Re: [ofa-general] [PATCH][RFC]: pte notifiers -- support for external page tables

Daniel J Blueman
2007-09-11T10:37:50Z

Andrew Hastings wrote:
> Avi Kivity wrote:
>> Gleb Natapov wrote:
>>> On Wed, Sep 05, 2007 at 07:38:48PM +0300, Avi Kivity wrote:
>>>
>>>> This sample patch adds a new mechanism, pte notifiers, that allows
>>>> drivers
>>>> to register an interest in a changes to ptes. Whenever Linux changes a
>>>> pte, it will call a notifier to allow the driver to adjust the external
>>>> page table and flush its tlb.
>>>>
>>> How is this different from http://lwn.net/Articles/133627/? AFAIR the
>>> patch was rejected because there was only one user for it and it was
>>> decided that it would be better to maintain it out of tree for a while.
>>>
>>
>> Your patch is more complete.
>>
>> There are now at least three users: you, kvm, and newer Infiniband
>> HCAs. Care to resurrect the patch?
>
> We (Cray) also use the ioproc patch. AFAIK the current maintainer is
> Dan Blueman at Quadrics.

I should add that the IOPROC patches are maintained internally to
loosely track mainline kernels; however, we do not generally release [1]
these until they've passed quite a lot of validation (driven by customer
demand mostly) on various configurations.

Quite a few large users/groups would benefit from this; the IOPROC
patches have been stable for quite a while now, so are a good option.

If you have any feedback/suggestions that would help forward progress,
I'm happy to hear and address them.

Thanks,
Daniel

--- [1]

http://www.quadrics.com/patches
--
Daniel J Blueman
Software Engineer, Quadrics Ltd