From: Rusty Russell <rusty@rustcorp.com.au>
To: "Luck, Tony" <tony.luck@intel.com>
Subject: Re: [patch 01/41] cpu_alloc: Increase percpu area size to 128k
Date: Tue, 3 Jun 2008 09:48:25 +1000
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Cc: "Christoph Lameter" <clameter@sgi.com>, akpm@linux-foundation.org,
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       "Eric Dumazet" <dada1@cosmosbay.com>,
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On Tuesday 03 June 2008 03:58:17 Luck, Tony wrote:
> > The per cpu allocator requires more per cpu space and we are already near
> > the limit on IA64. Increase the maximum size of the IA64 per cpu area
> > from 64K to 128K.
> >
> > -#define PERCPU_PAGE_SHIFT	16	/* log2() of max. size of per-CPU area */
> > +#define PERCPU_PAGE_SHIFT	17	/* log2() of max. size of per-CPU area */
>
> Don't you need some more changes to the alt_dtlb_miss handler in
> ivt.S for this to work?  128K is not a supported pagesize on any
> processor model.

Yes, this was one of the issues with IA64 and extending the per-cpu area.  
It's probable that the IA64 TLB nailing trick might have to give way for 
dynamic per-cpu...

Rusty.
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