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Add test and remove code comments

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cozis
2024-04-20 20:41:06 +02:00
parent 3acc0a80a8
commit 457bc24019
5 changed files with 91 additions and 99 deletions
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.gitignore
+2
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@@ -1,2 +1,4 @@
test
test.exe
test2
test2.exe
buddy.c
+6 -82
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@@ -547,8 +547,12 @@ void *buddy_malloc(struct buddy_alloc *alloc, size_t len)
void buddy_free(struct buddy_alloc *alloc,
size_t len, void *ptr)
{
if (ptr == NULL || len == 0) return;
if (len > MAX_BLOCK_SIZE) return;
if (ptr == NULL || len == 0)
return;
if (len > MAX_BLOCK_SIZE)
return;
len = normalize_len(len);
if (!is_allocated(alloc, ptr, len))
@@ -571,83 +575,3 @@ void buddy_free(struct buddy_alloc *alloc,
len <<= 1;
}
}
/*
#define ANSI_COLOR_RED "\x1b[31m"
#define ANSI_COLOR_GREEN "\x1b[32m"
#define ANSI_COLOR_YELLOW "\x1b[33m"
#define ANSI_COLOR_BLUE "\x1b[34m"
#define ANSI_COLOR_MAGENTA "\x1b[35m"
#define ANSI_COLOR_CYAN "\x1b[36m"
#define ANSI_COLOR_RESET "\x1b[0m"
static const char *block_size_label(size_t len)
{
const char *label = "???";
switch (len) {
case 1<<12: label = "4K"; break;
case 1<<11: label = "2K"; break;
case 1<<10: label = "1K"; break;
case 1<<9 : label = "512B"; break;
case 1<<8 : label = "256B"; break;
}
return label;
}
void print_lists(struct buddy_alloc *alloc)
{
for (int i = MIN_BLOCK_LOG2; i <= MAX_BLOCK_LOG2; i++) {
fprintf(stderr, "%s = {", block_size_label(1U<<i));
struct page *p = alloc->lists[i - MIN_BLOCK_LOG2];
while (p) {
assert((uintptr_t) p >= (uintptr_t) alloc->base);
fprintf(stderr, "%lu", (uintptr_t) p - (uintptr_t) alloc->base);
p = p->next;
if (p)
fprintf(stderr, ", ");
}
fprintf(stderr, "}\n");
}
}
void buddy_dump(struct buddy_alloc *alloc, FILE *out)
{
fprintf(out, "\n");
for (int i = 0; i < alloc->num_info; i++) {
for (int j = 0; j < 32; j++) {
if (alloc->info[i].bits[0] & (1U << j))
fprintf(stderr, "1");
else
fprintf(stderr, "0");
}
fprintf(stderr, " ");
}
fprintf(stderr, "\n");
for (int i = 0; i < alloc->num_info; i++) {
char *page = alloc->base + i * MAX_BLOCK_SIZE;
for (int j = MAX_BLOCK_LOG2; j >= MIN_BLOCK_LOG2; j--) {
size_t len = 1U << j;
const char *label = block_size_label(len);
for (size_t k = 0; k < MAX_BLOCK_SIZE / len; k++) {
char *ptr = page + k * len;
fprintf(out, "%-4lX ", (uintptr_t) ptr - (uintptr_t) alloc->base);
for (int q = 0; q < MAX_BLOCK_LOG2 - j; q++)
fprintf(out, " ");
if (is_allocated(alloc, ptr, len))
fprintf(out, ANSI_COLOR_GREEN "%s - allocated\n" ANSI_COLOR_RESET, label);
else
fprintf(out, "%s - free\n", label);
}
}
}
}
*/
buddy.h
+17 -15
View File
@@ -1,23 +1,25 @@
#include <stddef.h>
#include <stdint.h>
#define BUDDY_ALLOC_MAX_BLOCK_LOG2 12
#define BUDDY_ALLOC_MIN_BLOCK_LOG2 8
#define BUDDY_ALLOC_MAX_BLOCK_LOG2 13
#define BUDDY_ALLOC_MIN_BLOCK_LOG2 3
_Static_assert(BUDDY_ALLOC_MIN_BLOCK_LOG2 <= BUDDY_ALLOC_MAX_BLOCK_LOG2);
_Static_assert(BUDDY_ALLOC_MIN_BLOCK_LOG2 > 2);
#define BUDDY_ALLOC_NUM_LISTS (BUDDY_ALLOC_MAX_BLOCK_LOG2 - BUDDY_ALLOC_MIN_BLOCK_LOG2 + 1)
/*
* To keep track of the allocation state of a page,
* we need one bit for each possible block that can
* be made out of it. For instance, if the page can
* only be allocated in its entirety, 1 bit is required.
* If the blocks halfs can be allocated too, 3 bits
* are required: 1 for the page, 1 for the frist half
* and 1 for the second half. Allowing the allocation
* of page quarters requires 4 more bits, for a total
* of 7. In general, if we allow splitting a page N
* times (N=0 means only the entire page can be allocated),
* then 2^(N+1)-1 bits are necessary.
*/
// To keep track of the allocation state of a page,
// we need one bit for each possible block that can
// be made out of it. For instance, if the page can
// only be allocated in its entirety, 1 bit is required.
// If the blocks halfs can be allocated too, 3 bits
// are required: 1 for the page, 1 for the frist half
// and 1 for the second half. Allowing the allocation
// of page quarters requires 4 more bits, for a total
// of 7. In general, if we allow splitting a page N
// times (N=0 means only the entire page can be allocated),
// then 2^(N+1)-1 bits are necessary.
#define BUDDY_ALLOC_BITS_PER_PAGE ((1U << (BUDDY_ALLOC_NUM_LISTS)) - 1)
#define BUDDY_ALLOC_WORDS_PER_PAGE ((BUDDY_ALLOC_BITS_PER_PAGE + 31) / 32)
makefile
+1
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@@ -1,3 +1,4 @@
all:
gcc test.c buddy.c -o test -Wall -Wextra -ggdb #-fsanitize=address,undefined
gcc test2.c buddy.c -o test2 -Wall -Wextra -ggdb
test2.c
+63
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@@ -0,0 +1,63 @@
#include <stdio.h>
#include "buddy.h"
#define NUM_PAGES 16
#define MIN_ALLOC_SIZE (1U << BUDDY_ALLOC_MIN_BLOCK_LOG2)
#define PAGE_SIZE (1U << BUDDY_ALLOC_MAX_BLOCK_LOG2)
#define POOL_SIZE (NUM_PAGES * PAGE_SIZE)
#define MAX_ALLOCS (POOL_SIZE / MIN_ALLOC_SIZE)
int main(void)
{
_Alignas(PAGE_SIZE) char mem[POOL_SIZE];
struct page_info info[NUM_PAGES];
struct buddy_alloc alloc = buddy_startup(mem, POOL_SIZE, info, NUM_PAGES);
void *allocs[MAX_ALLOCS];
size_t performed = 0;
for (size_t i = 0; i < MAX_ALLOCS; i++) {
void *ptr = buddy_malloc(&alloc, MIN_ALLOC_SIZE);
if (ptr == NULL)
break;
performed++;
allocs[i] = ptr;
*(size_t*) ptr = i;
}
if (performed == MAX_ALLOCS) {
for (size_t i = 0; i < MAX_ALLOCS; i++) {
if (*(size_t*) allocs[i] != i)
fprintf(stderr, "%p allocated twice!\n", allocs[i]);
}
for (size_t i = 0; i < MAX_ALLOCS; i++) {
buddy_free(&alloc, MIN_ALLOC_SIZE, allocs[MAX_ALLOCS-i-1]);
}
performed = 0;
for (size_t i = 0; i < MAX_ALLOCS; i++) {
void *ptr = buddy_malloc(&alloc, MIN_ALLOC_SIZE);
performed++;
allocs[i] = ptr;
*(size_t*) ptr = i + MAX_ALLOCS;
}
for (size_t i = 0; i < MAX_ALLOCS; i++) {
if (*(size_t*) allocs[i] != MAX_ALLOCS + i)
fprintf(stderr, "%p reallocation error!\n", allocs[i]);
}
}
fprintf(stderr, "performed=%lu, expected=%u\n", performed, MAX_ALLOCS);
buddy_cleanup(&alloc);
return 0;
}