[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <4EBA5B3B.6010308@linux.vnet.ibm.com>
Date: Wed, 09 Nov 2011 16:21:39 +0530
From: Deepthi Dharwar <deepthi@...ux.vnet.ibm.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
CC: linux-kernel@...r.kernel.org, x86@...nel.org, len.brown@...el.com,
tglx@...utronix.de, jeremy@...p.org, hpa@...or.com, bp@...en8.de,
tj@...nel.org, trenn@...e.de, mingo@...hat.com,
xen-devel@...ts.xensource.com, stable@...nel.org
Subject: Re: [PATCH 1/3] cpuidle: If disable_cpuidle() is called, set pm_idle
to default_idle.
Just correcting the typo s/zen/xen/g .
On Wednesday 09 November 2011 03:49 PM, Deepthi Dharwar wrote:
> On Wednesday 09 November 2011 02:45 AM, Konrad Rzeszutek Wilk wrote:
>> . however we ignore the disable_cpuidle() directive and
>> in select_idle_routine() set it to type preferred by the CPU.
>>
>> This is a regression introduced by
>>
>> commit a0bfa1373859e9d11dc92561a8667588803e42d8
>> Author: Len Brown <len.brown@...el.com>
>> Date: Fri Apr 1 19:34:59 2011 -0400
>>
>> cpuidle: stop depending on pm_idle
>>
>> specifically this patch:
>>
>> commit d91ee5863b71e8c90eaf6035bff3078a85e2e7b5
>> Author: Len Brown <len.brown@...el.com>
>> Date: Fri Apr 1 18:28:35 2011 -0400
>>
>> cpuidle: replace xen access to x86 pm_idle and default_idle
>>
>> ..scribble on pm_idle and access default_idle,
>> have it simply disable_cpuidle() so acpi_idle will not load and
>> architecture default HLT will be used.
>>
>> .. but the default HLT does not get used. Instead we end up in the
>> situation that select_idle_routine() is called from arch/x86/kernel/cpu/common.c
>> and if we called cpuidle_disable(), then the pm_idle is not set, and
>> we end up setting pm_idle to mwait_idle or amd_e400_idle.
>>
>> This patch uses the cpuidle_disabled() functionality and
>> makes select_idle_routine() adhere to that.
>>
>> Reported-by: Stefan Bader <stefan.bader@...onical.com>
>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
>>
>> CC: Thomas Gleixner <tglx@...utronix.de>
>> CC: Ingo Molnar <mingo@...hat.com>
>> CC: "H. Peter Anvin" <hpa@...or.com>
>> CC: x86@...nel.org
>> CC: Len Brown <len.brown@...el.com>
>> CC: Borislav Petkov <bp@...en8.de>
>> CC: Tejun Heo <tj@...nel.org>
>> CC: Thomas Renninger <trenn@...e.de>
>> CC: stable@...nel.org
>> ---
>> arch/x86/kernel/process.c | 5 +++++
>> include/linux/cpuidle.h | 2 ++
>> 2 files changed, 7 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
>> index e7e3b01..1f7f8c8 100644
>> --- a/arch/x86/kernel/process.c
>> +++ b/arch/x86/kernel/process.c
>> @@ -14,6 +14,7 @@
>> #include <linux/utsname.h>
>> #include <trace/events/power.h>
>> #include <linux/hw_breakpoint.h>
>> +#include <linux/cpuidle.h>
>> #include <asm/cpu.h>
>> #include <asm/system.h>
>> #include <asm/apic.h>
>> @@ -587,6 +588,10 @@ void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
>> if (pm_idle)
>> return;
>>
>> + if (cpuidle_disabled()) {
>> + pm_idle = default_idle;
>> + return;
>> + }
>
>
> The above check is needed to initialise pm_idle to default_idle if
> cpuidle is disabled but this requirement here is xen specific.
> On other architectures, if cpuidle is disabled on boot then we
> rather would want mwait_idle or amd_e400_idle to be enabled than
> default_idle. Can we make this check xen specific ?
>
> ... if(XEN_ARCH && cpuidle_disabled()) ...
>
>
>
>
>> if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
>> /*
>> * One CPU supports mwait => All CPUs supports mwait
>> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
>> index b51629e..123fe9e 100644
>> --- a/include/linux/cpuidle.h
>> +++ b/include/linux/cpuidle.h
>> @@ -122,6 +122,7 @@ struct cpuidle_driver {
>> };
>>
>> #ifdef CONFIG_CPU_IDLE
>> +extern int cpuidle_disabled(void);
>> extern void disable_cpuidle(void);
>> extern int cpuidle_idle_call(void);
>>
>> @@ -137,6 +138,7 @@ extern int cpuidle_enable_device(struct cpuidle_device *dev);
>> extern void cpuidle_disable_device(struct cpuidle_device *dev);
>>
>> #else
>> +static inline int cpuidle_disabled(void) { return 1; }
>> static inline void disable_cpuidle(void) { }
>> static inline int cpuidle_idle_call(void) { return -ENODEV; }
>>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists