a46e0899ee
This patch #ifdefs RCU kthreads out of the kernel unless RCU_BOOST=y, thus eliminating context-switch overhead if RCU priority boosting has not been configured. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
515 lines
14 KiB
C
515 lines
14 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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#ifdef CONFIG_RCU_BOOST
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DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
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DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_cpu);
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DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
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DECLARE_PER_CPU(char, rcu_cpu_has_work);
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static char convert_kthread_status(unsigned int kthread_status)
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{
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if (kthread_status > RCU_KTHREAD_MAX)
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return '?';
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return "SRWOY"[kthread_status];
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}
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#endif /* #ifdef CONFIG_RCU_BOOST */
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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",
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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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#ifdef CONFIG_RCU_BOOST
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seq_printf(m, " kt=%d/%c/%d ktl=%x",
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per_cpu(rcu_cpu_has_work, rdp->cpu),
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convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
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rdp->cpu)),
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per_cpu(rcu_cpu_kthread_cpu, rdp->cpu),
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per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff);
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#endif /* #ifdef CONFIG_RCU_BOOST */
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seq_printf(m, " b=%ld", 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\"", 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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#ifdef CONFIG_RCU_BOOST
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seq_printf(m, ",%d,\"%c\"",
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per_cpu(rcu_cpu_has_work, rdp->cpu),
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convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
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rdp->cpu)));
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#endif /* #ifdef CONFIG_RCU_BOOST */
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seq_printf(m, ",%ld", 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\",\"qs\"");
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#ifdef CONFIG_RCU_BOOST
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seq_puts(m, "\"kt\",\"ktl\"");
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#endif /* #ifdef CONFIG_RCU_BOOST */
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seq_puts(m, ",\"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 kt=%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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convert_kthread_status(rnp->boost_kthread_status),
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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 void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
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{
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unsigned long flags;
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unsigned long completed;
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unsigned long gpnum;
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unsigned long gpage;
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unsigned long gpmax;
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struct rcu_node *rnp = &rsp->node[0];
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raw_spin_lock_irqsave(&rnp->lock, flags);
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completed = rsp->completed;
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gpnum = rsp->gpnum;
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if (rsp->completed == rsp->gpnum)
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gpage = 0;
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else
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gpage = jiffies - rsp->gp_start;
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gpmax = rsp->gp_max;
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raw_spin_unlock_irqrestore(&rnp->lock, flags);
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seq_printf(m, "%s: completed=%ld gpnum=%lu age=%ld max=%ld\n",
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rsp->name, completed, gpnum, gpage, gpmax);
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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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show_one_rcugp(m, &rcu_preempt_state);
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#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
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show_one_rcugp(m, &rcu_sched_state);
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show_one_rcugp(m, &rcu_bh_state);
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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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};
|
|
|
|
static int show_rcutorture(struct seq_file *m, void *unused)
|
|
{
|
|
seq_printf(m, "rcutorture test sequence: %lu %s\n",
|
|
rcutorture_testseq >> 1,
|
|
(rcutorture_testseq & 0x1) ? "(test in progress)" : "");
|
|
seq_printf(m, "rcutorture update version number: %lu\n",
|
|
rcutorture_vernum);
|
|
return 0;
|
|
}
|
|
|
|
static int rcutorture_open(struct inode *inode, struct file *file)
|
|
{
|
|
return single_open(file, show_rcutorture, NULL);
|
|
}
|
|
|
|
static const struct file_operations rcutorture_fops = {
|
|
.owner = THIS_MODULE,
|
|
.open = rcutorture_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = single_release,
|
|
};
|
|
|
|
static struct dentry *rcudir;
|
|
|
|
static int __init rcutree_trace_init(void)
|
|
{
|
|
struct dentry *retval;
|
|
|
|
rcudir = debugfs_create_dir("rcu", NULL);
|
|
if (!rcudir)
|
|
goto free_out;
|
|
|
|
retval = debugfs_create_file("rcudata", 0444, rcudir,
|
|
NULL, &rcudata_fops);
|
|
if (!retval)
|
|
goto free_out;
|
|
|
|
retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
|
|
NULL, &rcudata_csv_fops);
|
|
if (!retval)
|
|
goto free_out;
|
|
|
|
if (rcu_boost_trace_create_file(rcudir))
|
|
goto free_out;
|
|
|
|
retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
|
|
if (!retval)
|
|
goto free_out;
|
|
|
|
retval = debugfs_create_file("rcuhier", 0444, rcudir,
|
|
NULL, &rcuhier_fops);
|
|
if (!retval)
|
|
goto free_out;
|
|
|
|
retval = debugfs_create_file("rcu_pending", 0444, rcudir,
|
|
NULL, &rcu_pending_fops);
|
|
if (!retval)
|
|
goto free_out;
|
|
|
|
retval = debugfs_create_file("rcutorture", 0444, rcudir,
|
|
NULL, &rcutorture_fops);
|
|
if (!retval)
|
|
goto free_out;
|
|
return 0;
|
|
free_out:
|
|
debugfs_remove_recursive(rcudir);
|
|
return 1;
|
|
}
|
|
|
|
static void __exit rcutree_trace_cleanup(void)
|
|
{
|
|
debugfs_remove_recursive(rcudir);
|
|
}
|
|
|
|
|
|
module_init(rcutree_trace_init);
|
|
module_exit(rcutree_trace_cleanup);
|
|
|
|
MODULE_AUTHOR("Paul E. McKenney");
|
|
MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
|
|
MODULE_LICENSE("GPL");
|