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    Subject[tip:sched/core] cpuidle: Use wake_up_all_idle_cpus() to wake up all idle cpus
    Commit-ID:  2ed903c5485bad0eafdd3d59ff993598736e4f31
    Gitweb: http://git.kernel.org/tip/2ed903c5485bad0eafdd3d59ff993598736e4f31
    Author: Chuansheng Liu <chuansheng.liu@intel.com>
    AuthorDate: Thu, 4 Sep 2014 15:17:55 +0800
    Committer: Ingo Molnar <mingo@kernel.org>
    CommitDate: Fri, 19 Sep 2014 12:35:16 +0200

    cpuidle: Use wake_up_all_idle_cpus() to wake up all idle cpus

    Currently kick_all_cpus_sync() or smp_call_function() can not
    break the polling idle cpu immediately.

    Instead using wake_up_all_idle_cpus() which can wake up the polling idle
    cpu quickly is much more helpful for power.

    Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    Cc: linux-pm@vger.kernel.org
    Cc: changcheng.liu@intel.com
    Cc: xiaoming.wang@intel.com
    Cc: souvik.k.chakravarty@intel.com
    Cc: luto@amacapital.net
    Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
    Cc: linux-pm@vger.kernel.org
    Link: http://lkml.kernel.org/r/1409815075-4180-3-git-send-email-chuansheng.liu@intel.com
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    ---
    drivers/cpuidle/cpuidle.c | 9 ++-------
    1 file changed, 2 insertions(+), 7 deletions(-)

    diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
    index ee9df5e..d31e04c 100644
    --- a/drivers/cpuidle/cpuidle.c
    +++ b/drivers/cpuidle/cpuidle.c
    @@ -223,7 +223,7 @@ void cpuidle_uninstall_idle_handler(void)
    {
    if (enabled_devices) {
    initialized = 0;
    - kick_all_cpus_sync();
    + wake_up_all_idle_cpus();
    }
    }

    @@ -530,11 +530,6 @@ EXPORT_SYMBOL_GPL(cpuidle_register);

    #ifdef CONFIG_SMP

    -static void smp_callback(void *v)
    -{
    - /* we already woke the CPU up, nothing more to do */
    -}
    -
    /*
    * This function gets called when a part of the kernel has a new latency
    * requirement. This means we need to get all processors out of their C-state,
    @@ -544,7 +539,7 @@ static void smp_callback(void *v)
    static int cpuidle_latency_notify(struct notifier_block *b,
    unsigned long l, void *v)
    {
    - smp_call_function(smp_callback, NULL, 1);
    + wake_up_all_idle_cpus();
    return NOTIFY_OK;
    }


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