Messages in this thread | | | Date | Sun, 18 Oct 1998 07:07:33 +0200 (CEST) | From | MOLNAR Ingo <> | Subject | Re: [patch] jiffies wraparound [Re: 2.1.125 Show stopper list: Draft] |
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On Sun, 18 Oct 1998, Alan Cox wrote:
> 1.2 survives mostly, 2.0 survives mostly, 2.1.x doesnt survive
while being correct isnt the issue for 2.2, not hanging on a wraparound would be nice to have. Theres another problematic area, 'task->timeout' usage. The basic problem is that ->timeout is measured in absolute jiffies, instead of delta. timeout == -1 is used as an indicator of 'never time out', which is incorrect if we are near to a wraparound. Also, timeout == 0 is internally used as 'no manual timeout for this process', which is also incorrect when we wrap around.
these problems could as well result in a timer not being set, so this could theoretically explain the tty problems on wraparound as well.
the right thing i think is a 'delta' timeout instead of an absolute timeout, but this is definitely not a 2.2 issue. Since most places artifically add 'jiffies' to some delta timeout anyway before setting current->timeout, this looks clean as well.
-- mingo
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