Aryadev Chavali
a60108ae1d
Instead of using a linked list, which is incredibly fragmented, a vector keeps all pointers together. Keeps all our stuff together and in theory we should have less cache misses when deleting pages. It does introduce the issue of fragmenting, where if we allocate and then delete many times a lot of the heap vector will be empty so traversal will be over a ton of useless stuff.
80 lines
1.6 KiB
C
80 lines
1.6 KiB
C
/* Copyright (C) 2023 Aryadev Chavali
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* You may distribute and modify this code under the terms of the
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* GPLv2 license. You should have received a copy of the GPLv2
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* license with this file. If not, please write to:
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* aryadev@aryadevchavali.com.
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* Created: 2023-11-01
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* Author: Aryadev Chavali
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* Description: Arena allocator
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*/
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#include "./heap.h"
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#include <lib/darr.h>
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#include <malloc.h>
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#include <stdio.h>
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#include <string.h>
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page_t *page_create(size_t max)
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{
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if (max == 0)
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max = PAGE_DEFAULT_SIZE;
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page_t *page = calloc(1, sizeof(*page) + max);
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page->available = max;
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return page;
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}
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void page_delete(page_t *page)
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{
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free(page);
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}
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void heap_create(heap_t *heap)
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{
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memset(heap, 0, sizeof(*heap));
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}
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page_t *heap_allocate(heap_t *heap, size_t requested)
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{
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page_t *cur = page_create(requested);
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darr_append_bytes(&heap->page_vec, (byte_t *)cur, sizeof(cur));
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return cur;
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}
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bool heap_free(heap_t *heap, page_t *page)
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{
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if (!page || !heap)
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return false;
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for (size_t i = 0; i < (heap->page_vec.used / sizeof(page)); ++i)
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{
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page_t *cur = DARR_AT(page_t *, heap->page_vec.data, i);
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if (cur == page)
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{
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page_delete(cur);
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// TODO: When does this fragmentation become a performance
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// issue?
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DARR_AT(page_t *, heap->page_vec.data, i) = NULL;
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return true;
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}
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}
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return false;
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}
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void heap_stop(heap_t *heap)
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{
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for (size_t i = 0; i < (heap->page_vec.used / sizeof(page_t *)); i++)
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{
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page_t *ptr = DARR_AT(page_t *, heap->page_vec.data, i);
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if (ptr)
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page_delete(ptr);
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}
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free(heap->page_vec.data);
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heap->page_vec = (darr_t){0};
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}
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