Re: [RFC][PATCH 0/6] Critical Page Pool

[Sridhar Samudrala <sri@us.ibm.com>]

Matthew Dobson wrote:

> Pavel Machek wrote:
>  
>
> > > > And as you noticed, it does not work for your original usage case,
> > > > because reserved memory pool would have to be "sum of all network
> > > > interface bandwidths * ammount of time expected to survive without
> > > > network" which is way too much.
> > > >        
> > > Well, I never suggested it didn't work for my original usage case.  The
> > > discussion we had is that it would be incredibly difficult to 100%
> > > iron-clad guarantee that the pool would NEVER run out of pages.  But we can
> > > size the pool, especially given a decent workload approximation, so as to
> > > make failure far less likely.
> > >      
> > Perhaps you should add file in Documentation/ explaining it is not
> > reliable?
> >    
>
> That's a good suggestion.  I will rework the patch's additions to
> Documentation/sysctl/vm.txt to be more clear about exactly what we're
> providing.
>
>
>  
>
> > > > If you want few emergency pages for some strange hack you are doing
> > > > (swapping over network?), just put swap into ramdisk and swapon() it
> > > > when you are in emergency, or use memory hotplug and plug few more
> > > > gigabytes into your machine. But don't go introducing infrastructure
> > > > that _can't_ be used right.
> > > >        
> > > Well, that's basically the point of posting these patches as an RFC.  I'm
> > > not quite so delusional as to think they're going to get picked up right
> > > now.  I was, however, hoping for feedback to figure out how to design
> > > infrastructure that *can* be used right, as well as trying to find other
> > > potential users of such a feature.
> > >      
> > Well, we don't usually take infrastructure that has no in-kernel
> > users, and example user would indeed be nice.
> > 							Pavel
> >    
>
> Understood.  I certainly wouldn't expect otherwise.  I'll see if I can get
> Sridhar to post his networking changes that take advantage of this.
>  
I have posted these patches yesterday on lkml and netdev and here is a 
link to the thread.
   http://thread.gmane.org/gmane.linux.kernel/357835
 
Thanks
Sridhar

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