Re: PATCH(?): linux-2.4.4-pre2: fork should run child first

["Adam J. Richter" <adam@yggdrasil.com>]

Hubertus Franke <frankeh@us.ibm.com> writes:

>Try this ... this will guarantee that (p->counter) > (current->counter)
>and it seems not as radical

>         p->counter = (current->counter + 1) >> 1;
>        current->counter = (current->counter - 1) >> 1;
>        if (!current->counter)
>                current->need_resched = 1;

>instead of this


>-       p->counter = (current->counter + 1) >> 1;
>-       current->counter >>= 1;
>-       if (!current->counter)
>-               current->need_resched = 1;
>+       p->counter = current->counter;
>+       current->counter = 0;
>+       current->need_resched = 1;


	No.  I tried your change and also tried it with setting
current->need_resched to 1 in all cases, and it still seems to run the
parent first in at least half of the tries.  Evidently,
current->counter must be zero to make the currently running process
give up the CPU immediately, which is the important thing (so that the
parent does not touch its virtual memory for a while).

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