Re: [PATCH] change pts allocation behaviour in

[Andrew Morton]

Steve Young <sdyoung@xxxxxxxxx> wrote:
>
> On Fri, May 07, 2004 at 04:14:42AM -0700, Andrew Morton wrote:
> > >  in the range of 0-255 first.  However, if that fails, then it will search the
> > >  higher ranges. 
> > 
> > Wouldn't we be better off with plain old first-fit-from-zero?
> 
>   In the typical case where <256 pts devices are allocated, you're right that
> there will be no benefit over the first-fit-from-zero implementation.  However 
> when there are a lot of pts devices in use, the algorithm used for searching 
> the high ranges ought to generally find a new pts in fewer iterations than
> just linearly searching from 0 to the maximum pts number.  For example, if a 
> system allocates 5000 ptses in a row, when it goes to look for a new one with 
> first-fit-from-zero, that's 5001 iterations to find an available pts.

first-fit-from-zero does not imply linear search!  The idr.c code provides
a logarithmic-time search.
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