MS_ASYNC
if (msync (chunk, len, MS_ASYNC))
if ((flags & (MS_ASYNC|MS_INVALIDATE)) == (MS_ASYNC|MS_INVALIDATE))
rv = vm_map_sync(map, addr, addr + size, (flags & MS_ASYNC) == 0,
EXPECT_OK(msync(mem, mem_size, MS_ASYNC));
ATF_REQUIRE_MSG(msync(addr, ps[0], MS_ASYNC) == 0,
ATF_REQUIRE_MSG(msync(addr, ps[i], MS_ASYNC) == 0,
CHECK_SYSCALL_SUCCEEDS(msync, &fd_file, 8192, MS_ASYNC);