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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2016-04-15 19:35:29 -0400
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2016-06-14 19:01:41 -0400
commit3549c2bc2c4ea8ecfeb9d21cb81cb00c6002b011 (patch)
tree78d1e1e5af82cead573006d62a59cc2a0bfc1912 /kernel/rcu
parentd3acab65f274800dd0901f0816f8bca9f2a8c8ec (diff)
rcu: Move expedited code from tree.c to tree_exp.h
People have been having some difficulty finding their way around the RCU code. This commit therefore pulls some of the expedited grace-period code from tree.c to a new tree_exp.h file. This commit is strictly code movement, with the exception of a forward declaration that was added for the sync_sched_exp_online_cleanup() function. A subsequent commit will move the remaining expedited grace-period code from tree_plugin.h to tree_exp.h. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree.c545
-rw-r--r--kernel/rcu/tree_exp.h564
2 files changed, 566 insertions, 543 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 4aefeafb9a95..c844b6142a86 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -159,6 +159,7 @@ static void invoke_rcu_core(void);
159static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp); 159static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp);
160static void rcu_report_exp_rdp(struct rcu_state *rsp, 160static void rcu_report_exp_rdp(struct rcu_state *rsp,
161 struct rcu_data *rdp, bool wake); 161 struct rcu_data *rdp, bool wake);
162static void sync_sched_exp_online_cleanup(int cpu);
162 163
163/* rcuc/rcub kthread realtime priority */ 164/* rcuc/rcub kthread realtime priority */
164#ifdef CONFIG_RCU_KTHREAD_PRIO 165#ifdef CONFIG_RCU_KTHREAD_PRIO
@@ -3447,549 +3448,6 @@ static bool rcu_seq_done(unsigned long *sp, unsigned long s)
3447 return ULONG_CMP_GE(READ_ONCE(*sp), s); 3448 return ULONG_CMP_GE(READ_ONCE(*sp), s);
3448} 3449}
3449 3450
3450/* Wrapper functions for expedited grace periods. */
3451static void rcu_exp_gp_seq_start(struct rcu_state *rsp)
3452{
3453 rcu_seq_start(&rsp->expedited_sequence);
3454}
3455static void rcu_exp_gp_seq_end(struct rcu_state *rsp)
3456{
3457 rcu_seq_end(&rsp->expedited_sequence);
3458 smp_mb(); /* Ensure that consecutive grace periods serialize. */
3459}
3460static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp)
3461{
3462 unsigned long s;
3463
3464 smp_mb(); /* Caller's modifications seen first by other CPUs. */
3465 s = rcu_seq_snap(&rsp->expedited_sequence);
3466 trace_rcu_exp_grace_period(rsp->name, s, TPS("snap"));
3467 return s;
3468}
3469static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s)
3470{
3471 return rcu_seq_done(&rsp->expedited_sequence, s);
3472}
3473
3474/*
3475 * Reset the ->expmaskinit values in the rcu_node tree to reflect any
3476 * recent CPU-online activity. Note that these masks are not cleared
3477 * when CPUs go offline, so they reflect the union of all CPUs that have
3478 * ever been online. This means that this function normally takes its
3479 * no-work-to-do fastpath.
3480 */
3481static void sync_exp_reset_tree_hotplug(struct rcu_state *rsp)
3482{
3483 bool done;
3484 unsigned long flags;
3485 unsigned long mask;
3486 unsigned long oldmask;
3487 int ncpus = READ_ONCE(rsp->ncpus);
3488 struct rcu_node *rnp;
3489 struct rcu_node *rnp_up;
3490
3491 /* If no new CPUs onlined since last time, nothing to do. */
3492 if (likely(ncpus == rsp->ncpus_snap))
3493 return;
3494 rsp->ncpus_snap = ncpus;
3495
3496 /*
3497 * Each pass through the following loop propagates newly onlined
3498 * CPUs for the current rcu_node structure up the rcu_node tree.
3499 */
3500 rcu_for_each_leaf_node(rsp, rnp) {
3501 raw_spin_lock_irqsave_rcu_node(rnp, flags);
3502 if (rnp->expmaskinit == rnp->expmaskinitnext) {
3503 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
3504 continue; /* No new CPUs, nothing to do. */
3505 }
3506
3507 /* Update this node's mask, track old value for propagation. */
3508 oldmask = rnp->expmaskinit;
3509 rnp->expmaskinit = rnp->expmaskinitnext;
3510 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
3511
3512 /* If was already nonzero, nothing to propagate. */
3513 if (oldmask)
3514 continue;
3515
3516 /* Propagate the new CPU up the tree. */
3517 mask = rnp->grpmask;
3518 rnp_up = rnp->parent;
3519 done = false;
3520 while (rnp_up) {
3521 raw_spin_lock_irqsave_rcu_node(rnp_up, flags);
3522 if (rnp_up->expmaskinit)
3523 done = true;
3524 rnp_up->expmaskinit |= mask;
3525 raw_spin_unlock_irqrestore_rcu_node(rnp_up, flags);
3526 if (done)
3527 break;
3528 mask = rnp_up->grpmask;
3529 rnp_up = rnp_up->parent;
3530 }
3531 }
3532}
3533
3534/*
3535 * Reset the ->expmask values in the rcu_node tree in preparation for
3536 * a new expedited grace period.
3537 */
3538static void __maybe_unused sync_exp_reset_tree(struct rcu_state *rsp)
3539{
3540 unsigned long flags;
3541 struct rcu_node *rnp;
3542
3543 sync_exp_reset_tree_hotplug(rsp);
3544 rcu_for_each_node_breadth_first(rsp, rnp) {
3545 raw_spin_lock_irqsave_rcu_node(rnp, flags);
3546 WARN_ON_ONCE(rnp->expmask);
3547 rnp->expmask = rnp->expmaskinit;
3548 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
3549 }
3550}
3551
3552/*
3553 * Return non-zero if there is no RCU expedited grace period in progress
3554 * for the specified rcu_node structure, in other words, if all CPUs and
3555 * tasks covered by the specified rcu_node structure have done their bit
3556 * for the current expedited grace period. Works only for preemptible
3557 * RCU -- other RCU implementation use other means.
3558 *
3559 * Caller must hold the rcu_state's exp_mutex.
3560 */
3561static int sync_rcu_preempt_exp_done(struct rcu_node *rnp)
3562{
3563 return rnp->exp_tasks == NULL &&
3564 READ_ONCE(rnp->expmask) == 0;
3565}
3566
3567/*
3568 * Report the exit from RCU read-side critical section for the last task
3569 * that queued itself during or before the current expedited preemptible-RCU
3570 * grace period. This event is reported either to the rcu_node structure on
3571 * which the task was queued or to one of that rcu_node structure's ancestors,
3572 * recursively up the tree. (Calm down, calm down, we do the recursion
3573 * iteratively!)
3574 *
3575 * Caller must hold the rcu_state's exp_mutex and the specified rcu_node
3576 * structure's ->lock.
3577 */
3578static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
3579 bool wake, unsigned long flags)
3580 __releases(rnp->lock)
3581{
3582 unsigned long mask;
3583
3584 for (;;) {
3585 if (!sync_rcu_preempt_exp_done(rnp)) {
3586 if (!rnp->expmask)
3587 rcu_initiate_boost(rnp, flags);
3588 else
3589 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
3590 break;
3591 }
3592 if (rnp->parent == NULL) {
3593 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
3594 if (wake) {
3595 smp_mb(); /* EGP done before wake_up(). */
3596 swake_up(&rsp->expedited_wq);
3597 }
3598 break;
3599 }
3600 mask = rnp->grpmask;
3601 raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled */
3602 rnp = rnp->parent;
3603 raw_spin_lock_rcu_node(rnp); /* irqs already disabled */
3604 WARN_ON_ONCE(!(rnp->expmask & mask));
3605 rnp->expmask &= ~mask;
3606 }
3607}
3608
3609/*
3610 * Report expedited quiescent state for specified node. This is a
3611 * lock-acquisition wrapper function for __rcu_report_exp_rnp().
3612 *
3613 * Caller must hold the rcu_state's exp_mutex.
3614 */
3615static void __maybe_unused rcu_report_exp_rnp(struct rcu_state *rsp,
3616 struct rcu_node *rnp, bool wake)
3617{
3618 unsigned long flags;
3619
3620 raw_spin_lock_irqsave_rcu_node(rnp, flags);
3621 __rcu_report_exp_rnp(rsp, rnp, wake, flags);
3622}
3623
3624/*
3625 * Report expedited quiescent state for multiple CPUs, all covered by the
3626 * specified leaf rcu_node structure. Caller must hold the rcu_state's
3627 * exp_mutex.
3628 */
3629static void rcu_report_exp_cpu_mult(struct rcu_state *rsp, struct rcu_node *rnp,
3630 unsigned long mask, bool wake)
3631{
3632 unsigned long flags;
3633
3634 raw_spin_lock_irqsave_rcu_node(rnp, flags);
3635 if (!(rnp->expmask & mask)) {
3636 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
3637 return;
3638 }
3639 rnp->expmask &= ~mask;
3640 __rcu_report_exp_rnp(rsp, rnp, wake, flags); /* Releases rnp->lock. */
3641}
3642
3643/*
3644 * Report expedited quiescent state for specified rcu_data (CPU).
3645 */
3646static void rcu_report_exp_rdp(struct rcu_state *rsp, struct rcu_data *rdp,
3647 bool wake)
3648{
3649 rcu_report_exp_cpu_mult(rsp, rdp->mynode, rdp->grpmask, wake);
3650}
3651
3652/* Common code for synchronize_{rcu,sched}_expedited() work-done checking. */
3653static bool sync_exp_work_done(struct rcu_state *rsp, atomic_long_t *stat,
3654 unsigned long s)
3655{
3656 if (rcu_exp_gp_seq_done(rsp, s)) {
3657 trace_rcu_exp_grace_period(rsp->name, s, TPS("done"));
3658 /* Ensure test happens before caller kfree(). */
3659 smp_mb__before_atomic(); /* ^^^ */
3660 atomic_long_inc(stat);
3661 return true;
3662 }
3663 return false;
3664}
3665
3666/*
3667 * Funnel-lock acquisition for expedited grace periods. Returns true
3668 * if some other task completed an expedited grace period that this task
3669 * can piggy-back on, and with no mutex held. Otherwise, returns false
3670 * with the mutex held, indicating that the caller must actually do the
3671 * expedited grace period.
3672 */
3673static bool exp_funnel_lock(struct rcu_state *rsp, unsigned long s)
3674{
3675 struct rcu_data *rdp = per_cpu_ptr(rsp->rda, raw_smp_processor_id());
3676 struct rcu_node *rnp = rdp->mynode;
3677 struct rcu_node *rnp_root = rcu_get_root(rsp);
3678
3679 /* Low-contention fastpath. */
3680 if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s) &&
3681 (rnp == rnp_root ||
3682 ULONG_CMP_LT(READ_ONCE(rnp_root->exp_seq_rq), s)) &&
3683 !mutex_is_locked(&rsp->exp_mutex) &&
3684 mutex_trylock(&rsp->exp_mutex))
3685 goto fastpath;
3686
3687 /*
3688 * Each pass through the following loop works its way up
3689 * the rcu_node tree, returning if others have done the work or
3690 * otherwise falls through to acquire rsp->exp_mutex. The mapping
3691 * from CPU to rcu_node structure can be inexact, as it is just
3692 * promoting locality and is not strictly needed for correctness.
3693 */
3694 for (; rnp != NULL; rnp = rnp->parent) {
3695 if (sync_exp_work_done(rsp, &rdp->exp_workdone1, s))
3696 return true;
3697
3698 /* Work not done, either wait here or go up. */
3699 spin_lock(&rnp->exp_lock);
3700 if (ULONG_CMP_GE(rnp->exp_seq_rq, s)) {
3701
3702 /* Someone else doing GP, so wait for them. */
3703 spin_unlock(&rnp->exp_lock);
3704 trace_rcu_exp_funnel_lock(rsp->name, rnp->level,
3705 rnp->grplo, rnp->grphi,
3706 TPS("wait"));
3707 wait_event(rnp->exp_wq[(s >> 1) & 0x3],
3708 sync_exp_work_done(rsp,
3709 &rdp->exp_workdone2, s));
3710 return true;
3711 }
3712 rnp->exp_seq_rq = s; /* Followers can wait on us. */
3713 spin_unlock(&rnp->exp_lock);
3714 trace_rcu_exp_funnel_lock(rsp->name, rnp->level, rnp->grplo,
3715 rnp->grphi, TPS("nxtlvl"));
3716 }
3717 mutex_lock(&rsp->exp_mutex);
3718fastpath:
3719 if (sync_exp_work_done(rsp, &rdp->exp_workdone3, s)) {
3720 mutex_unlock(&rsp->exp_mutex);
3721 return true;
3722 }
3723 rcu_exp_gp_seq_start(rsp);
3724 trace_rcu_exp_grace_period(rsp->name, s, TPS("start"));
3725 return false;
3726}
3727
3728/* Invoked on each online non-idle CPU for expedited quiescent state. */
3729static void sync_sched_exp_handler(void *data)
3730{
3731 struct rcu_data *rdp;
3732 struct rcu_node *rnp;
3733 struct rcu_state *rsp = data;
3734
3735 rdp = this_cpu_ptr(rsp->rda);
3736 rnp = rdp->mynode;
3737 if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) ||
3738 __this_cpu_read(rcu_sched_data.cpu_no_qs.b.exp))
3739 return;
3740 if (rcu_is_cpu_rrupt_from_idle()) {
3741 rcu_report_exp_rdp(&rcu_sched_state,
3742 this_cpu_ptr(&rcu_sched_data), true);
3743 return;
3744 }
3745 __this_cpu_write(rcu_sched_data.cpu_no_qs.b.exp, true);
3746 resched_cpu(smp_processor_id());
3747}
3748
3749/* Send IPI for expedited cleanup if needed at end of CPU-hotplug operation. */
3750static void sync_sched_exp_online_cleanup(int cpu)
3751{
3752 struct rcu_data *rdp;
3753 int ret;
3754 struct rcu_node *rnp;
3755 struct rcu_state *rsp = &rcu_sched_state;
3756
3757 rdp = per_cpu_ptr(rsp->rda, cpu);
3758 rnp = rdp->mynode;
3759 if (!(READ_ONCE(rnp->expmask) & rdp->grpmask))
3760 return;
3761 ret = smp_call_function_single(cpu, sync_sched_exp_handler, rsp, 0);
3762 WARN_ON_ONCE(ret);
3763}
3764
3765/*
3766 * Select the nodes that the upcoming expedited grace period needs
3767 * to wait for.
3768 */
3769static void sync_rcu_exp_select_cpus(struct rcu_state *rsp,
3770 smp_call_func_t func)
3771{
3772 int cpu;
3773 unsigned long flags;
3774 unsigned long mask;
3775 unsigned long mask_ofl_test;
3776 unsigned long mask_ofl_ipi;
3777 int ret;
3778 struct rcu_node *rnp;
3779
3780 sync_exp_reset_tree(rsp);
3781 rcu_for_each_leaf_node(rsp, rnp) {
3782 raw_spin_lock_irqsave_rcu_node(rnp, flags);
3783
3784 /* Each pass checks a CPU for identity, offline, and idle. */
3785 mask_ofl_test = 0;
3786 for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++) {
3787 struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
3788 struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
3789
3790 if (raw_smp_processor_id() == cpu ||
3791 !(atomic_add_return(0, &rdtp->dynticks) & 0x1))
3792 mask_ofl_test |= rdp->grpmask;
3793 }
3794 mask_ofl_ipi = rnp->expmask & ~mask_ofl_test;
3795
3796 /*
3797 * Need to wait for any blocked tasks as well. Note that
3798 * additional blocking tasks will also block the expedited
3799 * GP until such time as the ->expmask bits are cleared.
3800 */
3801 if (rcu_preempt_has_tasks(rnp))
3802 rnp->exp_tasks = rnp->blkd_tasks.next;
3803 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
3804
3805 /* IPI the remaining CPUs for expedited quiescent state. */
3806 mask = 1;
3807 for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) {
3808 if (!(mask_ofl_ipi & mask))
3809 continue;
3810retry_ipi:
3811 ret = smp_call_function_single(cpu, func, rsp, 0);
3812 if (!ret) {
3813 mask_ofl_ipi &= ~mask;
3814 continue;
3815 }
3816 /* Failed, raced with offline. */
3817 raw_spin_lock_irqsave_rcu_node(rnp, flags);
3818 if (cpu_online(cpu) &&
3819 (rnp->expmask & mask)) {
3820 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
3821 schedule_timeout_uninterruptible(1);
3822 if (cpu_online(cpu) &&
3823 (rnp->expmask & mask))
3824 goto retry_ipi;
3825 raw_spin_lock_irqsave_rcu_node(rnp, flags);
3826 }
3827 if (!(rnp->expmask & mask))
3828 mask_ofl_ipi &= ~mask;
3829 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
3830 }
3831 /* Report quiescent states for those that went offline. */
3832 mask_ofl_test |= mask_ofl_ipi;
3833 if (mask_ofl_test)
3834 rcu_report_exp_cpu_mult(rsp, rnp, mask_ofl_test, false);
3835 }
3836}
3837
3838static void synchronize_sched_expedited_wait(struct rcu_state *rsp)
3839{
3840 int cpu;
3841 unsigned long jiffies_stall;
3842 unsigned long jiffies_start;
3843 unsigned long mask;
3844 int ndetected;
3845 struct rcu_node *rnp;
3846 struct rcu_node *rnp_root = rcu_get_root(rsp);
3847 int ret;
3848
3849 jiffies_stall = rcu_jiffies_till_stall_check();
3850 jiffies_start = jiffies;
3851
3852 for (;;) {
3853 ret = swait_event_timeout(
3854 rsp->expedited_wq,
3855 sync_rcu_preempt_exp_done(rnp_root),
3856 jiffies_stall);
3857 if (ret > 0 || sync_rcu_preempt_exp_done(rnp_root))
3858 return;
3859 if (ret < 0) {
3860 /* Hit a signal, disable CPU stall warnings. */
3861 swait_event(rsp->expedited_wq,
3862 sync_rcu_preempt_exp_done(rnp_root));
3863 return;
3864 }
3865 pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {",
3866 rsp->name);
3867 ndetected = 0;
3868 rcu_for_each_leaf_node(rsp, rnp) {
3869 ndetected += rcu_print_task_exp_stall(rnp);
3870 mask = 1;
3871 for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) {
3872 struct rcu_data *rdp;
3873
3874 if (!(rnp->expmask & mask))
3875 continue;
3876 ndetected++;
3877 rdp = per_cpu_ptr(rsp->rda, cpu);
3878 pr_cont(" %d-%c%c%c", cpu,
3879 "O."[!!cpu_online(cpu)],
3880 "o."[!!(rdp->grpmask & rnp->expmaskinit)],
3881 "N."[!!(rdp->grpmask & rnp->expmaskinitnext)]);
3882 }
3883 mask <<= 1;
3884 }
3885 pr_cont(" } %lu jiffies s: %lu root: %#lx/%c\n",
3886 jiffies - jiffies_start, rsp->expedited_sequence,
3887 rnp_root->expmask, ".T"[!!rnp_root->exp_tasks]);
3888 if (ndetected) {
3889 pr_err("blocking rcu_node structures:");
3890 rcu_for_each_node_breadth_first(rsp, rnp) {
3891 if (rnp == rnp_root)
3892 continue; /* printed unconditionally */
3893 if (sync_rcu_preempt_exp_done(rnp))
3894 continue;
3895 pr_cont(" l=%u:%d-%d:%#lx/%c",
3896 rnp->level, rnp->grplo, rnp->grphi,
3897 rnp->expmask,
3898 ".T"[!!rnp->exp_tasks]);
3899 }
3900 pr_cont("\n");
3901 }
3902 rcu_for_each_leaf_node(rsp, rnp) {
3903 mask = 1;
3904 for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) {
3905 if (!(rnp->expmask & mask))
3906 continue;
3907 dump_cpu_task(cpu);
3908 }
3909 }
3910 jiffies_stall = 3 * rcu_jiffies_till_stall_check() + 3;
3911 }
3912}
3913
3914/*
3915 * Wait for the current expedited grace period to complete, and then
3916 * wake up everyone who piggybacked on the just-completed expedited
3917 * grace period. Also update all the ->exp_seq_rq counters as needed
3918 * in order to avoid counter-wrap problems.
3919 */
3920static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s)
3921{
3922 struct rcu_node *rnp;
3923
3924 synchronize_sched_expedited_wait(rsp);
3925 rcu_exp_gp_seq_end(rsp);
3926 trace_rcu_exp_grace_period(rsp->name, s, TPS("end"));
3927
3928 /*
3929 * Switch over to wakeup mode, allowing the next GP, but -only- the
3930 * next GP, to proceed.
3931 */
3932 mutex_lock(&rsp->exp_wake_mutex);
3933 mutex_unlock(&rsp->exp_mutex);
3934
3935 rcu_for_each_node_breadth_first(rsp, rnp) {
3936 if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s)) {
3937 spin_lock(&rnp->exp_lock);
3938 /* Recheck, avoid hang in case someone just arrived. */
3939 if (ULONG_CMP_LT(rnp->exp_seq_rq, s))
3940 rnp->exp_seq_rq = s;
3941 spin_unlock(&rnp->exp_lock);
3942 }
3943 wake_up_all(&rnp->exp_wq[(rsp->expedited_sequence >> 1) & 0x3]);
3944 }
3945 trace_rcu_exp_grace_period(rsp->name, s, TPS("endwake"));
3946 mutex_unlock(&rsp->exp_wake_mutex);
3947}
3948
3949/**
3950 * synchronize_sched_expedited - Brute-force RCU-sched grace period
3951 *
3952 * Wait for an RCU-sched grace period to elapse, but use a "big hammer"
3953 * approach to force the grace period to end quickly. This consumes
3954 * significant time on all CPUs and is unfriendly to real-time workloads,
3955 * so is thus not recommended for any sort of common-case code. In fact,
3956 * if you are using synchronize_sched_expedited() in a loop, please
3957 * restructure your code to batch your updates, and then use a single
3958 * synchronize_sched() instead.
3959 *
3960 * This implementation can be thought of as an application of sequence
3961 * locking to expedited grace periods, but using the sequence counter to
3962 * determine when someone else has already done the work instead of for
3963 * retrying readers.
3964 */
3965void synchronize_sched_expedited(void)
3966{
3967 unsigned long s;
3968 struct rcu_state *rsp = &rcu_sched_state;
3969
3970 /* If only one CPU, this is automatically a grace period. */
3971 if (rcu_blocking_is_gp())
3972 return;
3973
3974 /* If expedited grace periods are prohibited, fall back to normal. */
3975 if (rcu_gp_is_normal()) {
3976 wait_rcu_gp(call_rcu_sched);
3977 return;
3978 }
3979
3980 /* Take a snapshot of the sequence number. */
3981 s = rcu_exp_gp_seq_snap(rsp);
3982 if (exp_funnel_lock(rsp, s))
3983 return; /* Someone else did our work for us. */
3984
3985 /* Initialize the rcu_node tree in preparation for the wait. */
3986 sync_rcu_exp_select_cpus(rsp, sync_sched_exp_handler);
3987
3988 /* Wait and clean up, including waking everyone. */
3989 rcu_exp_wait_wake(rsp, s);
3990}
3991EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
3992
3993/* 3451/*
3994 * Check to see if there is any immediate RCU-related work to be done 3452 * Check to see if there is any immediate RCU-related work to be done
3995 * by the current CPU, for the specified type of RCU, returning 1 if so. 3453 * by the current CPU, for the specified type of RCU, returning 1 if so.
@@ -4747,4 +4205,5 @@ void __init rcu_init(void)
4747 rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu); 4205 rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
4748} 4206}
4749 4207
4208#include "tree_exp.h"
4750#include "tree_plugin.h" 4209#include "tree_plugin.h"
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
new file mode 100644
index 000000000000..db0909cf7fe1
--- /dev/null
+++ b/kernel/rcu/tree_exp.h
@@ -0,0 +1,564 @@
1/*
2 * RCU expedited grace periods
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
17 *
18 * Copyright IBM Corporation, 2016
19 *
20 * Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
21 */
22
23/* Wrapper functions for expedited grace periods. */
24static void rcu_exp_gp_seq_start(struct rcu_state *rsp)
25{
26 rcu_seq_start(&rsp->expedited_sequence);
27}
28static void rcu_exp_gp_seq_end(struct rcu_state *rsp)
29{
30 rcu_seq_end(&rsp->expedited_sequence);
31 smp_mb(); /* Ensure that consecutive grace periods serialize. */
32}
33static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp)
34{
35 unsigned long s;
36
37 smp_mb(); /* Caller's modifications seen first by other CPUs. */
38 s = rcu_seq_snap(&rsp->expedited_sequence);
39 trace_rcu_exp_grace_period(rsp->name, s, TPS("snap"));
40 return s;
41}
42static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s)
43{
44 return rcu_seq_done(&rsp->expedited_sequence, s);
45}
46
47/*
48 * Reset the ->expmaskinit values in the rcu_node tree to reflect any
49 * recent CPU-online activity. Note that these masks are not cleared
50 * when CPUs go offline, so they reflect the union of all CPUs that have
51 * ever been online. This means that this function normally takes its
52 * no-work-to-do fastpath.
53 */
54static void sync_exp_reset_tree_hotplug(struct rcu_state *rsp)
55{
56 bool done;
57 unsigned long flags;
58 unsigned long mask;
59 unsigned long oldmask;
60 int ncpus = READ_ONCE(rsp->ncpus);
61 struct rcu_node *rnp;
62 struct rcu_node *rnp_up;
63
64 /* If no new CPUs onlined since last time, nothing to do. */
65 if (likely(ncpus == rsp->ncpus_snap))
66 return;
67 rsp->ncpus_snap = ncpus;
68
69 /*
70 * Each pass through the following loop propagates newly onlined
71 * CPUs for the current rcu_node structure up the rcu_node tree.
72 */
73 rcu_for_each_leaf_node(rsp, rnp) {
74 raw_spin_lock_irqsave_rcu_node(rnp, flags);
75 if (rnp->expmaskinit == rnp->expmaskinitnext) {
76 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
77 continue; /* No new CPUs, nothing to do. */
78 }
79
80 /* Update this node's mask, track old value for propagation. */
81 oldmask = rnp->expmaskinit;
82 rnp->expmaskinit = rnp->expmaskinitnext;
83 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
84
85 /* If was already nonzero, nothing to propagate. */
86 if (oldmask)
87 continue;
88
89 /* Propagate the new CPU up the tree. */
90 mask = rnp->grpmask;
91 rnp_up = rnp->parent;
92 done = false;
93 while (rnp_up) {
94 raw_spin_lock_irqsave_rcu_node(rnp_up, flags);
95 if (rnp_up->expmaskinit)
96 done = true;
97 rnp_up->expmaskinit |= mask;
98 raw_spin_unlock_irqrestore_rcu_node(rnp_up, flags);
99 if (done)
100 break;
101 mask = rnp_up->grpmask;
102 rnp_up = rnp_up->parent;
103 }
104 }
105}
106
107/*
108 * Reset the ->expmask values in the rcu_node tree in preparation for
109 * a new expedited grace period.
110 */
111static void __maybe_unused sync_exp_reset_tree(struct rcu_state *rsp)
112{
113 unsigned long flags;
114 struct rcu_node *rnp;
115
116 sync_exp_reset_tree_hotplug(rsp);
117 rcu_for_each_node_breadth_first(rsp, rnp) {
118 raw_spin_lock_irqsave_rcu_node(rnp, flags);
119 WARN_ON_ONCE(rnp->expmask);
120 rnp->expmask = rnp->expmaskinit;
121 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
122 }
123}
124
125/*
126 * Return non-zero if there is no RCU expedited grace period in progress
127 * for the specified rcu_node structure, in other words, if all CPUs and
128 * tasks covered by the specified rcu_node structure have done their bit
129 * for the current expedited grace period. Works only for preemptible
130 * RCU -- other RCU implementation use other means.
131 *
132 * Caller must hold the rcu_state's exp_mutex.
133 */
134static int sync_rcu_preempt_exp_done(struct rcu_node *rnp)
135{
136 return rnp->exp_tasks == NULL &&
137 READ_ONCE(rnp->expmask) == 0;
138}
139
140/*
141 * Report the exit from RCU read-side critical section for the last task
142 * that queued itself during or before the current expedited preemptible-RCU
143 * grace period. This event is reported either to the rcu_node structure on
144 * which the task was queued or to one of that rcu_node structure's ancestors,
145 * recursively up the tree. (Calm down, calm down, we do the recursion
146 * iteratively!)
147 *
148 * Caller must hold the rcu_state's exp_mutex and the specified rcu_node
149 * structure's ->lock.
150 */
151static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
152 bool wake, unsigned long flags)
153 __releases(rnp->lock)
154{
155 unsigned long mask;
156
157 for (;;) {
158 if (!sync_rcu_preempt_exp_done(rnp)) {
159 if (!rnp->expmask)
160 rcu_initiate_boost(rnp, flags);
161 else
162 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
163 break;
164 }
165 if (rnp->parent == NULL) {
166 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
167 if (wake) {
168 smp_mb(); /* EGP done before wake_up(). */
169 swake_up(&rsp->expedited_wq);
170 }
171 break;
172 }
173 mask = rnp->grpmask;
174 raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled */
175 rnp = rnp->parent;
176 raw_spin_lock_rcu_node(rnp); /* irqs already disabled */
177 WARN_ON_ONCE(!(rnp->expmask & mask));
178 rnp->expmask &= ~mask;
179 }
180}
181
182/*
183 * Report expedited quiescent state for specified node. This is a
184 * lock-acquisition wrapper function for __rcu_report_exp_rnp().
185 *
186 * Caller must hold the rcu_state's exp_mutex.
187 */
188static void __maybe_unused rcu_report_exp_rnp(struct rcu_state *rsp,
189 struct rcu_node *rnp, bool wake)
190{
191 unsigned long flags;
192
193 raw_spin_lock_irqsave_rcu_node(rnp, flags);
194 __rcu_report_exp_rnp(rsp, rnp, wake, flags);
195}
196
197/*
198 * Report expedited quiescent state for multiple CPUs, all covered by the
199 * specified leaf rcu_node structure. Caller must hold the rcu_state's
200 * exp_mutex.
201 */
202static void rcu_report_exp_cpu_mult(struct rcu_state *rsp, struct rcu_node *rnp,
203 unsigned long mask, bool wake)
204{
205 unsigned long flags;
206
207 raw_spin_lock_irqsave_rcu_node(rnp, flags);
208 if (!(rnp->expmask & mask)) {
209 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
210 return;
211 }
212 rnp->expmask &= ~mask;
213 __rcu_report_exp_rnp(rsp, rnp, wake, flags); /* Releases rnp->lock. */
214}
215
216/*
217 * Report expedited quiescent state for specified rcu_data (CPU).
218 */
219static void rcu_report_exp_rdp(struct rcu_state *rsp, struct rcu_data *rdp,
220 bool wake)
221{
222 rcu_report_exp_cpu_mult(rsp, rdp->mynode, rdp->grpmask, wake);
223}
224
225/* Common code for synchronize_{rcu,sched}_expedited() work-done checking. */
226static bool sync_exp_work_done(struct rcu_state *rsp, atomic_long_t *stat,
227 unsigned long s)
228{
229 if (rcu_exp_gp_seq_done(rsp, s)) {
230 trace_rcu_exp_grace_period(rsp->name, s, TPS("done"));
231 /* Ensure test happens before caller kfree(). */
232 smp_mb__before_atomic(); /* ^^^ */
233 atomic_long_inc(stat);
234 return true;
235 }
236 return false;
237}
238
239/*
240 * Funnel-lock acquisition for expedited grace periods. Returns true
241 * if some other task completed an expedited grace period that this task
242 * can piggy-back on, and with no mutex held. Otherwise, returns false
243 * with the mutex held, indicating that the caller must actually do the
244 * expedited grace period.
245 */
246static bool exp_funnel_lock(struct rcu_state *rsp, unsigned long s)
247{
248 struct rcu_data *rdp = per_cpu_ptr(rsp->rda, raw_smp_processor_id());
249 struct rcu_node *rnp = rdp->mynode;
250 struct rcu_node *rnp_root = rcu_get_root(rsp);
251
252 /* Low-contention fastpath. */
253 if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s) &&
254 (rnp == rnp_root ||
255 ULONG_CMP_LT(READ_ONCE(rnp_root->exp_seq_rq), s)) &&
256 !mutex_is_locked(&rsp->exp_mutex) &&
257 mutex_trylock(&rsp->exp_mutex))
258 goto fastpath;
259
260 /*
261 * Each pass through the following loop works its way up
262 * the rcu_node tree, returning if others have done the work or
263 * otherwise falls through to acquire rsp->exp_mutex. The mapping
264 * from CPU to rcu_node structure can be inexact, as it is just
265 * promoting locality and is not strictly needed for correctness.
266 */
267 for (; rnp != NULL; rnp = rnp->parent) {
268 if (sync_exp_work_done(rsp, &rdp->exp_workdone1, s))
269 return true;
270
271 /* Work not done, either wait here or go up. */
272 spin_lock(&rnp->exp_lock);
273 if (ULONG_CMP_GE(rnp->exp_seq_rq, s)) {
274
275 /* Someone else doing GP, so wait for them. */
276 spin_unlock(&rnp->exp_lock);
277 trace_rcu_exp_funnel_lock(rsp->name, rnp->level,
278 rnp->grplo, rnp->grphi,
279 TPS("wait"));
280 wait_event(rnp->exp_wq[(s >> 1) & 0x3],
281 sync_exp_work_done(rsp,
282 &rdp->exp_workdone2, s));
283 return true;
284 }
285 rnp->exp_seq_rq = s; /* Followers can wait on us. */
286 spin_unlock(&rnp->exp_lock);
287 trace_rcu_exp_funnel_lock(rsp->name, rnp->level, rnp->grplo,
288 rnp->grphi, TPS("nxtlvl"));
289 }
290 mutex_lock(&rsp->exp_mutex);
291fastpath:
292 if (sync_exp_work_done(rsp, &rdp->exp_workdone3, s)) {
293 mutex_unlock(&rsp->exp_mutex);
294 return true;
295 }
296 rcu_exp_gp_seq_start(rsp);
297 trace_rcu_exp_grace_period(rsp->name, s, TPS("start"));
298 return false;
299}
300
301/* Invoked on each online non-idle CPU for expedited quiescent state. */
302static void sync_sched_exp_handler(void *data)
303{
304 struct rcu_data *rdp;
305 struct rcu_node *rnp;
306 struct rcu_state *rsp = data;
307
308 rdp = this_cpu_ptr(rsp->rda);
309 rnp = rdp->mynode;
310 if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) ||
311 __this_cpu_read(rcu_sched_data.cpu_no_qs.b.exp))
312 return;
313 if (rcu_is_cpu_rrupt_from_idle()) {
314 rcu_report_exp_rdp(&rcu_sched_state,
315 this_cpu_ptr(&rcu_sched_data), true);
316 return;
317 }
318 __this_cpu_write(rcu_sched_data.cpu_no_qs.b.exp, true);
319 resched_cpu(smp_processor_id());
320}
321
322/* Send IPI for expedited cleanup if needed at end of CPU-hotplug operation. */
323static void sync_sched_exp_online_cleanup(int cpu)
324{
325 struct rcu_data *rdp;
326 int ret;
327 struct rcu_node *rnp;
328 struct rcu_state *rsp = &rcu_sched_state;
329
330 rdp = per_cpu_ptr(rsp->rda, cpu);
331 rnp = rdp->mynode;
332 if (!(READ_ONCE(rnp->expmask) & rdp->grpmask))
333 return;
334 ret = smp_call_function_single(cpu, sync_sched_exp_handler, rsp, 0);
335 WARN_ON_ONCE(ret);
336}
337
338/*
339 * Select the nodes that the upcoming expedited grace period needs
340 * to wait for.
341 */
342static void sync_rcu_exp_select_cpus(struct rcu_state *rsp,
343 smp_call_func_t func)
344{
345 int cpu;
346 unsigned long flags;
347 unsigned long mask;
348 unsigned long mask_ofl_test;
349 unsigned long mask_ofl_ipi;
350 int ret;
351 struct rcu_node *rnp;
352
353 sync_exp_reset_tree(rsp);
354 rcu_for_each_leaf_node(rsp, rnp) {
355 raw_spin_lock_irqsave_rcu_node(rnp, flags);
356
357 /* Each pass checks a CPU for identity, offline, and idle. */
358 mask_ofl_test = 0;
359 for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++) {
360 struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
361 struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
362
363 if (raw_smp_processor_id() == cpu ||
364 !(atomic_add_return(0, &rdtp->dynticks) & 0x1))
365 mask_ofl_test |= rdp->grpmask;
366 }
367 mask_ofl_ipi = rnp->expmask & ~mask_ofl_test;
368
369 /*
370 * Need to wait for any blocked tasks as well. Note that
371 * additional blocking tasks will also block the expedited
372 * GP until such time as the ->expmask bits are cleared.
373 */
374 if (rcu_preempt_has_tasks(rnp))
375 rnp->exp_tasks = rnp->blkd_tasks.next;
376 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
377
378 /* IPI the remaining CPUs for expedited quiescent state. */
379 mask = 1;
380 for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) {
381 if (!(mask_ofl_ipi & mask))
382 continue;
383retry_ipi:
384 ret = smp_call_function_single(cpu, func, rsp, 0);
385 if (!ret) {
386 mask_ofl_ipi &= ~mask;
387 continue;
388 }
389 /* Failed, raced with offline. */
390 raw_spin_lock_irqsave_rcu_node(rnp, flags);
391 if (cpu_online(cpu) &&
392 (rnp->expmask & mask)) {
393 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
394 schedule_timeout_uninterruptible(1);
395 if (cpu_online(cpu) &&
396 (rnp->expmask & mask))
397 goto retry_ipi;
398 raw_spin_lock_irqsave_rcu_node(rnp, flags);
399 }
400 if (!(rnp->expmask & mask))
401 mask_ofl_ipi &= ~mask;
402 raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
403 }
404 /* Report quiescent states for those that went offline. */
405 mask_ofl_test |= mask_ofl_ipi;
406 if (mask_ofl_test)
407 rcu_report_exp_cpu_mult(rsp, rnp, mask_ofl_test, false);
408 }
409}
410
411static void synchronize_sched_expedited_wait(struct rcu_state *rsp)
412{
413 int cpu;
414 unsigned long jiffies_stall;
415 unsigned long jiffies_start;
416 unsigned long mask;
417 int ndetected;
418 struct rcu_node *rnp;
419 struct rcu_node *rnp_root = rcu_get_root(rsp);
420 int ret;
421
422 jiffies_stall = rcu_jiffies_till_stall_check();
423 jiffies_start = jiffies;
424
425 for (;;) {
426 ret = swait_event_timeout(
427 rsp->expedited_wq,
428 sync_rcu_preempt_exp_done(rnp_root),
429 jiffies_stall);
430 if (ret > 0 || sync_rcu_preempt_exp_done(rnp_root))
431 return;
432 if (ret < 0) {
433 /* Hit a signal, disable CPU stall warnings. */
434 swait_event(rsp->expedited_wq,
435 sync_rcu_preempt_exp_done(rnp_root));
436 return;
437 }
438 pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {",
439 rsp->name);
440 ndetected = 0;
441 rcu_for_each_leaf_node(rsp, rnp) {
442 ndetected += rcu_print_task_exp_stall(rnp);
443 mask = 1;
444 for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) {
445 struct rcu_data *rdp;
446
447 if (!(rnp->expmask & mask))
448 continue;
449 ndetected++;
450 rdp = per_cpu_ptr(rsp->rda, cpu);
451 pr_cont(" %d-%c%c%c", cpu,
452 "O."[!!cpu_online(cpu)],
453 "o."[!!(rdp->grpmask & rnp->expmaskinit)],
454 "N."[!!(rdp->grpmask & rnp->expmaskinitnext)]);
455 }
456 mask <<= 1;
457 }
458 pr_cont(" } %lu jiffies s: %lu root: %#lx/%c\n",
459 jiffies - jiffies_start, rsp->expedited_sequence,
460 rnp_root->expmask, ".T"[!!rnp_root->exp_tasks]);
461 if (ndetected) {
462 pr_err("blocking rcu_node structures:");
463 rcu_for_each_node_breadth_first(rsp, rnp) {
464 if (rnp == rnp_root)
465 continue; /* printed unconditionally */
466 if (sync_rcu_preempt_exp_done(rnp))
467 continue;
468 pr_cont(" l=%u:%d-%d:%#lx/%c",
469 rnp->level, rnp->grplo, rnp->grphi,
470 rnp->expmask,
471 ".T"[!!rnp->exp_tasks]);
472 }
473 pr_cont("\n");
474 }
475 rcu_for_each_leaf_node(rsp, rnp) {
476 mask = 1;
477 for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) {
478 if (!(rnp->expmask & mask))
479 continue;
480 dump_cpu_task(cpu);
481 }
482 }
483 jiffies_stall = 3 * rcu_jiffies_till_stall_check() + 3;
484 }
485}
486
487/*
488 * Wait for the current expedited grace period to complete, and then
489 * wake up everyone who piggybacked on the just-completed expedited
490 * grace period. Also update all the ->exp_seq_rq counters as needed
491 * in order to avoid counter-wrap problems.
492 */
493static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s)
494{
495 struct rcu_node *rnp;
496
497 synchronize_sched_expedited_wait(rsp);
498 rcu_exp_gp_seq_end(rsp);
499 trace_rcu_exp_grace_period(rsp->name, s, TPS("end"));
500
501 /*
502 * Switch over to wakeup mode, allowing the next GP, but -only- the
503 * next GP, to proceed.
504 */
505 mutex_lock(&rsp->exp_wake_mutex);
506 mutex_unlock(&rsp->exp_mutex);
507
508 rcu_for_each_node_breadth_first(rsp, rnp) {
509 if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s)) {
510 spin_lock(&rnp->exp_lock);
511 /* Recheck, avoid hang in case someone just arrived. */
512 if (ULONG_CMP_LT(rnp->exp_seq_rq, s))
513 rnp->exp_seq_rq = s;
514 spin_unlock(&rnp->exp_lock);
515 }
516 wake_up_all(&rnp->exp_wq[(rsp->expedited_sequence >> 1) & 0x3]);
517 }
518 trace_rcu_exp_grace_period(rsp->name, s, TPS("endwake"));
519 mutex_unlock(&rsp->exp_wake_mutex);
520}
521
522/**
523 * synchronize_sched_expedited - Brute-force RCU-sched grace period
524 *
525 * Wait for an RCU-sched grace period to elapse, but use a "big hammer"
526 * approach to force the grace period to end quickly. This consumes
527 * significant time on all CPUs and is unfriendly to real-time workloads,
528 * so is thus not recommended for any sort of common-case code. In fact,
529 * if you are using synchronize_sched_expedited() in a loop, please
530 * restructure your code to batch your updates, and then use a single
531 * synchronize_sched() instead.
532 *
533 * This implementation can be thought of as an application of sequence
534 * locking to expedited grace periods, but using the sequence counter to
535 * determine when someone else has already done the work instead of for
536 * retrying readers.
537 */
538void synchronize_sched_expedited(void)
539{
540 unsigned long s;
541 struct rcu_state *rsp = &rcu_sched_state;
542
543 /* If only one CPU, this is automatically a grace period. */
544 if (rcu_blocking_is_gp())
545 return;
546
547 /* If expedited grace periods are prohibited, fall back to normal. */
548 if (rcu_gp_is_normal()) {
549 wait_rcu_gp(call_rcu_sched);
550 return;
551 }
552
553 /* Take a snapshot of the sequence number. */
554 s = rcu_exp_gp_seq_snap(rsp);
555 if (exp_funnel_lock(rsp, s))
556 return; /* Someone else did our work for us. */
557
558 /* Initialize the rcu_node tree in preparation for the wait. */
559 sync_rcu_exp_select_cpus(rsp, sync_sched_exp_handler);
560
561 /* Wait and clean up, including waking everyone. */
562 rcu_exp_wait_wake(rsp, s);
563}
564EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
generated by cgit v1.2.2 (git 2.25.0) at 2025-09-01 04:40:57 -0400