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authorPaul E. McKenney <paulmck@linux.ibm.com>2019-03-11 15:45:13 -0700
committerPaul E. McKenney <paulmck@linux.ibm.com>2019-03-26 14:38:38 -0700
commit85f2b60c4321b088ba08ec9a05b8a7b68e4ada2a (patch)
tree8cd995e818cc4de8f10482383af6b41a55586ef1 /kernel/rcu
parentb699cce1604e828f19c39845252626eb78cdf38a (diff)
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rcu: Update jiffies_to_sched_qs and adjust_jiffies_till_sched_qs() comments
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>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree.c3
1 files changed, 2 insertions, 1 deletions
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)