Slab memory allocator unit test

lib/Makefile

@@ -2,6 +2,6 @@ src := bitmap.c bitops.c blake2s.c blake2b.c checksum.c event.c flowspec.c idm.c
 obj := $(src-o-files)
 $(all-daemon)
 
-tests_src := bitmap_test.c heap_test.c buffer_test.c event_test.c flowspec_test.c bitops_test.c patmatch_test.c fletcher16_test.c slist_test.c checksum_test.c lists_test.c mac_test.c ip_test.c hash_test.c printf_test.c
+tests_src := bitmap_test.c heap_test.c buffer_test.c event_test.c flowspec_test.c bitops_test.c patmatch_test.c fletcher16_test.c slist_test.c checksum_test.c lists_test.c mac_test.c ip_test.c hash_test.c printf_test.c slab_test.c
 tests_targets := $(tests_targets) $(tests-target-files)
 tests_objs := $(tests_objs) $(src-o-files)

lib/slab.c

@@ -394,7 +394,7 @@ slab_memsize(resource *r)
   WALK_LIST(h, s->empty_heads)
     heads++;
 
-  size_t eff = items * s->obj_size;
+  size_t eff = items * s->data_size;
 
   return (struct resmem) {
     .effective = eff,

lib/slab_test.c

@@ -0,0 +1,177 @@
+/*
+ *	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();
+}