Messages in this thread | | | From | Daniel Phillips <> | Subject | Re: discontiguous memory platforms | Date | Thu, 2 May 2002 22:14:02 +0200 |
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On Thursday 02 May 2002 21:40, Roman Zippel wrote: > Daniel Phillips wrote: > > > Patching the kernel how, and where? > > Check for example in asm-ppc/page.h the __va/__pa functions.
OK, by 'patching the kernel' you must mean 'initialize the m68k_memory array'.
The loop you use does have one advantage: it can handle size variation vs a shift-lookup strategy. It's a lot more expensive though, and these are heavily used operations.
> > > Anyway, I agree with Andrea, that another mapping isn't really needed. > > > Clever use of the mmu should give you almost the same result. > > > > We *are* making clever use of the mmu in config_nonlinear, it is doing the > > nonlinear kernel virtual mapping for us. Did you have something more clever > > in mind? > > I mean to map the memory where you need it. The physical<->virtual > mapping won't be one to one, but you won't need another abstraction and > the current vm is already basically able to handle it.
I'll accept 'not needed for 68K', though I guess config_nonlinear will work perfectly well for you and be faster than the loops. However, some of the problems that config_nonlinear solves cannot be solved by any existing kernel mechanism. We've been over the NUMA-Q and mips32 cases in detail, so I won't reiterate.
Thanks for your input.
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