0ac3d136b2
This commit adds an indication of the state of the callback queue using a string of four characters following the "ql=" integer queue length. The first character is "N" if there are callbacks that have been queued that are not yet ready to be handled by the next grace period, or "." otherwise. The second character is "R" if there are callbacks queued that are ready to be handled by the next grace period, or "." otherwise. The third character is "W" if there are callbacks waiting for the current grace period, or "." otherwise. Finally, the fourth character is "D" if there are callbacks that have been handled by a prior grace period and are waiting to be invoked, or ".". Note that callbacks that are in the process of being invoked are not shown. These callbacks would have been removed from the rcu_data structure's list by rcu_do_batch() prior to being executed. (These callbacks are also not reflected in the "ql=" total, FWIW.) Also, document the new callback-queue trace information. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
434 lines
12 KiB
C
434 lines
12 KiB
C
/*
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* Read-Copy Update tracing for classic implementation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright IBM Corporation, 2008
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*
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* Papers: http://www.rdrop.com/users/paulmck/RCU
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*
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* For detailed explanation of Read-Copy Update mechanism see -
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* Documentation/RCU
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*
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/smp.h>
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#include <linux/rcupdate.h>
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#include <linux/interrupt.h>
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#include <linux/sched.h>
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#include <asm/atomic.h>
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#include <linux/bitops.h>
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#include <linux/module.h>
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#include <linux/completion.h>
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#include <linux/moduleparam.h>
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#include <linux/percpu.h>
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#include <linux/notifier.h>
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#include <linux/cpu.h>
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#include <linux/mutex.h>
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#include <linux/debugfs.h>
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#include <linux/seq_file.h>
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#define RCU_TREE_NONCORE
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#include "rcutree.h"
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static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
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{
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if (!rdp->beenonline)
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return;
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seq_printf(m, "%3d%cc=%lu g=%lu pq=%d pqc=%lu qp=%d",
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rdp->cpu,
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cpu_is_offline(rdp->cpu) ? '!' : ' ',
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rdp->completed, rdp->gpnum,
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rdp->passed_quiesc, rdp->passed_quiesc_completed,
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rdp->qs_pending);
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#ifdef CONFIG_NO_HZ
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seq_printf(m, " dt=%d/%d/%d df=%lu",
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atomic_read(&rdp->dynticks->dynticks),
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rdp->dynticks->dynticks_nesting,
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rdp->dynticks->dynticks_nmi_nesting,
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rdp->dynticks_fqs);
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#endif /* #ifdef CONFIG_NO_HZ */
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seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi);
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seq_printf(m, " ql=%ld qs=%c%c%c%c b=%ld",
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rdp->qlen,
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".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
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rdp->nxttail[RCU_NEXT_TAIL]],
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".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
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rdp->nxttail[RCU_NEXT_READY_TAIL]],
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".W"[rdp->nxttail[RCU_DONE_TAIL] !=
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rdp->nxttail[RCU_WAIT_TAIL]],
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".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]],
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rdp->blimit);
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seq_printf(m, " ci=%lu co=%lu ca=%lu\n",
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rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
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}
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#define PRINT_RCU_DATA(name, func, m) \
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do { \
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int _p_r_d_i; \
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\
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for_each_possible_cpu(_p_r_d_i) \
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func(m, &per_cpu(name, _p_r_d_i)); \
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} while (0)
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static int show_rcudata(struct seq_file *m, void *unused)
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{
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#ifdef CONFIG_TREE_PREEMPT_RCU
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seq_puts(m, "rcu_preempt:\n");
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PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data, m);
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#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
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seq_puts(m, "rcu_sched:\n");
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PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data, m);
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seq_puts(m, "rcu_bh:\n");
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PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data, m);
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return 0;
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}
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static int rcudata_open(struct inode *inode, struct file *file)
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{
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return single_open(file, show_rcudata, NULL);
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}
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static const struct file_operations rcudata_fops = {
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.owner = THIS_MODULE,
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.open = rcudata_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
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{
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if (!rdp->beenonline)
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return;
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seq_printf(m, "%d,%s,%lu,%lu,%d,%lu,%d",
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rdp->cpu,
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cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
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rdp->completed, rdp->gpnum,
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rdp->passed_quiesc, rdp->passed_quiesc_completed,
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rdp->qs_pending);
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#ifdef CONFIG_NO_HZ
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seq_printf(m, ",%d,%d,%d,%lu",
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atomic_read(&rdp->dynticks->dynticks),
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rdp->dynticks->dynticks_nesting,
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rdp->dynticks->dynticks_nmi_nesting,
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rdp->dynticks_fqs);
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#endif /* #ifdef CONFIG_NO_HZ */
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seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);
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seq_printf(m, ",%ld,\"%c%c%c%c\",%ld", rdp->qlen,
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".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
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rdp->nxttail[RCU_NEXT_TAIL]],
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".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
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rdp->nxttail[RCU_NEXT_READY_TAIL]],
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".W"[rdp->nxttail[RCU_DONE_TAIL] !=
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rdp->nxttail[RCU_WAIT_TAIL]],
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".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]],
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rdp->blimit);
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seq_printf(m, ",%lu,%lu,%lu\n",
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rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
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}
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static int show_rcudata_csv(struct seq_file *m, void *unused)
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{
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seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",");
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#ifdef CONFIG_NO_HZ
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seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\",");
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#endif /* #ifdef CONFIG_NO_HZ */
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seq_puts(m, "\"of\",\"ri\",\"ql\",\"b\",\"ci\",\"co\",\"ca\"\n");
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#ifdef CONFIG_TREE_PREEMPT_RCU
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seq_puts(m, "\"rcu_preempt:\"\n");
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PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data_csv, m);
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#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
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seq_puts(m, "\"rcu_sched:\"\n");
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PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data_csv, m);
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seq_puts(m, "\"rcu_bh:\"\n");
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PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data_csv, m);
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return 0;
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}
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static int rcudata_csv_open(struct inode *inode, struct file *file)
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{
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return single_open(file, show_rcudata_csv, NULL);
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}
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static const struct file_operations rcudata_csv_fops = {
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.owner = THIS_MODULE,
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.open = rcudata_csv_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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#ifdef CONFIG_RCU_BOOST
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static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
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{
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seq_printf(m, "%d:%d tasks=%c%c%c%c ntb=%lu neb=%lu nnb=%lu "
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"j=%04x bt=%04x\n",
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rnp->grplo, rnp->grphi,
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"T."[list_empty(&rnp->blkd_tasks)],
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"N."[!rnp->gp_tasks],
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"E."[!rnp->exp_tasks],
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"B."[!rnp->boost_tasks],
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rnp->n_tasks_boosted, rnp->n_exp_boosts,
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rnp->n_normal_boosts,
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(int)(jiffies & 0xffff),
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(int)(rnp->boost_time & 0xffff));
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seq_printf(m, "%s: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
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" balk",
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rnp->n_balk_blkd_tasks,
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rnp->n_balk_exp_gp_tasks,
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rnp->n_balk_boost_tasks,
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rnp->n_balk_notblocked,
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rnp->n_balk_notyet,
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rnp->n_balk_nos);
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}
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static int show_rcu_node_boost(struct seq_file *m, void *unused)
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{
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struct rcu_node *rnp;
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rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
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print_one_rcu_node_boost(m, rnp);
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return 0;
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}
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static int rcu_node_boost_open(struct inode *inode, struct file *file)
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{
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return single_open(file, show_rcu_node_boost, NULL);
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}
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static const struct file_operations rcu_node_boost_fops = {
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.owner = THIS_MODULE,
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.open = rcu_node_boost_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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/*
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* Create the rcuboost debugfs entry. Standard error return.
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*/
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static int rcu_boost_trace_create_file(struct dentry *rcudir)
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{
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return !debugfs_create_file("rcuboost", 0444, rcudir, NULL,
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&rcu_node_boost_fops);
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}
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#else /* #ifdef CONFIG_RCU_BOOST */
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static int rcu_boost_trace_create_file(struct dentry *rcudir)
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{
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return 0; /* There cannot be an error if we didn't create it! */
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}
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#endif /* #else #ifdef CONFIG_RCU_BOOST */
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static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
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{
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unsigned long gpnum;
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int level = 0;
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struct rcu_node *rnp;
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gpnum = rsp->gpnum;
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seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x "
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"nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n",
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rsp->completed, gpnum, rsp->signaled,
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(long)(rsp->jiffies_force_qs - jiffies),
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(int)(jiffies & 0xffff),
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rsp->n_force_qs, rsp->n_force_qs_ngp,
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rsp->n_force_qs - rsp->n_force_qs_ngp,
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rsp->n_force_qs_lh);
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for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
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if (rnp->level != level) {
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seq_puts(m, "\n");
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level = rnp->level;
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}
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seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d ",
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rnp->qsmask, rnp->qsmaskinit,
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".G"[rnp->gp_tasks != NULL],
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".E"[rnp->exp_tasks != NULL],
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".T"[!list_empty(&rnp->blkd_tasks)],
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rnp->grplo, rnp->grphi, rnp->grpnum);
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}
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seq_puts(m, "\n");
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}
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static int show_rcuhier(struct seq_file *m, void *unused)
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{
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#ifdef CONFIG_TREE_PREEMPT_RCU
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seq_puts(m, "rcu_preempt:\n");
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print_one_rcu_state(m, &rcu_preempt_state);
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#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
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seq_puts(m, "rcu_sched:\n");
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print_one_rcu_state(m, &rcu_sched_state);
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seq_puts(m, "rcu_bh:\n");
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print_one_rcu_state(m, &rcu_bh_state);
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return 0;
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}
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static int rcuhier_open(struct inode *inode, struct file *file)
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{
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return single_open(file, show_rcuhier, NULL);
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}
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static const struct file_operations rcuhier_fops = {
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.owner = THIS_MODULE,
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.open = rcuhier_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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static int show_rcugp(struct seq_file *m, void *unused)
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{
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#ifdef CONFIG_TREE_PREEMPT_RCU
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seq_printf(m, "rcu_preempt: completed=%ld gpnum=%lu\n",
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rcu_preempt_state.completed, rcu_preempt_state.gpnum);
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#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
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seq_printf(m, "rcu_sched: completed=%ld gpnum=%lu\n",
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rcu_sched_state.completed, rcu_sched_state.gpnum);
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seq_printf(m, "rcu_bh: completed=%ld gpnum=%lu\n",
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rcu_bh_state.completed, rcu_bh_state.gpnum);
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return 0;
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}
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static int rcugp_open(struct inode *inode, struct file *file)
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{
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return single_open(file, show_rcugp, NULL);
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}
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static const struct file_operations rcugp_fops = {
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.owner = THIS_MODULE,
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.open = rcugp_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
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{
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seq_printf(m, "%3d%cnp=%ld "
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"qsp=%ld rpq=%ld cbr=%ld cng=%ld "
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"gpc=%ld gps=%ld nf=%ld nn=%ld\n",
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rdp->cpu,
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cpu_is_offline(rdp->cpu) ? '!' : ' ',
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rdp->n_rcu_pending,
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rdp->n_rp_qs_pending,
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rdp->n_rp_report_qs,
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rdp->n_rp_cb_ready,
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rdp->n_rp_cpu_needs_gp,
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rdp->n_rp_gp_completed,
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rdp->n_rp_gp_started,
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rdp->n_rp_need_fqs,
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rdp->n_rp_need_nothing);
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}
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static void print_rcu_pendings(struct seq_file *m, struct rcu_state *rsp)
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{
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int cpu;
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struct rcu_data *rdp;
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for_each_possible_cpu(cpu) {
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rdp = per_cpu_ptr(rsp->rda, cpu);
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if (rdp->beenonline)
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print_one_rcu_pending(m, rdp);
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}
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}
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static int show_rcu_pending(struct seq_file *m, void *unused)
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{
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#ifdef CONFIG_TREE_PREEMPT_RCU
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seq_puts(m, "rcu_preempt:\n");
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print_rcu_pendings(m, &rcu_preempt_state);
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#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
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seq_puts(m, "rcu_sched:\n");
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print_rcu_pendings(m, &rcu_sched_state);
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seq_puts(m, "rcu_bh:\n");
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print_rcu_pendings(m, &rcu_bh_state);
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return 0;
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}
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static int rcu_pending_open(struct inode *inode, struct file *file)
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{
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return single_open(file, show_rcu_pending, NULL);
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}
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static const struct file_operations rcu_pending_fops = {
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.owner = THIS_MODULE,
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.open = rcu_pending_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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static struct dentry *rcudir;
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static int __init rcutree_trace_init(void)
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{
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struct dentry *retval;
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rcudir = debugfs_create_dir("rcu", NULL);
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if (!rcudir)
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goto free_out;
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retval = debugfs_create_file("rcudata", 0444, rcudir,
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NULL, &rcudata_fops);
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if (!retval)
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goto free_out;
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retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
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NULL, &rcudata_csv_fops);
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if (!retval)
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goto free_out;
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if (rcu_boost_trace_create_file(rcudir))
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goto free_out;
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retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
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if (!retval)
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goto free_out;
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retval = debugfs_create_file("rcuhier", 0444, rcudir,
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NULL, &rcuhier_fops);
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if (!retval)
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goto free_out;
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retval = debugfs_create_file("rcu_pending", 0444, rcudir,
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NULL, &rcu_pending_fops);
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if (!retval)
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goto free_out;
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return 0;
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free_out:
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debugfs_remove_recursive(rcudir);
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return 1;
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}
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static void __exit rcutree_trace_cleanup(void)
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{
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debugfs_remove_recursive(rcudir);
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}
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module_init(rcutree_trace_init);
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module_exit(rcutree_trace_cleanup);
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MODULE_AUTHOR("Paul E. McKenney");
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MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
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MODULE_LICENSE("GPL");
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