On 12.05.24 14:35, Chen Taotao wrote:
When a folio belongs exclusively to one process after a COW event, folio_move_anon_rmap() always moves the folio into the anon_vma belongs only to this process. However, if the folio already belongs to the anon_vma of the this process, we don't need to move it again. In this case, we first check if the folio already belongs to the anna_vma of the this process, and only move it if it does not. The above changes may improve the performance of vm faults in some scenarios, because the performance loss caused by WRITE_ONCE() is much more than the performance loss caused by add a judgment.
Please proof that by real numbers. I don't think it will make a real difference, and we likely don't want that change.
-- Cheers, David / dhildenb
