Subject: Re: [patch] sched: fix SMT scheduler regression in
 find_busiest_queue()
From: Peter Zijlstra <peterz@infradead.org>
To: svaidy@linux.vnet.ibm.com
Cc: Suresh Siddha <suresh.b.siddha@intel.com>, Ingo Molnar <mingo@redhat.com>,
       LKML <linux-kernel@vger.kernel.org>, "Ma, Ling" <ling.ma@intel.com>,
       "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>, ego@in.ibm.com
In-Reply-To: <20100216182346.GA19327@dirshya.in.ibm.com>
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Date: Tue, 16 Feb 2010 19:48:55 +0100
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On Tue, 2010-02-16 at 23:55 +0530, Vaidyanathan Srinivasan wrote:
> The sched_domain will be rebuilt with the sched_group_cpus()
> representing only online siblings right?  sched_group_cpus(group) will
> always be a subset of cpu_active_mask.  Can please explain your
> comment. 

__build_*_sched_domain() seems to only rebuild the sd->span, not the
sched_group's mask, cpu_to_*_group() only picks an existing group based
on the cpumask passed in, it doesn't change sg->cpumask afaict.

That is also the reason we drag load_balance_tmpmask all through
load_balance() afaict.


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