Re: [PATCH v2] x86: enable RCU based table free

From: Peter Zijlstra
Date: Thu Aug 24 2017 - 12:07:31 EST


On Thu, Aug 24, 2017 at 05:27:21PM +0200, Vitaly Kuznetsov wrote:
> Do you think adding something like
>
> /*
> * While x86 architecture in general requires an IPI to perform TLB
> * shootdown, enablement code for several hypervisors overrides
> * .flush_tlb_others hook in pv_mmu_ops and implements it by issuing
> * a hypercall. To keep software pagetable walkers safe in this case we
> * switch to RCU based table free (HAVE_RCU_TABLE_FREE). See the comment
> * below 'ifdef CONFIG_HAVE_RCU_TABLE_FREE' in include/asm-generic/tlb.h
> * for more details.
> */
>
> before __tlb_remove_table would suffice? Or do you see a better place
> for such comment?

Yes, that seems fine. Thanks!