Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 25 Feb 2003 16:32:13 +0100 | From | Andrea Arcangeli <> | Subject | Re: vm issues (2) |
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On Tue, Feb 25, 2003 at 01:13:28PM +0100, Dejan Muhamedagic wrote: > Hello, > > The new kernel 2.4.21-pre4aa3 is running now, but the box behaves > similarly. It still swaps quite a lot and much more than the rmap > vm. Both servers are under the same load. > > One difference is the amount of free memory: > > r b w swpd free buff cache si so bi bo in cs us sy id > aa: > 0 7 0 5773620 202416 118076 2069716 5330 746 5330 766 4845 5597 12 14 74 > rmap: > 0 0 0 3498044 13572 4144 4754596 74 0 75 6 642 598 5 3 92 > > The aa kernel keeps ~200MB out of 6GB of memory unused. I'm not > sure, but if we could reduce it perhaps there would be much less > swapping. Is there a way to achieve this?
that is a feature, it guarantees highmem unfreeable allocations like pagetables can't eat all your normal zone. You can reduce the 200MB with this boot command:
lower_zone_reserve=256,256
As to decrease the swapping I just told you how to do that tweaking vm_mapped_ratio.
> > Another notable difference between the two vm versions is that the > rmap vm maintains about 80% of memory on the active list and the > aa vm much less: between 4% and 12%. The rmap vm must use more > CPU, but these servers have a lot of processing power so it is not > noticeable.
the theory was that rmap would reduce the cpu utilization but of course the patch don't do juts rmap.
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