Back in December Linux kernel patches were posted by a Meta engineer for making use of the AMD INVLPGB instruction found with Zen 3 and newer processors. The Linux kernel would use INVLPGB for invalidating TLB entries for a range of pages with broadcast. After these patches went through 14 rounds of review since December, it looks like this AMD broadcast TLB invalidation support is now ready for the mainline Linux kernel!
The AMD broadcast TLB invalidation code has looked quite promising and my AMD INVLPGB benchmarking of the early patches was looking very good. Last week the v14 patches were posted and now it looks like the code is all in good enough shape that it could be ready for merging during the next Linux kernel cycle if all goes well.
AMD engineer Borislav Petkov queued up these patches by Meta’s Rik van Riel and commented:
“Ok, I’ve got the whole thing here now:
https://web.git.kernel.org/pub/scm/linux/kernel/git/bp/bp.git/log/?h=tip-x86-cpu-tlbi
Lemme take it for a spin on my machines, see whether the cat catches fire…”
Petkov already followed up with:
“Well, it boots on Zen3 and 4, laptops and servers – although only server has the broadcast thing – but all look good.
I guess ship it!
:-)
Srsly, I’ll send out the whole set tomorrow to have it on the ML and see whether people have more opinions.
Thx.”
So with that it’s looking like the patches could be ready for shipping — possibly as soon as the Linux 6.15 merge window at the end of March, if no last minute objections are raised during a final round of the patches on the mailing list.
I’ll work on more AMD INVLPGB benchmarking soon as these patches are queued for landing.
