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https://github.com/LadybirdBrowser/ladybird.git
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476f17b3f1
This implements memory commitments and lazy-allocation of committed memory.
101 lines
3.3 KiB
C++
101 lines
3.3 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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#pragma once
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#include <AK/OwnPtr.h>
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#include <AK/WeakPtr.h>
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#include <Kernel/VM/AnonymousVMObject.h>
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#include <Kernel/VM/MemoryManager.h>
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namespace Kernel {
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class SharedBuffer {
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private:
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struct Reference {
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Reference(ProcessID pid, unsigned count = 0)
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: pid(pid)
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, count(count)
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{
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}
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ProcessID pid;
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unsigned count { 0 };
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WeakPtr<Region> region;
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};
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public:
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SharedBuffer(int id, NonnullRefPtr<AnonymousVMObject>&& vmobject)
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: m_shbuf_id(id)
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, m_vmobject(move(vmobject))
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{
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#ifdef SHARED_BUFFER_DEBUG
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dbg() << "Created shared buffer " << m_shbuf_id << " of size " << m_vmobject->size();
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#endif
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}
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~SharedBuffer()
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{
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#ifdef SHARED_BUFFER_DEBUG
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dbg() << "Destroyed shared buffer " << m_shbuf_id << " of size " << size();
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#endif
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}
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void sanity_check(const char* what);
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bool is_shared_with(ProcessID peer_pid) const;
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void* ref_for_process_and_get_address(Process& process);
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void share_with(ProcessID peer_pid);
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void share_globally() { m_global = true; }
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void deref_for_process(Process& process);
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bool disown(ProcessID pid);
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static void share_all_shared_buffers(Process& from_process, Process& with_process);
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size_t size() const { return m_vmobject->size(); }
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void destroy_if_unused();
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void seal();
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enum class SetVolatileError {
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Success = 0,
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NotPurgeable,
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OutOfMemory,
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NotMapped
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};
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SetVolatileError set_volatile_all(bool is_volatile, bool& was_purged);
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AnonymousVMObject& vmobject() { return m_vmobject; }
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const AnonymousVMObject& vmobject() const { return m_vmobject; }
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int id() const { return m_shbuf_id; }
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private:
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int m_shbuf_id { -1 };
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bool m_writable { true };
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bool m_global { false };
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NonnullRefPtr<AnonymousVMObject> m_vmobject;
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Vector<Reference, 2> m_refs;
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unsigned m_total_refs { 0 };
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};
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Lockable<HashMap<int, NonnullOwnPtr<SharedBuffer>>>& shared_buffers();
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}
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