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https://github.com/RGBCube/serenity
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beaec6bd2d
This caused us to report one purged page per occurrence of the shared zero page in a purgeable memory region, despite it being a no-op. Thanks to Sergey for spotting the bad assertion removal that led to this being found!
90 lines
2.7 KiB
C++
90 lines
2.7 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <Kernel/VM/MemoryManager.h>
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#include <Kernel/VM/PhysicalPage.h>
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#include <Kernel/VM/PurgeableVMObject.h>
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namespace Kernel {
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NonnullRefPtr<PurgeableVMObject> PurgeableVMObject::create_with_size(size_t size)
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{
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return adopt(*new PurgeableVMObject(size));
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}
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PurgeableVMObject::PurgeableVMObject(size_t size)
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: AnonymousVMObject(size)
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{
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}
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PurgeableVMObject::PurgeableVMObject(const PurgeableVMObject& other)
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: AnonymousVMObject(other)
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{
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}
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PurgeableVMObject::~PurgeableVMObject()
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{
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}
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NonnullRefPtr<VMObject> PurgeableVMObject::clone()
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{
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return adopt(*new PurgeableVMObject(*this));
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}
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int PurgeableVMObject::purge()
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{
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LOCKER(m_paging_lock);
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return purge_impl();
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}
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int PurgeableVMObject::purge_with_interrupts_disabled(Badge<MemoryManager>)
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{
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ASSERT_INTERRUPTS_DISABLED();
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if (m_paging_lock.is_locked())
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return 0;
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return purge_impl();
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}
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int PurgeableVMObject::purge_impl()
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{
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if (!m_volatile)
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return 0;
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int purged_page_count = 0;
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for (size_t i = 0; i < m_physical_pages.size(); ++i) {
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if (m_physical_pages[i] && !m_physical_pages[i]->is_shared_zero_page())
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++purged_page_count;
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m_physical_pages[i] = MM.shared_zero_page();
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}
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m_was_purged = true;
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for_each_region([&](auto& region) {
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region.remap();
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});
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return purged_page_count;
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}
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}
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