Re: [PATCH] sched: fix env->src_cpu for active migration

From: Damien Wyart
Date: Wed Feb 13 2013 - 09:15:15 EST

* Vincent Guittot <vincent.guittot@xxxxxxxxxx> [2013-02-13 13:08]:
> Damien,
> Regarding your sched_domain config and especially the flags field, you
> should not be impacted by my patch because
> - need_active_balance is the only new place that use env->src_cpu in
> the load_balance function
> - and your machine will never test the condition: "env->src_cpu >
> env->dst_cpu" in need_active_balance because SD_ASYM_PACKING is not
> set in your config

> Have you tested the patch with others that could have modified the
> load_balance function ?

Yes, sorry, I should have been more precise in my initial report: your
patch was not applied on top of vanilla 3.8-rc7, but a few other patches
were also present. Seems the ones impacting load_balance are from
Frederic's nohz work

The patches from there modifying load_balance are:
- "sched: Update nohz rq clock before searching busiest group on load balancing"
- "sched: Update clock of nohz busiest rq before balancing"

In this test, I did not use any kernel parameter related to this
patchset (full_nohz, etc.).

I am adding Frederic in Cc, not sure if the breakage is to be
investigated on your side or his...

Thanks for your explanations,
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