Messages in this thread |  | | Date | Tue, 19 Sep 2000 16:21:19 +0200 | From | Andrea Arcangeli <> | Subject | Re: An elevator algorithm (patch) |
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On Tue, Sep 19, 2000 at 07:17:42AM -0300, Rik van Riel wrote: > This is a bug in Andrea's idea. The request should only > be inserted at the end of the list if: > > 1) the block numbre is bigger than head->prev (which you > already have)
If you read the code you'll see that in his previous patch he wasn't doing that. That's what I suggested to change to return in O(1) behaviour.
> 2) the block number is smaller than head (or head->next > if the current request is unplugged)
You're wrong. While the queue is unplugged there are peaks in the queue caused by the latency control and head->next is not guarnateed to be the lower block in the queue.
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