SWAP_CACHE_STALE
sf->cache_flags |= SWAP_CACHE_STALE;
sa->cache_flags |= SWAP_CACHE_STALE;
sf->cache_flags &= ~SWAP_CACHE_STALE;
sa->cache_flags &= ~SWAP_CACHE_STALE;
sa->cache_flags &= ~SWAP_CACHE_STALE;
if (sa->cache_flags & SWAP_CACHE_STALE) {
sf->cache_flags &= ~SWAP_CACHE_STALE;
if (sf->cache_flags & SWAP_CACHE_STALE) {