Increasing MAXPHYS

Alexander Motin mav at FreeBSD.org
Sun Mar 21 17:04:01 UTC 2010


Scott Long wrote:
> On Mar 20, 2010, at 1:26 PM, Alexander Motin wrote:
>> As you should remember, we have made it in such way, that all unchecked
>> drivers keep using DFLTPHYS, which is not going to be changed ever. So
>> there is no problem. I would more worry about non-CAM storages and above
>> stuff, like some rare GEOM classes.
> 
> And that's why I say that everything needs to be audited.  Are there CAM drivers
> that default to being silent on cpi->maxio, but still look at DFLTPHYS and MAXPHYS?

If some (most of) drivers silent on cpi->maxio - they will be limited by
safe level of DFLTPHYS, which should not be changed ever. There should
be no problem.

> Are there non-CAM drivers that look at MAXPHYS, or that silently assume that
> MAXPHYS will never be more than 128k?

That is a question.

-- 
Alexander Motin


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