On 10/26/21 12:08 PM, Matthew Wilcox wrote: > On Tue, Oct 26, 2021 at 10:01:20AM -0600, Jens Axboe wrote: >> The fast path here is not needing any writeback, yet we spend time setting >> up the xarray lookup data upfront. Move the part that actually needs to >> iterate the address space mapping into a separate helper, saving ~30% of >> the time here. > > No objection to this patch, but it did remind me that I never saw an answer to > https://lore.kernel.org/all/CAHk-=wg_-EwefQ_3Osz4iJxTrTk3tfrV53Z7-jaGg=tm9i5TXg@xxxxxxxxxxxxxx/ > (and nor did lore) Totally missed that, and yes there could be cases where that lookup is going to be way too slow. I'll take a look. -- Jens Axboe
