Re: [PATCH 0/7] abstract pagetable locking and pte updates

Christoph Lameter
2004-11-02T00:15:41Z

On Fri, 29 Oct 2004, William Lee Irwin III wrote:

> On Fri, Oct 29, 2004 at 05:20:13PM +1000, Nick Piggin wrote:
> > Known issues: Hugepages, nonlinear pages haven't been looked at
> > and are quite surely broken. TLB flushing (gather/finish) runs
> > without the page table lock, which will break at least SPARC64.
> > Additional atomic ops in copy_page_range slow down lmbench fork
> > by 7%.
>
> This raises the rather serious question of what you actually did
> besides rearranging Lameter's code. It had all the same problems;
> resolving them is a prerequisite to going anywhere with all this.

Could you be specific as to the actual problems? I have worked through
several archs over time and my code offers a fallback to the use of the
page_table_lock if an arch does not provide the necessary atomic ops.
So what are the issues with my code? I fixed the PAE code based on Nick's
work. AFAIK this was the only known issue.