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Release 4.15 kernel/rcu/tree_exp.h

Directory: kernel/rcu
/*
 * RCU expedited grace periods
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you can access it online at
 * http://www.gnu.org/licenses/gpl-2.0.html.
 *
 * Copyright IBM Corporation, 2016
 *
 * Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
 */

/*
 * Record the start of an expedited grace period.
 */

static void rcu_exp_gp_seq_start(struct rcu_state *rsp) { rcu_seq_start(&rsp->expedited_sequence); }

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/* * Record the end of an expedited grace period. */
static void rcu_exp_gp_seq_end(struct rcu_state *rsp) { rcu_seq_end(&rsp->expedited_sequence); smp_mb(); /* Ensure that consecutive grace periods serialize. */ }

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/* * Take a snapshot of the expedited-grace-period counter. */
static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp) { unsigned long s; smp_mb(); /* Caller's modifications seen first by other CPUs. */ s = rcu_seq_snap(&rsp->expedited_sequence); trace_rcu_exp_grace_period(rsp->name, s, TPS("snap")); return s; }

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/* * Given a counter snapshot from rcu_exp_gp_seq_snap(), return true * if a full expedited grace period has elapsed since that snapshot * was taken. */
static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s) { return rcu_seq_done(&rsp->expedited_sequence, s); }

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/* * Reset the ->expmaskinit values in the rcu_node tree to reflect any * recent CPU-online activity. Note that these masks are not cleared * when CPUs go offline, so they reflect the union of all CPUs that have * ever been online. This means that this function normally takes its * no-work-to-do fastpath. */
static void sync_exp_reset_tree_hotplug(struct rcu_state *rsp) { bool done; unsigned long flags; unsigned long mask; unsigned long oldmask; int ncpus = smp_load_acquire(&rsp->ncpus); /* Order against locking. */ struct rcu_node *rnp; struct rcu_node *rnp_up; /* If no new CPUs onlined since last time, nothing to do. */ if (likely(ncpus == rsp->ncpus_snap)) return; rsp->ncpus_snap = ncpus; /* * Each pass through the following loop propagates newly onlined * CPUs for the current rcu_node structure up the rcu_node tree. */ rcu_for_each_leaf_node(rsp, rnp) { raw_spin_lock_irqsave_rcu_node(rnp, flags); if (rnp->expmaskinit == rnp->expmaskinitnext) { raw_spin_unlock_irqrestore_rcu_node(rnp, flags); continue; /* No new CPUs, nothing to do. */ } /* Update this node's mask, track old value for propagation. */ oldmask = rnp->expmaskinit; rnp->expmaskinit = rnp->expmaskinitnext; raw_spin_unlock_irqrestore_rcu_node(rnp, flags); /* If was already nonzero, nothing to propagate. */ if (oldmask) continue; /* Propagate the new CPU up the tree. */ mask = rnp->grpmask; rnp_up = rnp->parent; done = false; while (rnp_up) { raw_spin_lock_irqsave_rcu_node(rnp_up, flags); if (rnp_up->expmaskinit) done = true; rnp_up->expmaskinit |= mask; raw_spin_unlock_irqrestore_rcu_node(rnp_up, flags); if (done) break; mask = rnp_up->grpmask; rnp_up = rnp_up->parent; } } }

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/* * Reset the ->expmask values in the rcu_node tree in preparation for * a new expedited grace period. */
static void __maybe_unused sync_exp_reset_tree(struct rcu_state *rsp) { unsigned long flags; struct rcu_node *rnp; sync_exp_reset_tree_hotplug(rsp); rcu_for_each_node_breadth_first(rsp, rnp) { raw_spin_lock_irqsave_rcu_node(rnp, flags); WARN_ON_ONCE(rnp->expmask); rnp->expmask = rnp->expmaskinit; raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } }

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/* * Return non-zero if there is no RCU expedited grace period in progress * for the specified rcu_node structure, in other words, if all CPUs and * tasks covered by the specified rcu_node structure have done their bit * for the current expedited grace period. Works only for preemptible * RCU -- other RCU implementation use other means. * * Caller must hold the rcu_state's exp_mutex. */
static bool sync_rcu_preempt_exp_done(struct rcu_node *rnp) { return rnp->exp_tasks == NULL && READ_ONCE(rnp->expmask) == 0; }

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/* * Report the exit from RCU read-side critical section for the last task * that queued itself during or before the current expedited preemptible-RCU * grace period. This event is reported either to the rcu_node structure on * which the task was queued or to one of that rcu_node structure's ancestors, * recursively up the tree. (Calm down, calm down, we do the recursion * iteratively!) * * Caller must hold the rcu_state's exp_mutex and the specified rcu_node * structure's ->lock. */
static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, bool wake, unsigned long flags) __releases(rnp->lock) { unsigned long mask; for (;;) { if (!sync_rcu_preempt_exp_done(rnp)) { if (!rnp->expmask) rcu_initiate_boost(rnp, flags); else raw_spin_unlock_irqrestore_rcu_node(rnp, flags); break; } if (rnp->parent == NULL) { raw_spin_unlock_irqrestore_rcu_node(rnp, flags); if (wake) { smp_mb(); /* EGP done before wake_up(). */ swake_up(&rsp->expedited_wq); } break; } mask = rnp->grpmask; raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled */ rnp = rnp->parent; raw_spin_lock_rcu_node(rnp); /* irqs already disabled */ WARN_ON_ONCE(!(rnp->expmask & mask)); rnp->expmask &= ~mask; } }

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/* * Report expedited quiescent state for specified node. This is a * lock-acquisition wrapper function for __rcu_report_exp_rnp(). * * Caller must hold the rcu_state's exp_mutex. */
static void __maybe_unused rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, bool wake) { unsigned long flags; raw_spin_lock_irqsave_rcu_node(rnp, flags); __rcu_report_exp_rnp(rsp, rnp, wake, flags); }

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/* * Report expedited quiescent state for multiple CPUs, all covered by the * specified leaf rcu_node structure. Caller must hold the rcu_state's * exp_mutex. */
static void rcu_report_exp_cpu_mult(struct rcu_state *rsp, struct rcu_node *rnp, unsigned long mask, bool wake) { unsigned long flags; raw_spin_lock_irqsave_rcu_node(rnp, flags); if (!(rnp->expmask & mask)) { raw_spin_unlock_irqrestore_rcu_node(rnp, flags); return; } rnp->expmask &= ~mask; __rcu_report_exp_rnp(rsp, rnp, wake, flags); /* Releases rnp->lock. */ }

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/* * Report expedited quiescent state for specified rcu_data (CPU). */
static void rcu_report_exp_rdp(struct rcu_state *rsp, struct rcu_data *rdp, bool wake) { rcu_report_exp_cpu_mult(rsp, rdp->mynode, rdp->grpmask, wake); }

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/* Common code for synchronize_{rcu,sched}_expedited() work-done checking. */
static bool sync_exp_work_done(struct rcu_state *rsp, atomic_long_t *stat, unsigned long s) { if (rcu_exp_gp_seq_done(rsp, s)) { trace_rcu_exp_grace_period(rsp->name, s, TPS("done")); /* Ensure test happens before caller kfree(). */ smp_mb__before_atomic(); /* ^^^ */ atomic_long_inc(stat); return true; } return false; }

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/* * Funnel-lock acquisition for expedited grace periods. Returns true * if some other task completed an expedited grace period that this task * can piggy-back on, and with no mutex held. Otherwise, returns false * with the mutex held, indicating that the caller must actually do the * expedited grace period. */
static bool exp_funnel_lock(struct rcu_state *rsp, unsigned long s) { struct rcu_data *rdp = per_cpu_ptr(rsp->rda, raw_smp_processor_id()); struct rcu_node *rnp = rdp->mynode; struct rcu_node *rnp_root = rcu_get_root(rsp); /* Low-contention fastpath. */ if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s) && (rnp == rnp_root || ULONG_CMP_LT(READ_ONCE(rnp_root->exp_seq_rq), s)) && mutex_trylock(&rsp->exp_mutex)) goto fastpath; /* * Each pass through the following loop works its way up * the rcu_node tree, returning if others have done the work or * otherwise falls through to acquire rsp->exp_mutex. The mapping * from CPU to rcu_node structure can be inexact, as it is just * promoting locality and is not strictly needed for correctness. */ for (; rnp != NULL; rnp = rnp->parent) { if (sync_exp_work_done(rsp, &rdp->exp_workdone1, s)) return true; /* Work not done, either wait here or go up. */ spin_lock(&rnp->exp_lock); if (ULONG_CMP_GE(rnp->exp_seq_rq, s)) { /* Someone else doing GP, so wait for them. */ spin_unlock(&rnp->exp_lock); trace_rcu_exp_funnel_lock(rsp->name, rnp->level, rnp->grplo, rnp->grphi, TPS("wait")); wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3], sync_exp_work_done(rsp, &rdp->exp_workdone2, s)); return true; } rnp->exp_seq_rq = s; /* Followers can wait on us. */ spin_unlock(&rnp->exp_lock); trace_rcu_exp_funnel_lock(rsp->name, rnp->level, rnp->grplo, rnp->grphi, TPS("nxtlvl")); } mutex_lock(&rsp->exp_mutex); fastpath: if (sync_exp_work_done(rsp, &rdp->exp_workdone3, s)) { mutex_unlock(&rsp->exp_mutex); return true; } rcu_exp_gp_seq_start(rsp); trace_rcu_exp_grace_period(rsp->name, s, TPS("start")); return false; }

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/* Invoked on each online non-idle CPU for expedited quiescent state. */
static void sync_sched_exp_handler(void *data) { struct rcu_data *rdp; struct rcu_node *rnp; struct rcu_state *rsp = data; rdp = this_cpu_ptr(rsp->rda); rnp = rdp->mynode; if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) || __this_cpu_read(rcu_sched_data.cpu_no_qs.b.exp)) return; if (rcu_is_cpu_rrupt_from_idle()) { rcu_report_exp_rdp(&rcu_sched_state, this_cpu_ptr(&rcu_sched_data), true); return; } __this_cpu_write(rcu_sched_data.cpu_no_qs.b.exp, true); /* Store .exp before .rcu_urgent_qs. */ smp_store_release(this_cpu_ptr(&rcu_dynticks.rcu_urgent_qs), true); resched_cpu(smp_processor_id()); }

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/* Send IPI for expedited cleanup if needed at end of CPU-hotplug operation. */
static void sync_sched_exp_online_cleanup(int cpu) { struct rcu_data *rdp; int ret; struct rcu_node *rnp; struct rcu_state *rsp = &rcu_sched_state; rdp = per_cpu_ptr(rsp->rda, cpu); rnp = rdp->mynode; if (!(READ_ONCE(rnp->expmask) & rdp->grpmask)) return; ret = smp_call_function_single(cpu, sync_sched_exp_handler, rsp, 0); WARN_ON_ONCE(ret); }

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/* * 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) { int cpu; unsigned long flags; unsigned long mask_ofl_test; unsigned long mask_ofl_ipi; int ret; struct rcu_node *rnp; sync_exp_reset_tree(rsp); 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_possible_cpu(rnp, cpu) { struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); rdp->exp_dynticks_snap = rcu_dynticks_snap(rdp->dynticks); if (raw_smp_processor_id() == cpu || rcu_dynticks_in_eqs(rdp->exp_dynticks_snap) || !(rnp->qsmaskinitnext & rdp->grpmask)) mask_ofl_test |= rdp->grpmask; } 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); /* IPI the remaining CPUs for expedited quiescent state. */ for_each_leaf_node_possible_cpu(rnp, cpu) { 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; 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); 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); } }

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static void synchronize_sched_expedited_wait(struct rcu_state *rsp) { int cpu; unsigned long jiffies_stall; unsigned long jiffies_start; unsigned long mask; int ndetected; struct rcu_node *rnp; struct rcu_node *rnp_root = rcu_get_root(rsp); int ret; jiffies_stall = rcu_jiffies_till_stall_check(); jiffies_start = jiffies; for (;;) { ret = swait_event_timeout( rsp->expedited_wq, sync_rcu_preempt_exp_done(rnp_root), jiffies_stall); if (ret > 0 || sync_rcu_preempt_exp_done(rnp_root)) return; WARN_ON(ret < 0); /* workqueues should not be signaled. */ if (rcu_cpu_stall_suppress) continue; panic_on_rcu_stall(); pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {", rsp->name); ndetected = 0; rcu_for_each_leaf_node(rsp, rnp) { ndetected += rcu_print_task_exp_stall(rnp); for_each_leaf_node_possible_cpu(rnp, cpu) { struct rcu_data *rdp; mask = leaf_node_cpu_bit(rnp, cpu); if (!(rnp->expmask & mask)) continue; ndetected++; rdp = per_cpu_ptr(rsp->rda, cpu); pr_cont(" %d-%c%c%c", cpu, "O."[!!cpu_online(cpu)], "o."[!!(rdp->grpmask & rnp->expmaskinit)], "N."[!!(rdp->grpmask & rnp->expmaskinitnext)]); } } pr_cont(" } %lu jiffies s: %lu root: %#lx/%c\n", jiffies - jiffies_start, rsp->expedited_sequence, rnp_root->expmask, ".T"[!!rnp_root->exp_tasks]); if (ndetected) { pr_err("blocking rcu_node structures:"); rcu_for_each_node_breadth_first(rsp, rnp) { if (rnp == rnp_root) continue; /* printed unconditionally */ if (sync_rcu_preempt_exp_done(rnp)) continue; pr_cont(" l=%u:%d-%d:%#lx/%c", rnp->level, rnp->grplo, rnp->grphi, rnp->expmask, ".T"[!!rnp->exp_tasks]); } pr_cont("\n"); } rcu_for_each_leaf_node(rsp, rnp) { for_each_leaf_node_possible_cpu(rnp, cpu) { mask = leaf_node_cpu_bit(rnp, cpu); if (!(rnp->expmask & mask)) continue; dump_cpu_task(cpu); } } jiffies_stall = 3 * rcu_jiffies_till_stall_check() + 3; } }

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/* * Wait for the current expedited grace period to complete, and then * wake up everyone who piggybacked on the just-completed expedited * grace period. Also update all the ->exp_seq_rq counters as needed * in order to avoid counter-wrap problems. */
static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s) { struct rcu_node *rnp; synchronize_sched_expedited_wait(rsp); rcu_exp_gp_seq_end(rsp); trace_rcu_exp_grace_period(rsp->name, s, TPS("end")); /* * Switch over to wakeup mode, allowing the next GP, but -only- the * next GP, to proceed. */ mutex_lock(&rsp->exp_wake_mutex); rcu_for_each_node_breadth_first(rsp, rnp) { if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s)) { spin_lock(&rnp->exp_lock); /* Recheck, avoid hang in case someone just arrived. */ if (ULONG_CMP_LT(rnp->exp_seq_rq, s)) rnp->exp_seq_rq = s; spin_unlock(&rnp->exp_lock); } smp_mb(); /* All above changes before wakeup. */ wake_up_all(&rnp->exp_wq[rcu_seq_ctr(rsp->expedited_sequence) & 0x3]); } trace_rcu_exp_grace_period(rsp->name, s, TPS("endwake")); mutex_unlock(&rsp->exp_wake_mutex); }

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/* 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. */
static void rcu_exp_sel_wait_wake(struct rcu_state *rsp, smp_call_func_t func, unsigned long s) { /* Initialize the rcu_node tree in preparation for the wait. */ sync_rcu_exp_select_cpus(rsp, func); /* Wait and clean up, including waking everyone. */ rcu_exp_wait_wake(rsp, s); }

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/* * Work-queue handler to drive an expedited grace period forward. */
static void wait_rcu_exp_gp(struct work_struct *wp) { struct rcu_exp_work *rewp; rewp = container_of(wp, struct rcu_exp_work, rew_work); rcu_exp_sel_wait_wake(rewp->rew_rsp, rewp->rew_func, rewp->rew_s); }

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/* * Given an rcu_state pointer and a smp_call_function() handler, kick * off the specified flavor of expedited grace period. */
static void _synchronize_rcu_expedited(struct rcu_state *rsp, smp_call_func_t func) { struct rcu_data *rdp; struct rcu_exp_work rew; struct rcu_node *rnp; unsigned long s; /* If expedited grace periods are prohibited, fall back to normal. */ if (rcu_gp_is_normal()) { wait_rcu_gp(rsp->call); return; } /* Take a snapshot of the sequence number. */ s = rcu_exp_gp_seq_snap(rsp); if (exp_funnel_lock(rsp, s)) return; /* Someone else did our work for us. */ /* Ensure that load happens before action based on it. */ if (unlikely(rcu_scheduler_active == RCU_SCHEDULER_INIT)) { /* Direct call during scheduler init and early_initcalls(). */ rcu_exp_sel_wait_wake(rsp, func, s); } else { /* Marshall arguments & schedule the expedited grace period. */ rew.rew_func = func; rew.rew_rsp = rsp; rew.rew_s = s; INIT_WORK_ONSTACK(&rew.rew_work, wait_rcu_exp_gp); schedule_work(&rew.rew_work); } /* Wait for expedited grace period to complete. */ rdp = per_cpu_ptr(rsp->rda, raw_smp_processor_id()); rnp = rcu_get_root(rsp); wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3], sync_exp_work_done(rsp, &rdp->exp_workdone0, s)); smp_mb(); /* Workqueue actions happen before return. */ /* Let the next expedited grace period start. */ mutex_unlock(&rsp->exp_mutex); }

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/** * synchronize_sched_expedited - Brute-force RCU-sched grace period * * Wait for an RCU-sched grace period to elapse, but use a "big hammer" * approach to force the grace period to end quickly. This consumes * significant time on all CPUs and is unfriendly to real-time workloads, * so is thus not recommended for any sort of common-case code. In fact, * if you are using synchronize_sched_expedited() in a loop, please * restructure your code to batch your updates, and then use a single * synchronize_sched() instead. * * This implementation can be thought of as an application of sequence * locking to expedited grace periods, but using the sequence counter to * determine when someone else has already done the work instead of for * retrying readers. */
void synchronize_sched_expedited(void) { struct rcu_state *rsp = &rcu_sched_state; 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_sched_expedited() in RCU read-side critical section"); /* If only one CPU, this is automatically a grace period. */ if (rcu_blocking_is_gp()) return; _synchronize_rcu_expedited(rsp, sync_sched_exp_handler); }

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EXPORT_SYMBOL_GPL(synchronize_sched_expedited); #ifdef CONFIG_PREEMPT_RCU /* * Remote handler for smp_call_function_single(). If there is an * RCU read-side critical section in effect, request that the * next rcu_read_unlock() record the quiescent state up the * ->expmask fields in the rcu_node tree. Otherwise, immediately * report the quiescent state. */
static void sync_rcu_exp_handler(void *info) { struct rcu_data *rdp; struct rcu_state *rsp = info; struct task_struct *t = current; /* * Within an RCU read-side critical section, request that the next * rcu_read_unlock() report. Unless this RCU read-side critical * section has already blocked, in which case it is already set * up for the expedited grace period to wait on it. */ if (t->rcu_read_lock_nesting > 0 && !t->rcu_read_unlock_special.b.blocked) { t->rcu_read_unlock_special.b.exp_need_qs = true; return; } /* * We are either exiting an RCU read-side critical section (negative * values of t->rcu_read_lock_nesting) or are not in one at all * (zero value of t->rcu_read_lock_nesting). Or we are in an RCU * read-side critical section that blocked before this expedited * grace period started. Either way, we can immediately report * the quiescent state. */ rdp = this_cpu_ptr(rsp->rda); rcu_report_exp_rdp(rsp, rdp, true); }

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Paul E. McKenney79100.00%1100.00%
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/** * synchronize_rcu_expedited - Brute-force RCU grace period * * Wait for an RCU-preempt grace period, but expedite it. The basic * idea is to IPI all non-idle non-nohz online CPUs. The IPI handler * checks whether the CPU is in an RCU-preempt critical section, and * if so, it sets a flag that causes the outermost rcu_read_unlock() * to report the quiescent state. On the other hand, if the CPU is * not in an RCU read-side critical section, the IPI handler reports * the quiescent state immediately. * * Although this is a greate improvement over previous expedited * implementations, it is still unfriendly to real-time workloads, so is * thus not recommended for any sort of common-case code. In fact, if * you are using synchronize_rcu_expedited() in a loop, please restructure * your code to batch your updates, and then Use a single synchronize_rcu() * instead. */
void synchronize_rcu_expedited(void) { struct rcu_state *rsp = rcu_state_p; 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_expedited() in RCU read-side critical section"); if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE) return; _synchronize_rcu_expedited(rsp, sync_rcu_exp_handler); }

Contributors

PersonTokensPropCommitsCommitProp
Paul E. McKenney51100.00%4100.00%
Total51100.00%4100.00%

EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); #else /* #ifdef CONFIG_PREEMPT_RCU */ /* * Wait for an rcu-preempt grace period, but make it happen quickly. * But because preemptible RCU does not exist, map to rcu-sched. */
void synchronize_rcu_expedited(void) { synchronize_sched_expedited(); }

Contributors

PersonTokensPropCommitsCommitProp
Paul E. McKenney10100.00%1100.00%
Total10100.00%1100.00%

EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); #endif /* #else #ifdef CONFIG_PREEMPT_RCU */

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PersonTokensPropCommitsCommitProp
Paul E. McKenney263898.21%1995.00%
Mark Rutland481.79%15.00%
Total2686100.00%20100.00%
Directory: kernel/rcu
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