On 4/28/23 9:13?AM, David Hildenbrand wrote: >>> I know, Jason und John will disagree, but I don't think we want to be very >>> careful with changing the default. >>> >>> Sure, we could warn, or convert individual users using a flag (io_uring). >>> But maybe we should invest more energy on a fix? >> >> This is proactively blocking a cleanup (eliminating vmas) that I believe >> will be useful in moving things forward. I am not against an opt-in option >> (I have been responding to community feedback in adapting my approach), >> which is the way I implemented it all the way back then :) > > There are alternatives: just use a flag as Jason initially suggested > and use that in io_uring code. Then, you can also bail out on the > GUP-fast path as "cannot support it right now, never do GUP-fast". Since I've seen this brougth up a few times, what's the issue on the io_uring side? We already dropped the special vma checking, it's in -git right. Hence I don't believe there are any special cases left for io_uring at all, and we certainly don't allow real file backings either, never have done. -- Jens Axboe
