linux-kernel - Re: [PATCH] sched: use rq_lock/unlock in online_fair_sched

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Date:   Tue, 6 Aug 2019 09:58:59 -0400
From:   Phil Auld <pauld@...hat.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>
Subject: Re: [PATCH] sched: use rq_lock/unlock in online_fair_sched_group

On Tue, Aug 06, 2019 at 03:03:34PM +0200 Peter Zijlstra wrote:
> On Thu, Aug 01, 2019 at 09:37:49AM -0400, Phil Auld wrote:
> > Enabling WARN_DOUBLE_CLOCK in /sys/kernel/debug/sched_features causes
> 
> ISTR there were more issues; but it sure is good to start picking them
> off.

I haven't hit any others but if/when I'll try to dig into them. 

> 
> > warning to fire in update_rq_clock. This seems to be caused by onlining
> > a new fair sched group not using the rq lock wrappers.
> > 
> > [472978.683085] rq->clock_update_flags & RQCF_UPDATED
> > [472978.683100] WARNING: CPU: 5 PID: 54385 at kernel/sched/core.c:210 update_rq_clock+0xec/0x150
> 
> > Using the wrappers in online_fair_sched_group instead of the raw locking 
> > removes this warning. 
> 
> Yeah, that seems sane. Thanks!

Thanks,
Phil

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