Messages in this thread | | | Date | Mon, 23 Jun 1997 09:04:21 +0300 (EET DST) | From | Johan Myréen <> | Subject | Re: KERNEL: Swapping Kernel Pages |
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On Sat, 21 Jun 1997, Randal Koene wrote:
> I've been going over the _old_ documentation to the Kernel's memory > management and the related sources, as well as the exception handlers. > And still it isn't clear to me what the actual reason is why Kernel pages > are taboo w.r.t. paging?
> Theoretically of course anything but the paging-code&page-fault handler > can be paged out (and since Kernel code is usually clean, it doesn't even > need to be swapped out as such, just reloaded). Is it just an issue of > speed? If so, I'd think that a cunningly efficient method could be devised > to offer just that extra little bit of physical memory at the minimum > possible swapping speed cost.
From a practical point of view, I don't see any reason why kernel code should be swapped, given the complexity and risks involved. The kernel size is essentially constant, only growing slightly with time with each release. The kernel is also just one piece of software, and the size of the kernel is not substantial compared to the typical amount of RAM in a machine today. In the old days it would have made sense to swap parts of the kernel too, today it could make sense to do that on very low-end hardware. Otherwise it is just putting off memory starvation just a little bit. I'd say install an extra megabyte of memory and be happy.
Johan Myreen jem@iki.fi
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