diff options
| -rw-r--r-- | include/trace/events/rcu.h | 3 | ||||
| -rw-r--r-- | kernel/rcu/tree.h | 9 | ||||
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 26 |
3 files changed, 28 insertions, 10 deletions
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index aca382266411..9b56f37148cf 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -180,9 +180,12 @@ TRACE_EVENT(rcu_grace_period_init, * argument is a string as follows: * * "WakeEmpty": Wake rcuo kthread, first CB to empty list. + * "WakeEmptyIsDeferred": Wake rcuo kthread later, first CB to empty list. * "WakeOvf": Wake rcuo kthread, CB list is huge. + * "WakeOvfIsDeferred": Wake rcuo kthread later, CB list is huge. * "WakeNot": Don't wake rcuo kthread. * "WakeNotPoll": Don't wake rcuo kthread because it is polling. + * "DeferredWake": Carried out the "IsDeferred" wakeup. * "Poll": Start of new polling cycle for rcu_nocb_poll. * "Sleep": Sleep waiting for CBs for !rcu_nocb_poll. * "WokeEmpty": rcuo kthread woke to find empty list. diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 6a86eb7bac45..e33562f2a655 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -350,7 +350,7 @@ struct rcu_data { int nocb_p_count_lazy; /* (approximate). */ wait_queue_head_t nocb_wq; /* For nocb kthreads to sleep on. */ struct task_struct *nocb_kthread; - bool nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */ + int nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */ /* The following fields are used by the leader, hence own cacheline. */ struct rcu_head *nocb_gp_head ____cacheline_internodealigned_in_smp; @@ -383,6 +383,11 @@ struct rcu_data { #define RCU_FORCE_QS 3 /* Need to force quiescent state. */ #define RCU_SIGNAL_INIT RCU_SAVE_DYNTICK +/* Values for nocb_defer_wakeup field in struct rcu_data. */ +#define RCU_NOGP_WAKE_NOT 0 +#define RCU_NOGP_WAKE 1 +#define RCU_NOGP_WAKE_FORCE 2 + #define RCU_JIFFIES_TILL_FORCE_QS (1 + (HZ > 250) + (HZ > 500)) /* For jiffies_till_first_fqs and */ /* and jiffies_till_next_fqs. */ @@ -589,7 +594,7 @@ static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp, static bool rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp, struct rcu_data *rdp, unsigned long flags); -static bool rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp); +static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp); static void do_nocb_deferred_wakeup(struct rcu_data *rdp); static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp); static void rcu_spawn_nocb_kthreads(struct rcu_state *rsp); diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index bb564560aeb8..d67cc5c375c5 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2121,16 +2121,23 @@ static void __call_rcu_nocb_enqueue(struct rcu_data *rdp, trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WakeEmpty")); } else { - rdp->nocb_defer_wakeup = true; + rdp->nocb_defer_wakeup = RCU_NOGP_WAKE; trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WakeEmptyIsDeferred")); } rdp->qlen_last_fqs_check = 0; } else if (len > rdp->qlen_last_fqs_check + qhimark) { /* ... or if many callbacks queued. */ - wake_nocb_leader(rdp, true); + if (!irqs_disabled_flags(flags)) { + wake_nocb_leader(rdp, true); + trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, + TPS("WakeOvf")); + } else { + rdp->nocb_defer_wakeup = RCU_NOGP_WAKE_FORCE; + trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, + TPS("WakeOvfIsDeferred")); + } rdp->qlen_last_fqs_check = LONG_MAX / 2; - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WakeOvf")); } else { trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WakeNot")); } @@ -2438,7 +2445,7 @@ static int rcu_nocb_kthread(void *arg) } /* Is a deferred wakeup of rcu_nocb_kthread() required? */ -static bool rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp) +static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp) { return ACCESS_ONCE(rdp->nocb_defer_wakeup); } @@ -2446,11 +2453,14 @@ static bool rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp) /* Do a deferred wakeup of rcu_nocb_kthread(). */ static void do_nocb_deferred_wakeup(struct rcu_data *rdp) { + int ndw; + if (!rcu_nocb_need_deferred_wakeup(rdp)) return; - ACCESS_ONCE(rdp->nocb_defer_wakeup) = false; - wake_nocb_leader(rdp, false); - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("DeferredWakeEmpty")); + ndw = ACCESS_ONCE(rdp->nocb_defer_wakeup); + ACCESS_ONCE(rdp->nocb_defer_wakeup) = RCU_NOGP_WAKE_NOT; + wake_nocb_leader(rdp, ndw == RCU_NOGP_WAKE_FORCE); + trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("DeferredWake")); } /* Initialize per-rcu_data variables for no-CBs CPUs. */ @@ -2557,7 +2567,7 @@ static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp) { } -static bool rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp) +static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp) { return false; } |