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

Gleb Natapov
2007-09-11T11:19:00Z

On Tue, Sep 11, 2007 at 11:37:50AM +0100, Daniel J Blueman wrote:
> 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.
>
Posting the patch against current kernel (-mm or mainline) here would
be certainly helpful.

Thanks,

--
Gleb.