From patchwork Fri Feb  8 03:14:47 2013
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Subject: [4/8] cputime: Generic on-demand virtual cputime accounting
From: Stephen Rothwell <sfr@canb.auug.org.au>
X-Patchwork-Id: 219032
Message-Id: <20130208141447.03914013db9a5f7308fc1675@canb.auug.org.au>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>, Li Zhong <zhong@linux.vnet.ibm.com>, 
 Peter Zijlstra <peterz@infradead.org>,
 LKML <linux-kernel@vger.kernel.org>, Steven Rostedt <rostedt@goodmis.org>,
 Paul Gortmaker <paul.gortmaker@windriver.com>,
 Thomas Gleixner <tglx@linutronix.de>,
 Andrew Morton <akpm@linux-foundation.org>,
 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
 ppc-dev <linuxppc-dev@lists.ozlabs.org>, Ingo Molnar <mingo@kernel.org>
Date: Fri, 8 Feb 2013 14:14:47 +1100

Hi Frederic,

On Fri, 8 Feb 2013 14:07:49 +1100 Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
> This patch has the side effect of changing the default configurations:
> (This is PowerPC pseries_defconfig before/after this patch)
> 
> @@ -119,8 +120,8 @@
>  #
>  # CPU/Task time and stats accounting
>  #
> -# CONFIG_TICK_CPU_ACCOUNTING is not set
> -CONFIG_VIRT_CPU_ACCOUNTING=y
> +CONFIG_TICK_CPU_ACCOUNTING=y
> +# CONFIG_VIRT_CPU_ACCOUNTING_NATIVE is not set
>  # CONFIG_BSD_PROCESS_ACCT is not set
>  CONFIG_TASKSTATS=y
>  CONFIG_TASK_DELAY_ACCT=y
> 
> I don't know if that was deliberate, but it was suprising.  I noticed
> when this patch entered next-20130207.

I suspect that this is caused by the changes to init/Kconfig:


The next line of context is:

        default VIRT_CPU_ACCOUNTING if PPC64

Which may have needed changing as well?  Indeed, changing that to
VIRT_CPU_ACCOUNTING_NATIVE restores the old defaults.


diff --git a/init/Kconfig b/init/Kconfig
index be8b7f5..a05f843 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -326,6 +326,9 @@ source "kernel/time/Kconfig"
 
 menu "CPU/Task time and stats accounting"
 
+config VIRT_CPU_ACCOUNTING
+	bool
+
 choice
 	prompt "Cputime accounting"
 	default TICK_CPU_ACCOUNTING if !PPC64