/*
 * Copyright (C) 2017 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#include "Scavenger.h"

#include "Heap.h"
#include <thread>

namespace bmalloc {

Scavenger::Scavenger(std::lock_guard<StaticMutex>&)
{
#if BOS(DARWIN)
    auto queue = dispatch_queue_create("WebKit Malloc Memory Pressure Handler", DISPATCH_QUEUE_SERIAL);
    m_pressureHandlerDispatchSource = dispatch_source_create(DISPATCH_SOURCE_TYPE_MEMORYPRESSURE, 0, DISPATCH_MEMORYPRESSURE_CRITICAL, queue);
    dispatch_source_set_event_handler(m_pressureHandlerDispatchSource, ^{
        scavenge();
    });
    dispatch_resume(m_pressureHandlerDispatchSource);
    dispatch_release(queue);
#endif
}

void Scavenger::scavenge()
{
    std::lock_guard<StaticMutex> lock(Heap::mutex());
    for (unsigned i = numHeaps; i--;)
        PerProcess<PerHeapKind<Heap>>::get()->at(i).scavenge(lock);
}

} // namespace bmalloc