> > // lru list lock held > > shrink_memcg_cb() > > swpentry = entry->swpentry > > // Don't isolate entry from lru list here, just use list_lru_putback() > > spin_unlock(lru list lock) > > > > folio = __read_swap_cache_async(swpentry) > > if (!folio) > > return > > > > if (!folio_was_allocated) > > folio_put(folio) > > return > > > > // folio is locked, swapcache is secured against swapoff > > tree = get tree from swpentry > > spin_lock(&tree->lock) > > That will not work well with zswap to xarray change. We want to remove > the tree lock and only use the xarray lock. > The lookup should just hold xarray RCU read lock and return the entry > with ref count increased. In this path, we also invalidate the zswap entry, which would require holding the xarray lock anyway.
