On 18 Sep 2000, Peter Osterlund wrote:
> Andrea Arcangeli <[EMAIL PROTECTED]> writes:
> 
> > > The only disadvantage I can see is that the new patch doesn't handle
> > > consecutive insertions in O(1) time, but then again, the pre-latency
> > 
> > We can still do that by trivially fixing a bit your code. You should first
> > check if the new inserted request is over the last in the current queue before
> > entering the tmp1/tmp2 logic.
> 
> Yes this can be done, but it will affect where requests are inserted.
> Suppose the queue currently contains:
> 
>       100 200 300 400 10 20 30
> 
> If request 150 is to be inserted, then with my previous patch it
> will be inserted between 100 and 200, but with the proposed
> change it will instead be inserted at the end.

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)

AND

2) the block number is smaller than head (or head->next
   if the current request is unplugged)

regards,

Rik
--
"What you're running that piece of shit Gnome?!?!"
       -- Miguel de Icaza, UKUUG 2000

http://www.conectiva.com/               http://www.surriel.com/

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