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    Subject[patch V2 50/64] hangcheck-timer: Use ktime_get_ns()
    There is no point in having a S390 private implementation and there is
    no point in using the raw monotonic time. The NTP freqeuency
    adjustment of CLOCK_MONOTONIC is really not doing any harm for the
    hang check timer.

    Use ktime_get_ns() for everything and get rid of the timespec
    conversions.

    V2: Drop the raw monotonic and the S390 special case

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
    ---
    drivers/char/hangcheck-timer.c | 33 +++++----------------------------
    1 file changed, 5 insertions(+), 28 deletions(-)

    Index: tip/drivers/char/hangcheck-timer.c
    ===================================================================
    --- tip.orig/drivers/char/hangcheck-timer.c
    +++ tip/drivers/char/hangcheck-timer.c
    @@ -49,7 +49,7 @@
    #include <asm/uaccess.h>
    #include <linux/sysrq.h>
    #include <linux/timer.h>
    -#include <linux/time.h>
    +#include <linux/hrtimer.h>

    #define VERSION_STR "0.9.1"

    @@ -117,24 +117,7 @@ __setup("hcheck_reboot", hangcheck_parse
    __setup("hcheck_dump_tasks", hangcheck_parse_dump_tasks);
    #endif /* not MODULE */

    -#if defined(CONFIG_S390)
    -# define HAVE_MONOTONIC
    -# define TIMER_FREQ 1000000000ULL
    -#else
    -# define TIMER_FREQ 1000000000ULL
    -#endif
    -
    -#ifdef HAVE_MONOTONIC
    -extern unsigned long long monotonic_clock(void);
    -#else
    -static inline unsigned long long monotonic_clock(void)
    -{
    - struct timespec ts;
    - getrawmonotonic(&ts);
    - return timespec_to_ns(&ts);
    -}
    -#endif /* HAVE_MONOTONIC */
    -
    +#define TIMER_FREQ 1000000000ULL

    /* Last time scheduled */
    static unsigned long long hangcheck_tsc, hangcheck_tsc_margin;
    @@ -143,12 +126,11 @@ static void hangcheck_fire(unsigned long

    static DEFINE_TIMER(hangcheck_ticktock, hangcheck_fire, 0, 0);

    -
    static void hangcheck_fire(unsigned long data)
    {
    unsigned long long cur_tsc, tsc_diff;

    - cur_tsc = monotonic_clock();
    + cur_tsc = ktime_get_ns();

    if (cur_tsc > hangcheck_tsc)
    tsc_diff = cur_tsc - hangcheck_tsc;
    @@ -177,7 +159,7 @@ static void hangcheck_fire(unsigned long
    tsc_diff, tsc_diff - hangcheck_tick*TIMER_FREQ);
    #endif
    mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
    - hangcheck_tsc = monotonic_clock();
    + hangcheck_tsc = ktime_get_ns();
    }


    @@ -185,16 +167,11 @@ static int __init hangcheck_init(void)
    {
    printk("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n",
    VERSION_STR, hangcheck_tick, hangcheck_margin);
    -#if defined (HAVE_MONOTONIC)
    - printk("Hangcheck: Using monotonic_clock().\n");
    -#else
    - printk("Hangcheck: Using getrawmonotonic().\n");
    -#endif /* HAVE_MONOTONIC */
    hangcheck_tsc_margin =
    (unsigned long long)(hangcheck_margin + hangcheck_tick);
    hangcheck_tsc_margin *= (unsigned long long)TIMER_FREQ;

    - hangcheck_tsc = monotonic_clock();
    + hangcheck_tsc = ktime_get_ns();
    mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));

    return 0;



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