lkml.org 
[lkml]   [2011]   [Jan]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Subject[PATCH v2 03/20] provide get_xtime_and_monotonic_offset() and use it in hrtimer.c
    From
    Date
    2 places in hrtimer need to take the xtime_lock, but we want it
    to be private to kernel/time...

    we just provide a function, which gets the values with proper
    read locking the xtime_lock.

    Signed-off-by: Torben Hohn <torbenh@gmx.de>
    ---
    include/linux/time.h | 1 +
    kernel/hrtimer.c | 12 ++----------
    kernel/time/timekeeping.c | 21 +++++++++++++++++++++
    3 files changed, 24 insertions(+), 10 deletions(-)

    diff --git a/include/linux/time.h b/include/linux/time.h
    index 86a9c48..b9b2f5b 100644
    --- a/include/linux/time.h
    +++ b/include/linux/time.h
    @@ -127,6 +127,7 @@ struct timespec current_kernel_time(void);
    struct timespec __current_kernel_time(void); /* does not take xtime_lock */
    struct timespec __get_wall_to_monotonic(void); /* does not take xtime_lock */
    struct timespec get_monotonic_coarse(void);
    +void get_xtime_and_monotonic_offset(struct timespec *xts, struct timespec *tom);

    #define CURRENT_TIME (current_kernel_time())
    #define CURRENT_TIME_SEC ((struct timespec) { get_seconds(), 0 })
    diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
    index 0c8d7c0..6ef9d47 100644
    --- a/kernel/hrtimer.c
    +++ b/kernel/hrtimer.c
    @@ -85,13 +85,8 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
    {
    ktime_t xtim, tomono;
    struct timespec xts, tom;
    - unsigned long seq;

    - do {
    - seq = read_seqbegin(&xtime_lock);
    - xts = __current_kernel_time();
    - tom = __get_wall_to_monotonic();
    - } while (read_seqretry(&xtime_lock, seq));
    + get_xtime_and_monotonic_offset(&xts, &tom);

    xtim = timespec_to_ktime(xts);
    tomono = timespec_to_ktime(tom);
    @@ -617,10 +612,7 @@ static void retrigger_next_event(void *arg)
    if (!hrtimer_hres_active())
    return;

    - do {
    - seq = read_seqbegin(&xtime_lock);
    - wtm = __get_wall_to_monotonic();
    - } while (read_seqretry(&xtime_lock, seq));
    + get_xtime_and_monotonic_offset(NULL, &wtm);
    set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);

    base = &__get_cpu_var(hrtimer_bases);
    diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
    index e4fd957..6085fa5 100644
    --- a/kernel/time/timekeeping.c
    +++ b/kernel/time/timekeeping.c
    @@ -957,3 +957,24 @@ void do_timer(unsigned long ticks)
    jiffies_64 += ticks;
    update_wall_time();
    }
    +
    +/**
    + * get_xtime_and_monotonic_offset() - get xtime and wall_to_monotonic
    + * @xts: pointer to struct timespec, filled with the current_time
    + * @tom: pointer to struct timespec, filled with the wall_to_monotonic offset
    + *
    + * this function does proper locking.
    + * and it allows passing NULL, when one is not interested in the value.
    + */
    +void get_xtime_and_monotonic_offset(struct timespec *xts, struct timespec *tom)
    +{
    + unsigned long seq;
    +
    + do {
    + seq = read_seqbegin(&xtime_lock);
    + if (xts)
    + *xts = xtime;
    + if (tom)
    + *tom = wall_to_monotonic;
    + } while (read_seqretry(&xtime_lock, seq));
    +}


    \
     
     \ /
      Last update: 2011-01-27 16:03    [W:0.022 / U:0.700 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site