On 2025/2/27 05:08, Zi Yan wrote:
During shmem_split_large_entry(), large swap entries are covering n slots and an order-0 folio needs to be inserted. Instead of splitting all n slots, only the 1 slot covered by the folio need to be split and the remaining n-1 shadow entries can be retained with orders ranging from 0 to n-1. This method only requires (n/XA_CHUNK_SHIFT) new xa_nodes instead of (n % XA_CHUNK_SHIFT) * (n/XA_CHUNK_SHIFT) new xa_nodes, compared to the original xas_split_alloc() + xas_split() one. For example, to split an order-9 large swap entry (assuming XA_CHUNK_SHIFT is 6), 1 xa_node is needed instead of 8. xas_try_split_min_order() is used to reduce the number of calls to xas_try_split() during split. Signed-off-by: Zi Yan <ziy@xxxxxxxxxx> Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Kairui Song <kasong@xxxxxxxxxxx> Cc: Mattew Wilcox <willy@xxxxxxxxxxxxx> Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: John Hubbard <jhubbard@xxxxxxxxxx> Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> Cc: Kirill A. Shuemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Ryan Roberts <ryan.roberts@xxxxxxx> Cc: Yang Shi <yang@xxxxxxxxxxxxxxxxxxxxxx> Cc: Yu Zhao <yuzhao@xxxxxxxxxx> > ---
LGTM. Feel free to add: Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> Tested-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
