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rcu: Default jiffies_to_sched_qs to jiffies_till_sched_qs 

The current code only calls adjust_jiffies_till_sched_qs() if
jiffies_till_sched_qs is left at its default value, so when the
jiffies_till_sched_qs kernel-boot parameter actually is specified,
jiffies_to_sched_qs will be left with the value zero, which
will result in useless slowdowns of cond_resched().  This commit
therefore changes rcu_init_geometry() to unconditionally invoke
adjust_jiffies_till_sched_qs(), which ensures that jiffies_to_sched_qs
will be initialized in all cases, thus maintaining good cond_resched()
performance.

Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
This commit is contained in:
Neeraj Upadhyay 2019-03-11 15:16:11 +05:30 committed by Paul E. McKenney
parent 0f58d2ac2c
commit 6973032a60
1 changed files with 1 additions and 2 deletions
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3
kernel/rcu/tree.c
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@ -3739,8 +3739,7 @@ static void __init rcu_init_geometry(void)
jiffies_till_first_fqs = d;
if (jiffies_till_next_fqs == ULONG_MAX)
jiffies_till_next_fqs = d;
if (jiffies_till_sched_qs == ULONG_MAX)
adjust_jiffies_till_sched_qs();
adjust_jiffies_till_sched_qs();
/* If the compile-time values are accurate, just leave. */
if (rcu_fanout_leaf == RCU_FANOUT_LEAF &&