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    Subject[PATCH tip/core/rcu 14/18] rcu: Update jiffies_to_sched_qs and adjust_jiffies_till_sched_qs() comments
    Date
    This commit better documents the jiffies_to_sched_qs default-value
    strategy used by adjust_jiffies_till_sched_qs()

    Reported-by: Joel Fernandes <joel@joelfernandes.org>
    Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
    ---
    kernel/rcu/tree.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
    index 466299c3d2da..e117732bcd5d 100644
    --- a/kernel/rcu/tree.c
    +++ b/kernel/rcu/tree.c
    @@ -406,7 +406,7 @@ static bool rcu_kick_kthreads;
    */
    static ulong jiffies_till_sched_qs = ULONG_MAX;
    module_param(jiffies_till_sched_qs, ulong, 0444);
    -static ulong jiffies_to_sched_qs; /* Adjusted version of above if not default */
    +static ulong jiffies_to_sched_qs; /* See adjust_jiffies_till_sched_qs(). */
    module_param(jiffies_to_sched_qs, ulong, 0444); /* Display only! */

    /*
    @@ -424,6 +424,7 @@ static void adjust_jiffies_till_sched_qs(void)
    WRITE_ONCE(jiffies_to_sched_qs, jiffies_till_sched_qs);
    return;
    }
    + /* Otherwise, set to third fqs scan, but bound below on large system. */
    j = READ_ONCE(jiffies_till_first_fqs) +
    2 * READ_ONCE(jiffies_till_next_fqs);
    if (j < HZ / 10 + nr_cpu_ids / RCU_JIFFIES_FQS_DIV)
    --
    2.17.1
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