diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 11 | ||||
| -rw-r--r-- | kernel/rcutree.c | 25 |
2 files changed, 33 insertions, 3 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index ad7e2e5088c1..55ada0471f93 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2385,6 +2385,17 @@ bytes respectively. Such letter suffixes can also be entirely omitted. rcutree.rcu_cpu_stall_timeout= [KNL,BOOT] Set timeout for RCU CPU stall warning messages. + rcutree.jiffies_till_first_fqs= [KNL,BOOT] + Set delay from grace-period initialization to + first attempt to force quiescent states. + Units are jiffies, minimum value is zero, + and maximum value is HZ. + + rcutree.jiffies_till_next_fqs= [KNL,BOOT] + Set delay between subsequent attempts to force + quiescent states. Units are jiffies, minimum + value is one, and maximum value is HZ. + rcutorture.fqs_duration= [KNL,BOOT] Set duration of force_quiescent_state bursts. 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. */ |