Re: [Devel] Re: [RFC] Virtualization steps

From: Andi Kleen
Date: Wed Apr 12 2006 - 13:03:42 EST


Kirill Korotaev <dev@xxxxx> writes:
>
> -------------- cut ---------------
> Changing PAGE_OFFSET this way would break at least Valgrind (the latest
> release 3.1.0 by default is statically linked at address 0xb0000000, and
> PIE support does not seem to be present in that release). I remember
> that similar changes were also breaking Lisp implementations (cmucl,
> sbcl), however, I am not really sure about this.
> -------------- cut ---------------

valgrind only breaks when you decrease TASK_SIZE to 2GB, not when you
enlarge it. In general 2GB VM breaks a lot of apps, that is why
the new CONFIGs that were added for this were a very bad idea imho.

Obviously the x86-64 kernel doesn't support such things.

> Also, why would one expect 4GB of VM on x86-64 if normally have 3GB on
> i686? Anyway, as it is tunable, people can select which one they
> prefer.

Because near all programs that need can actually take advance of it.

-Andi

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