Re: Q: PAGE_CACHE_SIZE?

[Ralf Baechle <ralf@uni-koblenz.de>]

On Fri, May 28, 1999 at 09:46:01PM +0100, Stephen C. Tweedie wrote:


> If we did in fact use the 4k minipage for all kernel get_free_page()
> allocations as usual, but used the larger 32k buddy heap pages for all
> VM allocations, then 8K kernel allocations (eg. stack allocations and
> large NFS packets) become trivial to deal with.
> 
> The biggest problem we have had with these multi-page allocations up to
> now is fragmentation in the VM.  If we populate the _entire_ VM in
> multiples of 8k or more then we can never see such fragmentation at all.
> 8k might actually be a reasonable pagesize even on low memory machines:
> we found in 2.2 that the increased size of the kernel was compensated
> for by more efficient swapping so that things still went faster in low
> memory than under 2.2, and large pages may well have the same tradeoff.

I'm working on Linux/MIPS64 and I intend to cleanup the code such that the
kernel can be built for different page sizes.  I intend to benchmark
things for curiosity.  Maybe it's some viable system tuning option, even
though a compile time one.

  Ralf
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