[openib-general] Re: Re: Re: madvise MADV_DONTFORK/MADV_DOFORK

Gleb Natapov glebn at voltaire.com
Wed Feb 15 06:46:46 PST 2006


On Wed, Feb 15, 2006 at 04:36:22PM +0200, Michael S. Tsirkin wrote:
> Quoting r. Gleb Natapov <glebn at voltaire.com>:
> > > ibv_reg_mr works fine for sub-page regions. Doesnt it?
> > > 
> > Not really. It gives you the impression that it works by not returning an
> > error and aligning address and lengths for you. Same case with mmap(). You
> > can provide nonaligned length and it will not fail.
> 
> As far as I know hardware supports non-aligned regions and so does ibv_reg_mr:
> try to access outside the region and you'll get completion with error.
> No? If not, let me know - it should be easy to fix.
> 
Of cause you are right about reg_mr effect in regards to infiniband protocol. 
I was talked about the effect on VM subsystem. Any real program can't
ignore this. I just want to move complexity to one place.

--
			Gleb.



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