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From: Andrew Morton <akpm@osdl.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
	Jim Gettys <jg@laptop.org>, John Stultz <johnstul@us.ibm.com>,
	David Woodhouse <dwmw2@infradead.org>,
	Arjan van de Ven <arjan@infradead.org>,
	Dave Jones <davej@redhat.com>
Subject: Re: [patch 18/23] dynticks: i386 arch code
Date: Sat, 30 Sep 2006 01:45:24 -0700	[thread overview]
Message-ID: <20060930014524.64b49016.akpm@osdl.org> (raw)
In-Reply-To: <20060929234440.865232000@cruncher.tec.linutronix.de>

On Fri, 29 Sep 2006 23:58:37 -0000
Thomas Gleixner <tglx@linutronix.de> wrote:

> From: Ingo Molnar <mingo@elte.hu>
> 
> prepare i386 for dyntick: idle handler callbacks and IRQ callback.
> 
> Index: linux-2.6.18-mm2/arch/i386/kernel/nmi.c
> ===================================================================
> --- linux-2.6.18-mm2.orig/arch/i386/kernel/nmi.c	2006-09-30 01:41:10.000000000 +0200
> +++ linux-2.6.18-mm2/arch/i386/kernel/nmi.c	2006-09-30 01:41:19.000000000 +0200
> @@ -20,6 +20,7 @@
>  #include <linux/sysdev.h>
>  #include <linux/sysctl.h>
>  #include <linux/percpu.h>
> +#include <linux/kernel_stat.h>
>  #include <linux/dmi.h>
>  #include <linux/kprobes.h>
>  
> @@ -908,7 +909,7 @@ __kprobes int nmi_watchdog_tick(struct p
>  		touched = 1;
>  	}
>  
> -	sum = per_cpu(irq_stat, cpu).apic_timer_irqs;
> +	sum = per_cpu(irq_stat, cpu).apic_timer_irqs + kstat_irqs(0);

Why?

> ===================================================================
> --- linux-2.6.18-mm2.orig/arch/i386/kernel/process.c	2006-09-30 01:41:10.000000000 +0200
> +++ linux-2.6.18-mm2/arch/i386/kernel/process.c	2006-09-30 01:41:19.000000000 +0200
> @@ -178,24 +178,27 @@ void cpu_idle(void)
>  
>  	/* endless idle loop with no priority at all */
>  	while (1) {
> -		while (!need_resched()) {
> -			void (*idle)(void);
> +		if (!hrtimer_stop_sched_tick()) {
> +			while (!need_resched()) {

I don't see why hrtimer_stop_sched_tick() returns need_resched().  We
immediately reevaluate it anyway.  hrtimer_stop_sched_tick() could return 1.

> +				void (*idle)(void);
>  
> -			if (__get_cpu_var(cpu_idle_state))
> -				__get_cpu_var(cpu_idle_state) = 0;
> +				if (__get_cpu_var(cpu_idle_state))
> +					__get_cpu_var(cpu_idle_state) = 0;
>  
> -			rmb();
> -			idle = pm_idle;
> +				rmb();
> +				idle = pm_idle;
>  
> -			if (!idle)
> -				idle = default_idle;
> +				if (!idle)
> +					idle = default_idle;
>  
> -			if (cpu_is_offline(cpu))
> -				play_dead();
> +				if (cpu_is_offline(cpu))
> +					play_dead();
>  
> -			__get_cpu_var(irq_stat).idle_timestamp = jiffies;
> -			idle();
> +				__get_cpu_var(irq_stat).idle_timestamp = jiffies;
> +				idle();
> +			}
>  		}
> +		hrtimer_restart_sched_tick();
>  		preempt_enable_no_resched();
>  		schedule();
>  		preempt_disable();
> 


  reply	other threads:[~2006-09-30  8:46 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-09-29 23:58 [patch 00/23] Thomas Gleixner
2006-09-29 23:58 ` [patch 01/23] GTOD: exponential update_wall_time Thomas Gleixner
2006-09-29 23:58 ` [patch 02/23] GTOD: persistent clock support, core Thomas Gleixner
2006-09-30  8:35   ` Andrew Morton
2006-09-30 17:15     ` Jan Engelhardt
2006-10-02 21:49     ` john stultz
2006-09-29 23:58 ` [patch 03/23] GTOD: persistent clock support, i386 Thomas Gleixner
2006-09-30  8:36   ` Andrew Morton
2006-10-02 22:03     ` john stultz
2006-10-02 22:44       ` Andrew Morton
2006-10-02 23:09         ` john stultz
2006-10-03 23:30         ` Thomas Gleixner
2006-09-29 23:58 ` [patch 04/23] time: uninline jiffies.h Thomas Gleixner
2006-09-29 23:58 ` [patch 05/23] time: fix msecs_to_jiffies() bug Thomas Gleixner
2006-09-29 23:58 ` [patch 06/23] time: fix timeout overflow Thomas Gleixner
2006-09-29 23:58 ` [patch 07/23] cleanup: uninline irq_enter() and move it into a function Thomas Gleixner
2006-09-30  8:36   ` Andrew Morton
2006-09-29 23:58 ` [patch 08/23] dynticks: prepare the RCU code Thomas Gleixner
2006-09-30  8:36   ` Andrew Morton
2006-09-30 12:25     ` Dipankar Sarma
2006-09-30 13:09       ` Ingo Molnar
2006-09-30 13:52         ` Dipankar Sarma
2006-09-30 21:35           ` Ingo Molnar
2006-09-29 23:58 ` [patch 09/23] dynticks: extend next_timer_interrupt() to use a reference jiffie Thomas Gleixner
2006-09-30  8:37   ` Andrew Morton
2006-09-29 23:58 ` [patch 10/23] hrtimers: clean up locking Thomas Gleixner
2006-09-30  8:37   ` Andrew Morton
2006-09-29 23:58 ` [patch 11/23] hrtimers: state tracking Thomas Gleixner
2006-09-30  8:37   ` Andrew Morton
2006-09-29 23:58 ` [patch 12/23] hrtimers: clean up callback tracking Thomas Gleixner
2006-09-29 23:58 ` [patch 13/23] clockevents: core Thomas Gleixner
2006-09-30  8:39   ` Andrew Morton
2006-10-03  4:33     ` John Kacur
2006-09-29 23:58 ` [patch 14/23] clockevents: drivers for i386 Thomas Gleixner
2006-09-30  8:40   ` Andrew Morton
2006-09-29 23:58 ` [patch 15/23] high-res timers: core Thomas Gleixner
2006-09-30  8:43   ` Andrew Morton
2006-09-29 23:58 ` [patch 16/23] dynticks: core Thomas Gleixner
2006-09-30  8:44   ` Andrew Morton
2006-09-30 12:11     ` Dipankar Sarma
2006-09-29 23:58 ` [patch 17/23] dyntick: add nohz stats to /proc/stat Thomas Gleixner
2006-09-29 23:58 ` [patch 18/23] dynticks: i386 arch code Thomas Gleixner
2006-09-30  8:45   ` Andrew Morton [this message]
2006-09-29 23:58 ` [patch 19/23] high-res timers, dynticks: enable i386 support Thomas Gleixner
2006-09-29 23:58 ` [patch 20/23] add /proc/sys/kernel/timeout_granularity Thomas Gleixner
2006-09-30  8:45   ` Andrew Morton
2006-09-29 23:58 ` [patch 21/23] debugging feature: timer stats Thomas Gleixner
2006-09-30  8:46   ` Andrew Morton
2006-09-29 23:58 ` [patch 22/23] dynticks: increase SLAB timeouts Thomas Gleixner
2006-09-30  8:49   ` Andrew Morton
2006-09-29 23:58 ` [patch 23/23] dynticks: decrease I8042_POLL_PERIOD Thomas Gleixner
2006-09-30  8:49   ` Andrew Morton
2006-09-30  8:35 ` [patch 00/23] Andrew Morton
2006-09-30 19:17   ` Thomas Gleixner
2006-09-30  8:35 ` Andrew Morton

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