Messages in this thread | | | Date | Wed, 23 Jan 2002 16:31:18 +1100 | From | Anton Blanchard <> | Subject | Re: [PATCH] One-liner typo 2.5.3-pre3 in ppc/kernel/idle.c |
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> Looks like need_resched conversion error.
Actually there is a (badly commented) optimisation here. (OK so it isn't commented at all :)
The code used to say:
int oldval = xchg(¤t->need_resched, -1);
if (!oldval) { while(current->need_resched == -1) ; /* Do Nothing */ }
We atomically grab the current value of need_resched and replace it with -1. The -1 tells the scheduler that we are busy looping and it doesnt need to send an IPI to force a reschedule.
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