120 lines
1.8 KiB
C
120 lines
1.8 KiB
C
/* Copyright (c) 2024 Barcelona Supercomputing Center (BSC)
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* SPDX-License-Identifier: MIT
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* Author: Rodrigo Arias Mallo <rodrigo.arias@bsc.es> */
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/* This is just a small tool to exercise the memory which attempts to
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* stress the virtual memory, in a crude attempt to reproduce the hangs
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* that we were observing while booting NixOS. */
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#define MAX_SIZE (1024L * 1024L)
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struct block {
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struct block *next;
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size_t size;
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uint32_t data[];
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};
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struct block *front = NULL;
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struct block *tail = NULL;
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long nblocks = 0;
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long nbytes = 0;
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static int
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allocate(void)
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{
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long n = (long) rand() % MAX_SIZE;
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/* Constraint the size */
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n = n % MAX_SIZE;
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size_t size = sizeof(struct block) + n * sizeof(uint32_t);
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struct block *b = malloc(size);
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/* No mem */
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if (b == NULL)
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return -1;
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b->size = size;
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b->next = NULL;
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/* Populate the block with some data */
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for (long i = 0; i < n; i++)
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b->data[i] = rand();
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/* Add it to the chain */
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if (tail)
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tail->next = b;
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tail = b;
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/* And to the front if it is the first */
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if (!front)
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front = b;
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nblocks++;
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nbytes += size;
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return 0;
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}
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static int
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deallocate(void)
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{
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/* May run out of blocks */
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if (!front)
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return -1;
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struct block *b = front;
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front = b->next;
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/* Last block */
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if (tail == b)
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tail = NULL;
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nblocks--;
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nbytes -= b->size;
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free(b);
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return 0;
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}
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static void
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torture(void)
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{
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srand(123);
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for (long iter = 0; ; iter++) {
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int p = rand() % 100;
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int is_alloc = (p > 10);
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int ret = 0;
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char c;
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if (is_alloc) {
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if (allocate() == 0)
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c = 'A';
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else
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c = '-';
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} else {
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if (deallocate() == 0)
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c = 'D';
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else
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c = '-';
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}
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printf("iter %ld, nblocks %ld, nbytes %.1fM (%c)\n",
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iter, nblocks, (double) nbytes / (1024. * 1024.),
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c);
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}
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}
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int main(int argc, char *argv[])
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{
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torture();
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return 0;
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}
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