Messages in this thread |  | | Date | Mon, 3 Oct 2016 14:49:07 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 1/7] sched/fair: Update the rq clock before detaching tasks |
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On Wed, Sep 21, 2016 at 02:38:07PM +0100, Matt Fleming wrote: > detach_task_cfs_rq() may indirectly call rq_clock() to inform the > cpufreq code that the rq utilisation has changed. In which case, we > need to update the rq clock.
Hurm,. so it would've been good to know the callchain that got you there.
There's two functions that use detach_task_cfs_rq(), one is through sched_change_group() and that does indeed lack a rq_clock update.
The other is through switched_from() where its far harder (but still possible afaict) to miss the update.
Now, neither cases are really fast paths, but it would be good to try and avoid too many update_rq_clock() calls in the same rq-lock section. So I'm not entirely sure about the placement here.
But let me go stare at the actual debug framework thing first.. I think this patch is fallout/fixups from that.
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