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Re: uarea swap-out



Mindaugas Rasiukevicius wrote:
matthew green <mrg%eterna.com.au@localhost> wrote:
i'm really curious how this affects platforms with very
few hardware pages, like acorn26.


I cannot measure that empirically, therefore CC'ing port-acorn26 and
port-acorn32 lists. There are few points regarding this:

- Merge of lwp_cache and uarea (it puts struct lwp, pcb and kstack together)
  should have positive effect i.e. it would increase the utilisation of pages.

- The criteria when LWP can be swapped-out is relatively strict i.e. there
  are already many states when it cannot, see swappable() in uvm_glue.c.

- If your machine starts swapping uareas, I think it is already quite a
  hammer, especially for machines like acorn26/32.

Newer patch removing uarea swap-out:

I'll give it a try on an acorn32 machine next weekend. I assume the patch is for a current kernel.

Mike



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