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// 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/resource_pool.h"
#include "cc/resources/resource_provider.h"
#include "cc/resources/scoped_resource.h"
namespace cc {
ResourcePool::ResourcePool(ResourceProvider* resource_provider,
GLenum target,
ResourceFormat format)
: resource_provider_(resource_provider),
target_(target),
format_(format),
max_memory_usage_bytes_(0),
max_unused_memory_usage_bytes_(0),
max_resource_count_(0),
memory_usage_bytes_(0),
unused_memory_usage_bytes_(0),
resource_count_(0) {
}
ResourcePool::~ResourcePool() {
while (!busy_resources_.empty()) {
DidFinishUsingResource(busy_resources_.front());
busy_resources_.pop_front();
}
SetResourceUsageLimits(0, 0, 0);
DCHECK_EQ(0u, unused_resources_.size());
DCHECK_EQ(0u, memory_usage_bytes_);
DCHECK_EQ(0u, unused_memory_usage_bytes_);
DCHECK_EQ(0u, resource_count_);
}
scoped_ptr<ScopedResource> ResourcePool::AcquireResource(gfx::Size size) {
for (ResourceList::iterator it = unused_resources_.begin();
it != unused_resources_.end(); ++it) {
ScopedResource* resource = *it;
DCHECK(resource_provider_->CanLockForWrite(resource->id()));
if (resource->size() != size)
continue;
unused_resources_.erase(it);
unused_memory_usage_bytes_ -= resource->bytes();
return make_scoped_ptr(resource);
}
// Create new resource.
scoped_ptr<ScopedResource> resource =
ScopedResource::Create(resource_provider_);
resource->AllocateManaged(size, target_, format_);
// Extend all read locks on all resources until the resource is
// finished being used, such that we know when resources are
// truly safe to recycle.
resource_provider_->EnableReadLockFences(resource->id(), true);
memory_usage_bytes_ += resource->bytes();
++resource_count_;
return resource.Pass();
}
void ResourcePool::ReleaseResource(scoped_ptr<ScopedResource> resource) {
busy_resources_.push_back(resource.release());
}
void ResourcePool::SetResourceUsageLimits(
size_t max_memory_usage_bytes,
size_t max_unused_memory_usage_bytes,
size_t max_resource_count) {
max_memory_usage_bytes_ = max_memory_usage_bytes;
max_unused_memory_usage_bytes_ = max_unused_memory_usage_bytes;
max_resource_count_ = max_resource_count;
ReduceResourceUsage();
}
void ResourcePool::ReduceResourceUsage() {
while (!unused_resources_.empty()) {
if (!ResourceUsageTooHigh())
break;
// LRU eviction pattern. Most recently used might be blocked by
// a read lock fence but it's still better to evict the least
// recently used as it prevents a resource that is hard to reuse
// because of unique size from being kept around. Resources that
// can't be locked for write might also not be truly free-able.
// We can free the resource here but it doesn't mean that the
// memory is necessarily returned to the OS.
ScopedResource* resource = unused_resources_.front();
unused_resources_.pop_front();
memory_usage_bytes_ -= resource->bytes();
unused_memory_usage_bytes_ -= resource->bytes();
--resource_count_;
delete resource;
}
}
bool ResourcePool::ResourceUsageTooHigh() {
if (resource_count_ > max_resource_count_)
return true;
if (memory_usage_bytes_ > max_memory_usage_bytes_)
return true;
if (unused_memory_usage_bytes_ > max_unused_memory_usage_bytes_)
return true;
return false;
}
void ResourcePool::CheckBusyResources() {
ResourceList::iterator it = busy_resources_.begin();
while (it != busy_resources_.end()) {
ScopedResource* resource = *it;
if (resource_provider_->CanLockForWrite(resource->id())) {
DidFinishUsingResource(resource);
it = busy_resources_.erase(it);
} else {
++it;
}
}
}
void ResourcePool::DidFinishUsingResource(ScopedResource* resource) {
unused_memory_usage_bytes_ += resource->bytes();
unused_resources_.push_back(resource);
}
} // namespace cc
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