Locking data structures

If a data structure is associated with a lock, having a public
and a private part, there are now useful macros for these data
structures.

lib/locking_test.c

@@ -0,0 +1,91 @@
+#include "test/birdtest.h"
+#include "test/bt-utils.h"
+
+#include "lib/locking.h"
+#include <stdatomic.h>
+#include <pthread.h>
+
+DEFINE_DOMAIN(proto);
+
+#define FOO_PUBLIC \
+  const char *name;	\
+  _Atomic uint counter;	\
+  DOMAIN(proto) lock;	\
+
+struct foo_private {
+  struct { FOO_PUBLIC; };
+  struct foo_private **locked_at;
+  uint private_counter;
+};
+
+typedef union foo {
+  struct { FOO_PUBLIC; };
+  struct foo_private priv;
+} foo;
+
+LOBJ_UNLOCK_CLEANUP(foo, proto);
+#define FOO_LOCK(_foo, _fpp)	LOBJ_LOCK(_foo, _fpp, foo, proto)
+#define FOO_LOCKED(_foo, _fpp)	LOBJ_LOCKED(_foo, _fpp, foo, proto)
+#define FOO_IS_LOCKED(_foo)	LOBJ_IS_LOCKED(_foo, proto)
+
+static uint
+inc_public(foo *f)
+{
+  return atomic_fetch_add_explicit(&f->counter, 1, memory_order_relaxed) + 1;
+}
+
+static uint
+inc_private(foo *f)
+{
+  FOO_LOCKED(f, fp) return ++fp->private_counter;
+  bug("Returning always");
+}
+
+#define BLOCKCOUNT  4096
+#define THREADS	    16
+#define REPEATS	    128
+
+static void *
+thread_run(void *_foo)
+{
+  foo *f = _foo;
+
+  for (int i=0; i<REPEATS; i++)
+    if (i % 2)
+      for (int j=0; j<BLOCKCOUNT; j++)
+	inc_public(f);
+    else
+      for (int j=0; j<BLOCKCOUNT; j++)
+	inc_private(f);
+
+  return NULL;
+}
+
+static int
+t_locking(void)
+{
+  pthread_t thr[THREADS];
+  foo f = { .lock = DOMAIN_NEW(proto), };
+
+  for (int i=0; i<THREADS; i++)
+    bt_assert(pthread_create(&thr[i], NULL, thread_run, &f) == 0);
+
+  for (int i=0; i<THREADS; i++)
+    bt_assert(pthread_join(thr[i], NULL) == 0);
+
+  bt_assert(f.priv.private_counter == atomic_load_explicit(&f.counter, memory_order_relaxed));
+  bt_assert(f.priv.private_counter == THREADS * BLOCKCOUNT * REPEATS / 2);
+
+  return 1;
+}
+
+int
+main(int argc, char **argv)
+{
+  bt_init(argc, argv);
+  bt_bird_init();
+
+  bt_test_suite(t_locking, "Testing locks");
+
+  return bt_exit_value();
+}