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

From: Peter Zijlstra
Date: Tue Nov 04 2014 - 05:52:19 EST


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?

Also, try and introduce some newlines in the changelog, paragraphs of
3-5 lines are best.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/