Messages in this thread | | | Date | Fri, 16 Mar 2007 13:47:18 -0700 (PDT) | Subject | Re: [PATCH 00/18] Make common x86 arch area for i386 and x86_64 - Take 2 | From | David Miller <> |
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From: Christoph Lameter <clameter@sgi.com> Date: Fri, 16 Mar 2007 13:15:38 -0700 (PDT)
> On Fri, 16 Mar 2007, Andi Kleen wrote: > > > > x86_64 is going to acquire more functionality that will not be available > > > for i386. We plan f.e. to add virtual memmap support for x86_64. Virtual > > > > What advantage would that have over the current setup? > > We already should handle holes between nodes reasonably efficiently > > and with nonlinear memory even holes inside nodes shouldn't be a problem. > > It is primarily a performance improvement since the sparsemem table > lookups would no longer be necessary and it also streamlines other > frequent cacheline uses. These page -> page_struct and vice versa > operations are key to the performance of various subsystem among them > the slab allocator.
If you set the bit range small enough and don't use sparsemem-extreme, the cost is extremely low considering the flexibility you obtain.
There are always going to be holes on large systems, there isn't really a way to avoid this given how addressing is done on those machines. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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