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From: Ingo Molnar <mingo@elte.hu>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@osdl.org>,
	LKML <linux-kernel@vger.kernel.org>,
	John Stultz <johnstul@us.ibm.com>,
	Arjan van de Veen <arjan@infradead.org>,
	Roman Zippel <zippel@linux-m68k.org>
Subject: [patch] clocksource: add verification (watchdog) helper, fix
Date: Wed, 24 Jan 2007 16:42:27 +0100	[thread overview]
Message-ID: <20070124154227.GA20726@elte.hu> (raw)
In-Reply-To: <20070123211205.541044000@localhost.localdomain>


one out of my 10 testsystems didnt properly enter high-res mode (but 
safely fell back to low-res mode), the patch below fixes this.

	Ingo

---------------------------->
Subject: [patch] clocksource: add verification (watchdog) helper, fix
From: Ingo Molnar <mingo@elte.hu>

if a clocksource is being verified by the watchdog, but the watchdog 
clocksource is registered /after/ the possibly-unstable clocksource has 
been registered, then when we switch that clocksource into high-res 
capable mode we also need to propagate this fact to the rest of the 
system - so that it properly switches into high-res mode.

this solves one particular system not entering high-res mode (but 
falling back to low-res mode) - with this patch it properly enters 
high-res mode:

 Switched to high resolution mode on CPU 0
 Switched to high resolution mode on CPU 1
 Switched to high resolution mode on CPU 2
 Switched to high resolution mode on CPU 3

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/time/clocksource.c |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

Index: linux/kernel/time/clocksource.c
===================================================================
--- linux.orig/kernel/time/clocksource.c
+++ linux/kernel/time/clocksource.c
@@ -28,6 +28,7 @@
 #include <linux/sysdev.h>
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/tick.h>
 
 /* XXX - Would like a better way for initializing curr_clocksource */
 extern struct clocksource clocksource_jiffies;
@@ -106,8 +107,16 @@ static void clocksource_watchdog(unsigne
 		/* Initialized ? */
 		if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) {
 			if ((cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) &&
-			    (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS))
+			    (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) {
 				cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
+				/*
+				 * We just marked the clocksource as
+				 * highres-capable, notify the rest of the
+				 * system as well so that we transition
+				 * into high-res mode:
+				 */
+				tick_clock_notify();
+			}
 			cs->flags |= CLOCK_SOURCE_WATCHDOG;
 			cs->wd_last = csnow;
 		} else {

  reply	other threads:[~2007-01-24 15:44 UTC|newest]

Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-23 22:00 [patch 00/46] High resolution timer / dynamic tick update Thomas Gleixner
2007-01-23 22:00 ` [patch 01/46] Add irq flag to disable balancing for an interrupt Thomas Gleixner
2007-01-23 22:00 ` [patch 02/46] Add a functions to handle interrupt affinity setting Thomas Gleixner
2007-01-23 22:00 ` [patch 03/46] [RFC] HZ free ntp Thomas Gleixner
2007-01-23 22:00 ` [patch 04/46] Uninline jiffies.h functions Thomas Gleixner
2007-01-23 22:01 ` [patch 05/46] Thomas Gleixner
2007-01-23 22:01 ` [patch 06/46] Fix timeout overflow with jiffies Thomas Gleixner
2007-01-23 22:01 ` [patch 07/46] GTOD: persistent clock support Thomas Gleixner
2007-01-23 22:01 ` [patch 08/46] i386: use GTOD " Thomas Gleixner
2007-01-23 22:01 ` [patch 09/46] i386 Remove useless code in tsc.c Thomas Gleixner
2007-01-23 22:01 ` [patch 10/46] Simplify the registration of clocksources Thomas Gleixner
2007-01-23 22:01 ` [patch 11/46] x86: rewrite SMP TSC sync code Thomas Gleixner
2007-01-23 22:01 ` [patch 12/46] clocksource: replace is_continuous by a flag field Thomas Gleixner
2007-01-24 11:23   ` [patch] clocksource: fixup is_continous changes in vmitime.c Ingo Molnar
2007-01-24 11:53     ` Thomas Gleixner
2007-01-23 22:01 ` [patch 13/46] clocksource: fixup is_continous changes on ARM Thomas Gleixner
2007-01-23 22:01 ` [patch 14/46] clocksource: fixup is_continous changes on AVR32 Thomas Gleixner
2007-01-23 22:01 ` [patch 15/46] clocksource: fixup is_continous changes on S390 Thomas Gleixner
2007-01-23 22:01 ` [patch 16/46] clocksource: fixup is_continous changes on MIPS Thomas Gleixner
2007-01-23 22:01 ` [patch 17/46] clocksource: Remove the update callback Thomas Gleixner
2007-01-23 22:01 ` [patch 18/46] clocksource: Add verification (watchdog) helper Thomas Gleixner
2007-01-24 15:42   ` Ingo Molnar [this message]
2007-01-23 22:01 ` [patch 19/46] Mark TSC on GeodeLX reliable Thomas Gleixner
2007-01-23 22:01 ` [patch 20/46] uninline irq_enter() Thomas Gleixner
2007-01-23 22:01 ` [patch 21/46] Fix cascade lookup of next_timer_interrupt Thomas Gleixner
2007-01-23 22:01 ` [patch 22/46] Extend next_timer_interrupt() to use a reference jiffie Thomas Gleixner
2007-01-23 22:01 ` [patch 23/46] hrtimers: namespace and enum cleanup Thomas Gleixner
2007-01-23 22:01 ` [patch 24/46] hrtimers: namespace and enum cleanup vs. git-input Thomas Gleixner
2007-01-23 22:01 ` [patch 25/46] hrtimers: cleanup locking Thomas Gleixner
2007-01-23 22:01 ` [patch 26/46] hrtimers; add state tracking Thomas Gleixner
2007-01-23 22:01 ` [patch 27/46] hrtimers: clean up callback tracking Thomas Gleixner
2007-01-23 22:01 ` [patch 28/46] hrtimers: move and add documentation Thomas Gleixner
2007-01-23 22:01 ` [patch 29/46] ACPI: fix missing include for UP Thomas Gleixner
2007-01-23 22:01 ` [patch 30/46] ACPI keep track of timer broadcasting Thomas Gleixner
2007-01-23 22:01 ` [patch 31/46] Allow early access to the power management timer Thomas Gleixner
2007-01-23 22:01 ` [patch 32/46] i386, apic: clean up the APIC code Thomas Gleixner
2007-01-23 22:01 ` [patch 33/46] clockevents: add core functionality Thomas Gleixner
2007-01-23 22:01 ` [patch 34/46] tick-management: " Thomas Gleixner
2007-01-23 22:01 ` [patch 35/46] tick-management: broadcast functionality Thomas Gleixner
2007-01-23 22:01 ` [patch 36/46] tick-management: dyntick / highres functionality Thomas Gleixner
2007-01-28  2:03   ` [PATCH] high_res_timers: precisely update_process_times; " Karsten Wiese
2007-01-23 22:01 ` [patch 37/46] clockevents: i383 drivers Thomas Gleixner
2007-01-23 22:01 ` [patch 38/46] i386 rework local apic timer calibration Thomas Gleixner
2007-01-23 22:01 ` [patch 39/46] i386 prepare for dyntick Thomas Gleixner
2007-01-23 22:01 ` [patch 40/46] i386 prepare nmi watchdog for dynticks Thomas Gleixner
2007-01-23 22:01 ` [patch 41/46] i386: enable dynticks in kconfig Thomas Gleixner
2007-01-23 22:01 ` [patch 42/46] hrtimers: add high resolution timer support Thomas Gleixner
2007-01-23 22:01 ` [patch 43/46] hrtimers: prevent possible itimer DoS Thomas Gleixner
2007-01-23 22:01 ` [patch 44/46] Add debugging feature /proc/timer_stat Thomas Gleixner
2007-01-23 22:01 ` [patch 45/46] Add debugging feature /proc/timer_list Thomas Gleixner
2007-01-23 22:01 ` [patch 46/46] Add SysRq-Q to print timer_list debug info Thomas Gleixner
2007-01-24  2:16 ` [patch 00/46] High resolution timer / dynamic tick update Daniel Walker
2007-01-24  2:23   ` Andrew Morton
2007-01-24  3:25     ` Daniel Walker
2007-01-24  7:07   ` Ingo Molnar
2007-01-24  9:30     ` Daniel Walker
2007-01-24  9:51       ` Ingo Molnar
2007-01-24 10:23         ` Daniel Walker
2007-01-24 10:29           ` Ingo Molnar
2007-01-24 10:53             ` Daniel Walker
2007-01-24 11:04               ` Ingo Molnar
2007-01-24 11:13           ` Thomas Gleixner
2007-01-24 15:53             ` Daniel Walker
     [not found]               ` <20070124160046.GA24798@elte.hu>
2007-01-24 17:21                 ` Daniel Walker
     [not found]                 ` <1169655076.19471.241.camel@imap.mvista.com>
2007-01-24 19:38                   ` Ingo Molnar
2007-01-24 20:09                     ` Daniel Walker
2007-01-24 20:13                       ` Ingo Molnar
2007-01-24 19:57       ` john stultz
2007-01-24 20:51         ` Daniel Walker
2007-01-24 21:23           ` john stultz
2007-01-24 21:37             ` Daniel Walker
2007-01-25  6:10           ` Ingo Molnar
2007-01-25  6:37           ` Ingo Molnar
2007-01-25  6:32         ` Ingo Molnar
2007-01-25 16:38           ` Daniel Walker
2007-01-28  2:17 ` Andrew Morton
2007-01-29 21:31   ` john stultz
2007-01-29 21:45     ` john stultz

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