Re: [PATCH] sched/fair: Care divide error in update_task_scan_period()

From: Yasuaki Ishimatsu
Date: Thu Oct 09 2014 - 01:20:31 EST


(2014/10/09 1:54), Peter Zijlstra wrote:
On Wed, Oct 08, 2014 at 12:42:24PM -0400, Rik van Riel wrote:
On 10/08/2014 02:43 AM, Yasuaki Ishimatsu wrote:

The divide error is rare case because the trigger is node offline.
By this patch, when both of private and shared are set to 0, diff
is just set to 0, not calculating the division.

How about a simple

if (private + shared) == 0)
return;

higher up in the function, to avoid adding an extra
layer of indentation and confusion to the main part
of the function?

At which point we'll have 3 different return semantics. Should we not
clear numa_faults_localityp[], even in this case?


I'm not familiar with Numa balancing feature. So I want to know it too.
If it's not necessary to clear numa_faults_locality[], I'll apply the idea.

Thanks,
Yasuaki Ishimatsu

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