linux-kernel - Re: [v8 PATCH 1/8]: cpuidle: cleanup drivers/cpuidle/cpuidle.c

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Message-ID: <20091012113602.GC3007@balbir.in.ibm.com>
Date:	Mon, 12 Oct 2009 17:06:02 +0530
From:	Balbir Singh <balbir@...ux.vnet.ibm.com>
To:	Arun R Bharadwaj <arun@...ux.vnet.ibm.com>
Cc:	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Ingo Molnar <mingo@...e.hu>,
	Vaidyanathan Srinivasan <svaidy@...ux.vnet.ibm.com>,
	Dipankar Sarma <dipankar@...ibm.com>,
	Arjan van de Ven <arjan@...radead.org>,
	linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
	linux-arch@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: Re: [v8 PATCH 1/8]: cpuidle: cleanup drivers/cpuidle/cpuidle.c

* Arun R B <arun@...ux.vnet.ibm.com> [2009-10-08 15:19:42]:

> * Arun R Bharadwaj <arun@...ux.vnet.ibm.com> [2009-10-08 15:18:28]:
> 
> This patch cleans up drivers/cpuidle/cpuidle.c
> Earlier cpuidle assumed pm_idle as the default idle loop. Break that
> assumption and make it more generic. cpuidle_idle_call() which is the
> main idle loop of cpuidle is to be called by architectures which have
> registered to cpuidle.
> 
> Remove routines cpuidle_install/uninstall_idle_handler() which are not
> needed anymore.
> 
>

[snip]

  /**
> - * cpuidle_install_idle_handler - installs the cpuidle idle loop handler
> - */
> -void cpuidle_install_idle_handler(void)
> -{
> -	if (enabled_devices && (pm_idle != cpuidle_idle_call)) {
> -		/* Make sure all changes finished before we switch to new idle */
> -		smp_wmb();
> -		pm_idle = cpuidle_idle_call;
> -	}
> -}
> -
> -/**
> - * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
> - */
> -void cpuidle_uninstall_idle_handler(void)
> -{
> -	if (enabled_devices && pm_idle_old && (pm_idle != pm_idle_old)) {
> -		pm_idle = pm_idle_old;
> -		cpuidle_kick_cpus();
> -	}
> -}
> -

I see the routines above being called in from
cpuidle_pause/resume_and_lock/unlock below and they are entries from
ACPI on ACPI_PROCESSOR_NOTIFY_POWER and from the hotplug path, could
you test them to make sure they are not broken. We also seem to be
missing a cpuidle_kick_cpus() in cpuidle_pause_and_lock()

[snip]

-- 
	Balbir
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