On Tue, Nov 28, 2023 at 11:16:04AM +0100, Michal Hocko wrote: > On Tue 28-11-23 09:31:06, Huang, Ying wrote: > > Michal Hocko <mhocko@xxxxxxxx> writes: > [...] > > > Right. On the other hand we could be more aggressive when dropping the > > > swapcache. Is there any actual reason why we cannot try to folio_free_swap > > > even when mem_cgroup_swap_full == F? > > > > If there are plenty free space in swap device, why not take advantage of > > it? > > Maybe a stupid question but what is the advantage of keeping around in > the swap cache? If the page is shared, we avoids addtional IO to bring them back so swap cache. If the page is still clean on reclaim moment since swap-in, VM doesn't need to write them out to the swap disk since original data is already there.