ladybird/Kernel/Syscalls/purge.cpp

/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 * 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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT HOLDER 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 <AK/NonnullRefPtrVector.h>
#include <Kernel/Process.h>
#include <Kernel/VM/AnonymousVMObject.h>
#include <Kernel/VM/InodeVMObject.h>
#include <Kernel/VM/MemoryManager.h>

namespace Kernel {

int Process::sys$purge(int mode)
{
    REQUIRE_NO_PROMISES;
    if (!is_superuser())
        return -EPERM;
    int purged_page_count = 0;
    if (mode & PURGE_ALL_VOLATILE) {
        NonnullRefPtrVector<AnonymousVMObject> vmobjects;
        {
            InterruptDisabler disabler;
            MM.for_each_vmobject([&](auto& vmobject) {
                if (vmobject.is_anonymous())
                    vmobjects.append(vmobject);
                return IterationDecision::Continue;
            });
        }
        for (auto& vmobject : vmobjects) {
            purged_page_count += vmobject.purge();
        }
    }
    if (mode & PURGE_ALL_CLEAN_INODE) {
        NonnullRefPtrVector<InodeVMObject> vmobjects;
        {
            InterruptDisabler disabler;
            MM.for_each_vmobject([&](auto& vmobject) {
                if (vmobject.is_inode())
                    vmobjects.append(static_cast<InodeVMObject&>(vmobject));
                return IterationDecision::Continue;
            });
        }
        for (auto& vmobject : vmobjects) {
            purged_page_count += vmobject.release_all_clean_pages();
        }
    }
    return purged_page_count;
}

}