1 files changed, 171 insertions, 0 deletions
diff --git a/lib/slab_test.c b/lib/slab_test.c
new file mode 100644
index 00000000..803d0215
--- /dev/null
+++ b/lib/slab_test.c
@@ -0,0 +1,171 @@
+/*
+ *	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 )
+
+struct test_request {
+  int size;
+  enum strategy {
+    TEST_NONE,
+    TEST_FORWARDS,
+    TEST_BACKWARDS,
+    TEST_RANDOM,
+    TEST_MIXED,
+    TEST__MAX,
+  } strategy;
+};
+
+const char * const strategy_name[TEST__MAX] = {
+  [TEST_FORWARDS] = "forwards",
+  [TEST_BACKWARDS] = "backwards",
+  [TEST_RANDOM] = "random",
+  [TEST_MIXED] = "mixed",
+};
+
+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(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(const void *data)
+{
+  const struct test_request *tr = data;
+  int sz = tr->size;
+
+  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));
+
+  switch (tr->strategy) {
+    case TEST_FORWARDS:
+      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);
+
+      break;
+
+    case TEST_BACKWARDS:
+      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);
+
+      break;
+
+    case TEST_RANDOM:
+      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];
+      }
+
+      break;
+
+    case TEST_MIXED:
+      {
+	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--;
+	  }
+	}
+
+	break;
+      }
+
+    default: bug("This shouldn't happen");
+  }
+
+  mb_free(block);
+  return 1;
+}
+int main(int argc, char *argv[])
+{
+  bt_init(argc, argv);
+
+  struct test_request tr;
+
+  for (uint i = 0; i < sizeof(sizes) / sizeof(*sizes); i++)
+      for (uint strategy = TEST_FORWARDS; strategy < TEST__MAX; strategy++)
+      {
+	tr = (struct test_request) {
+	  .size = sizes[i],
+	  .strategy = strategy,
+	};
+	bt_test_suite_arg(t_slab, &tr, "Slab allocator test, size=%d, strategy=%s",
+	    tr.size, strategy_name[strategy]);
+      }
+
+  return bt_exit_value();
+}