From: Paul E. McKenney Date: Mon, 21 Dec 2020 19:17:16 +0000 (-0800) Subject: rcu/nocb: Code-style nits in callback-offloading toggling X-Git-Tag: microblaze-v5.13~155^2~1^2^5~1 X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=f759081e8f5ac640df1c7125540759bbcb4eb0e2;p=linux-2.6-microblaze.git rcu/nocb: Code-style nits in callback-offloading toggling This commit addresses a few code-style nits in callback-offloading toggling, including one that predates this toggling. Cc: Frederic Weisbecker Signed-off-by: Paul E. McKenney --- diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h index 311060279f1a..9a19328ff251 100644 --- a/kernel/rcu/rcu_segcblist.h +++ b/kernel/rcu/rcu_segcblist.h @@ -80,17 +80,12 @@ static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp) return rcu_segcblist_test_flags(rsclp, SEGCBLIST_ENABLED); } -/* Is the specified rcu_segcblist offloaded? */ +/* Is the specified rcu_segcblist offloaded, or is SEGCBLIST_SOFTIRQ_ONLY set? */ static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp) { - if (IS_ENABLED(CONFIG_RCU_NOCB_CPU)) { - /* - * Complete de-offloading happens only when SEGCBLIST_SOFTIRQ_ONLY - * is set. - */ - if (!rcu_segcblist_test_flags(rsclp, SEGCBLIST_SOFTIRQ_ONLY)) - return true; - } + if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) && + !rcu_segcblist_test_flags(rsclp, SEGCBLIST_SOFTIRQ_ONLY)) + return true; return false; } @@ -99,10 +94,8 @@ static inline bool rcu_segcblist_completely_offloaded(struct rcu_segcblist *rscl { int flags = SEGCBLIST_KTHREAD_CB | SEGCBLIST_KTHREAD_GP | SEGCBLIST_OFFLOADED; - if (IS_ENABLED(CONFIG_RCU_NOCB_CPU)) { - if ((rsclp->flags & flags) == flags) - return true; - } + if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) && (rsclp->flags & flags) == flags) + return true; return false; } diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 22735bc3eacc..b9dd63c166b9 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1606,7 +1606,7 @@ rcu_torture_stats_print(void) data_race(n_barrier_successes), data_race(n_barrier_attempts), data_race(n_rcu_torture_barrier_error)); - pr_cont("read-exits: %ld ", data_race(n_read_exits)); + pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic. pr_cont("nocb-toggles: %ld:%ld\n", atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload)); diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index bc63a6b9d532..6f56f9e51e67 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -1962,17 +1962,17 @@ static inline bool nocb_gp_update_state(struct rcu_data *rdp, bool *needwake_sta *needwake_state = true; } return true; - } else { - /* - * De-offloading. Clear our flag and notify the de-offload worker. - * We will ignore this rdp until it ever gets re-offloaded. - */ - WARN_ON_ONCE(!rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_GP)); - rcu_segcblist_clear_flags(cblist, SEGCBLIST_KTHREAD_GP); - if (!rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_CB)) - *needwake_state = true; - return false; } + + /* + * De-offloading. Clear our flag and notify the de-offload worker. + * We will ignore this rdp until it ever gets re-offloaded. + */ + WARN_ON_ONCE(!rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_GP)); + rcu_segcblist_clear_flags(cblist, SEGCBLIST_KTHREAD_GP); + if (!rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_CB)) + *needwake_state = true; + return false; } @@ -2005,6 +2005,7 @@ static void nocb_gp_wait(struct rcu_data *my_rdp) WARN_ON_ONCE(my_rdp->nocb_gp_rdp != my_rdp); for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_cb_rdp) { bool needwake_state = false; + if (!nocb_gp_enabled_cb(rdp)) continue; trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("Check")); @@ -2160,11 +2161,11 @@ static inline bool nocb_cb_wait_cond(struct rcu_data *rdp) static void nocb_cb_wait(struct rcu_data *rdp) { struct rcu_segcblist *cblist = &rdp->cblist; - struct rcu_node *rnp = rdp->mynode; - bool needwake_state = false; - bool needwake_gp = false; unsigned long cur_gp_seq; unsigned long flags; + bool needwake_state = false; + bool needwake_gp = false; + struct rcu_node *rnp = rdp->mynode; local_irq_save(flags); rcu_momentary_dyntick_idle(); @@ -2217,8 +2218,8 @@ static void nocb_cb_wait(struct rcu_data *rdp) swait_event_interruptible_exclusive(rdp->nocb_cb_wq, nocb_cb_wait_cond(rdp)); - /* ^^^ Ensure CB invocation follows _sleep test. */ - if (smp_load_acquire(&rdp->nocb_cb_sleep)) { + // VVV Ensure CB invocation follows _sleep test. + if (smp_load_acquire(&rdp->nocb_cb_sleep)) { // ^^^ WARN_ON(signal_pending(current)); trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WokeEmpty")); } @@ -2323,7 +2324,7 @@ static int __rcu_nocb_rdp_deoffload(struct rcu_data *rdp) unsigned long flags; int ret; - printk("De-offloading %d\n", rdp->cpu); + pr_info("De-offloading %d\n", rdp->cpu); rcu_nocb_lock_irqsave(rdp, flags); /* @@ -2384,11 +2385,10 @@ int rcu_nocb_cpu_deoffload(int cpu) mutex_lock(&rcu_state.barrier_mutex); cpus_read_lock(); if (rcu_segcblist_is_offloaded(&rdp->cblist)) { - if (cpu_online(cpu)) { + if (cpu_online(cpu)) ret = work_on_cpu(cpu, rcu_nocb_rdp_deoffload, rdp); - } else { + else ret = __rcu_nocb_rdp_deoffload(rdp); - } if (!ret) cpumask_clear_cpu(cpu, rcu_nocb_mask); } @@ -2412,7 +2412,7 @@ static int __rcu_nocb_rdp_offload(struct rcu_data *rdp) if (!rdp->nocb_gp_rdp) return -EINVAL; - printk("Offloading %d\n", rdp->cpu); + pr_info("Offloading %d\n", rdp->cpu); /* * Can't use rcu_nocb_lock_irqsave() while we are in * SEGCBLIST_SOFTIRQ_ONLY mode. @@ -2460,11 +2460,10 @@ int rcu_nocb_cpu_offload(int cpu) mutex_lock(&rcu_state.barrier_mutex); cpus_read_lock(); if (!rcu_segcblist_is_offloaded(&rdp->cblist)) { - if (cpu_online(cpu)) { + if (cpu_online(cpu)) ret = work_on_cpu(cpu, rcu_nocb_rdp_offload, rdp); - } else { + else ret = __rcu_nocb_rdp_offload(rdp); - } if (!ret) cpumask_set_cpu(cpu, rcu_nocb_mask); } diff --git a/kernel/time/timer.c b/kernel/time/timer.c index f9b2096456e5..f475f1a027c8 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1243,6 +1243,7 @@ bool timer_curr_running(struct timer_list *timer) for (i = 0; i < NR_BASES; i++) { struct timer_base *base = this_cpu_ptr(&timer_bases[i]); + if (base->running_timer == timer) return true; }