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-rw-r--r--kernel/rcutree.c25
1 files changed, 22 insertions, 3 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 43d57a17fcc5..c0d3d56f0404 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -226,6 +226,12 @@ int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
module_param(rcu_cpu_stall_suppress, int, 0644);
module_param(rcu_cpu_stall_timeout, int, 0644);
+static ulong jiffies_till_first_fqs = RCU_JIFFIES_TILL_FORCE_QS;
+static ulong jiffies_till_next_fqs = RCU_JIFFIES_TILL_FORCE_QS;
+
+module_param(jiffies_till_first_fqs, ulong, 0644);
+module_param(jiffies_till_next_fqs, ulong, 0644);
+
static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *));
static void force_quiescent_state(struct rcu_state *rsp);
static int rcu_pending(int cpu);
@@ -1177,6 +1183,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
static int __noreturn rcu_gp_kthread(void *arg)
{
int fqs_state;
+ unsigned long j;
int ret;
struct rcu_state *rsp = arg;
struct rcu_node *rnp = rcu_get_root(rsp);
@@ -1197,14 +1204,18 @@ static int __noreturn rcu_gp_kthread(void *arg)
/* Handle quiescent-state forcing. */
fqs_state = RCU_SAVE_DYNTICK;
+ j = jiffies_till_first_fqs;
+ if (j > HZ) {
+ j = HZ;
+ jiffies_till_first_fqs = HZ;
+ }
for (;;) {
- rsp->jiffies_force_qs = jiffies +
- RCU_JIFFIES_TILL_FORCE_QS;
+ rsp->jiffies_force_qs = jiffies + j;
ret = wait_event_interruptible_timeout(rsp->gp_wq,
(rsp->gp_flags & RCU_GP_FLAG_FQS) ||
(!ACCESS_ONCE(rnp->qsmask) &&
!rcu_preempt_blocked_readers_cgp(rnp)),
- RCU_JIFFIES_TILL_FORCE_QS);
+ j);
/* If grace period done, leave loop. */
if (!ACCESS_ONCE(rnp->qsmask) &&
!rcu_preempt_blocked_readers_cgp(rnp))
@@ -1218,6 +1229,14 @@ static int __noreturn rcu_gp_kthread(void *arg)
cond_resched();
flush_signals(current);
}
+ j = jiffies_till_next_fqs;
+ if (j > HZ) {
+ j = HZ;
+ jiffies_till_next_fqs = HZ;
+ } else if (j < 1) {
+ j = 1;
+ jiffies_till_next_fqs = 1;
+ }
}
/* Handle grace-period end. */
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