Re: [PATCH] sched/fair: fix use stale overloaded status to find busiest group

From: Wanpeng Li
Date: Tue Nov 04 2014 - 06:08:37 EST


Hi Peter,
On 14/11/4 äå6:52, Peter Zijlstra wrote:
On Tue, Nov 04, 2014 at 01:30:56PM +0800, Wanpeng Li wrote:
Commit caeb178c60f4 ("sched/fair: Make update_sd_pick_busiest() return
'true' on a busier sd") makes groups are ranked in the order overloaded >
imbalance > other and busiest group is picked according to this order.
sgs->group_capacity_factor is used to check if group is overloaded. In
the case of the child domain prefers tasks go to siblings first, the
sgs->group_capacity_factor will be set lower to one in order to move all
the excess tasks away. However, group overloaded status is not updated
in the case of sgs->group_capacity_factor be set lower to one which
leads to miss find the busiest group. This patch fix it by updating
group overloaded status in the case of sg capacity factor is set to
one in order to find busiest group accurately.
You noticed this while going over Vincents patches, right?

Indeed. ;-)


Also, try and introduce some newlines in the changelog, paragraphs of
3-5 lines are best.

Ok, I will send a new version tomorrow. ;-)

Regards,
Wanpeng Li

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