/* * Read-Copy Update mechanism for mutual exclusion * * 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, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * Copyright IBM Corporation, 2008 * * Authors: Dipankar Sarma * Manfred Spraul * Paul E. McKenney Hierarchical version * * Based on the original work by Paul McKenney * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen. * * For detailed explanation of Read-Copy Update mechanism see - * Documentation/RCU */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "rcutree.h" #include #include "rcu.h" static struct lock_class_key rcu_node_class[NUM_RCU_LVLS]; #define RCU_STATE_INITIALIZER(structname) { \ .level = { &structname##_state.node[0] }, \ .levelcnt = { \ NUM_RCU_LVL_0, \ NUM_RCU_LVL_1, \ NUM_RCU_LVL_2, \ NUM_RCU_LVL_3, \ NUM_RCU_LVL_4, \ }, \ .fqs_state = RCU_GP_IDLE, \ .gpnum = -300, \ .completed = -300, \ .onofflock = __RAW_SPIN_LOCK_UNLOCKED(&structname##_state.onofflock), \ .fqslock = __RAW_SPIN_LOCK_UNLOCKED(&structname##_state.fqslock), \ .n_force_qs = 0, \ .n_force_qs_ngp = 0, \ .name = #structname, \ } struct rcu_state rcu_sched_state = RCU_STATE_INITIALIZER(rcu_sched); DEFINE_PER_CPU(struct rcu_data, rcu_sched_data); struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh); DEFINE_PER_CPU(struct rcu_data, rcu_bh_data); static struct rcu_state *rcu_state; int rcu_scheduler_active __read_mostly; EXPORT_SYMBOL_GPL(rcu_scheduler_active); static int rcu_scheduler_fully_active __read_mostly; #ifdef CONFIG_RCU_BOOST static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task); DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_status); DEFINE_PER_CPU(int, rcu_cpu_kthread_cpu); DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_loops); DEFINE_PER_CPU(char, rcu_cpu_has_work); #endif static void rcu_node_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu); static void invoke_rcu_core(void); static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp); unsigned long rcutorture_testseq; unsigned long rcutorture_vernum; static int rcu_gp_in_progress(struct rcu_state *rsp) { return ACCESS_ONCE(rsp->completed) != ACCESS_ONCE(rsp->gpnum); } void rcu_sched_qs(int cpu) { struct rcu_data *rdp = &per_cpu(rcu_sched_data, cpu); rdp->passed_quiesce_gpnum = rdp->gpnum; barrier(); if (rdp->passed_quiesce == 0) trace_rcu_grace_period("rcu_sched", rdp->gpnum, "cpuqs"); rdp->passed_quiesce = 1; } void rcu_bh_qs(int cpu) { struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu); rdp->passed_quiesce_gpnum = rdp->gpnum; barrier(); if (rdp->passed_quiesce == 0) trace_rcu_grace_period("rcu_bh", rdp->gpnum, "cpuqs"); rdp->passed_quiesce = 1; } void rcu_note_context_switch(int cpu) { trace_rcu_utilization("Start context switch"); rcu_sched_qs(cpu); rcu_preempt_note_context_switch(cpu); trace_rcu_utilization("End context switch"); } EXPORT_SYMBOL_GPL(rcu_note_context_switch); DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = { .dynticks_nesting = DYNTICK_TASK_EXIT_IDLE, .dynticks = ATOMIC_INIT(1), }; static int blimit = 10; static int qhimark = 10000; static int qlowmark = 100; module_param(blimit, int, 0); module_param(qhimark, int, 0); module_param(qlowmark, int, 0); int rcu_cpu_stall_suppress __read_mostly; int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT; module_param(rcu_cpu_stall_suppress, int, 0644); module_param(rcu_cpu_stall_timeout, int, 0644); static void force_quiescent_state(struct rcu_state *rsp, int relaxed); static int rcu_pending(int cpu); long rcu_batches_completed_sched(void) { return rcu_sched_state.completed; } EXPORT_SYMBOL_GPL(rcu_batches_completed_sched); long rcu_batches_completed_bh(void) { return rcu_bh_state.completed; } EXPORT_SYMBOL_GPL(rcu_batches_completed_bh); void rcu_bh_force_quiescent_state(void) { force_quiescent_state(&rcu_bh_state, 0); } EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state); void rcutorture_record_test_transition(void) { rcutorture_testseq++; rcutorture_vernum = 0; } EXPORT_SYMBOL_GPL(rcutorture_record_test_transition); void rcutorture_record_progress(unsigned long vernum) { rcutorture_vernum++; } EXPORT_SYMBOL_GPL(rcutorture_record_progress); void rcu_sched_force_quiescent_state(void) { force_quiescent_state(&rcu_sched_state, 0); } EXPORT_SYMBOL_GPL(rcu_sched_force_quiescent_state); static int cpu_has_callbacks_ready_to_invoke(struct rcu_data *rdp) { return &rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]; } static int cpu_needs_another_gp(struct rcu_state *rsp, struct rcu_data *rdp) { return *rdp->nxttail[RCU_DONE_TAIL + ACCESS_ONCE(rsp->completed) != rdp->completed] && !rcu_gp_in_progress(rsp); } static struct rcu_node *rcu_get_root(struct rcu_state *rsp) { return &rsp->node[0]; } static int rcu_implicit_offline_qs(struct rcu_data *rdp) { if (cpu_is_offline(rdp->cpu) && ULONG_CMP_LT(rdp->rsp->gp_start + 2, jiffies)) { trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, "ofl"); rdp->offline_fqs++; return 1; } return 0; } static void rcu_idle_enter_common(struct rcu_dynticks *rdtp, long long oldval) { trace_rcu_dyntick("Start", oldval, 0); if (!is_idle_task(current)) { struct task_struct *idle = idle_task(smp_processor_id()); trace_rcu_dyntick("Error on entry: not idle task", oldval, 0); ftrace_dump(DUMP_ALL); WARN_ONCE(1, "Current pid: %d comm: %s / Idle pid: %d comm: %s", current->pid, current->comm, idle->pid, idle->comm); } rcu_prepare_for_idle(smp_processor_id()); smp_mb__before_atomic_inc(); atomic_inc(&rdtp->dynticks); smp_mb__after_atomic_inc(); WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1); rcu_lockdep_assert(!lock_is_held(&rcu_lock_map), "Illegal idle entry in RCU read-side critical section."); rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map), "Illegal idle entry in RCU-bh read-side critical section."); rcu_lockdep_assert(!lock_is_held(&rcu_sched_lock_map), "Illegal idle entry in RCU-sched read-side critical section."); } void rcu_idle_enter(void) { unsigned long flags; long long oldval; struct rcu_dynticks *rdtp; local_irq_save(flags); rdtp = &__get_cpu_var(rcu_dynticks); oldval = rdtp->dynticks_nesting; WARN_ON_ONCE((oldval & DYNTICK_TASK_NEST_MASK) == 0); if ((oldval & DYNTICK_TASK_NEST_MASK) == DYNTICK_TASK_NEST_VALUE) rdtp->dynticks_nesting = 0; else rdtp->dynticks_nesting -= DYNTICK_TASK_NEST_VALUE; rcu_idle_enter_common(rdtp, oldval); local_irq_restore(flags); } EXPORT_SYMBOL_GPL(rcu_idle_enter); void rcu_irq_exit(void) { unsigned long flags; long long oldval; struct rcu_dynticks *rdtp; local_irq_save(flags); rdtp = &__get_cpu_var(rcu_dynticks); oldval = rdtp->dynticks_nesting; rdtp->dynticks_nesting--; WARN_ON_ONCE(rdtp->dynticks_nesting < 0); if (rdtp->dynticks_nesting) trace_rcu_dyntick("--=", oldval, rdtp->dynticks_nesting); else rcu_idle_enter_common(rdtp, oldval); local_irq_restore(flags); } static void rcu_idle_exit_common(struct rcu_dynticks *rdtp, long long oldval) { smp_mb__before_atomic_inc(); atomic_inc(&rdtp->dynticks); smp_mb__after_atomic_inc(); WARN_ON_ONCE(!(atomic_read(&rdtp->dynticks) & 0x1)); rcu_cleanup_after_idle(smp_processor_id()); trace_rcu_dyntick("End", oldval, rdtp->dynticks_nesting); if (!is_idle_task(current)) { struct task_struct *idle = idle_task(smp_processor_id()); trace_rcu_dyntick("Error on exit: not idle task", oldval, rdtp->dynticks_nesting); ftrace_dump(DUMP_ALL); WARN_ONCE(1, "Current pid: %d comm: %s / Idle pid: %d comm: %s", current->pid, current->comm, idle->pid, idle->comm); } } void rcu_idle_exit(void) { unsigned long flags; struct rcu_dynticks *rdtp; long long oldval; local_irq_save(flags); rdtp = &__get_cpu_var(rcu_dynticks); oldval = rdtp->dynticks_nesting; WARN_ON_ONCE(oldval < 0); if (oldval & DYNTICK_TASK_NEST_MASK) rdtp->dynticks_nesting += DYNTICK_TASK_NEST_VALUE; else rdtp->dynticks_nesting = DYNTICK_TASK_EXIT_IDLE; rcu_idle_exit_common(rdtp, oldval); local_irq_restore(flags); } EXPORT_SYMBOL_GPL(rcu_idle_exit); void rcu_irq_enter(void) { unsigned long flags; struct rcu_dynticks *rdtp; long long oldval; local_irq_save(flags); rdtp = &__get_cpu_var(rcu_dynticks); oldval = rdtp->dynticks_nesting; rdtp->dynticks_nesting++; WARN_ON_ONCE(rdtp->dynticks_nesting == 0); if (oldval) trace_rcu_dyntick("++=", oldval, rdtp->dynticks_nesting); else rcu_idle_exit_common(rdtp, oldval); local_irq_restore(flags); } void rcu_nmi_enter(void) { struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks); if (rdtp->dynticks_nmi_nesting == 0 && (atomic_read(&rdtp->dynticks) & 0x1)) return; rdtp->dynticks_nmi_nesting++; smp_mb__before_atomic_inc(); atomic_inc(&rdtp->dynticks); smp_mb__after_atomic_inc(); WARN_ON_ONCE(!(atomic_read(&rdtp->dynticks) & 0x1)); } void rcu_nmi_exit(void) { struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks); if (rdtp->dynticks_nmi_nesting == 0 || --rdtp->dynticks_nmi_nesting != 0) return; smp_mb__before_atomic_inc(); atomic_inc(&rdtp->dynticks); smp_mb__after_atomic_inc(); WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1); } #ifdef CONFIG_PROVE_RCU int rcu_is_cpu_idle(void) { int ret; preempt_disable(); ret = (atomic_read(&__get_cpu_var(rcu_dynticks).dynticks) & 0x1) == 0; preempt_enable(); return ret; } EXPORT_SYMBOL(rcu_is_cpu_idle); #ifdef CONFIG_HOTPLUG_CPU bool rcu_lockdep_current_cpu_online(void) { struct rcu_data *rdp; struct rcu_node *rnp; bool ret; if (in_nmi()) return 1; preempt_disable(); rdp = &__get_cpu_var(rcu_sched_data); rnp = rdp->mynode; ret = (rdp->grpmask & rnp->qsmaskinit) || !rcu_scheduler_fully_active; preempt_enable(); return ret; } EXPORT_SYMBOL_GPL(rcu_lockdep_current_cpu_online); #endif #endif int rcu_is_cpu_rrupt_from_idle(void) { return __get_cpu_var(rcu_dynticks).dynticks_nesting <= 1; } static int dyntick_save_progress_counter(struct rcu_data *rdp) { rdp->dynticks_snap = atomic_add_return(0, &rdp->dynticks->dynticks); return (rdp->dynticks_snap & 0x1) == 0; } static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) { unsigned int curr; unsigned int snap; curr = (unsigned int)atomic_add_return(0, &rdp->dynticks->dynticks); snap = (unsigned int)rdp->dynticks_snap; if ((curr & 0x1) == 0 || UINT_CMP_GE(curr, snap + 2)) { trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, "dti"); rdp->dynticks_fqs++; return 1; } return rcu_implicit_offline_qs(rdp); } static int jiffies_till_stall_check(void) { int till_stall_check = ACCESS_ONCE(rcu_cpu_stall_timeout); if (till_stall_check < 3) { ACCESS_ONCE(rcu_cpu_stall_timeout) = 3; till_stall_check = 3; } else if (till_stall_check > 300) { ACCESS_ONCE(rcu_cpu_stall_timeout) = 300; till_stall_check = 300; } return till_stall_check * HZ + RCU_STALL_DELAY_DELTA; } static void record_gp_stall_check_time(struct rcu_state *rsp) { rsp->gp_start = jiffies; rsp->jiffies_stall = jiffies + jiffies_till_stall_check(); } static void print_other_cpu_stall(struct rcu_state *rsp) { int cpu; long delta; unsigned long flags; int ndetected = 0; struct rcu_node *rnp = rcu_get_root(rsp); raw_spin_lock_irqsave(&rnp->lock, flags); delta = jiffies - rsp->jiffies_stall; if (delta < RCU_STALL_RAT_DELAY || !rcu_gp_in_progress(rsp)) { raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } rsp->jiffies_stall = jiffies + 3 * jiffies_till_stall_check() + 3; raw_spin_unlock_irqrestore(&rnp->lock, flags); printk(KERN_ERR "INFO: %s detected stalls on CPUs/tasks:", rsp->name); print_cpu_stall_info_begin(); rcu_for_each_leaf_node(rsp, rnp) { raw_spin_lock_irqsave(&rnp->lock, flags); ndetected += rcu_print_task_stall(rnp); raw_spin_unlock_irqrestore(&rnp->lock, flags); if (rnp->qsmask == 0) continue; for (cpu = 0; cpu <= rnp->grphi - rnp->grplo; cpu++) if (rnp->qsmask & (1UL << cpu)) { print_cpu_stall_info(rsp, rnp->grplo + cpu); ndetected++; } } rnp = rcu_get_root(rsp); raw_spin_lock_irqsave(&rnp->lock, flags); ndetected = rcu_print_task_stall(rnp); raw_spin_unlock_irqrestore(&rnp->lock, flags); print_cpu_stall_info_end(); printk(KERN_CONT "(detected by %d, t=%ld jiffies)\n", smp_processor_id(), (long)(jiffies - rsp->gp_start)); if (ndetected == 0) printk(KERN_ERR "INFO: Stall ended before state dump start\n"); else if (!trigger_all_cpu_backtrace()) dump_stack(); rcu_print_detail_task_stall(rsp); force_quiescent_state(rsp, 0); } static void print_cpu_stall(struct rcu_state *rsp) { unsigned long flags; struct rcu_node *rnp = rcu_get_root(rsp); printk(KERN_ERR "INFO: %s self-detected stall on CPU", rsp->name); print_cpu_stall_info_begin(); print_cpu_stall_info(rsp, smp_processor_id()); print_cpu_stall_info_end(); printk(KERN_CONT " (t=%lu jiffies)\n", jiffies - rsp->gp_start); if (!trigger_all_cpu_backtrace()) dump_stack(); raw_spin_lock_irqsave(&rnp->lock, flags); if (ULONG_CMP_GE(jiffies, rsp->jiffies_stall)) rsp->jiffies_stall = jiffies + 3 * jiffies_till_stall_check() + 3; raw_spin_unlock_irqrestore(&rnp->lock, flags); set_need_resched(); } static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) { unsigned long j; unsigned long js; struct rcu_node *rnp; if (rcu_cpu_stall_suppress) return; j = ACCESS_ONCE(jiffies); js = ACCESS_ONCE(rsp->jiffies_stall); rnp = rdp->mynode; if ((ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && ULONG_CMP_GE(j, js)) { print_cpu_stall(rsp); } else if (rcu_gp_in_progress(rsp) && ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY)) { print_other_cpu_stall(rsp); } } static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr) { rcu_cpu_stall_suppress = 1; return NOTIFY_DONE; } void rcu_cpu_stall_reset(void) { rcu_sched_state.jiffies_stall = jiffies + ULONG_MAX / 2; rcu_bh_state.jiffies_stall = jiffies + ULONG_MAX / 2; rcu_preempt_stall_reset(); } static struct notifier_block rcu_panic_block = { .notifier_call = rcu_panic, }; static void __init check_cpu_stall_init(void) { atomic_notifier_chain_register(&panic_notifier_list, &rcu_panic_block); } static void __note_new_gpnum(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) { if (rdp->gpnum != rnp->gpnum) { rdp->gpnum = rnp->gpnum; trace_rcu_grace_period(rsp->name, rdp->gpnum, "cpustart"); if (rnp->qsmask & rdp->grpmask) { rdp->qs_pending = 1; rdp->passed_quiesce = 0; } else rdp->qs_pending = 0; zero_cpu_stall_ticks(rdp); } } static void note_new_gpnum(struct rcu_state *rsp, struct rcu_data *rdp) { unsigned long flags; struct rcu_node *rnp; local_irq_save(flags); rnp = rdp->mynode; if (rdp->gpnum == ACCESS_ONCE(rnp->gpnum) || !raw_spin_trylock(&rnp->lock)) { local_irq_restore(flags); return; } __note_new_gpnum(rsp, rnp, rdp); raw_spin_unlock_irqrestore(&rnp->lock, flags); } static int check_for_new_grace_period(struct rcu_state *rsp, struct rcu_data *rdp) { unsigned long flags; int ret = 0; local_irq_save(flags); if (rdp->gpnum != rsp->gpnum) { note_new_gpnum(rsp, rdp); ret = 1; } local_irq_restore(flags); return ret; } static void __rcu_process_gp_end(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) { if (rdp->completed != rnp->completed) { rdp->nxttail[RCU_DONE_TAIL] = rdp->nxttail[RCU_WAIT_TAIL]; rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_READY_TAIL]; rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; rdp->completed = rnp->completed; trace_rcu_grace_period(rsp->name, rdp->gpnum, "cpuend"); if (ULONG_CMP_LT(rdp->gpnum, rdp->completed)) rdp->gpnum = rdp->completed; if ((rnp->qsmask & rdp->grpmask) == 0) rdp->qs_pending = 0; } } static void rcu_process_gp_end(struct rcu_state *rsp, struct rcu_data *rdp) { unsigned long flags; struct rcu_node *rnp; local_irq_save(flags); rnp = rdp->mynode; if (rdp->completed == ACCESS_ONCE(rnp->completed) || !raw_spin_trylock(&rnp->lock)) { local_irq_restore(flags); return; } __rcu_process_gp_end(rsp, rnp, rdp); raw_spin_unlock_irqrestore(&rnp->lock, flags); } static void rcu_start_gp_per_cpu(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) { __rcu_process_gp_end(rsp, rnp, rdp); rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; __note_new_gpnum(rsp, rnp, rdp); } static void rcu_start_gp(struct rcu_state *rsp, unsigned long flags) __releases(rcu_get_root(rsp)->lock) { struct rcu_data *rdp = this_cpu_ptr(rsp->rda); struct rcu_node *rnp = rcu_get_root(rsp); if (!rcu_scheduler_fully_active || !cpu_needs_another_gp(rsp, rdp)) { raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } if (rsp->fqs_active) { rsp->fqs_need_gp = 1; raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } rsp->gpnum++; trace_rcu_grace_period(rsp->name, rsp->gpnum, "start"); WARN_ON_ONCE(rsp->fqs_state == RCU_GP_INIT); rsp->fqs_state = RCU_GP_INIT; rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; record_gp_stall_check_time(rsp); raw_spin_unlock(&rnp->lock); raw_spin_lock(&rsp->onofflock); rcu_for_each_node_breadth_first(rsp, rnp) { raw_spin_lock(&rnp->lock); rcu_preempt_check_blocked_tasks(rnp); rnp->qsmask = rnp->qsmaskinit; rnp->gpnum = rsp->gpnum; rnp->completed = rsp->completed; if (rnp == rdp->mynode) rcu_start_gp_per_cpu(rsp, rnp, rdp); rcu_preempt_boost_start_gp(rnp); trace_rcu_grace_period_init(rsp->name, rnp->gpnum, rnp->level, rnp->grplo, rnp->grphi, rnp->qsmask); raw_spin_unlock(&rnp->lock); } rnp = rcu_get_root(rsp); raw_spin_lock(&rnp->lock); rsp->fqs_state = RCU_SIGNAL_INIT; raw_spin_unlock(&rnp->lock); raw_spin_unlock_irqrestore(&rsp->onofflock, flags); } static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags) __releases(rcu_get_root(rsp)->lock) { unsigned long gp_duration; struct rcu_node *rnp = rcu_get_root(rsp); struct rcu_data *rdp = this_cpu_ptr(rsp->rda); WARN_ON_ONCE(!rcu_gp_in_progress(rsp)); smp_mb(); gp_duration = jiffies - rsp->gp_start; if (gp_duration > rsp->gp_max) rsp->gp_max = gp_duration; if (*rdp->nxttail[RCU_WAIT_TAIL] == NULL) { raw_spin_unlock(&rnp->lock); rcu_for_each_node_breadth_first(rsp, rnp) { raw_spin_lock(&rnp->lock); rnp->completed = rsp->gpnum; raw_spin_unlock(&rnp->lock); } rnp = rcu_get_root(rsp); raw_spin_lock(&rnp->lock); } rsp->completed = rsp->gpnum; trace_rcu_grace_period(rsp->name, rsp->completed, "end"); rsp->fqs_state = RCU_GP_IDLE; rcu_start_gp(rsp, flags); } static void rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp, struct rcu_node *rnp, unsigned long flags) __releases(rnp->lock) { struct rcu_node *rnp_c; for (;;) { if (!(rnp->qsmask & mask)) { raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } rnp->qsmask &= ~mask; trace_rcu_quiescent_state_report(rsp->name, rnp->gpnum, mask, rnp->qsmask, rnp->level, rnp->grplo, rnp->grphi, !!rnp->gp_tasks); if (rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) { raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } mask = rnp->grpmask; if (rnp->parent == NULL) { break; } raw_spin_unlock_irqrestore(&rnp->lock, flags); rnp_c = rnp; rnp = rnp->parent; raw_spin_lock_irqsave(&rnp->lock, flags); WARN_ON_ONCE(rnp_c->qsmask); } rcu_report_qs_rsp(rsp, flags); } static void rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastgp) { unsigned long flags; unsigned long mask; struct rcu_node *rnp; rnp = rdp->mynode; raw_spin_lock_irqsave(&rnp->lock, flags); if (lastgp != rnp->gpnum || rnp->completed == rnp->gpnum) { rdp->passed_quiesce = 0; raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } mask = rdp->grpmask; if ((rnp->qsmask & mask) == 0) { raw_spin_unlock_irqrestore(&rnp->lock, flags); } else { rdp->qs_pending = 0; rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; rcu_report_qs_rnp(mask, rsp, rnp, flags); } } static void rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp) { if (check_for_new_grace_period(rsp, rdp)) return; if (!rdp->qs_pending) return; if (!rdp->passed_quiesce) return; rcu_report_qs_rdp(rdp->cpu, rsp, rdp, rdp->passed_quiesce_gpnum); } #ifdef CONFIG_HOTPLUG_CPU static void rcu_cleanup_dying_cpu(struct rcu_state *rsp) { int i; unsigned long mask; int receive_cpu = cpumask_any(cpu_online_mask); struct rcu_data *rdp = this_cpu_ptr(rsp->rda); struct rcu_data *receive_rdp = per_cpu_ptr(rsp->rda, receive_cpu); RCU_TRACE(struct rcu_node *rnp = rdp->mynode); if (rdp->nxtlist != NULL) { receive_rdp->qlen_lazy += rdp->qlen_lazy; receive_rdp->qlen += rdp->qlen; rdp->qlen_lazy = 0; rdp->qlen = 0; } if (rdp->nxtlist != NULL && rdp->nxttail[RCU_DONE_TAIL] != &rdp->nxtlist) { struct rcu_head *oldhead; struct rcu_head **oldtail; struct rcu_head **newtail; oldhead = rdp->nxtlist; oldtail = receive_rdp->nxttail[RCU_DONE_TAIL]; rdp->nxtlist = *rdp->nxttail[RCU_DONE_TAIL]; *rdp->nxttail[RCU_DONE_TAIL] = *oldtail; *receive_rdp->nxttail[RCU_DONE_TAIL] = oldhead; newtail = rdp->nxttail[RCU_DONE_TAIL]; for (i = RCU_DONE_TAIL; i < RCU_NEXT_SIZE; i++) { if (receive_rdp->nxttail[i] == oldtail) receive_rdp->nxttail[i] = newtail; if (rdp->nxttail[i] == newtail) rdp->nxttail[i] = &rdp->nxtlist; } } if (rdp->nxtlist != NULL) { *receive_rdp->nxttail[RCU_NEXT_TAIL] = rdp->nxtlist; receive_rdp->nxttail[RCU_NEXT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; receive_rdp->n_cbs_adopted += rdp->qlen; rdp->n_cbs_orphaned += rdp->qlen; rdp->nxtlist = NULL; for (i = 0; i < RCU_NEXT_SIZE; i++) rdp->nxttail[i] = &rdp->nxtlist; } mask = rdp->grpmask; trace_rcu_grace_period(rsp->name, rnp->gpnum + 1 - !!(rnp->qsmask & mask), "cpuofl"); rcu_report_qs_rdp(smp_processor_id(), rsp, rdp, rsp->gpnum); } static void rcu_cleanup_dead_cpu(int cpu, struct rcu_state *rsp) { unsigned long flags; unsigned long mask; int need_report = 0; struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); struct rcu_node *rnp = rdp->mynode; rcu_stop_cpu_kthread(cpu); rcu_node_kthread_setaffinity(rnp, -1); raw_spin_lock_irqsave(&rsp->onofflock, flags); mask = rdp->grpmask; do { raw_spin_lock(&rnp->lock); rnp->qsmaskinit &= ~mask; if (rnp->qsmaskinit != 0) { if (rnp != rdp->mynode) raw_spin_unlock(&rnp->lock); break; } if (rnp == rdp->mynode) need_report = rcu_preempt_offline_tasks(rsp, rnp, rdp); else raw_spin_unlock(&rnp->lock); mask = rnp->grpmask; rnp = rnp->parent; } while (rnp != NULL); raw_spin_unlock(&rsp->onofflock); rnp = rdp->mynode; if (need_report & RCU_OFL_TASKS_NORM_GP) rcu_report_unblock_qs_rnp(rnp, flags); else raw_spin_unlock_irqrestore(&rnp->lock, flags); if (need_report & RCU_OFL_TASKS_EXP_GP) rcu_report_exp_rnp(rsp, rnp, true); } #else static void rcu_cleanup_dying_cpu(struct rcu_state *rsp) { } static void rcu_cleanup_dead_cpu(int cpu, struct rcu_state *rsp) { } #endif static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) { unsigned long flags; struct rcu_head *next, *list, **tail; int bl, count, count_lazy; if (!cpu_has_callbacks_ready_to_invoke(rdp)) { trace_rcu_batch_start(rsp->name, rdp->qlen_lazy, rdp->qlen, 0); trace_rcu_batch_end(rsp->name, 0, !!ACCESS_ONCE(rdp->nxtlist), need_resched(), is_idle_task(current), rcu_is_callbacks_kthread()); return; } local_irq_save(flags); WARN_ON_ONCE(cpu_is_offline(smp_processor_id())); bl = rdp->blimit; trace_rcu_batch_start(rsp->name, rdp->qlen_lazy, rdp->qlen, bl); list = rdp->nxtlist; rdp->nxtlist = *rdp->nxttail[RCU_DONE_TAIL]; *rdp->nxttail[RCU_DONE_TAIL] = NULL; tail = rdp->nxttail[RCU_DONE_TAIL]; for (count = RCU_NEXT_SIZE - 1; count >= 0; count--) if (rdp->nxttail[count] == rdp->nxttail[RCU_DONE_TAIL]) rdp->nxttail[count] = &rdp->nxtlist; local_irq_restore(flags); count = count_lazy = 0; while (list) { next = list->next; prefetch(next); debug_rcu_head_unqueue(list); if (__rcu_reclaim(rsp->name, list)) count_lazy++; list = next; if (++count >= bl && (need_resched() || (!is_idle_task(current) && !rcu_is_callbacks_kthread()))) break; } local_irq_save(flags); trace_rcu_batch_end(rsp->name, count, !!list, need_resched(), is_idle_task(current), rcu_is_callbacks_kthread()); rdp->qlen_lazy -= count_lazy; rdp->qlen -= count; rdp->n_cbs_invoked += count; if (list != NULL) { *tail = rdp->nxtlist; rdp->nxtlist = list; for (count = 0; count < RCU_NEXT_SIZE; count++) if (&rdp->nxtlist == rdp->nxttail[count]) rdp->nxttail[count] = tail; else break; } if (rdp->blimit == LONG_MAX && rdp->qlen <= qlowmark) rdp->blimit = blimit; if (rdp->qlen == 0 && rdp->qlen_last_fqs_check != 0) { rdp->qlen_last_fqs_check = 0; rdp->n_force_qs_snap = rsp->n_force_qs; } else if (rdp->qlen < rdp->qlen_last_fqs_check - qhimark) rdp->qlen_last_fqs_check = rdp->qlen; local_irq_restore(flags); if (cpu_has_callbacks_ready_to_invoke(rdp)) invoke_rcu_core(); } void rcu_check_callbacks(int cpu, int user) { trace_rcu_utilization("Start scheduler-tick"); increment_cpu_stall_ticks(); if (user || rcu_is_cpu_rrupt_from_idle()) { rcu_sched_qs(cpu); rcu_bh_qs(cpu); } else if (!in_softirq()) { rcu_bh_qs(cpu); } rcu_preempt_check_callbacks(cpu); if (rcu_pending(cpu)) invoke_rcu_core(); trace_rcu_utilization("End scheduler-tick"); } static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *)) { unsigned long bit; int cpu; unsigned long flags; unsigned long mask; struct rcu_node *rnp; rcu_for_each_leaf_node(rsp, rnp) { mask = 0; raw_spin_lock_irqsave(&rnp->lock, flags); if (!rcu_gp_in_progress(rsp)) { raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } if (rnp->qsmask == 0) { rcu_initiate_boost(rnp, flags); continue; } cpu = rnp->grplo; bit = 1; for (; cpu <= rnp->grphi; cpu++, bit <<= 1) { if ((rnp->qsmask & bit) != 0 && f(per_cpu_ptr(rsp->rda, cpu))) mask |= bit; } if (mask != 0) { rcu_report_qs_rnp(mask, rsp, rnp, flags); continue; } raw_spin_unlock_irqrestore(&rnp->lock, flags); } rnp = rcu_get_root(rsp); if (rnp->qsmask == 0) { raw_spin_lock_irqsave(&rnp->lock, flags); rcu_initiate_boost(rnp, flags); } } static void force_quiescent_state(struct rcu_state *rsp, int relaxed) { unsigned long flags; struct rcu_node *rnp = rcu_get_root(rsp); trace_rcu_utilization("Start fqs"); if (!rcu_gp_in_progress(rsp)) { trace_rcu_utilization("End fqs"); return; } if (!raw_spin_trylock_irqsave(&rsp->fqslock, flags)) { rsp->n_force_qs_lh++; trace_rcu_utilization("End fqs"); return; } if (relaxed && ULONG_CMP_GE(rsp->jiffies_force_qs, jiffies)) goto unlock_fqs_ret; rsp->n_force_qs++; raw_spin_lock(&rnp->lock); rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; if(!rcu_gp_in_progress(rsp)) { rsp->n_force_qs_ngp++; raw_spin_unlock(&rnp->lock); goto unlock_fqs_ret; } rsp->fqs_active = 1; switch (rsp->fqs_state) { case RCU_GP_IDLE: case RCU_GP_INIT: break; case RCU_SAVE_DYNTICK: if (RCU_SIGNAL_INIT != RCU_SAVE_DYNTICK) break; raw_spin_unlock(&rnp->lock); force_qs_rnp(rsp, dyntick_save_progress_counter); raw_spin_lock(&rnp->lock); if (rcu_gp_in_progress(rsp)) rsp->fqs_state = RCU_FORCE_QS; break; case RCU_FORCE_QS: raw_spin_unlock(&rnp->lock); force_qs_rnp(rsp, rcu_implicit_dynticks_qs); raw_spin_lock(&rnp->lock); break; } rsp->fqs_active = 0; if (rsp->fqs_need_gp) { raw_spin_unlock(&rsp->fqslock); rsp->fqs_need_gp = 0; rcu_start_gp(rsp, flags); trace_rcu_utilization("End fqs"); return; } raw_spin_unlock(&rnp->lock); unlock_fqs_ret: raw_spin_unlock_irqrestore(&rsp->fqslock, flags); trace_rcu_utilization("End fqs"); } static void __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp) { unsigned long flags; WARN_ON_ONCE(rdp->beenonline == 0); if (ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs), jiffies)) force_quiescent_state(rsp, 1); rcu_process_gp_end(rsp, rdp); rcu_check_quiescent_state(rsp, rdp); if (cpu_needs_another_gp(rsp, rdp)) { raw_spin_lock_irqsave(&rcu_get_root(rsp)->lock, flags); rcu_start_gp(rsp, flags); } if (cpu_has_callbacks_ready_to_invoke(rdp)) invoke_rcu_callbacks(rsp, rdp); } static void rcu_process_callbacks(struct softirq_action *unused) { trace_rcu_utilization("Start RCU core"); __rcu_process_callbacks(&rcu_sched_state, &__get_cpu_var(rcu_sched_data)); __rcu_process_callbacks(&rcu_bh_state, &__get_cpu_var(rcu_bh_data)); rcu_preempt_process_callbacks(); trace_rcu_utilization("End RCU core"); } static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp) { if (unlikely(!ACCESS_ONCE(rcu_scheduler_fully_active))) return; if (likely(!rsp->boost)) { rcu_do_batch(rsp, rdp); return; } invoke_rcu_callbacks_kthread(); } static void invoke_rcu_core(void) { raise_softirq(RCU_SOFTIRQ); } static void __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), struct rcu_state *rsp, bool lazy) { unsigned long flags; struct rcu_data *rdp; WARN_ON_ONCE((unsigned long)head & 0x3); debug_rcu_head_queue(head); head->func = func; head->next = NULL; smp_mb(); local_irq_save(flags); rdp = this_cpu_ptr(rsp->rda); *rdp->nxttail[RCU_NEXT_TAIL] = head; rdp->nxttail[RCU_NEXT_TAIL] = &head->next; rdp->qlen++; if (lazy) rdp->qlen_lazy++; if (__is_kfree_rcu_offset((unsigned long)func)) trace_rcu_kfree_callback(rsp->name, head, (unsigned long)func, rdp->qlen_lazy, rdp->qlen); else trace_rcu_callback(rsp->name, head, rdp->qlen_lazy, rdp->qlen); if (irqs_disabled_flags(flags)) { local_irq_restore(flags); return; } if (unlikely(rdp->qlen > rdp->qlen_last_fqs_check + qhimark)) { rcu_process_gp_end(rsp, rdp); check_for_new_grace_period(rsp, rdp); if (!rcu_gp_in_progress(rsp)) { unsigned long nestflag; struct rcu_node *rnp_root = rcu_get_root(rsp); raw_spin_lock_irqsave(&rnp_root->lock, nestflag); rcu_start_gp(rsp, nestflag); } else { rdp->blimit = LONG_MAX; if (rsp->n_force_qs == rdp->n_force_qs_snap && *rdp->nxttail[RCU_DONE_TAIL] != head) force_quiescent_state(rsp, 0); rdp->n_force_qs_snap = rsp->n_force_qs; rdp->qlen_last_fqs_check = rdp->qlen; } } else if (ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs), jiffies)) force_quiescent_state(rsp, 1); local_irq_restore(flags); } void call_rcu_sched(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) { __call_rcu(head, func, &rcu_sched_state, 0); } EXPORT_SYMBOL_GPL(call_rcu_sched); void call_rcu_bh(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) { __call_rcu(head, func, &rcu_bh_state, 0); } EXPORT_SYMBOL_GPL(call_rcu_bh); void synchronize_sched(void) { rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) && !lock_is_held(&rcu_lock_map) && !lock_is_held(&rcu_sched_lock_map), "Illegal synchronize_sched() in RCU-sched read-side critical section"); if (rcu_blocking_is_gp()) return; wait_rcu_gp(call_rcu_sched); } EXPORT_SYMBOL_GPL(synchronize_sched); void synchronize_rcu_bh(void) { rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) && !lock_is_held(&rcu_lock_map) && !lock_is_held(&rcu_sched_lock_map), "Illegal synchronize_rcu_bh() in RCU-bh read-side critical section"); if (rcu_blocking_is_gp()) return; wait_rcu_gp(call_rcu_bh); } EXPORT_SYMBOL_GPL(synchronize_rcu_bh); static atomic_t sync_sched_expedited_started = ATOMIC_INIT(0); static atomic_t sync_sched_expedited_done = ATOMIC_INIT(0); static int synchronize_sched_expedited_cpu_stop(void *data) { smp_mb(); return 0; } void synchronize_sched_expedited(void) { int firstsnap, s, snap, trycount = 0; firstsnap = snap = atomic_inc_return(&sync_sched_expedited_started); get_online_cpus(); WARN_ON_ONCE(cpu_is_offline(raw_smp_processor_id())); while (try_stop_cpus(cpu_online_mask, synchronize_sched_expedited_cpu_stop, NULL) == -EAGAIN) { put_online_cpus(); if (trycount++ < 10) udelay(trycount * num_online_cpus()); else { synchronize_sched(); return; } s = atomic_read(&sync_sched_expedited_done); if (UINT_CMP_GE((unsigned)s, (unsigned)firstsnap)) { smp_mb(); return; } get_online_cpus(); snap = atomic_read(&sync_sched_expedited_started); smp_mb(); } do { s = atomic_read(&sync_sched_expedited_done); if (UINT_CMP_GE((unsigned)s, (unsigned)snap)) { smp_mb(); break; } } while (atomic_cmpxchg(&sync_sched_expedited_done, s, snap) != s); put_online_cpus(); } EXPORT_SYMBOL_GPL(synchronize_sched_expedited); static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) { struct rcu_node *rnp = rdp->mynode; rdp->n_rcu_pending++; check_cpu_stall(rsp, rdp); if (rcu_scheduler_fully_active && rdp->qs_pending && !rdp->passed_quiesce) { rdp->n_rp_qs_pending++; if (!rdp->preemptible && ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs) - 1, jiffies)) set_need_resched(); } else if (rdp->qs_pending && rdp->passed_quiesce) { rdp->n_rp_report_qs++; return 1; } if (cpu_has_callbacks_ready_to_invoke(rdp)) { rdp->n_rp_cb_ready++; return 1; } if (cpu_needs_another_gp(rsp, rdp)) { rdp->n_rp_cpu_needs_gp++; return 1; } if (ACCESS_ONCE(rnp->completed) != rdp->completed) { rdp->n_rp_gp_completed++; return 1; } if (ACCESS_ONCE(rnp->gpnum) != rdp->gpnum) { rdp->n_rp_gp_started++; return 1; } if (rcu_gp_in_progress(rsp) && ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs), jiffies)) { rdp->n_rp_need_fqs++; return 1; } rdp->n_rp_need_nothing++; return 0; } static int rcu_pending(int cpu) { return __rcu_pending(&rcu_sched_state, &per_cpu(rcu_sched_data, cpu)) || __rcu_pending(&rcu_bh_state, &per_cpu(rcu_bh_data, cpu)) || rcu_preempt_pending(cpu); } static int rcu_cpu_has_callbacks(int cpu) { return per_cpu(rcu_sched_data, cpu).nxtlist || per_cpu(rcu_bh_data, cpu).nxtlist || rcu_preempt_cpu_has_callbacks(cpu); } static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL}; static atomic_t rcu_barrier_cpu_count; static DEFINE_MUTEX(rcu_barrier_mutex); static struct completion rcu_barrier_completion; static void rcu_barrier_callback(struct rcu_head *notused) { if (atomic_dec_and_test(&rcu_barrier_cpu_count)) complete(&rcu_barrier_completion); } static void rcu_barrier_func(void *type) { int cpu = smp_processor_id(); struct rcu_head *head = &per_cpu(rcu_barrier_head, cpu); void (*call_rcu_func)(struct rcu_head *head, void (*func)(struct rcu_head *head)); atomic_inc(&rcu_barrier_cpu_count); call_rcu_func = type; call_rcu_func(head, rcu_barrier_callback); } static void _rcu_barrier(struct rcu_state *rsp, void (*call_rcu_func)(struct rcu_head *head, void (*func)(struct rcu_head *head))) { BUG_ON(in_interrupt()); mutex_lock(&rcu_barrier_mutex); init_completion(&rcu_barrier_completion); atomic_set(&rcu_barrier_cpu_count, 1); on_each_cpu(rcu_barrier_func, (void *)call_rcu_func, 1); if (atomic_dec_and_test(&rcu_barrier_cpu_count)) complete(&rcu_barrier_completion); wait_for_completion(&rcu_barrier_completion); mutex_unlock(&rcu_barrier_mutex); } void rcu_barrier_bh(void) { _rcu_barrier(&rcu_bh_state, call_rcu_bh); } EXPORT_SYMBOL_GPL(rcu_barrier_bh); void rcu_barrier_sched(void) { _rcu_barrier(&rcu_sched_state, call_rcu_sched); } EXPORT_SYMBOL_GPL(rcu_barrier_sched); static void __init rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp) { unsigned long flags; int i; struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); struct rcu_node *rnp = rcu_get_root(rsp); raw_spin_lock_irqsave(&rnp->lock, flags); rdp->grpmask = 1UL << (cpu - rdp->mynode->grplo); rdp->nxtlist = NULL; for (i = 0; i < RCU_NEXT_SIZE; i++) rdp->nxttail[i] = &rdp->nxtlist; rdp->qlen_lazy = 0; rdp->qlen = 0; rdp->dynticks = &per_cpu(rcu_dynticks, cpu); WARN_ON_ONCE(rdp->dynticks->dynticks_nesting != DYNTICK_TASK_EXIT_IDLE); WARN_ON_ONCE(atomic_read(&rdp->dynticks->dynticks) != 1); rdp->cpu = cpu; rdp->rsp = rsp; raw_spin_unlock_irqrestore(&rnp->lock, flags); } static void __cpuinit rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptible) { unsigned long flags; unsigned long mask; struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); struct rcu_node *rnp = rcu_get_root(rsp); raw_spin_lock_irqsave(&rnp->lock, flags); rdp->beenonline = 1; rdp->preemptible = preemptible; rdp->qlen_last_fqs_check = 0; rdp->n_force_qs_snap = rsp->n_force_qs; rdp->blimit = blimit; rdp->dynticks->dynticks_nesting = DYNTICK_TASK_EXIT_IDLE; atomic_set(&rdp->dynticks->dynticks, (atomic_read(&rdp->dynticks->dynticks) & ~0x1) + 1); rcu_prepare_for_idle_init(cpu); raw_spin_unlock(&rnp->lock); raw_spin_lock(&rsp->onofflock); rnp = rdp->mynode; mask = rdp->grpmask; do { raw_spin_lock(&rnp->lock); rnp->qsmaskinit |= mask; mask = rnp->grpmask; if (rnp == rdp->mynode) { rdp->gpnum = rnp->completed; rdp->completed = rnp->completed; rdp->passed_quiesce = 0; rdp->qs_pending = 0; rdp->passed_quiesce_gpnum = rnp->gpnum - 1; trace_rcu_grace_period(rsp->name, rdp->gpnum, "cpuonl"); } raw_spin_unlock(&rnp->lock); rnp = rnp->parent; } while (rnp != NULL && !(rnp->qsmaskinit & mask)); raw_spin_unlock_irqrestore(&rsp->onofflock, flags); } static void __cpuinit rcu_prepare_cpu(int cpu) { rcu_init_percpu_data(cpu, &rcu_sched_state, 0); rcu_init_percpu_data(cpu, &rcu_bh_state, 0); rcu_preempt_init_percpu_data(cpu); } static int __cpuinit rcu_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { long cpu = (long)hcpu; struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu); struct rcu_node *rnp = rdp->mynode; trace_rcu_utilization("Start CPU hotplug"); switch (action) { case CPU_UP_PREPARE: case CPU_UP_PREPARE_FROZEN: rcu_prepare_cpu(cpu); rcu_prepare_kthreads(cpu); break; case CPU_ONLINE: case CPU_DOWN_FAILED: rcu_node_kthread_setaffinity(rnp, -1); rcu_cpu_kthread_setrt(cpu, 1); break; case CPU_DOWN_PREPARE: rcu_node_kthread_setaffinity(rnp, cpu); rcu_cpu_kthread_setrt(cpu, 0); break; case CPU_DYING: case CPU_DYING_FROZEN: rcu_cleanup_dying_cpu(&rcu_bh_state); rcu_cleanup_dying_cpu(&rcu_sched_state); rcu_preempt_cleanup_dying_cpu(); rcu_cleanup_after_idle(cpu); break; case CPU_DEAD: case CPU_DEAD_FROZEN: case CPU_UP_CANCELED: case CPU_UP_CANCELED_FROZEN: rcu_cleanup_dead_cpu(cpu, &rcu_bh_state); rcu_cleanup_dead_cpu(cpu, &rcu_sched_state); rcu_preempt_cleanup_dead_cpu(cpu); break; default: break; } trace_rcu_utilization("End CPU hotplug"); return NOTIFY_OK; } void rcu_scheduler_starting(void) { WARN_ON(num_online_cpus() != 1); WARN_ON(nr_context_switches() > 0); rcu_scheduler_active = 1; } #ifdef CONFIG_RCU_FANOUT_EXACT static void __init rcu_init_levelspread(struct rcu_state *rsp) { int i; for (i = NUM_RCU_LVLS - 1; i > 0; i--) rsp->levelspread[i] = CONFIG_RCU_FANOUT; rsp->levelspread[0] = RCU_FANOUT_LEAF; } #else static void __init rcu_init_levelspread(struct rcu_state *rsp) { int ccur; int cprv; int i; cprv = NR_CPUS; for (i = NUM_RCU_LVLS - 1; i >= 0; i--) { ccur = rsp->levelcnt[i]; rsp->levelspread[i] = (cprv + ccur - 1) / ccur; cprv = ccur; } } #endif static void __init rcu_init_one(struct rcu_state *rsp, struct rcu_data __percpu *rda) { static char *buf[] = { "rcu_node_level_0", "rcu_node_level_1", "rcu_node_level_2", "rcu_node_level_3" }; int cpustride = 1; int i; int j; struct rcu_node *rnp; BUILD_BUG_ON(MAX_RCU_LVLS > ARRAY_SIZE(buf)); for (i = 1; i < NUM_RCU_LVLS; i++) rsp->level[i] = rsp->level[i - 1] + rsp->levelcnt[i - 1]; rcu_init_levelspread(rsp); for (i = NUM_RCU_LVLS - 1; i >= 0; i--) { cpustride *= rsp->levelspread[i]; rnp = rsp->level[i]; for (j = 0; j < rsp->levelcnt[i]; j++, rnp++) { raw_spin_lock_init(&rnp->lock); lockdep_set_class_and_name(&rnp->lock, &rcu_node_class[i], buf[i]); rnp->gpnum = 0; rnp->qsmask = 0; rnp->qsmaskinit = 0; rnp->grplo = j * cpustride; rnp->grphi = (j + 1) * cpustride - 1; if (rnp->grphi >= NR_CPUS) rnp->grphi = NR_CPUS - 1; if (i == 0) { rnp->grpnum = 0; rnp->grpmask = 0; rnp->parent = NULL; } else { rnp->grpnum = j % rsp->levelspread[i - 1]; rnp->grpmask = 1UL << rnp->grpnum; rnp->parent = rsp->level[i - 1] + j / rsp->levelspread[i - 1]; } rnp->level = i; INIT_LIST_HEAD(&rnp->blkd_tasks); } } rsp->rda = rda; rnp = rsp->level[NUM_RCU_LVLS - 1]; for_each_possible_cpu(i) { while (i > rnp->grphi) rnp++; per_cpu_ptr(rsp->rda, i)->mynode = rnp; rcu_boot_init_percpu_data(i, rsp); } } void __init rcu_init(void) { int cpu; rcu_bootup_announce(); rcu_init_one(&rcu_sched_state, &rcu_sched_data); rcu_init_one(&rcu_bh_state, &rcu_bh_data); __rcu_init_preempt(); open_softirq(RCU_SOFTIRQ, rcu_process_callbacks); cpu_notifier(rcu_cpu_notify, 0); for_each_online_cpu(cpu) rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu); check_cpu_stall_init(); } #include "rcutree_plugin.h"