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From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Tue, 4 Apr 2017 22:25:19 -0700
Message-ID: <CAM_iQpVTmDfATw1HMPE9NnRBNnhgidz+UZOQDqyeq2uo0=c-+g@mail.gmail.com>
Subject: Re: net/sched: latent livelock in dev_deactivate_many() due to
 yield() usage
To: Mike Galbraith <efault@gmx.de>
Cc: netdev <netdev@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>
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On Tue, Apr 4, 2017 at 8:20 PM, Mike Galbraith <efault@gmx.de> wrote:
> -               while (some_qdisc_is_busy(dev))
> -                       yield();
> +               swait_event_timeout(swait, !some_qdisc_is_busy(dev), 1);
>  }

I don't see why this is an improvement even if I don't care about the
hardcoded timeout for now... Why the scheduler can make a better
decision with swait_event_timeout() than with cond_resched()?