On Wednesday 07 August 2002 04:57, Andrew Morton wrote:
> Anton Blanchard wrote:
> > On ppc64 shared pagetables will require significant changes to the way
> > we handle the hardware hashtable. So add that to the "more and more crap
> > in there to support these pte_chains"
>
> Last I heard, pagetable sharing wasn't working out too well
> because they all get unshared.
That's only when you fork from a process with a minimal amount of VM mapped,
such as bash, which has 3 page tables allocated to it, all of which get
unshared. The situation is entirely different if you fork from a process
that has malloced more than a few meg, or beaten on a large mmap. Page table
sharing turns in a significant win there.
> > Will shared pagetables be a requirement or can we turn it on per arch?
>
> It's doubtful if per-arch would be an option.
It's currently expressed as a config option. As it's purely an optimization
there's no reason to do otherwise. Disabling it per-arch should be trivial.
> - We'll continue to suck for the University workload.
That seems likely ;-)
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This archive was generated by hypermail 2b29 : Thu Aug 15 2002 - 22:00:19 EST