linux-kernel - Re: [tip:x86/urgent] x86, mce: therm_throt

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Message-ID: <d1af83620908110531x5c7fb448r2a082a63ae22b95c@mail.gmail.com>
Date:	Tue, 11 Aug 2009 09:31:14 -0300
From:	Kevin Winchester <kjwinchester@...il.com>
To:	mingo@...hat.com, hpa@...or.com, linux-kernel@...r.kernel.org,
	dmitry.torokhov@...il.com, dtor@...l.ru, tglx@...utronix.de,
	mingo@...e.hu
Cc:	linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/urgent] x86, mce: therm_throt - change when we print 
	messages

2009/8/11 tip-bot for Dmitry Torokhov <dmitry.torokhov@...il.com>:
> Commit-ID:  0d01f31439c1e4d602bf9fdc924ab66f407f5e38
> Gitweb:     http://git.kernel.org/tip/0d01f31439c1e4d602bf9fdc924ab66f407f5e38
> Author:     Dmitry Torokhov <dmitry.torokhov@...il.com>
> AuthorDate: Sun, 9 Aug 2009 21:44:49 -0700
> Committer:  Ingo Molnar <mingo@...e.hu>
> CommitDate: Tue, 11 Aug 2009 09:54:17 +0200
>
> x86, mce: therm_throt - change when we print messages
>
> My Latitude d630 seems to be handling thermal events in SMI by
> lowering the max frequency of the CPU till it cools down but
> still leaks the "everything is normal" events.
>
> This spams the console and with high priority printks.
>
> Adjust therm_throt driver to only print messages about the fact
> that temperatire returned back to normal when leaving the
> throttling state.
>
> Also lower the severity of "back to normal" message from
> KERN_CRIT to KERN_INFO.
>
> Signed-off-by: Dmitry Torokhov <dtor@...l.ru>
> Acked-by: H. Peter Anvin <hpa@...or.com>
> LKML-Reference: <20090810051513.0558F526EC9@...lhub.coreip.homeip.net>
> Signed-off-by: Ingo Molnar <mingo@...e.hu>
>
>
> ---
>  arch/x86/kernel/cpu/mcheck/therm_throt.c |   18 +++++++++++-------
>  1 files changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
> index bff8dd1..8bc64cf 100644
> --- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
> +++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
> @@ -36,6 +36,7 @@
>
>  static DEFINE_PER_CPU(__u64, next_check) = INITIAL_JIFFIES;
>  static DEFINE_PER_CPU(unsigned long, thermal_throttle_count);
> +static DEFINE_PER_CPU(bool, thermal_throttle_active);
>
>  static atomic_t therm_throt_en         = ATOMIC_INIT(0);
>
> @@ -96,24 +97,27 @@ static int therm_throt_process(int curr)
>  {
>        unsigned int cpu = smp_processor_id();
>        __u64 tmp_jiffs = get_jiffies_64();
> +       bool was_throttled = __get_cpu_var(thermal_throttle_active);
> +       bool is_throttled = __get_cpu_var(thermal_throttle_active) = curr;

This seems a little odd (or perhaps my lack of experience is
showing...) - should it be:

bool is_throttled = __get_cpu_var(thermal_throttle_active) == curr;

?

>
> -       if (curr)
> +       if (is_throttled)
>                __get_cpu_var(thermal_throttle_count)++;
>
> -       if (time_before64(tmp_jiffs, __get_cpu_var(next_check)))
> +       if (!(was_throttled ^ is_throttled) &&
> +           time_before64(tmp_jiffs, __get_cpu_var(next_check)))
>                return 0;
>
>        __get_cpu_var(next_check) = tmp_jiffs + CHECK_INTERVAL;
>
>        /* if we just entered the thermal event */
> -       if (curr) {
> +       if (is_throttled) {
>                printk(KERN_CRIT "CPU%d: Temperature above threshold, "
> -                      "cpu clock throttled (total events = %lu)\n", cpu,
> -                      __get_cpu_var(thermal_throttle_count));
> +                      "cpu clock throttled (total events = %lu)\n",
> +                      cpu, __get_cpu_var(thermal_throttle_count));
>
>                add_taint(TAINT_MACHINE_CHECK);
> -       } else {
> -               printk(KERN_CRIT "CPU%d: Temperature/speed normal\n", cpu);
> +       } else if (was_throttled) {
> +               printk(KERN_INFO "CPU%d: Temperature/speed normal\n", cpu);
>        }
>
>        return 1;
> --
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