diff options
Diffstat (limited to 'kernel/rcutree.c')
| -rw-r--r-- | kernel/rcutree.c | 31 |
1 files changed, 25 insertions, 6 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 055f1a941a9e..69f4efec3449 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -61,7 +61,7 @@ static struct lock_class_key rcu_root_class; NUM_RCU_LVL_2, \ NUM_RCU_LVL_3, /* == MAX_RCU_LVLS */ \ }, \ - .signaled = RCU_SIGNAL_INIT, \ + .signaled = RCU_GP_IDLE, \ .gpnum = -300, \ .completed = -300, \ .onofflock = __SPIN_LOCK_UNLOCKED(&name.onofflock), \ @@ -659,14 +659,17 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) * irqs disabled. */ rcu_for_each_node_breadth_first(rsp, rnp) { - spin_lock(&rnp->lock); /* irqs already disabled. */ + spin_lock(&rnp->lock); /* irqs already disabled. */ rcu_preempt_check_blocked_tasks(rnp); rnp->qsmask = rnp->qsmaskinit; rnp->gpnum = rsp->gpnum; - spin_unlock(&rnp->lock); /* irqs already disabled. */ + spin_unlock(&rnp->lock); /* irqs remain disabled. */ } + rnp = rcu_get_root(rsp); + spin_lock(&rnp->lock); /* irqs already disabled. */ rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state now OK. */ + spin_unlock(&rnp->lock); /* irqs remain disabled. */ spin_unlock_irqrestore(&rsp->onofflock, flags); } @@ -708,6 +711,7 @@ static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags) { WARN_ON_ONCE(!rcu_gp_in_progress(rsp)); rsp->completed = rsp->gpnum; + rsp->signaled = RCU_GP_IDLE; rcu_process_gp_end(rsp, rsp->rda[smp_processor_id()]); rcu_start_gp(rsp, flags); /* releases root node's rnp->lock. */ } @@ -915,7 +919,20 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) spin_unlock(&rnp->lock); /* irqs remain disabled. */ break; } - rcu_preempt_offline_tasks(rsp, rnp, rdp); + + /* + * If there was a task blocking the current grace period, + * and if all CPUs have checked in, we need to propagate + * the quiescent state up the rcu_node hierarchy. But that + * is inconvenient at the moment due to deadlock issues if + * this should end the current grace period. So set the + * offlined CPU's bit in ->qsmask in order to force the + * next force_quiescent_state() invocation to clean up this + * mess in a deadlock-free manner. + */ + if (rcu_preempt_offline_tasks(rsp, rnp, rdp) && !rnp->qsmask) + rnp->qsmask |= mask; + mask = rnp->grpmask; spin_unlock(&rnp->lock); /* irqs remain disabled. */ rnp = rnp->parent; @@ -1151,9 +1168,10 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) } spin_unlock(&rnp->lock); switch (signaled) { + case RCU_GP_IDLE: case RCU_GP_INIT: - break; /* grace period still initializing, ignore. */ + break; /* grace period idle or initializing, ignore. */ case RCU_SAVE_DYNTICK: @@ -1167,7 +1185,8 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) /* Update state, record completion counter. */ spin_lock(&rnp->lock); - if (lastcomp == rsp->completed) { + if (lastcomp == rsp->completed && + rsp->signaled == RCU_SAVE_DYNTICK) { rsp->signaled = RCU_FORCE_QS; dyntick_record_completed(rsp, lastcomp); } |