On Tue, 16 Mar 2021 at 13:28, Thomas Backlund <tmb@xxxxxx> wrote: > > > Den 16.3.2021 kl. 14:15, skrev Thomas Backlund: > > > > Den 16.3.2021 kl. 12:17, skrev Ard Biesheuvel: > >> On Tue, 16 Mar 2021 at 10:21, Thomas Backlund <tmb@xxxxxx> wrote: > >>> Den 16.3.2021 kl. 08:37, skrev Ard Biesheuvel: > >>>> Please consider backporting commit > >>>> > >>>> 86ad60a65f29dd862a11c22bb4b5be28d6c5cef1 > >>>> crypto: x86/aes-ni-xts - use direct calls to and 4-way stride > >>>> > >>>> to stable. It addresses a rather substantial retpoline-related > >>>> performance regression in the AES-NI XTS code, which is a widely used > >>>> disk encryption algorithm on x86. > >>>> > >>> To get all the nice bits, we added the following in Mageia 5.10 / 5.11 > >>> series kerenels (the 2 first is needed to get the third to apply/build > >>> nicely): > >>> > >> I will leave it up to the -stable maintainers to decide, but I will > >> point out that none of the additional patches fix any bugs, so this > >> may violate the stable kernel rules. In fact, I deliberately split the > >> XTS changes into two patches so that the first one could be > >> backported individually. > > > > Yes, I understand that. > > > > but commit > > > > 86ad60a65f29dd862a11c22bb4b5be28d6c5cef1 > > crypto: x86/aes-ni-xts - use direct calls to and 4-way stride > > > > only applies cleanly on 5.11. > > > > > > So if it's wanted in 5.10 you need the 2 others too... unless you intend to provide a tested backport... > > and IIRC GregKH prefers 1:1 matching of patches between -stable and linus tree unless they are too intrusive. > > > > > > As for the last one I seem to remember comments that it too was part of the "affects performance", but I might be remembering wrong... and since you are Author of them I assume you know better about the facts :) > > > > > > That's why I listed them as an extra "hopefully helfpful" info and datapoint that they work... > > We have been carrying them in 5.10 series since we rebased to 5.10.8 on January 17th, 2021 > > > > > > but in the end it's up to the -stable maintainers as you point out... > > > and now I re-checked... > > Only the first is needed to get your fix to apply cleanly on 5.10 > > > the second came in as a pre-req for the fourth patch... > OK so that would be 032d049ea0f45b45c21f3f02b542aa18bc6b6428 Uros Bizjak <ubizjak@xxxxxxxxx> crypto: aesni - Use TEST %reg,%reg instead of CMP $0,%reg which is already in 5.11, but needs to be backported as well for the originally requested backport to apply cleanly to 5.10 and earlier. Thanks for digging that up. -- Ard.
