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ad3f931707
Previously, when deallocating a range of VM, we would sort and merge the range list. This was quite slow for large processes. This patch optimizes VM deallocation in the following ways: - Use binary search instead of linear scan to find the place to insert the deallocated range. - Insert at the right place immediately, removing the need to sort. - Merge the inserted range with any adjacent range(s) in-line instead of doing a separate merge pass into a list copy. - Add Traits<Range> to inform Vector that Range objects are trivial and can be moved using memmove(). I've also added an assertion that deallocated ranges are actually part of the RangeAllocator's initial address range. I've benchmarked this using g++ to compile Kernel/Process.cpp. With these changes, compilation goes from ~41 sec to ~35 sec.
68 lines
2.3 KiB
C++
68 lines
2.3 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/StdLibExtras.h>
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#include <AK/Types.h>
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namespace AK {
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template<typename T>
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int integral_compare(const T& a, const T& b)
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{
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return a - b;
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}
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template<typename T, typename Compare>
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T* binary_search(T* haystack, size_t haystack_size, const T& needle, Compare compare = integral_compare, int* nearby_index = nullptr)
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{
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int low = 0;
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int high = haystack_size - 1;
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while (low <= high) {
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int middle = (low + high) / 2;
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int comparison = compare(needle, haystack[middle]);
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if (comparison < 0)
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high = middle - 1;
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else if (comparison > 0)
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low = middle + 1;
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else {
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if (nearby_index)
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*nearby_index = middle;
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return &haystack[middle];
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}
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}
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if (nearby_index)
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*nearby_index = max(0, min(low, high));
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return nullptr;
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}
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}
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using AK::binary_search;
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