKES_PRIORITY:
-        mts.bin = tree_bin[ACTIVE_TREE];
-        tile_priority = active_priority;
-        break;
-      case NEW_CONTENT_TAKES_PRIORITY:
-        mts.bin = tree_bin[PENDING_TREE];
-        tile_priority = pending_priority;
-        break;
-    }
-
-    // Bump up the priority if we determined it's NEVER_BIN on one tree,
-    // but is still required on the other tree.
-    bool is_in_never_bin_on_both_trees = tree_bin[ACTIVE_TREE] == NEVER_BIN &&
-                                         tree_bin[PENDING_TREE] == NEVER_BIN;
-
-    if (mts.bin == NEVER_BIN && !is_in_never_bin_on_both_trees)
-      mts.bin = tile_is_active ? AT_LAST_AND_ACTIVE_BIN : AT_LAST_BIN;
-
-    mts.resolution = tile_priority.resolution;
-    mts.priority_bin = tile_priority.priority_bin;
-    mts.distance_to_visible = tile_priority.distance_to_visible;
-    mts.required_for_activation = tile_priority.required_for_activation;
-
-    mts.visible_and_ready_to_draw =
-        tree_bin[ACTIVE_TREE] == NOW_AND_READY_TO_DRAW_BIN;
-
-    // Tiles that are required for activation shouldn't be in NEVER_BIN unless
-    // smoothness takes priority or memory policy allows nothing to be
-    // initialized.
-    DCHECK(!mts.required_for_activation || mts.bin != NEVER_BIN ||
-           tree_priority == SMOOTHNESS_TAKES_PRIORITY ||
-           memory_policy == ALLOW_NOTHING);
-
-    // If the tile is in NEVER_BIN and it does not have an active task, then we
-    // can release the resources early. If it does have the task however, we
-    // should keep it in the prioritized tile set to ensure that AssignGpuMemory
-    // can visit it.
-    if (mts.bin == NEVER_BIN &&
-        !mts.tile_versions[mts.raster_mode].raster_task_) {
-      FreeResourcesForTileAndNotifyClientIfTileWasReadyToDraw(tile);
-      continue;
-    }
-
-    // Insert the tile into a priority set.
-    tiles->InsertTile(tile, mts.bin);
-  }
-}
-
 void TileManager::ManageTiles(const GlobalStateThatImpactsTilePriority& state) {
   TRACE_EVENT0("cc", "TileManager::ManageTiles");
 
   // Update internal state.

[reveman, 2014/06/18 03:35:42]

Silly comment. Keep it if you like but I don't mind if you remove it.

[vmpstr, 2014/06/18 06:45:00]

Removed.

-  if (state != global_state_) {
-    global_state_ = state;
-    prioritized_tiles_dirty_ = true;
-  }
+  global_state_ = state;
+
+  // TODO(vmpstr): See if we still need to keep tiles alive when layers release
+  // them.
+  CleanUpReleasedTiles();

[reveman, 2014/06/18 03:35:42]

Note: we should instead call this after CheckForCompletedTasks() if we keep
around released tiles until they have no raster task. No need to change anything
in this patch though.

[vmpstr, 2014/06/18 06:45:00]

I've moved it. The previous code would effectively call it after as well, so
it's better for consistency.

 
   // We need to call CheckForCompletedTasks() once in-between each call
   // to ScheduleTasks() to prevent canceled tasks from being scheduled.
   if (!did_check_for_completed_tasks_since_last_schedule_tasks_) {
     rasterizer_->CheckForCompletedTasks();
     did_check_for_completed_tasks_since_last_schedule_tasks_ = true;
   }
 
-  UpdatePrioritizedTileSetIfNeeded();
-
   TileVector tiles_that_need_to_be_rasterized;
-  AssignGpuMemoryToTiles(&prioritized_tiles_,
-                         &tiles_that_need_to_be_rasterized);
+  AssignGpuMemoryToTiles(&tiles_that_need_to_be_rasterized);
 
   // Finally, schedule rasterizer tasks.
   ScheduleTasks(tiles_that_need_to_be_rasterized);
 
   TRACE_EVENT_INSTANT1("cc",
                        "DidManage",
                        TRACE_EVENT_SCOPE_THREAD,
                        "state",
                        TracedValue::FromValue(BasicStateAsValue().release()));
 
@@ skipping 21 matching lines @@
 
   bool did_initialize_visible_tile = did_initialize_visible_tile_;
   did_initialize_visible_tile_ = false;
   return did_initialize_visible_tile;
 }
 
 void TileManager::GetMemoryStats(size_t* memory_required_bytes,
                                  size_t* memory_nice_to_have_bytes,
                                  size_t* memory_allocated_bytes,
                                  size_t* memory_used_bytes) const {
-  *memory_required_bytes = memory_required_bytes_;
-  *memory_nice_to_have_bytes = memory_nice_to_have_bytes_;
-  *memory_allocated_bytes = resource_pool_->total_memory_usage_bytes();
-  *memory_used_bytes = resource_pool_->acquired_memory_usage_bytes();
+  // TODO(vmpstr): Remove this function.

[vmpstr, 2014/06/17 23:48:18]

I'll try and remove this in parallel with this patch. This is no longer used as
of https://codereview.chromium.org/338593003

[reveman, 2014/06/18 03:35:42]

Great! Please remove the function in this or a separate patch so it's clear what
code is left in case it affects this patch.

[vmpstr, 2014/06/18 06:45:00]

That's here https://codereview.chromium.org/342483007/ I just have to test it a
bit more before publishing.

+  *memory_required_bytes = 0;
+  *memory_nice_to_have_bytes = 0;
+  *memory_allocated_bytes = 0;
+  *memory_used_bytes = 0;
 }
 
 scoped_ptr<base::Value> TileManager::BasicStateAsValue() const {
   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
   state->SetInteger("tile_count", tiles_.size());
   state->Set("global_state", global_state_.AsValue().release());
   state->Set("memory_requirements", GetMemoryRequirementsAsValue().release());
   return state.PassAs<base::Value>();
 }
 
@@ skipping 17 matching lines @@
                  &memory_allocated_bytes,
                  &memory_used_bytes);
   requirements->SetInteger("memory_required_bytes", memory_required_bytes);
   requirements->SetInteger("memory_nice_to_have_bytes",
                            memory_nice_to_have_bytes);
   requirements->SetInteger("memory_allocated_bytes", memory_allocated_bytes);
   requirements->SetInteger("memory_used_bytes", memory_used_bytes);
   return requirements.PassAs<base::Value>();
 }
 
+bool TileManager::FreeTileResourcesUntilUsageIsWithinLimit(
+    EvictionTileIterator* iterator,
+    const MemoryUsage& limit,
+    MemoryUsage* usage) {
+  while (usage->Exceeds(limit)) {
+    if (!*iterator)
+      return false;
+
+    Tile* tile = **iterator;
+    *usage -= MemoryUsage::FromTile(tile);
+
+    FreeResourcesForTileAndNotifyClientIfTileWasReadyToDraw(tile);
+    ++(*iterator);
+  }
+  return true;
+}
+
+bool TileManager::FreeTileResourcesWithLowerPriorityUntilUsageIsWithinLimit(
+    EvictionTileIterator* iterator,
+    const MemoryUsage& limit,
+    const TilePriority& max_priority,

[reveman, 2014/06/18 03:35:42]

other_priority

[vmpstr, 2014/06/18 06:45:00]

Done.

+    MemoryUsage* usage) {
+  while (usage->Exceeds(limit)) {
+    if (!*iterator)
+      return false;
+
+    Tile* tile = **iterator;
+    if (!max_priority.IsHigherPriorityThan(
+            tile->priority_for_tree_priority(global_state_.tree_priority))) {
+      return false;
+    }
+
+    *usage -= MemoryUsage::FromTile(tile);

[reveman, 2014/06/18 03:35:42]

nit: please use blank lines consistently. why group this line with "Tile* tile =
**iterator;" in the function above but with "FreeResourcesFo.." here instead?

[vmpstr, 2014/06/18 06:45:01]

Done.

+    FreeResourcesForTileAndNotifyClientIfTileWasReadyToDraw(tile);
+    ++(*iterator);
+  }
+  return true;
+}
+
+bool TileManager::TilePriorityViolatesMemoryPolicy(
+    const TilePriority& priority) {
+  switch (global_state_.memory_limit_policy) {
+    case ALLOW_NOTHING:
+      return true;
+    case ALLOW_ABSOLUTE_MINIMUM:
+      return priority.priority_bin > TilePriority::NOW;
+    case ALLOW_PREPAINT_ONLY:
+      return priority.priority_bin > TilePriority::SOON;
+    case ALLOW_ANYTHING:
+      return priority.distance_to_visible ==
+             std::numeric_limits<float>::infinity();
+  }
+  NOTREACHED();
+  return true;
+}
+
 void TileManager::AssignGpuMemoryToTiles(
-    PrioritizedTileSet* tiles,
     TileVector* tiles_that_need_to_be_rasterized) {
   TRACE_EVENT0("cc", "TileManager::AssignGpuMemoryToTiles");
 
   // Maintain the list of released resources that can potentially be re-used
   // or deleted.
   // If this operation becomes expensive too, only do this after some
   // resource(s) was returned. Note that in that case, one also need to
   // invalidate when releasing some resource from the pool.
   resource_pool_->CheckBusyResources();
 
   // Now give memory out to the tiles until we're out, and build
   // the needs-to-be-rasterized queue.
   all_tiles_that_need_to_be_rasterized_have_memory_ = true;
-  all_tiles_required_for_activation_have_memory_ = true;
 
-  // Cast to prevent overflow.
-  int64 soft_bytes_available =
-      static_cast<int64>(bytes_releasable_) +
-      static_cast<int64>(global_state_.soft_memory_limit_in_bytes) -
-      static_cast<int64>(resource_pool_->acquired_memory_usage_bytes());
-  int64 hard_bytes_available =
-      static_cast<int64>(bytes_releasable_) +
-      static_cast<int64>(global_state_.hard_memory_limit_in_bytes) -
-      static_cast<int64>(resource_pool_->acquired_memory_usage_bytes());
-  int resources_available = resources_releasable_ +
-                            global_state_.num_resources_limit -
-                            resource_pool_->acquired_resource_count();
-  size_t soft_bytes_allocatable =
-      std::max(static_cast<int64>(0), soft_bytes_available);
-  size_t hard_bytes_allocatable =
-      std::max(static_cast<int64>(0), hard_bytes_available);
-  size_t resources_allocatable = std::max(0, resources_available);
+  MemoryUsage hard_memory_limit(global_state_.hard_memory_limit_in_bytes,
+                                global_state_.num_resources_limit);
+  MemoryUsage soft_memory_limit(global_state_.soft_memory_limit_in_bytes,
+                                global_state_.num_resources_limit);
+  MemoryUsage memory_usage(resource_pool_->acquired_memory_usage_bytes(),
+                           resource_pool_->acquired_resource_count());
 
-  size_t bytes_that_exceeded_memory_budget = 0;
-  size_t soft_bytes_left = soft_bytes_allocatable;
-  size_t hard_bytes_left = hard_bytes_allocatable;
+  EvictionTileIterator eviction_it(this, global_state_.tree_priority);
 
-  size_t resources_left = resources_allocatable;
+  FreeTileResourcesUntilUsageIsWithinLimit(
+      &eviction_it, hard_memory_limit, &memory_usage);

[reveman, 2014/06/18 03:35:42]

Why this call here rather than after the loop? Makes me wonder if it has to
happen before the loop.. If you're doing it after then it sort of becomes a noop
if usage has already been reduced as a result of calling
FreeTileResourcesWithLowerPriorityUntilUsageIsWithinLimit, which is almost
always going to be the case, right? Maybe at least worth a comment if not moved.

[vmpstr, 2014/06/18 06:45:00]

I think this has to happen before. Check out the latest patch. I mean if we
can't reduce usage to be within memory limit before the loop, then I think we
have to cancel the currently running tasks, right? Currently, the problem is
that we would finish the raster (and all of the scheduled but not running tasks)
before releasing that memory, which I think is wrong. What do you think?

[reveman, 2014/06/18 16:41:09]

Ah, I think I understand. See my comments on latest patch.

+
   bool oomed_soft = false;

[reveman, 2014/06/18 03:35:42]

I don't think you need this anymore. You break out of the loop whenever you set
it.

[vmpstr, 2014/06/18 06:45:00]

Done.

   bool oomed_hard = false;
-  bool have_hit_soft_memory = false;  // Soft memory comes after hard.
 
   unsigned schedule_priority = 1u;
-  for (PrioritizedTileSet::Iterator it(tiles, true); it; ++it) {
+  for (RasterTileIterator it(this, global_state_.tree_priority); it; ++it) {
     Tile* tile = *it;
+    TilePriority priority =
+        tile->priority_for_tree_priority(global_state_.tree_priority);
+
+    if (TilePriorityViolatesMemoryPolicy(priority))
+      break;
+
     ManagedTileState& mts = tile->managed_state();
-
     mts.scheduled_priority = schedule_priority++;
-
     mts.raster_mode = tile->DetermineOverallRasterMode();
-
     ManagedTileState::TileVersion& tile_version =
         mts.tile_versions[mts.raster_mode];
 
-    // If this tile doesn't need a resource, then nothing to do.
-    if (!tile_version.requires_resource())
-      continue;
+    DCHECK(!tile_version.IsReadyToDraw());
 
-    // If the tile is not needed, free it up.
-    if (mts.bin == NEVER_BIN) {
-      FreeResourcesForTileAndNotifyClientIfTileWasReadyToDraw(tile);
-      continue;
-    }
+    // If the tile version is not in flight, then we'll have to pay to create a
+    // new task. Additionally, we might have to evict some tiles for this to
+    // happen.
+    if (!tile_version.raster_task_) {
+      MemoryUsage additional_memory_required = MemoryUsage::FromConfig(
+          tile->size(), resource_pool_->resource_format());
 
-    const bool tile_uses_hard_limit = mts.bin <= NOW_BIN;
-    const size_t bytes_if_allocated = BytesConsumedIfAllocated(tile);
-    const size_t tile_bytes_left =
-        (tile_uses_hard_limit) ? hard_bytes_left : soft_bytes_left;
+      bool tile_uses_hard_limit = priority.priority_bin == TilePriority::NOW;
+      MemoryUsage& memory_limit =
+          tile_uses_hard_limit ? hard_memory_limit : soft_memory_limit;
 
-    // Hard-limit is reserved for tiles that would cause a calamity
-    // if they were to go away, so by definition they are the highest
-    // priority memory, and must be at the front of the list.
-    DCHECK(!(have_hit_soft_memory && tile_uses_hard_limit));
-    have_hit_soft_memory |= !tile_uses_hard_limit;
-
-    size_t tile_bytes = 0;
-    size_t tile_resources = 0;
-
-    // It costs to maintain a resource.
-    for (int mode = 0; mode < NUM_RASTER_MODES; ++mode) {
-      if (mts.tile_versions[mode].resource_) {
-        tile_bytes += bytes_if_allocated;
-        tile_resources++;
+      bool memory_reduced_successfully =
+          FreeTileResourcesWithLowerPriorityUntilUsageIsWithinLimit(
+              &eviction_it,
+              memory_limit - additional_memory_required,
+              priority,
+              &memory_usage);
+      if (memory_reduced_successfully) {
+        memory_usage += additional_memory_required;

[reveman, 2014/06/18 03:35:42]

hm, this might adjust memory_usage even if the tile can't be scheduled. ie. we
might have reached kScheduledRasterTasksLimit. should we add up the usage at the
time we push the tiles to the need_to_be_rasterized queue?

also, maybe change the name of this variable to something like
"memory_usage_required_by_tile_to_be_scheduled" to make it really clear what it
is and what's happening when using it.

[vmpstr, 2014/06/18 06:45:01]

Done.

+      } else {
+        oomed_soft = true;
+        if (tile_uses_hard_limit)
+          oomed_hard = true;
       }
     }
 
-    // Allow lower priority tiles with initialized resources to keep
-    // their memory by only assigning memory to new raster tasks if
-    // they can be scheduled.
-    bool reached_scheduled_raster_tasks_limit =
-        tiles_that_need_to_be_rasterized->size() >= kScheduledRasterTasksLimit;
-    if (!reached_scheduled_raster_tasks_limit) {
-      // If we don't have the required version, and it's not in flight
-      // then we'll have to pay to create a new task.
-      if (!tile_version.resource_ && !tile_version.raster_task_) {
-        tile_bytes += bytes_if_allocated;
-        tile_resources++;
-      }
-    }
-
-    // Tile is OOM.
-    if (tile_bytes > tile_bytes_left || tile_resources > resources_left) {
-      bool was_ready_to_draw = tile->IsReadyToDraw();
-
-      FreeResourcesForTile(tile);
-
-      // This tile was already on screen and now its resources have been
-      // released. In order to prevent checkerboarding, set this tile as
-      // rasterize on demand immediately.
-      if (mts.visible_and_ready_to_draw)
-        tile_version.set_rasterize_on_demand();
-
-      if (was_ready_to_draw)
-        client_->NotifyTileStateChanged(tile);
-
-      oomed_soft = true;
-      if (tile_uses_hard_limit) {
-        oomed_hard = true;
-        bytes_that_exceeded_memory_budget += tile_bytes;
-      }
-    } else {
-      resources_left -= tile_resources;
-      hard_bytes_left -= tile_bytes;
-      soft_bytes_left =
-          (soft_bytes_left > tile_bytes) ? soft_bytes_left - tile_bytes : 0;
-      if (tile_version.resource_)
-        continue;
-    }
-
-    DCHECK(!tile_version.resource_);
-
     // Tile shouldn't be rasterized if |tiles_that_need_to_be_rasterized|
     // has reached it's limit or we've failed to assign gpu memory to this
     // or any higher priority tile. Preventing tiles that fit into memory
     // budget to be rasterized when higher priority tile is oom is
     // important for two reasons:
     // 1. Tile size should not impact raster priority.
     // 2. Tiles with existing raster task could otherwise incorrectly
     //    be added as they are not affected by |bytes_allocatable|.

[reveman, 2014/06/18 03:35:42]

I don't think this comment apply anymore now that we can simply break out of the
loop when failing to schedule a tile. I think it can be removed.

[vmpstr, 2014/06/18 06:45:00]

Done.

     bool can_schedule_tile =
-        !oomed_soft && !reached_scheduled_raster_tasks_limit;
+        !oomed_soft &&
+        tiles_that_need_to_be_rasterized->size() < kScheduledRasterTasksLimit;

[reveman, 2014/06/18 03:35:42]

I wonder if some of this can be moved up to make this even cleaner and represent
the intent of this loop better. Something like this maybe:

{
  Tile* tile = *it;

  if (tiles_that_need_to_be_rasterized->size() >=
          kScheduledRasterTasksLimit) {
    all_tiles_that_need_to_be_rasterized_are_scheduled_ = false;
    break;
  }

  if (!raster_task) {
    FreeTileResourcesWithLowerPrio...

    if (!memory_usage_successfully_reduced_for_tile_to_be_scheduled) {
      all_tiles_that_need_to_be_rasterized_are_scheduled_ = false;
      break;
    }
    memory_usage += memory_usage_required_by_tile_to_be_scheduled;
  }

  tiles_that_need_to_be_rasterized->push_back(tile);
}

This way we also don't evict tiles unnecessarily unless we're actually allowed
to schedule a new tile.

[vmpstr, 2014/06/18 06:45:00]

Done (more or less?). I think it kind of naturally evolved to be this after I
did the rest of the updates.

 
     if (!can_schedule_tile) {
       all_tiles_that_need_to_be_rasterized_have_memory_ = false;
-      if (tile->required_for_activation())
-        all_tiles_required_for_activation_have_memory_ = false;
-      it.DisablePriorityOrdering();
-      continue;
+      break;
     }
 
     tiles_that_need_to_be_rasterized->push_back(tile);
   }
 
   // OOM reporting uses hard-limit, soft-OOM is normal depending on limit.
   ever_exceeded_memory_budget_ |= oomed_hard;
   if (ever_exceeded_memory_budget_) {
-    TRACE_COUNTER_ID2("cc",
+    TRACE_COUNTER_ID1("cc",
                       "over_memory_budget",
                       this,
-                      "budget",
-                      global_state_.hard_memory_limit_in_bytes,
-                      "over",
-                      bytes_that_exceeded_memory_budget);
+                      global_state_.hard_memory_limit_in_bytes);

[reveman, 2014/06/18 03:35:42]

does this counter still make sense? how is showing a counter of
hard_memory_limit_in_bytes useful only after we've failed to assign memory to a
visible tile?

[vmpstr, 2014/06/18 06:45:01]

Removed.

   }
   memory_stats_from_last_assign_.total_budget_in_bytes =
       global_state_.hard_memory_limit_in_bytes;
   memory_stats_from_last_assign_.bytes_allocated =
-      hard_bytes_allocatable - hard_bytes_left;
+      resource_pool_->acquired_memory_usage_bytes();
   memory_stats_from_last_assign_.bytes_unreleasable =
-      resource_pool_->acquired_memory_usage_bytes() - bytes_releasable_;
-  memory_stats_from_last_assign_.bytes_over = bytes_that_exceeded_memory_budget;
+      memory_usage.memory_bytes() -
+      resource_pool_->acquired_memory_usage_bytes();

[reveman, 2014/06/18 03:35:42]

not sure this is completely true (as it doesn't include currently scheduled
tasks) but I'm also not sure how useful this value really is to report. this
looks like another chunk of code that doesn't belong in the tile manager.

[vmpstr, 2014/06/18 06:45:00]

Yeah, I agree. However, I would prefer to keep it here for now. The reasoning
behind the math is that after all of the rasterization is scheduled (or even
after this run actually schedules the tasks), the memory is correct, which I
think is good enough for the hud.

[reveman, 2014/06/18 16:41:09]

I don't think it will be correct. memory_usage and acquired_memory_usage_bytes
both include tiles scheduled by the previous call to AssignGpuMem but not this
call. That memory is unreleasable but not accounted for here as this math only
considers the memory for tiles scheduled in this AssignGpuMem call as
unreleasable.

Unless my reasoning above is incorrect, I suggest that we simply remove the
bytes_unreleasable field from memory_stats struct.

+  memory_stats_from_last_assign_.had_enough_memory = !oomed_hard;
 }
 
 void TileManager::FreeResourceForTile(Tile* tile, RasterMode mode) {
   ManagedTileState& mts = tile->managed_state();
-  if (mts.tile_versions[mode].resource_) {
+  if (mts.tile_versions[mode].resource_)
     resource_pool_->ReleaseResource(mts.tile_versions[mode].resource_.Pass());
-
-    DCHECK_GE(bytes_releasable_, BytesConsumedIfAllocated(tile));
-    DCHECK_GE(resources_releasable_, 1u);
-
-    bytes_releasable_ -= BytesConsumedIfAllocated(tile);
-    --resources_releasable_;
-  }
 }
 
 void TileManager::FreeResourcesForTile(Tile* tile) {
   for (int mode = 0; mode < NUM_RASTER_MODES; ++mode) {
     FreeResourceForTile(tile, static_cast<RasterMode>(mode));
   }
 }
 
 void TileManager::FreeUnusedResourcesForTile(Tile* tile) {
   DCHECK(tile->IsReadyToDraw());
@@ skipping 181 matching lines @@
   }
 
   ++update_visible_tiles_stats_.completed_count;
 
   if (analysis.is_solid_color) {
     tile_version.set_solid_color(analysis.solid_color);
     resource_pool_->ReleaseResource(resource.Pass());
   } else {
     tile_version.set_use_resource();
     tile_version.resource_ = resource.Pass();
-
-    bytes_releasable_ += BytesConsumedIfAllocated(tile);
-    ++resources_releasable_;
   }
 
   FreeUnusedResourcesForTile(tile);
   if (tile->priority(ACTIVE_TREE).distance_to_visible == 0.f)
     did_initialize_visible_tile_ = true;
 
   client_->NotifyTileStateChanged(tile);
 }
 
 scoped_refptr<Tile> TileManager::CreateTile(PicturePileImpl* picture_pile,
@@ skipping 10 matching lines @@
                                                          content_rect,
                                                          opaque_rect,
                                                          contents_scale,
                                                          layer_id,
                                                          source_frame_number,
                                                          flags));
   DCHECK(tiles_.find(tile->id()) == tiles_.end());
 
   tiles_[tile->id()] = tile;
   used_layer_counts_[tile->layer_id()]++;
-  prioritized_tiles_dirty_ = true;
   return tile;
 }
 
 void TileManager::GetPairedPictureLayers(
     std::vector<PairedPictureLayer>* paired_layers) const {
   const std::vector<PictureLayerImpl*>& layers = client_->GetPictureLayers();
 
   paired_layers->clear();
   // Reserve a maximum possible paired layers.
   paired_layers->reserve(layers.size());
@@ skipping 432 matching lines @@
 void TileManager::CheckIfReadyToActivate() {
   TRACE_EVENT0("cc", "TileManager::CheckIfReadyToActivate");
 
   rasterizer_->CheckForCompletedTasks();
   did_check_for_completed_tasks_since_last_schedule_tasks_ = true;
 
   if (IsReadyToActivate())
     client_->NotifyReadyToActivate();
 }
 
+TileManager::MemoryUsage::MemoryUsage() : memory_bytes_(0), resource_count_(0) {
+}
+
+TileManager::MemoryUsage::MemoryUsage(int64 memory_bytes, int resource_count)
+    : memory_bytes_(memory_bytes), resource_count_(resource_count) {
+}
+
+// static
+TileManager::MemoryUsage TileManager::MemoryUsage::FromConfig(
+    const gfx::Size& size,
+    ResourceFormat format) {
+  return MemoryUsage(Resource::MemorySizeBytes(size, format), 1);
+}
+
+// static
+TileManager::MemoryUsage TileManager::MemoryUsage::FromTile(const Tile* tile) {
+  const ManagedTileState& mts = tile->managed_state();
+  MemoryUsage total_usage;
+  for (int mode = 0; mode < NUM_RASTER_MODES; ++mode) {
+    if (mts.tile_versions[mode].resource_) {
+      total_usage += MemoryUsage::FromConfig(
+          tile->size(), mts.tile_versions[mode].resource_->format());
+    }
+  }
+  return total_usage;
+}
+
+TileManager::MemoryUsage& TileManager::MemoryUsage::operator+=(
+    const MemoryUsage& other) {
+  memory_bytes_ += other.memory_bytes_;
+  resource_count_ += other.resource_count_;
+  return *this;
+}
+
+TileManager::MemoryUsage& TileManager::MemoryUsage::operator-=(
+    const MemoryUsage& other) {
+  memory_bytes_ -= other.memory_bytes_;
+  resource_count_ -= other.resource_count_;
+  return *this;
+}
+
+TileManager::MemoryUsage TileManager::MemoryUsage::operator-(
+    const MemoryUsage& other) {
+  MemoryUsage result = *this;
+  result -= other;
+  return result;
+}
+
+bool TileManager::MemoryUsage::Exceeds(const MemoryUsage& limit) const {
+  return memory_bytes_ > limit.memory_bytes_ ||
+         resource_count_ > limit.resource_count_;
+}
+
 }  // namespace cc