bird/lib/slab_test.c

/*
 *	BIRD Library -- Slab Alloc / Dealloc Tests
 *
 *	(c) 2022 Maria Matejka <mq@jmq.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#include "test/birdtest.h"
#include "lib/resource.h"
#include "lib/bitops.h"

static const int sizes[] = {
  8, 12, 18, 27, 41, 75, 131, 269,
};

#define TEST_SIZE	1024 * 128
#define ITEMS(sz)	TEST_SIZE / ( (sz) >> u32_log2((sz))/2 )

static inline byte *test_alloc(slab *s, int sz, struct resmem *sliz)
{
  byte *out = sl_alloc(s);

  for (int p=0; p < sz; p++)
    out[p] = p & 0xff;

  struct resmem ns = rmemsize((resource *) s);

  bt_assert(sliz->effective + sz == ns.effective);
  bt_assert((sliz->overhead - sz - ns.overhead) % page_size == 0);

  *sliz = ns;

  return out;
}

static inline void test_free(slab *s, byte *block, int sz, struct resmem *sliz)
{
  for (int p=0; p < sz; p++)
  {
    bt_assert(block[p] == (p & 0xff));
    block[p]++;
  }

  sl_free(s, block);

  struct resmem ns = rmemsize((resource *) s);

  bt_assert(sliz->effective - sz == ns.effective);
  bt_assert((sliz->overhead + sz - ns.overhead) % page_size == 0);

  *sliz = ns;
}

static inline struct resmem get_memsize(slab *s)
{
  struct resmem sz = rmemsize((resource *) s);
  bt_assert(sz.effective == 0);
  return sz;
}

static int
t_slab_forwards(const void *data)
{
  int sz = (intptr_t) data;
  slab *s = sl_new(&root_pool, sz);

  struct resmem sliz = get_memsize(s);

  int n = ITEMS(sz);
  byte **block = mb_alloc(&root_pool, n * sizeof(*block));

  for (int i = 0; i < n; i++)
    block[i] = test_alloc(s, sz, &sliz);

  for (int i = 0; i < n; i++)
    test_free(s, block[i], sz, &sliz);

  mb_free(block);

  return 1;
}

static int
t_slab_backwards(const void *data)
{
  int sz = (intptr_t) data;
  slab *s = sl_new(&root_pool, sz);

  struct resmem sliz = get_memsize(s);

  int n = ITEMS(sz);
  byte **block = mb_alloc(&root_pool, n * sizeof(*block));

  for (int i = 0; i < n; i++)
    block[i] = test_alloc(s, sz, &sliz);

  for (int i = n - 1; i >= 0; i--)
    test_free(s, block[i], sz, &sliz);

  mb_free(block);

  return 1;
}

static int
t_slab_random(const void *data)
{
  int sz = (intptr_t) data;
  slab *s = sl_new(&root_pool, sz);

  struct resmem sliz = get_memsize(s);

  int n = ITEMS(sz);
  byte **block = mb_alloc(&root_pool, n * sizeof(*block));

  for (int i = 0; i < n; i++)
    block[i] = test_alloc(s, sz, &sliz);

  for (int i = 0; i < n; i++)
  {
    int pos = bt_random() % (n - i);
    test_free(s, block[pos], sz, &sliz);
    if (pos != n - i - 1)
      block[pos] = block[n - i - 1];
  }

  mb_free(block);

  return 1;
}

static int
t_slab_mixed(const void *data)
{
  int sz = (intptr_t) data;
  slab *s = sl_new(&root_pool, sz);

  struct resmem sliz = get_memsize(s);

  int n = ITEMS(sz);
  byte **block = mb_alloc(&root_pool, n * sizeof(*block));

  int cur = 0;
  int pending = n;

  while (cur + pending > 0) {
    int action = bt_random() % (cur + pending);

    if (action < cur) {
      test_free(s, block[action], sz, &sliz);
      if (action != --cur)
	block[action] = block[cur];
    } else {
      block[cur++] = test_alloc(s, sz, &sliz);
      pending--;
    }
  }

  mb_free(block);

  return 1;
}
int main(int argc, char *argv[])
{
  bt_init(argc, argv);

  for (uint i = 0; i < sizeof(sizes) / sizeof(*sizes); i++)
  {
    bt_test_suite_arg(t_slab_forwards, (void *) (intptr_t) sizes[i], "Slab deallocation from beginning to end, size=%d", sizes[i]);
    bt_test_suite_arg(t_slab_backwards, (void *) (intptr_t) sizes[i], "Slab deallocation from end to beginning, size=%d", sizes[i]);
    bt_test_suite_arg(t_slab_random, (void *) (intptr_t) sizes[i], "Slab deallocation in random order, size=%d", sizes[i]);
    bt_test_suite_arg(t_slab_mixed, (void *) (intptr_t) sizes[i], "Slab deallocation in mixed order, size=%d", sizes[i]);
  }

  return bt_exit_value();
}