On 09/03/2015 01:59 PM, Luis R. Rodriguez wrote: > On Thu, Sep 03, 2015 at 08:17:02AM -0400, Prarit Bhargava wrote: >> >> >> On 09/02/2015 10:45 PM, Luis R. Rodriguez wrote: >>> On Mon, Aug 31, 2015 at 11:05:33AM -0500, Stuart Hayes wrote: >>>> Increase the range of chunk sizes tried in mtrr_cleanup() so it is able >>>> to map large memory configs into MTRRs. >>>> >>>> Currently, mtrr_cleanup() will fail with large memory configurations, >>>> because it limits chunk_size to 2GB, which means that each MTRR can only >>>> cover 2GB of memory. With a memory size of, say, 256GB, and ten variable >>>> MTRRs (such as some recent Intel CPUs have), it is not possible to set up >>>> the MTRRs to cover all of memory. >>> >>> Linux drivers no longer use MTRR so why is the cleanup needed, ie, what >>> would >>> happen if the cleanup is just skipped in your case ? >> >> The infiniband & video drivers still use MTRR (or at least it was my >> understanding that they do). > > There were a few stragglers left on v4.2, I have transformed them in the > latest > development changes and those tranformations are now part of linux-next. If > this is specific to a driver you may want to first ensure you backport the > required patch that transforms the driver to use proper PAT interfaces, v4.2 > should have most updates but there were still a few left. Just make sure your > driver doesn't call mtrr_add() directly and if it doesn't then you should be > OK. > >> In any case, Stuart -- could you try booting with >> 'disable_mtrr_cleanup' as a kernel parameter? > > Indeed, please I'd like to hear back. Be sure to have the respective driver > transformation in place, what driver are you using exactly? In the event that > you argue this is still needed I'd like to know exaclty *why*, the comit log > does not mention any of that at all. >
Well ... we are trying to also fix this in older kernels too, *cough* RHEL *cough*, so that's where the patch comes from. If upstream is going to deprecate/remove mtrr support so be it. We can do a stable fix instead to fix older stable kernels. P. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
