On Mon, Sep 27, 2021 at 12:10:47PM -0400, Hamza Mahfooz wrote: > Commit 833f4154ed56 ("aio: fold lookup_kiocb() into its sole caller") > suggests that, the fact that active_reqs is a linked-list means aio_kiocb > lookups in io_cancel() are inefficient. So, to get faster lookups while > maintaining similar characteristics elsewhere, turn active_reqs into an > array and keep track of the free indices of the array (so we know which > indices are safe to use). As requested last time: please explain what workload you have where cancellation performance actually matters.