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    Subject[PATCH 31/33] sched: Remove broken check for skip clock update
    Date
    rq->skip_clock_update shouldn't be negative. Thus the check
    in put_prev_task() is useless.

    It was probably intended to do the following check:

    if (prev->on_rq && !rq->skip_clock_update)

    We only want to update the clock if it's not voluntarily
    sleeping: otherwise deactivate_task() already did the rq
    clock update in schedule(). But we want to ignore that
    update if a ttwu did it for us, in which case
    rq->skip_clock_update is 1.

    But update_rq_clock() already takes care of that so we
    can just remove the broken condition.

    Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Alessio Igor Bogani <abogani@kernel.org>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Chris Metcalf <cmetcalf@tilera.com>
    Cc: Christoph Lameter <cl@linux.com>
    Cc: Geoff Levand <geoff@infradead.org>
    Cc: Gilad Ben Yossef <gilad@benyossef.com>
    Cc: Hakan Akkan <hakanakkan@gmail.com>
    Cc: Ingo Molnar <mingo@kernel.org>
    Cc: Li Zhong <zhong@linux.vnet.ibm.com>
    Cc: Namhyung Kim <namhyung.kim@lge.com>
    Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
    Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    ---
    kernel/sched/core.c | 2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)

    diff --git a/kernel/sched/core.c b/kernel/sched/core.c
    index 15ba35e..8dfc461 100644
    --- a/kernel/sched/core.c
    +++ b/kernel/sched/core.c
    @@ -2886,7 +2886,7 @@ static inline void schedule_debug(struct task_struct *prev)

    static void put_prev_task(struct rq *rq, struct task_struct *prev)
    {
    - if (prev->on_rq || rq->skip_clock_update < 0)
    + if (prev->on_rq)
    update_rq_clock(rq);
    prev->sched_class->put_prev_task(rq, prev);
    }
    --
    1.7.5.4


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