diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rcu/rcu.h | 1 | ||||
| -rw-r--r-- | kernel/rcu/tree.c | 3 | ||||
| -rw-r--r-- | kernel/rcu/tree.h | 10 | ||||
| -rw-r--r-- | kernel/rcu/tree_exp.h | 184 |
4 files changed, 120 insertions, 78 deletions
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 7a693e31184a..976019d6fa06 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -486,6 +486,7 @@ void rcu_force_quiescent_state(void); void rcu_bh_force_quiescent_state(void); void rcu_sched_force_quiescent_state(void); extern struct workqueue_struct *rcu_gp_wq; +extern struct workqueue_struct *rcu_par_gp_wq; #endif /* #else #ifdef CONFIG_TINY_RCU */ #ifdef CONFIG_RCU_NOCB_CPU diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 2a734692a581..23781fc90830 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -4168,6 +4168,7 @@ static void __init rcu_dump_rcu_node_tree(struct rcu_state *rsp) } struct workqueue_struct *rcu_gp_wq; +struct workqueue_struct *rcu_par_gp_wq; void __init rcu_init(void) { @@ -4199,6 +4200,8 @@ void __init rcu_init(void) /* Create workqueue for expedited GPs and for Tree SRCU. */ rcu_gp_wq = alloc_workqueue("rcu_gp", WQ_MEM_RECLAIM, 0); WARN_ON(!rcu_gp_wq); + rcu_par_gp_wq = alloc_workqueue("rcu_par_gp", WQ_MEM_RECLAIM, 0); + WARN_ON(!rcu_par_gp_wq); } #include "tree_exp.h" diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index f491ab4f2e8e..98d33902b65c 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -58,6 +58,14 @@ struct rcu_dynticks { #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ }; +/* Communicate arguments to a workqueue handler. */ +struct rcu_exp_work { + smp_call_func_t rew_func; + struct rcu_state *rew_rsp; + unsigned long rew_s; + struct work_struct rew_work; +}; + /* RCU's kthread states for tracing. */ #define RCU_KTHREAD_STOPPED 0 #define RCU_KTHREAD_RUNNING 1 @@ -157,6 +165,8 @@ struct rcu_node { spinlock_t exp_lock ____cacheline_internodealigned_in_smp; unsigned long exp_seq_rq; wait_queue_head_t exp_wq[4]; + struct rcu_exp_work rew; + bool exp_need_flush; /* Need to flush workitem? */ } ____cacheline_internodealigned_in_smp; /* diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index f72eefab8543..73e1d3dca5b1 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -362,93 +362,129 @@ static void sync_sched_exp_online_cleanup(int cpu) } /* - * Select the nodes that the upcoming expedited grace period needs - * to wait for. + * Select the CPUs within the specified rcu_node that the upcoming + * expedited grace period needs to wait for. */ -static void sync_rcu_exp_select_cpus(struct rcu_state *rsp, - smp_call_func_t func) +static void sync_rcu_exp_select_node_cpus(struct work_struct *wp) { int cpu; unsigned long flags; + smp_call_func_t func; unsigned long mask_ofl_test; unsigned long mask_ofl_ipi; int ret; - struct rcu_node *rnp; + struct rcu_exp_work *rewp = + container_of(wp, struct rcu_exp_work, rew_work); + struct rcu_node *rnp = container_of(rewp, struct rcu_node, rew); + struct rcu_state *rsp = rewp->rew_rsp; - trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("reset")); - sync_exp_reset_tree(rsp); - trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("select")); - rcu_for_each_leaf_node(rsp, rnp) { - raw_spin_lock_irqsave_rcu_node(rnp, flags); - - /* Each pass checks a CPU for identity, offline, and idle. */ - mask_ofl_test = 0; - for_each_leaf_node_cpu_mask(rnp, cpu, rnp->expmask) { - unsigned long mask = leaf_node_cpu_bit(rnp, cpu); - struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); - struct rcu_dynticks *rdtp = per_cpu_ptr(&rcu_dynticks, cpu); - int snap; + func = rewp->rew_func; + raw_spin_lock_irqsave_rcu_node(rnp, flags); - if (raw_smp_processor_id() == cpu || - !(rnp->qsmaskinitnext & mask)) { + /* Each pass checks a CPU for identity, offline, and idle. */ + mask_ofl_test = 0; + for_each_leaf_node_cpu_mask(rnp, cpu, rnp->expmask) { + unsigned long mask = leaf_node_cpu_bit(rnp, cpu); + struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); + struct rcu_dynticks *rdtp = per_cpu_ptr(&rcu_dynticks, cpu); + int snap; + + if (raw_smp_processor_id() == cpu || + !(rnp->qsmaskinitnext & mask)) { + mask_ofl_test |= mask; + } else { + snap = rcu_dynticks_snap(rdtp); + if (rcu_dynticks_in_eqs(snap)) mask_ofl_test |= mask; - } else { - snap = rcu_dynticks_snap(rdtp); - if (rcu_dynticks_in_eqs(snap)) - mask_ofl_test |= mask; - else - rdp->exp_dynticks_snap = snap; - } + else + rdp->exp_dynticks_snap = snap; } - mask_ofl_ipi = rnp->expmask & ~mask_ofl_test; - - /* - * Need to wait for any blocked tasks as well. Note that - * additional blocking tasks will also block the expedited - * GP until such time as the ->expmask bits are cleared. - */ - if (rcu_preempt_has_tasks(rnp)) - rnp->exp_tasks = rnp->blkd_tasks.next; - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + } + mask_ofl_ipi = rnp->expmask & ~mask_ofl_test; - /* IPI the remaining CPUs for expedited quiescent state. */ - for_each_leaf_node_cpu_mask(rnp, cpu, rnp->expmask) { - unsigned long mask = leaf_node_cpu_bit(rnp, cpu); - struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); + /* + * Need to wait for any blocked tasks as well. Note that + * additional blocking tasks will also block the expedited GP + * until such time as the ->expmask bits are cleared. + */ + if (rcu_preempt_has_tasks(rnp)) + rnp->exp_tasks = rnp->blkd_tasks.next; + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + + /* IPI the remaining CPUs for expedited quiescent state. */ + for_each_leaf_node_cpu_mask(rnp, cpu, rnp->expmask) { + unsigned long mask = leaf_node_cpu_bit(rnp, cpu); + struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); - if (!(mask_ofl_ipi & mask)) - continue; + if (!(mask_ofl_ipi & mask)) + continue; retry_ipi: - if (rcu_dynticks_in_eqs_since(rdp->dynticks, - rdp->exp_dynticks_snap)) { - mask_ofl_test |= mask; - continue; - } - ret = smp_call_function_single(cpu, func, rsp, 0); - if (!ret) { - mask_ofl_ipi &= ~mask; - continue; - } - /* Failed, raced with CPU hotplug operation. */ - raw_spin_lock_irqsave_rcu_node(rnp, flags); - if ((rnp->qsmaskinitnext & mask) && - (rnp->expmask & mask)) { - /* Online, so delay for a bit and try again. */ - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("selectofl")); - schedule_timeout_uninterruptible(1); - goto retry_ipi; - } - /* CPU really is offline, so we can ignore it. */ - if (!(rnp->expmask & mask)) - mask_ofl_ipi &= ~mask; + if (rcu_dynticks_in_eqs_since(rdp->dynticks, + rdp->exp_dynticks_snap)) { + mask_ofl_test |= mask; + continue; + } + ret = smp_call_function_single(cpu, func, rsp, 0); + if (!ret) { + mask_ofl_ipi &= ~mask; + continue; + } + /* Failed, raced with CPU hotplug operation. */ + raw_spin_lock_irqsave_rcu_node(rnp, flags); + if ((rnp->qsmaskinitnext & mask) && + (rnp->expmask & mask)) { + /* Online, so delay for a bit and try again. */ raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("selectofl")); + schedule_timeout_uninterruptible(1); + goto retry_ipi; + } + /* CPU really is offline, so we can ignore it. */ + if (!(rnp->expmask & mask)) + mask_ofl_ipi &= ~mask; + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + } + /* Report quiescent states for those that went offline. */ + mask_ofl_test |= mask_ofl_ipi; + if (mask_ofl_test) + rcu_report_exp_cpu_mult(rsp, rnp, mask_ofl_test, false); +} + +/* + * Select the nodes that the upcoming expedited grace period needs + * to wait for. + */ +static void sync_rcu_exp_select_cpus(struct rcu_state *rsp, + smp_call_func_t func) +{ + struct rcu_node *rnp; + + trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("reset")); + sync_exp_reset_tree(rsp); + trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("select")); + + /* Schedule work for each leaf rcu_node structure. */ + rcu_for_each_leaf_node(rsp, rnp) { + rnp->exp_need_flush = false; + if (!READ_ONCE(rnp->expmask)) + continue; /* Avoid early boot non-existent wq. */ + rnp->rew.rew_func = func; + rnp->rew.rew_rsp = rsp; + if (!READ_ONCE(rcu_par_gp_wq) || + rcu_scheduler_active != RCU_SCHEDULER_RUNNING) { + /* No workqueues yet. */ + sync_rcu_exp_select_node_cpus(&rnp->rew.rew_work); + continue; } - /* Report quiescent states for those that went offline. */ - mask_ofl_test |= mask_ofl_ipi; - if (mask_ofl_test) - rcu_report_exp_cpu_mult(rsp, rnp, mask_ofl_test, false); + INIT_WORK(&rnp->rew.rew_work, sync_rcu_exp_select_node_cpus); + queue_work_on(rnp->grplo, rcu_par_gp_wq, &rnp->rew.rew_work); + rnp->exp_need_flush = true; } + + /* Wait for workqueue jobs (if any) to complete. */ + rcu_for_each_leaf_node(rsp, rnp) + if (rnp->exp_need_flush) + flush_work(&rnp->rew.rew_work); } static void synchronize_sched_expedited_wait(struct rcu_state *rsp) @@ -560,14 +596,6 @@ static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s) mutex_unlock(&rsp->exp_wake_mutex); } -/* Let the workqueue handler know what it is supposed to do. */ -struct rcu_exp_work { - smp_call_func_t rew_func; - struct rcu_state *rew_rsp; - unsigned long rew_s; - struct work_struct rew_work; -}; - /* * Common code to drive an expedited grace period forward, used by * workqueues and mid-boot-time tasks. |