xa_lock
lockmgr(&xa->xa_lock, LK_EXCLUSIVE);
lockmgr(&xa->xa_lock, LK_RELEASE);
lockmgr(&xa->xa_lock, LK_EXCLUSIVE);
lockmgr(&xa->xa_lock, LK_RELEASE);
lockmgr(&xa->xa_lock, LK_EXCLUSIVE);
lockmgr(&xa->xa_lock, LK_RELEASE);
lockmgr(&xa->xa_lock, LK_EXCLUSIVE);
lockmgr(&xa->xa_lock, LK_RELEASE);
lockmgr(&xa->xa_lock, LK_EXCLUSIVE);
lockmgr(&xa->xa_lock, LK_RELEASE);
struct lock xa_lock;
lockmgr(&(_xa)->xa_lock, LK_EXCLUSIVE); \
lockmgr(&(_xa)->xa_lock, LK_RELEASE); \
lockmgr(&(_xa)->xa_lock, LK_EXCLUSIVE); \
lockmgr(&(_xa)->xa_lock, LK_RELEASE); \
lockmgr(&(_xa)->xa_lock, LK_EXCLUSIVE); \
lockmgr(&(_xa)->xa_lock, LK_RELEASE); \