On Thu, 2012-06-28 at 13:19 +0200, Martin Schwidefsky wrote: > The cpu can create speculative TLB entries, but only if it runs in the > mode that uses the respective mm. We have two mm's active at the same > time, the kernel mm (init_mm) and the user mm. While the cpu runs only > in kernel mode it is not allowed to create TLBs for the user mm. > While running in user mode it is allowed to speculatively create TLBs. OK, that's neat. > Basically we have two special requirements on s390: > 1) do not modify ptes while attached to another cpu except with the > special IPTE / IDTE instructions Right, and your fullmm case works by doing a global invalidate after all threads have ceased userspace execution, this allows you to do away with the IPTE/IDTE instructions since there's no other active cpus on the userspace mm anymore. > 2) do a TLB flush before freeing any kind of page table page, s390 > needs a flush for pud, pmd & pte tables. Right, we do that (now).. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href