linux-kernel - Re: [BUG, bisect] hrtimer: severe lag after suspend & resume

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Date:	Thu, 4 Jun 2015 13:13:08 -0700
From:	Jeremiah Mahler <jmmahler@...il.com>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	Preeti U Murthy <preeti@...ux.vnet.ibm.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Marcelo Tosatti <mtosatti@...hat.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	John Stultz <john.stultz@...aro.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [BUG, bisect] hrtimer: severe lag after suspend & resume

Thomas,

On Thu, Jun 04, 2015 at 01:22:45PM +0200, Thomas Gleixner wrote:
> On Wed, 3 Jun 2015, Jeremiah Mahler wrote:
[...]
> 
> I had to wrap my head around that for quite a while, but I think I
> have decoded the issue. Can you please test the patch below whether it
> solves your problem?
> 
> Thanks,
> 
> 	tglx
> 
> ------------------------>
> 
> diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
> index 278d4b36fd94..e9dfcd0b8c41 100644
> --- a/kernel/time/hrtimer.c
> +++ b/kernel/time/hrtimer.c
> @@ -1492,6 +1492,12 @@ static void init_hrtimers_cpu(int cpu)
>  
>  	cpu_base->cpu = cpu;
>  	hrtimer_init_hres(cpu_base);
> +	/*
> +	 * Force an update by setting the clock was set sequence to an
> +	 * odd value.
> +	 */
> +	cpu_base->clock_was_set_seq = 1;
> +	hrtimer_update_base(cpu_base);
>  }
>  
>  #ifdef CONFIG_HOTPLUG_CPU
> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
> index 90ed5db67c1d..c97710137a9e 100644
> --- a/kernel/time/timekeeping.c
> +++ b/kernel/time/timekeeping.c
> @@ -593,7 +593,7 @@ static void timekeeping_update(struct timekeeper *tk, unsigned int action)
>  	update_fast_timekeeper(&tk->tkr_raw,  &tk_fast_raw);
>  
>  	if (action & TK_CLOCK_WAS_SET)
> -		tk->clock_was_set_seq++;
> +		tk->clock_was_set_seq += 2;
>  }
>  
>  /**

With this change it won't boot.  It just hangs at "Booting the kernel".

-- 
- Jeremiah Mahler
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