On Thu, Jun 28, 2018 at 10:34:54AM +0200, Ard Biesheuvel wrote:

On 28 June 2018 at 10:31, Peter Zijlstra [off-list ref] wrote:

quoted

On Wed, Jun 27, 2018 at 06:06:04PM +0200, Ard Biesheuvel wrote:

quoted

Similar to the arm64 case, 64-bit x86 can benefit from using 32-bit
relative references rather than 64-bit absolute ones when emitting
struct jump_entry instances. Not only does this reduce the memory
footprint of the entries themselves by 50%, it also removes the need
for carrying relocation metadata on relocatable builds (i.e., for KASLR)
which saves a fair chunk of .init space as well (although the savings
are not as dramatic as on arm64)

This will conflict with:

  https://lkml.kernel.org/r/20180622172212.199633-10-namit at vmware.com

Thanks for the head's up. Fortunately, it does not conflict
fundamentally, so it should be a straight-forward rebase after that
code is merged.

Yeah, shouldn't be hard to cure.

There's another patch set that might have a little conflict, but that's
not near ready I think, so that'll have to just cope with things
shifting underneath (and there too, the fixup shouldn't be hard).

Do you think this is likely to get merged for v4.19?

I'm thinking it is near ready so it might, but I'm not in charge of
those bits :-)