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Date: Tue, 8 Jul 2014 15:39:46 -0400 (EDT)
From: Rick Macklem <rmacklem@uoguelph.ca>
To: Hans Petter Selasky <hps@selasky.org>
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Subject: Re: [RFC] Allow m_dup() to use JUMBO clusters
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Hans Petter Selasky wrote:
> >
> > Hi,
> >
> > Would it be better if my patch used the PAGE_SIZE clusters instead
> > of
> > the 16K ones? Then it should not be affected by memory
> > defragmentation.
> > Thanks for shedding some light into this area?
> >
Well, I ran into the threads stuck on "btalloc" when I used PAGE_SIZE
clusters mixed with MCLBYTES clusters and from what I could figure, it
was a kernel address space fragmentation issue.

I would guess that PAGE_SIZE clusters aren't as bad as 16K clusters w.r.t.
fragmentation, but I believe that they could still be an issue. (My testing
was on a 256Mbyte i386, so I can't say if amd64 systems will have a problem,
just that small 32bit arches will.)

rick

> > --HPS
> >
> 
> Hi,
> 
> Updated patch attached.
> 
> --HPS
> 
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