Ryan Roberts <ryan.roberts@xxxxxxx> writes: > As preparation for supporting small-sized THP in the swap-out path, > without first needing to split to order-0, Remove the CLUSTER_FLAG_HUGE, > which, when present, always implies PMD-sized THP, which is the same as > the cluster size. > > The only use of the flag was to determine whether a swap entry refers to > a single page or a PMD-sized THP in swap_page_trans_huge_swapped(). > Instead of relying on the flag, we now pass in nr_pages, which > originates from the folio's number of pages. This allows the logic to > work for folios of any order. > > The one snag is that one of the swap_page_trans_huge_swapped() call > sites does not have the folio. But it was only being called there to > avoid bothering to call __try_to_reclaim_swap() in some cases. > __try_to_reclaim_swap() gets the folio and (via some other functions) > calls swap_page_trans_huge_swapped(). So I've removed the problematic > call site and believe the new logic should be equivalent. I believe this should be OK. Better to compare the performance too. > Removing CLUSTER_FLAG_HUGE also means we can remove split_swap_cluster() > which used to be called during folio splitting, since > split_swap_cluster()'s only job was to remove the flag. > -- Best Regards, Huang, Ying
