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b2a52f6208
By designating a committed page pool we can guarantee to have physical pages available for lazy allocation in mappings. However, when forking we will overcommit. The assumption is that worst-case it's better for the fork to die due to insufficient physical memory on COW access than the parent that created the region. If a fork wants to ensure that all memory is available (trigger a commit) then it can use madvise. This also means that fork now can gracefully fail if we don't have enough physical pages available.
67 lines
2.3 KiB
C++
67 lines
2.3 KiB
C++
/*
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* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
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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/ContiguousVMObject.h>
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#include <Kernel/VM/MemoryManager.h>
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#include <Kernel/VM/PhysicalPage.h>
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namespace Kernel {
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//#define CONTIGUOUS_VMOBJECT_DEBUG
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NonnullRefPtr<ContiguousVMObject> ContiguousVMObject::create_with_size(size_t size)
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{
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return adopt(*new ContiguousVMObject(size));
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}
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ContiguousVMObject::ContiguousVMObject(size_t size)
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: VMObject(size)
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{
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auto contiguous_physical_pages = MM.allocate_contiguous_supervisor_physical_pages(size);
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for (size_t i = 0; i < page_count(); i++) {
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physical_pages()[i] = contiguous_physical_pages[i];
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#ifdef CONTIGUOUS_VMOBJECT_DEBUG
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dbg() << "Contiguous page[" << i << "]: " << physical_pages()[i]->paddr();
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#endif
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}
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}
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ContiguousVMObject::ContiguousVMObject(const ContiguousVMObject& other)
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: VMObject(other)
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{
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}
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ContiguousVMObject::~ContiguousVMObject()
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{
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}
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RefPtr<VMObject> ContiguousVMObject::clone()
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{
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ASSERT_NOT_REACHED();
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}
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}
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