From 0ae86a272656b34edfe90a637363d10f470c65d8 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sat, 7 Jul 2018 18:12:26 -0700 Subject: [PATCH] rcu: Clean up flavor-related definitions and comments in tree_plugin.h Signed-off-by: Paul E. McKenney --- kernel/rcu/tree_plugin.h | 36 +++++++++++++++++------------------- 1 file changed, 17 insertions(+), 19 deletions(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index cd276c46bc14..cd4c1b979446 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -38,8 +38,7 @@ #include "../locking/rtmutex_common.h" /* - * Control variables for per-CPU and per-rcu_node kthreads. These - * handle all flavors of RCU. + * Control variables for per-CPU and per-rcu_node kthreads. */ static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task); DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_status); @@ -826,8 +825,8 @@ static void rcu_flavor_check_callbacks(int user) * * Note that this guarantee implies further memory-ordering guarantees. * On systems with more than one CPU, when synchronize_rcu() returns, - * each CPU is guaranteed to have executed a full memory barrier since the - * end of its last RCU-sched read-side critical section whose beginning + * each CPU is guaranteed to have executed a full memory barrier since + * the end of its last RCU read-side critical section whose beginning * preceded the call to synchronize_rcu(). In addition, each CPU having * an RCU read-side critical section that extends beyond the return from * synchronize_rcu() is guaranteed to have executed a full memory barrier @@ -1069,7 +1068,7 @@ void synchronize_rcu(void) RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) || lock_is_held(&rcu_lock_map) || lock_is_held(&rcu_sched_lock_map), - "Illegal synchronize_rcu() in RCU-sched read-side critical section"); + "Illegal synchronize_rcu() in RCU read-side critical section"); if (rcu_blocking_is_gp()) return; if (rcu_gp_is_expedited()) @@ -1341,9 +1340,9 @@ static int rcu_cpu_kthread_should_run(unsigned int cpu) } /* - * Per-CPU kernel thread that invokes RCU callbacks. This replaces the - * RCU softirq used in flavors and configurations of RCU that do not - * support RCU priority boosting. + * Per-CPU kernel thread that invokes RCU callbacks. This replaces + * the RCU softirq used in configurations of RCU that do not support RCU + * priority boosting. */ static void rcu_cpu_kthread(unsigned int cpu) { @@ -1484,8 +1483,8 @@ static void rcu_prepare_kthreads(int cpu) * 1 if so. This function is part of the RCU implementation; it is -not- * an exported member of the RCU API. * - * Because we not have RCU_FAST_NO_HZ, just check whether this CPU needs - * any flavor of RCU. + * Because we not have RCU_FAST_NO_HZ, just check whether or not this + * CPU has RCU callbacks queued. */ int rcu_needs_cpu(u64 basemono, u64 *nextevt) { @@ -1551,9 +1550,9 @@ static int rcu_idle_lazy_gp_delay = RCU_IDLE_LAZY_GP_DELAY; module_param(rcu_idle_lazy_gp_delay, int, 0644); /* - * Try to advance callbacks for all flavors of RCU on the current CPU, but - * only if it has been awhile since the last time we did so. Afterwards, - * if there are any callbacks ready for immediate invocation, return true. + * Try to advance callbacks on the current CPU, but only if it has been + * awhile since the last time we did so. Afterwards, if there are any + * callbacks ready for immediate invocation, return true. */ static bool __maybe_unused rcu_try_advance_all_cbs(void) { @@ -1808,7 +1807,7 @@ static void print_cpu_stall_info_end(void) pr_err("\t"); } -/* Zero ->ticks_this_gp for all flavors of RCU. */ +/* Zero ->ticks_this_gp and snapshot the number of RCU softirq handlers. */ static void zero_cpu_stall_ticks(struct rcu_data *rdp) { rdp->ticks_this_gp = 0; @@ -1939,7 +1938,7 @@ static void wake_nocb_leader_defer(struct rcu_data *rdp, int waketype, } /* - * Does the specified CPU need an RCU callback for the specified flavor + * Does the specified CPU need an RCU callback for this invocation * of rcu_barrier()? */ static bool rcu_nocb_cpu_needs_barrier(int cpu) @@ -2419,9 +2418,8 @@ static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp) /* * If the specified CPU is a no-CBs CPU that does not already have its - * rcuo kthread for the specified RCU flavor, spawn it. If the CPUs are - * brought online out of order, this can require re-organizing the - * leader-follower relationships. + * rcuo kthread, spawn it. If the CPUs are brought online out of order, + * this can require re-organizing the leader-follower relationships. */ static void rcu_spawn_one_nocb_kthread(int cpu) { @@ -2458,7 +2456,7 @@ static void rcu_spawn_one_nocb_kthread(int cpu) rdp_spawn->nocb_next_follower = rdp_old_leader; } - /* Spawn the kthread for this CPU and RCU flavor. */ + /* Spawn the kthread for this CPU. */ t = kthread_run(rcu_nocb_kthread, rdp_spawn, "rcuo%c/%d", rcu_state.abbr, cpu); BUG_ON(IS_ERR(t));