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

From: Kevin Hilman
Date: Thu Feb 02 2012 - 17:47:26 EST

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.


[ 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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