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39f0739381
Previously each malloc size class would keep around a limited number of unused blocks which were marked with MADV_SET_VOLATILE which could then be reinitialized when additional blocks were needed. This changes malloc() so that it also keeps around a number of blocks without marking them with MADV_SET_VOLATILE. I termed these "hot" blocks whereas blocks which were marked as MADV_SET_VOLATILE are called "cold" blocks because they're more expensive to reinitialize. In the worst case this could increase memory usage per process by 1MB when a program requests a bunch of memory and frees all of it. Also, in order to make more efficient use of these unused blocks they're now shared between size classes.
110 lines
2.7 KiB
C++
110 lines
2.7 KiB
C++
/*
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* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include "MmapRegion.h"
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#include "SoftMMU.h"
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#include <AK/Badge.h>
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#include <AK/HashMap.h>
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#include <AK/OwnPtr.h>
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#include <AK/Types.h>
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#include <AK/Vector.h>
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namespace UserspaceEmulator {
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class Emulator;
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class SoftCPU;
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struct GraphNode {
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Vector<FlatPtr> edges_from_node {};
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bool is_reachable { false };
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};
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using MemoryGraph = HashMap<FlatPtr, GraphNode>;
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struct Mallocation {
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bool contains(FlatPtr a) const
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{
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return a >= address && a < (address + size);
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}
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FlatPtr address { 0 };
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size_t size { 0 };
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bool used { false };
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bool freed { false };
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Vector<FlatPtr> malloc_backtrace;
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Vector<FlatPtr> free_backtrace;
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};
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class MallocRegionMetadata {
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public:
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MmapRegion& region;
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FlatPtr address { 0 };
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size_t chunk_size { 0 };
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Optional<size_t> chunk_index_for_address(FlatPtr) const;
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Mallocation* mallocation_for_address(FlatPtr) const;
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Vector<Mallocation> mallocations;
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};
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class MallocTracer {
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public:
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explicit MallocTracer(Emulator&);
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void target_did_malloc(Badge<Emulator>, FlatPtr address, size_t);
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void target_did_free(Badge<Emulator>, FlatPtr address);
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void target_did_realloc(Badge<Emulator>, FlatPtr address, size_t);
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void target_did_change_chunk_size(Badge<Emulator>, FlatPtr, size_t);
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void audit_read(const Region&, FlatPtr address, size_t);
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void audit_write(const Region&, FlatPtr address, size_t);
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void dump_leak_report();
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private:
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template<typename Callback>
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void for_each_mallocation(Callback callback) const;
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Mallocation* find_mallocation(const Region&, FlatPtr);
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Mallocation* find_mallocation(FlatPtr);
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Mallocation* find_mallocation_before(FlatPtr);
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Mallocation* find_mallocation_after(FlatPtr);
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void dump_memory_graph();
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void populate_memory_graph();
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void update_metadata(MmapRegion& mmap_region, size_t chunk_size);
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Emulator& m_emulator;
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MemoryGraph m_memory_graph {};
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bool m_auditing_enabled { true };
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};
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ALWAYS_INLINE Mallocation* MallocTracer::find_mallocation(const Region& region, FlatPtr address)
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{
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if (!is<MmapRegion>(region))
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return nullptr;
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if (!static_cast<const MmapRegion&>(region).is_malloc_block())
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return nullptr;
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auto* malloc_data = static_cast<MmapRegion&>(const_cast<Region&>(region)).malloc_metadata();
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if (!malloc_data)
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return nullptr;
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auto* mallocation = malloc_data->mallocation_for_address(address);
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if (!mallocation)
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return nullptr;
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if (!mallocation->used)
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return nullptr;
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if (!mallocation->contains(address))
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return nullptr;
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return mallocation;
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}
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}
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