Remove limit on number of resources in cc

android_webview/browser/global_tile_manager.cc

-// Copyright 2014 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 "android_webview/browser/global_tile_manager.h"
-#include "android_webview/browser/global_tile_manager_client.h"
-#include "base/lazy_instance.h"
-
-using content::SynchronousCompositorMemoryPolicy;
-
-namespace android_webview {
-
-namespace {
-
-base::LazyInstance<GlobalTileManager>::Leaky g_tile_manager =
-    LAZY_INSTANCE_INITIALIZER;
-
-// The soft limit of the number of file descriptors per process is 1024 on
-// Android and gralloc buffers may not be the only thing that uses file
-// descriptors. For each tile, there is a gralloc buffer backing it, which
-// uses 2 FDs.
-const size_t kNumTilesLimit = 450;
-
-}  // namespace
-
-// static
-GlobalTileManager* GlobalTileManager::GetInstance() {
-  return g_tile_manager.Pointer();
-}
-
-void GlobalTileManager::Remove(Key key) {
-  DCHECK(sequence_checker_.CalledOnValidSequencedThread());
-  DCHECK(mru_list_.end() != key);
-
-  total_allocated_tiles_ -= (*key)->GetMemoryPolicy().num_resources_limit;
-  mru_list_.erase(key);
-  DCHECK(IsConsistent());
-}
-
-size_t GlobalTileManager::Evict(size_t desired_num_tiles, Key key) {
-  DCHECK(sequence_checker_.CalledOnValidSequencedThread());
-  size_t total_evicted_tiles = 0;
-
-  // Evicts from the least recent drawn view, until the disired number of tiles
-  // can be reclaimed, or until we've evicted all inactive views.
-  ListType::reverse_iterator it;
-  for (it = mru_list_.rbegin(); it != mru_list_.rend(); it++) {
-    // key represents the view that requested the eviction, so we don't need to
-    // evict the requester itself. And we only evict the inactive views,
-    // which are all the views after the requester.
-    if (*it == *key)
-      break;
-
-    size_t evicted_tiles = (*it)->GetMemoryPolicy().num_resources_limit;
-    SynchronousCompositorMemoryPolicy zero_policy;
-    (*it)->SetMemoryPolicy(zero_policy, true);
-
-    total_evicted_tiles += evicted_tiles;
-    if (total_evicted_tiles >= desired_num_tiles)
-      break;
-  }
-
-  return total_evicted_tiles;
-}
-
-void GlobalTileManager::SetTileLimit(size_t num_tiles_limit) {
-  num_tiles_limit_ = num_tiles_limit;
-}
-
-void GlobalTileManager::RequestTiles(
-    SynchronousCompositorMemoryPolicy new_policy,
-    Key key) {
-  DCHECK(IsConsistent());
-  DCHECK(sequence_checker_.CalledOnValidSequencedThread());
-  size_t new_num_of_tiles = new_policy.num_resources_limit;
-  size_t old_num_of_tiles = (*key)->GetMemoryPolicy().num_resources_limit;
-  size_t num_of_active_views = std::distance(mru_list_.begin(), key) + 1;
-  size_t tiles_per_view_limit;
-  if (num_of_active_views == 0)
-    tiles_per_view_limit = num_tiles_limit_;
-  else
-    tiles_per_view_limit = num_tiles_limit_ / num_of_active_views;
-  new_num_of_tiles = std::min(new_num_of_tiles, tiles_per_view_limit);
-  size_t new_total_allocated_tiles =
-      total_allocated_tiles_ - old_num_of_tiles + new_num_of_tiles;
-  // Has enough tiles to satisfy the request.
-  if (new_total_allocated_tiles <= num_tiles_limit_) {
-    total_allocated_tiles_ = new_total_allocated_tiles;
-    new_policy.num_resources_limit = new_num_of_tiles;
-    (*key)->SetMemoryPolicy(new_policy, false);
-    return;
-  }
-
-  // Does not have enough tiles. Now evict other clients' tiles.
-  size_t tiles_left = num_tiles_limit_ - total_allocated_tiles_;
-
-  size_t evicted_tiles =
-      Evict(new_total_allocated_tiles - num_tiles_limit_, key);
-  if (evicted_tiles >= new_total_allocated_tiles - num_tiles_limit_) {
-    new_total_allocated_tiles -= evicted_tiles;
-    total_allocated_tiles_ = new_total_allocated_tiles;
-    new_policy.num_resources_limit = new_num_of_tiles;
-    (*key)->SetMemoryPolicy(new_policy, false);
-    return;
-  } else {
-    total_allocated_tiles_ = num_tiles_limit_;
-    new_policy.num_resources_limit =
-        tiles_left + old_num_of_tiles + evicted_tiles;
-    (*key)->SetMemoryPolicy(new_policy, false);
-    return;
-  }
-}
-
-GlobalTileManager::Key GlobalTileManager::PushBack(
-    GlobalTileManagerClient* client) {
-  DCHECK(sequence_checker_.CalledOnValidSequencedThread());
-  DCHECK(mru_list_.end() ==
-         std::find(mru_list_.begin(), mru_list_.end(), client));
-  mru_list_.push_back(client);
-  Key back = mru_list_.end();
-  back--;
-  return back;
-}
-
-void GlobalTileManager::DidUse(Key key) {
-  DCHECK(sequence_checker_.CalledOnValidSequencedThread());
-  DCHECK(mru_list_.end() != key);
-
-  mru_list_.splice(mru_list_.begin(), mru_list_, key);
-}
-
-GlobalTileManager::GlobalTileManager()
-    : num_tiles_limit_(kNumTilesLimit), total_allocated_tiles_(0) {
-}
-
-GlobalTileManager::~GlobalTileManager() {
-}
-
-bool GlobalTileManager::IsConsistent() const {
-  size_t total_tiles = 0;
-  ListType::const_iterator it;
-  for (it = mru_list_.begin(); it != mru_list_.end(); it++) {
-    total_tiles += (*it)->GetMemoryPolicy().num_resources_limit;
-  }
-
-  bool is_consistent = (total_tiles <= num_tiles_limit_ &&
-                        total_tiles == total_allocated_tiles_);
-
-  return is_consistent;
-}
-
-}  // namespace webview