Messages in this thread | | | Date | Fri, 7 May 2004 05:52:51 -0600 | From | Steve Young <> | Subject | Re: [PATCH] change pts allocation behaviour in |
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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. Using the patch though, it will only take 257 iterations. As time goes on and ptses get allocated and freed the situation becomes a bit murkier, but the patch should still cut down the number of iterations required to find a free pts.
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