Re: [00/17] Large Blocksize Support V3

Nick Piggin
2007-04-27T09:46:45Z

William Lee Irwin III wrote:
> On Fri, Apr 27, 2007 at 01:38:30AM +1000, Nick Piggin wrote:
>
>>Or good grounds to increase the sg limit and push for io controller
>>manufacturers to do the same. If we have a hack in the kernel that
>>mostly works, they won't.
>
>
> On Fri, Apr 27, 2007 at 01:38:30AM +1000, Nick Piggin wrote:
>
>>Page colouring was always rejected, and lots of people who knew
>>better got upset because it was the only way the hardware would go
>>fast...
>
>
> Yes, stunning wisdom there. Reject the speedups.

Yeah, that's how lots of people felt. But there is a good argument
to do just that.

> On Fri, Apr 27, 2007 at 01:38:30AM +1000, Nick Piggin wrote:
>
>>You could put it that way. Or that it is wrong because of the
>>fragmenatation problem. Realise that it is somewhat fundamental
>>considering that it is basically an unsolvable problem with our
>>current kernel assumptions of unconstrained kernel allocations and
>>a 1:1 kernel mapping.
>
>
> Depends on what you consider a solution. A broadly used criterion is
> that improves performance significantly in important usage cases.

My criterion is that you are not suddenly unable to access your
filesystem because you cannot allocate a higher order page.

--
SUSE Labs, Novell Inc.