On Thu, 19 Aug 2021 15:23:02 -0600 Yu Zhao wrote: >On Thu, Aug 19, 2021 at 3:19 AM Will Deacon <will@xxxxxxxxxx> wrote: >> >> How accurate does this need to be? Heterogeneous (big/little) systems are >> very common on arm64, so the existing code enables hardware access flag >> unconditionally on CPUs that support it, meaning we could end up running >> on a system where some CPUs have hardware update and others do not. >> >> With your change, we only enable hardware access flag if _all_ CPUs support >> it (and furthermore, we prevent late onlining of CPUs without the feature >> if was detected at boot). This sacrifices a lot of flexibility, particularly >> if we end up tackling CPU errata in this area in future, and it's not clear >> that it's really required for what you're trying to do. > >It doesn't need to be accurate but then my question is how helpful it >is if it's not accurate. Alternatively to make the issue simpler, spin without arm64 included given that it will be revisited once MGLRU lands in the mainline tree. Hillf
