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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.
60 lines
2.2 KiB
C++
60 lines
2.2 KiB
C++
/*
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* Copyright (c) 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/FileSystem/Inode.h>
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#include <Kernel/VM/MemoryManager.h>
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#include <Kernel/VM/Region.h>
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#include <Kernel/VM/SharedInodeVMObject.h>
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namespace Kernel {
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NonnullRefPtr<SharedInodeVMObject> SharedInodeVMObject::create_with_inode(Inode& inode)
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{
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size_t size = inode.size();
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if (inode.shared_vmobject())
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return *inode.shared_vmobject();
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auto vmobject = adopt(*new SharedInodeVMObject(inode, size));
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vmobject->inode().set_shared_vmobject(*vmobject);
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return vmobject;
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}
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RefPtr<VMObject> SharedInodeVMObject::clone()
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{
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return adopt(*new SharedInodeVMObject(*this));
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}
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SharedInodeVMObject::SharedInodeVMObject(Inode& inode, size_t size)
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: InodeVMObject(inode, size)
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{
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}
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SharedInodeVMObject::SharedInodeVMObject(const SharedInodeVMObject& other)
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: InodeVMObject(other)
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{
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}
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}
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