SI_CACHED
ASSERT(!(sp->s_flags & SI_CACHED));
sp->s_flags |= SI_CACHED;
ASSERT(sp->s_flags & SI_CACHED);
sp->s_flags &= ~SI_CACHED;
tsp->s_flags &= ~SI_CACHED;
ASSERT(!sp->s_use && !sp->s_ref && !(sp->s_flags & SI_CACHED));