[PATCH for-4.8 V2 00/10] Use jump label for cpu/mmu_has_feature

Aneesh Kumar K.V aneesh.kumar at linux.vnet.ibm.com
Mon Jul 25 16:25:50 AEST 2016

Nicholas Piggin <npiggin at gmail.com> writes:

> On Sat, 23 Jul 2016 14:42:33 +0530
> "Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com> wrote:
>> Changes from V1:
>> * Update "powerpc/mm: Convert early cpu/mmu feature check to use the
>> new helpers" based on resend code changes in this area.
>> We now do feature fixup early and hence we can reduce the usage of
>>  __cpu/__mmu_has_feature.
> Is there a particular reason for for-4.8?
> I've only just started following this development so it might be
> obvious, but if you could add some small justifications for why
> a patch or series is done, it would be of great help to me.

The goal is to reduce the impact of radix series on existing MMU
function. With radix series, we do

if (radix_enabled())

We did try to reduce the impact in most code path like linux page table
accessors by moving linux pte bits around to match the radix/hardware
requirements. But we still have other code paths where we do the above

Now for-4.8 is mainly because, I was trying to make sure 4.8 release
will have a good performing radix/hash implementation which distros can
base their kernel on. This series was posted to external list multiple
times and I didn't receive many objections to the series. Hence I was
thinking it to be a good idea to get it upstream by 4.8.

More information about the Linuxppc-dev mailing list