lkml.org 
[lkml]   [2007]   [Jan]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[patch] clocksource: add verification (watchdog) helper, fix

    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 {
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/
    \
     
     \ /
      Last update: 2007-01-24 17:45    [W:0.039 / U:31.412 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site