Re: [PATCH RFC 0/41] RCU commits for 3.4

From: Paul E. McKenney
Date: Thu Feb 02 2012 - 19:00:19 EST


On Thu, Feb 02, 2012 at 02:47:14PM -0800, Kevin Hilman wrote:
> Hi Paul,
>
> "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> writes:
>
> > This patchset makes RCU more aggressive about entering dyntick-idle mode
> > in order to improve energy efficiency,
>
> I gave this series a spin on an ARM/SMP platform (OMAP4) and the boot
> hung (tail end of boot log below.) I then realized that had isolcpus=1
> on the cmdline from a previous experiment. Removing isolcpus from the
> cmdline got me back to a working boot.
>
> IIRC, some want to remove isolcpus, so I'm not sure if it's expected to
> work with your series, but thought you'd want to know.

Not expected behavior, thank you for testing!

Could you please share your .config?

Thanx, Paul

> Kevin
>
>
>
> [ 1.105834] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
> [ 1.353942] omap_uart.0: ttyO0 at MMIO 0x4806a000 (irq = 104) is a OMAP UART0
> [ 1.462707] omap_uart.1: ttyO1 at MMIO 0x4806c000 (irq = 105) is a OMAP UART1
> [ 1.548614] omap_uart.2: ttyO2 at MMIO 0x48020000 (irq = 106) is a OMAP UART2
> [ 1.556304] console [ttyO2] enabled, bootconsole disabled
> [ 1.556304] console [ttyO2] enabled, bootconsole disabled
> [ 61.587493] INFO: rcu_sched detected stalls on CPUs/tasks: { 1} (detected by 0, t=7682 jiffies)
> [ 61.596649] INFO: Stall ended before state dump start
>

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