Re: [PATCH v2] sched/fair: fix nohz next idle balance

[Mel Gorman]

On Tue, Jun 09, 2020 at 02:37:48PM +0200, Vincent Guittot wrote:
> With commit:
>   'b7031a02ec75 ("sched/fair: Add NOHZ_STATS_KICK")'
> rebalance_domains of the local cfs_rq happens before others idle cpus have
> updated nohz.next_balance and its value is overwritten.
> 
> Move the update of nohz.next_balance for other idles cpus before balancing
> and updating the next_balance of local cfs_rq.
> 
> Also, the nohz.next_balance is now updated only if all idle cpus got a
> chance to rebalance their domains and the idle balance has not been aborted
> because of new activities on the CPU. In case of need_resched, the idle
> load balance will be kick the next jiffie in order to address remaining
> ilb.
> 
> Reported-by: Peng Liu <iwtbavbm@xxxxxxxxx>
> Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>

Acked-by: Mel Gorman <mgorman@xxxxxxx>

-- 
Mel Gorman
SUSE Labs