Messages in this thread | | | Date | Thu, 18 Mar 1999 17:17:27 GMT | From | "Stephen C. Tweedie" <> | Subject | Re: swapping slow downs in 2.2.1 |
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Hi,
On Mon, 15 Mar 1999 02:24:34 +0100 (CET), Andrea Arcangeli <andrea@e-mind.com> said:
> Looks like due swapspace fragmentation.
>> is it a bug, or is it a feature?
> Sure not a feature but neither a bug. To recover from that you can swapoff > -a as you did. Or maybe we could defrag the swap at runtime but I don't > think it's time to do that and I don't know how much it worth to do that.
There are a number of ideas I've got which I may try for 2.2.3, but the only one which looks like an obvious win for 2.2 itself is to use the same allocation heuristics used in ext2fs, which is to look for large aligned free spaces in the swap bitmaps when we allocate swap pages in the first place. Doing search for a free longword or byte in the swap bitmaps is pretty quick, and we can resort to a bit search if that fails. Ext2fs benefits greatly from that simple algorithm.
--Stephen
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