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authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-05 14:49:11 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-05 14:49:11 -0800
commit3717f613f48df0222311f974cf8a06c8a6c97bae (patch)
tree454a8b48db876805e27038486af71d16d2be98de /kernel
parentb1b988a6a035212f5ea205155c49ce449beedee8 (diff)
parentcae45e1c6c541283a1bd155aa7b0a57e353b4df4 (diff)
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar: "The main RCU related changes in this cycle were: - Additional cleanups after RCU flavor consolidation - Grace-period forward-progress cleanups and improvements - Documentation updates - Miscellaneous fixes - spin_is_locked() conversions to lockdep - SPDX changes to RCU source and header files - SRCU updates - Torture-test updates, including nolibc updates and moving nolibc to tools/include" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits) locking/locktorture: Convert to SPDX license identifier linux/torture: Convert to SPDX license identifier torture: Convert to SPDX license identifier linux/srcu: Convert to SPDX license identifier linux/rcutree: Convert to SPDX license identifier linux/rcutiny: Convert to SPDX license identifier linux/rcu_sync: Convert to SPDX license identifier linux/rcu_segcblist: Convert to SPDX license identifier linux/rcupdate: Convert to SPDX license identifier linux/rcu_node_tree: Convert to SPDX license identifier rcu/update: Convert to SPDX license identifier rcu/tree: Convert to SPDX license identifier rcu/tiny: Convert to SPDX license identifier rcu/sync: Convert to SPDX license identifier rcu/srcu: Convert to SPDX license identifier rcu/rcutorture: Convert to SPDX license identifier rcu/rcu_segcblist: Convert to SPDX license identifier rcu/rcuperf: Convert to SPDX license identifier rcu/rcu.h: Convert to SPDX license identifier RCU/torture.txt: Remove section MODULE PARAMETERS ...
Diffstat (limited to 'kernel')
-rw-r--r--kernel/locking/locktorture.c21
-rw-r--r--kernel/rcu/rcu.h21
-rw-r--r--kernel/rcu/rcu_segcblist.c17
-rw-r--r--kernel/rcu/rcu_segcblist.h17
-rw-r--r--kernel/rcu/rcuperf.c27
-rw-r--r--kernel/rcu/rcutorture.c59
-rw-r--r--kernel/rcu/srcutiny.c17
-rw-r--r--kernel/rcu/srcutree.c72
-rw-r--r--kernel/rcu/sync.c15
-rw-r--r--kernel/rcu/tiny.c19
-rw-r--r--kernel/rcu/tree.c267
-rw-r--r--kernel/rcu/tree.h53
-rw-r--r--kernel/rcu/tree_exp.h201
-rw-r--r--kernel/rcu/tree_plugin.h238
-rw-r--r--kernel/rcu/update.c17
-rw-r--r--kernel/sched/cpufreq.c4
-rw-r--r--kernel/sched/cpufreq_schedutil.c2
-rw-r--r--kernel/sched/sched.h2
-rw-r--r--kernel/sched/topology.c4
-rw-r--r--kernel/time/timer.c2
-rw-r--r--kernel/torture.c25
21 files changed, 409 insertions, 691 deletions
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 7d0b0ed74404..ad40a2617063 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -1,23 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0+
/*
* Module-based torture test facility for locking
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright (C) IBM Corporation, 2014
*
- * Authors: Paul E. McKenney <paulmck@us.ibm.com>
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
* Davidlohr Bueso <dave@stgolabs.net>
* Based on kernel/rcu/torture.c.
*/
@@ -45,7 +32,7 @@
#include <linux/torture.h>
MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
torture_param(int, nwriters_stress, -1,
"Number of write-locking stress-test threads");
@@ -970,7 +957,7 @@ static int __init lock_torture_init(void)
/* Prepare torture context. */
if (onoff_interval > 0) {
firsterr = torture_onoff_init(onoff_holdoff * HZ,
- onoff_interval * HZ);
+ onoff_interval * HZ, NULL);
if (firsterr)
goto unwind;
}
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index a393e24a9195..acee72c0b24b 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -1,23 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Read-Copy Update definitions shared among RCU implementations.
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright IBM Corporation, 2011
*
- * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+ * Author: Paul E. McKenney <paulmck@linux.ibm.com>
*/
#ifndef __LINUX_RCU_H
@@ -30,7 +17,7 @@
#define RCU_TRACE(stmt)
#endif /* #else #ifdef CONFIG_RCU_TRACE */
-/* Offset to allow for unmatched rcu_irq_{enter,exit}(). */
+/* Offset to allow distinguishing irq vs. task-based idle entry/exit. */
#define DYNTICK_IRQ_NONIDLE ((LONG_MAX / 2) + 1)
@@ -462,8 +449,6 @@ void rcu_request_urgent_qs_task(struct task_struct *t);
enum rcutorture_type {
RCU_FLAVOR,
- RCU_BH_FLAVOR,
- RCU_SCHED_FLAVOR,
RCU_TASKS_FLAVOR,
SRCU_FLAVOR,
INVALID_RCU_FLAVOR
diff --git a/kernel/rcu/rcu_segcblist.c b/kernel/rcu/rcu_segcblist.c
index 5aff271adf1e..9bd5f6023c21 100644
--- a/kernel/rcu/rcu_segcblist.c
+++ b/kernel/rcu/rcu_segcblist.c
@@ -1,23 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0+
/*
* RCU segmented callback lists, function definitions
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright IBM Corporation, 2017
*
- * Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
*/
#include <linux/types.h>
diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h
index 948470cef385..71b64648464e 100644
--- a/kernel/rcu/rcu_segcblist.h
+++ b/kernel/rcu/rcu_segcblist.h
@@ -1,23 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
/*
* RCU segmented callback lists, internal-to-rcu header file
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright IBM Corporation, 2017
*
- * Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
*/
#include <linux/rcu_segcblist.h>
diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c
index b459da70b4fc..c29761152874 100644
--- a/kernel/rcu/rcuperf.c
+++ b/kernel/rcu/rcuperf.c
@@ -1,23 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0+
/*
* Read-Copy Update module-based performance-test facility
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright (C) IBM Corporation, 2015
*
- * Authors: Paul E. McKenney <paulmck@us.ibm.com>
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
*/
#define pr_fmt(fmt) fmt
@@ -54,7 +41,7 @@
#include "rcu.h"
MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.vnet.ibm.com>");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
#define PERF_FLAG "-perf:"
#define PERFOUT_STRING(s) \
@@ -83,13 +70,19 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.vnet.ibm.com>");
* Various other use cases may of course be specified.
*/
+#ifdef MODULE
+# define RCUPERF_SHUTDOWN 0
+#else
+# define RCUPERF_SHUTDOWN 1
+#endif
+
torture_param(bool, gp_async, false, "Use asynchronous GP wait primitives");
torture_param(int, gp_async_max, 1000, "Max # outstanding waits per reader");
torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
torture_param(int, holdoff, 10, "Holdoff time before test start (s)");
torture_param(int, nreaders, -1, "Number of RCU reader threads");
torture_param(int, nwriters, -1, "Number of RCU updater threads");
-torture_param(bool, shutdown, !IS_ENABLED(MODULE),
+torture_param(bool, shutdown, RCUPERF_SHUTDOWN,
"Shutdown at end of performance tests.");
torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
torture_param(int, writer_holdoff, 0, "Holdoff (us) between GPs, zero to disable");
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index f6e85faa4ff4..f14d1b18a74f 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1,23 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0+
/*
* Read-Copy Update module-based torture test facility
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright (C) IBM Corporation, 2005, 2006
*
- * Authors: Paul E. McKenney <paulmck@us.ibm.com>
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
* Josh Triplett <josh@joshtriplett.org>
*
* See also: Documentation/RCU/torture.txt
@@ -61,7 +48,7 @@
#include "rcu.h"
MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
/* Bits for ->extendables field, extendables param, and related definitions. */
@@ -1630,21 +1617,34 @@ static bool rcu_fwd_emergency_stop;
#define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
#define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
#define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
-static long n_launders_hist[2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV)];
+struct rcu_launder_hist {
+ long n_launders;
+ unsigned long launder_gp_seq;
+};
+#define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
+static struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
+static unsigned long rcu_launder_gp_seq_start;
static void rcu_torture_fwd_cb_hist(void)
{
+ unsigned long gps;
+ unsigned long gps_old;
int i;
int j;
for (i = ARRAY_SIZE(n_launders_hist) - 1; i > 0; i--)
- if (n_launders_hist[i] > 0)
+ if (n_launders_hist[i].n_launders > 0)
break;
pr_alert("%s: Callback-invocation histogram (duration %lu jiffies):",
__func__, jiffies - rcu_fwd_startat);
- for (j = 0; j <= i; j++)
- pr_cont(" %ds/%d: %ld",
- j + 1, FWD_CBS_HIST_DIV, n_launders_hist[j]);
+ gps_old = rcu_launder_gp_seq_start;
+ for (j = 0; j <= i; j++) {
+ gps = n_launders_hist[j].launder_gp_seq;
+ pr_cont(" %ds/%d: %ld:%ld",
+ j + 1, FWD_CBS_HIST_DIV, n_launders_hist[j].n_launders,
+ rcutorture_seq_diff(gps, gps_old));
+ gps_old = gps;
+ }
pr_cont("\n");
}
@@ -1666,7 +1666,8 @@ static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
i = ((jiffies - rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
if (i >= ARRAY_SIZE(n_launders_hist))
i = ARRAY_SIZE(n_launders_hist) - 1;
- n_launders_hist[i]++;
+ n_launders_hist[i].n_launders++;
+ n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
spin_unlock_irqrestore(&rcu_fwd_lock, flags);
}
@@ -1786,9 +1787,10 @@ static void rcu_torture_fwd_prog_cr(void)
n_max_cbs = 0;
n_max_gps = 0;
for (i = 0; i < ARRAY_SIZE(n_launders_hist); i++)
- n_launders_hist[i] = 0;
+ n_launders_hist[i].n_launders = 0;
cver = READ_ONCE(rcu_torture_current_version);
gps = cur_ops->get_gp_seq();
+ rcu_launder_gp_seq_start = gps;
while (time_before(jiffies, stopat) &&
!READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
rfcp = READ_ONCE(rcu_fwd_cb_head);
@@ -2228,6 +2230,14 @@ static void rcu_test_debug_objects(void)
#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
}
+static void rcutorture_sync(void)
+{
+ static unsigned long n;
+
+ if (cur_ops->sync && !(++n & 0xfff))
+ cur_ops->sync();
+}
+
static int __init
rcu_torture_init(void)
{
@@ -2389,7 +2399,8 @@ rcu_torture_init(void)
firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
if (firsterr)
goto unwind;
- firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval);
+ firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
+ rcutorture_sync);
if (firsterr)
goto unwind;
firsterr = rcu_torture_stall_init();
diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
index 32dfd6522548..5d4a39a6505a 100644
--- a/kernel/rcu/srcutiny.c
+++ b/kernel/rcu/srcutiny.c
@@ -1,24 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0+
/*
* Sleepable Read-Copy Update mechanism for mutual exclusion,
* tiny version for non-preemptible single-CPU use.
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright (C) IBM Corporation, 2017
*
- * Author: Paul McKenney <paulmck@us.ibm.com>
+ * Author: Paul McKenney <paulmck@linux.ibm.com>
*/
#include <linux/export.h>
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 3600d88d8956..a60b8ba9e1ac 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -1,24 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0+
/*
* Sleepable Read-Copy Update mechanism for mutual exclusion.
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright (C) IBM Corporation, 2006
* Copyright (C) Fujitsu, 2012
*
- * Author: Paul McKenney <paulmck@us.ibm.com>
+ * Author: Paul McKenney <paulmck@linux.ibm.com>
* Lai Jiangshan <laijs@cn.fujitsu.com>
*
* For detailed explanation of Read-Copy Update mechanism see -
@@ -58,6 +45,7 @@ static bool __read_mostly srcu_init_done;
static void srcu_invoke_callbacks(struct work_struct *work);
static void srcu_reschedule(struct srcu_struct *ssp, unsigned long delay);
static void process_srcu(struct work_struct *work);
+static void srcu_delay_timer(struct timer_list *t);
/* Wrappers for lock acquisition and release, see raw_spin_lock_rcu_node(). */
#define spin_lock_rcu_node(p) \
@@ -156,7 +144,8 @@ static void init_srcu_struct_nodes(struct srcu_struct *ssp, bool is_static)
snp->grphi = cpu;
}
sdp->cpu = cpu;
- INIT_DELAYED_WORK(&sdp->work, srcu_invoke_callbacks);
+ INIT_WORK(&sdp->work, srcu_invoke_callbacks);
+ timer_setup(&sdp->delay_work, srcu_delay_timer, 0);
sdp->ssp = ssp;
sdp->grpmask = 1 << (cpu - sdp->mynode->grplo);
if (is_static)
@@ -386,13 +375,19 @@ void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)
} else {
flush_delayed_work(&ssp->work);
}
- for_each_possible_cpu(cpu)
+ for_each_possible_cpu(cpu) {
+ struct srcu_data *sdp = per_cpu_ptr(ssp->sda, cpu);
+
if (quiesced) {
- if (WARN_ON(delayed_work_pending(&per_cpu_ptr(ssp->sda, cpu)->work)))
+ if (WARN_ON(timer_pending(&sdp->delay_work)))
+ return; /* Just leak it! */
+ if (WARN_ON(work_pending(&sdp->work)))
return; /* Just leak it! */
} else {
- flush_delayed_work(&per_cpu_ptr(ssp->sda, cpu)->work);
+ del_timer_sync(&sdp->delay_work);
+ flush_work(&sdp->work);
}
+ }
if (WARN_ON(rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
WARN_ON(srcu_readers_active(ssp))) {
pr_info("%s: Active srcu_struct %p state: %d\n",
@@ -463,39 +458,23 @@ static void srcu_gp_start(struct srcu_struct *ssp)
WARN_ON_ONCE(state != SRCU_STATE_SCAN1);
}
-/*
- * Track online CPUs to guide callback workqueue placement.
- */
-DEFINE_PER_CPU(bool, srcu_online);
-void srcu_online_cpu(unsigned int cpu)
+static void srcu_delay_timer(struct timer_list *t)
{
- WRITE_ONCE(per_cpu(srcu_online, cpu), true);
-}
+ struct srcu_data *sdp = container_of(t, struct srcu_data, delay_work);
-void srcu_offline_cpu(unsigned int cpu)
-{
- WRITE_ONCE(per_cpu(srcu_online, cpu), false);
+ queue_work_on(sdp->cpu, rcu_gp_wq, &sdp->work);
}
-/*
- * Place the workqueue handler on the specified CPU if online, otherwise
- * just run it whereever. This is useful for placing workqueue handlers
- * that are to invoke the specified CPU's callbacks.
- */
-static bool srcu_queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
- struct delayed_work *dwork,
+static void srcu_queue_delayed_work_on(struct srcu_data *sdp,
unsigned long delay)
{
- bool ret;
+ if (!delay) {
+ queue_work_on(sdp->cpu, rcu_gp_wq, &sdp->work);
+ return;
+ }
- preempt_disable();
- if (READ_ONCE(per_cpu(srcu_online, cpu)))
- ret = queue_delayed_work_on(cpu, wq, dwork, delay);
- else
- ret = queue_delayed_work(wq, dwork, delay);
- preempt_enable();
- return ret;
+ timer_reduce(&sdp->delay_work, jiffies + delay);
}
/*
@@ -504,7 +483,7 @@ static bool srcu_queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
*/
static void srcu_schedule_cbs_sdp(struct srcu_data *sdp, unsigned long delay)
{
- srcu_queue_delayed_work_on(sdp->cpu, rcu_gp_wq, &sdp->work, delay);
+ srcu_queue_delayed_work_on(sdp, delay);
}
/*
@@ -1186,7 +1165,8 @@ static void srcu_invoke_callbacks(struct work_struct *work)
struct srcu_data *sdp;
struct srcu_struct *ssp;
- sdp = container_of(work, struct srcu_data, work.work);
+ sdp = container_of(work, struct srcu_data, work);
+
ssp = sdp->ssp;
rcu_cblist_init(&ready_cbs);
spin_lock_irq_rcu_node(sdp);
diff --git a/kernel/rcu/sync.c b/kernel/rcu/sync.c
index be10036fa621..a8304d90573f 100644
--- a/kernel/rcu/sync.c
+++ b/kernel/rcu/sync.c
@@ -1,20 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0+
/*
* RCU-based infrastructure for lightweight reader-writer locking
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright (c) 2015, Red Hat, Inc.
*
* Author: Oleg Nesterov <oleg@redhat.com>
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index 5f5963ba313e..911bd9076d43 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -1,23 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0+
/*
* Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright IBM Corporation, 2008
*
- * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+ * Author: Paul E. McKenney <paulmck@linux.ibm.com>
*
* For detailed explanation of Read-Copy Update mechanism see -
* Documentation/RCU
@@ -76,7 +63,7 @@ void rcu_qs(void)
* be called from hardirq context. It is normally called from the
* scheduling-clock interrupt.
*/
-void rcu_check_callbacks(int user)
+void rcu_sched_clock_irq(int user)
{
if (user) {
rcu_qs();
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 9180158756d2..3b084dbfb4bc 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1,27 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0+
/*
* Read-Copy Update mechanism for mutual exclusion
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright IBM Corporation, 2008
*
* Authors: Dipankar Sarma <dipankar@in.ibm.com>
* Manfred Spraul <manfred@colorfullife.com>
- * Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical version
+ * Paul E. McKenney <paulmck@linux.ibm.com> Hierarchical version
*
- * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
+ * Based on the original work by Paul McKenney <paulmck@linux.ibm.com>
* and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
*
* For detailed explanation of Read-Copy Update mechanism see -
@@ -62,6 +49,7 @@
#include <linux/suspend.h>
#include <linux/ftrace.h>
#include <linux/tick.h>
+#include <linux/sysrq.h>
#include "tree.h"
#include "rcu.h"
@@ -115,6 +103,9 @@ int num_rcu_lvl[] = NUM_RCU_LVL_INIT;
int rcu_num_nodes __read_mostly = NUM_RCU_NODES; /* Total # rcu_nodes in use. */
/* panic() on RCU Stall sysctl. */
int sysctl_panic_on_rcu_stall __read_mostly;
+/* Commandeer a sysrq key to dump RCU's tree. */
+static bool sysrq_rcu;
+module_param(sysrq_rcu, bool, 0444);
/*
* The rcu_scheduler_active variable is initialized to the value
@@ -479,7 +470,6 @@ module_param_cb(jiffies_till_next_fqs, &next_fqs_jiffies_ops, &jiffies_till_next
module_param(rcu_kick_kthreads, bool, 0644);
static void force_qs_rnp(int (*f)(struct rcu_data *rdp));
-static void force_quiescent_state(void);
static int rcu_pending(void);
/*
@@ -504,13 +494,12 @@ unsigned long rcu_exp_batches_completed(void)
EXPORT_SYMBOL_GPL(rcu_exp_batches_completed);
/*
- * Force a quiescent state.
+ * Return the root node of the rcu_state structure.
*/
-void rcu_force_quiescent_state(void)
+static struct rcu_node *rcu_get_root(void)
{
- force_quiescent_state();
+ return &rcu_state.node[0];
}
-EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);
/*
* Convert a ->gp_state value to a character string.
@@ -529,19 +518,30 @@ void show_rcu_gp_kthreads(void)
{
int cpu;
unsigned long j;
+ unsigned long ja;
+ unsigned long jr;
+ unsigned long jw;
struct rcu_data *rdp;
struct rcu_node *rnp;
- j = jiffies - READ_ONCE(rcu_state.gp_activity);
- pr_info("%s: wait state: %s(%d) ->state: %#lx delta ->gp_activity %ld\n",
+ j = jiffies;
+ ja = j - READ_ONCE(rcu_state.gp_activity);
+ jr = j - READ_ONCE(rcu_state.gp_req_activity);
+ jw = j - READ_ONCE(rcu_state.gp_wake_time);
+ pr_info("%s: wait state: %s(%d) ->state: %#lx delta ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_flags %#x\n",
rcu_state.name, gp_state_getname(rcu_state.gp_state),
- rcu_state.gp_state, rcu_state.gp_kthread->state, j);
+ rcu_state.gp_state,
+ rcu_state.gp_kthread ? rcu_state.gp_kthread->state : 0x1ffffL,
+ ja, jr, jw, (long)READ_ONCE(rcu_state.gp_wake_seq),
+ (long)READ_ONCE(rcu_state.gp_seq),
+ (long)READ_ONCE(rcu_get_root()->gp_seq_needed),
+ READ_ONCE(rcu_state.gp_flags));
rcu_for_each_node_breadth_first(rnp) {
if (ULONG_CMP_GE(rcu_state.gp_seq, rnp->gp_seq_needed))
continue;
- pr_info("\trcu_node %d:%d ->gp_seq %lu ->gp_seq_needed %lu\n",
- rnp->grplo, rnp->grphi, rnp->gp_seq,
- rnp->gp_seq_needed);
+ pr_info("\trcu_node %d:%d ->gp_seq %ld ->gp_seq_needed %ld\n",
+ rnp->grplo, rnp->grphi, (long)rnp->gp_seq,
+ (long)rnp->gp_seq_needed);
if (!rcu_is_leaf_node(rnp))
continue;
for_each_leaf_node_possible_cpu(rnp, cpu) {
@@ -550,14 +550,35 @@ void show_rcu_gp_kthreads(void)
ULONG_CMP_GE(rcu_state.gp_seq,
rdp->gp_seq_needed))
continue;
- pr_info("\tcpu %d ->gp_seq_needed %lu\n",
- cpu, rdp->gp_seq_needed);
+ pr_info("\tcpu %d ->gp_seq_needed %ld\n",
+ cpu, (long)rdp->gp_seq_needed);
}
}
/* sched_show_task(rcu_state.gp_kthread); */
}
EXPORT_SYMBOL_GPL(show_rcu_gp_kthreads);
+/* Dump grace-period-request information due to commandeered sysrq. */
+static void sysrq_show_rcu(int key)
+{
+ show_rcu_gp_kthreads();
+}
+
+static struct sysrq_key_op sysrq_rcudump_op = {
+ .handler = sysrq_show_rcu,
+ .help_msg = "show-rcu(y)",
+ .action_msg = "Show RCU tree",
+ .enable_mask = SYSRQ_ENABLE_DUMP,
+};
+
+static int __init rcu_sysrq_init(void)
+{
+ if (sysrq_rcu)
+ return register_sysrq_key('y', &sysrq_rcudump_op);
+ return 0;
+}
+early_initcall(rcu_sysrq_init);
+
/*
* Send along grace-period-related data for rcutorture diagnostics.
*/
@@ -566,8 +587,6 @@ void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
{
switch (test_type) {
case RCU_FLAVOR:
- case RCU_BH_FLAVOR:
- case RCU_SCHED_FLAVOR:
*flags = READ_ONCE(rcu_state.gp_flags);
*gp_seq = rcu_seq_current(&rcu_state.gp_seq);
break;
@@ -578,14 +597,6 @@ void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
EXPORT_SYMBOL_GPL(rcutorture_get_gp_data);
/*
- * Return the root node of the rcu_state structure.
- */
-static struct rcu_node *rcu_get_root(void)
-{
- return &rcu_state.node[0];
-}
-
-/*
* Enter an RCU extended quiescent state, which can be either the
* idle loop or adaptive-tickless usermode execution.
*
@@ -701,7 +712,6 @@ static __always_inline void rcu_nmi_exit_common(bool irq)
/**
* rcu_nmi_exit - inform RCU of exit from NMI context
- * @irq: Is this call from rcu_irq_exit?
*
* If you add or remove a call to rcu_nmi_exit(), be sure to test
* with CONFIG_RCU_EQS_DEBUG=y.
@@ -1115,7 +1125,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
}
/*
- * NO_HZ_FULL CPUs can run in-kernel without rcu_check_callbacks!
+ * NO_HZ_FULL CPUs can run in-kernel without rcu_sched_clock_irq!
* The above code handles this, but only for straight cond_resched().
* And some in-kernel loops check need_resched() before calling
* cond_resched(), which defeats the above code for CPUs that are
@@ -1181,7 +1191,7 @@ static void rcu_check_gp_kthread_starvation(void)
pr_err("%s kthread starved for %ld jiffies! g%ld f%#x %s(%d) ->state=%#lx ->cpu=%d\n",
rcu_state.name, j,
(long)rcu_seq_current(&rcu_state.gp_seq),
- rcu_state.gp_flags,
+ READ_ONCE(rcu_state.gp_flags),
gp_state_getname(rcu_state.gp_state), rcu_state.gp_state,
gpk ? gpk->state : ~0, gpk ? task_cpu(gpk) : -1);
if (gpk) {
@@ -1310,7 +1320,7 @@ static void print_other_cpu_stall(unsigned long gp_seq)
panic_on_rcu_stall();
- force_quiescent_state(); /* Kick them all. */
+ rcu_force_quiescent_state(); /* Kick them all. */
}
static void print_cpu_stall(void)
@@ -1557,17 +1567,28 @@ static bool rcu_future_gp_cleanup(struct rcu_node *rnp)
}
/*
- * Awaken the grace-period kthread. Don't do a self-awaken, and don't
- * bother awakening when there is nothing for the grace-period kthread
- * to do (as in several CPUs raced to awaken, and we lost), and finally
- * don't try to awaken a kthread that has not yet been created.
+ * Awaken the grace-period kthread. Don't do a self-awaken (unless in
+ * an interrupt or softirq handler), and don't bother awakening when there
+ * is nothing for the grace-period kthread to do (as in several CPUs raced
+ * to awaken, and we lost), and finally don't try to awaken a kthread that
+ * has not yet been created. If all those checks are passed, track some
+ * debug information and awaken.
+ *
+ * So why do the self-wakeup when in an interrupt or softirq handler
+ * in the grace-period kthread's context? Because the kthread might have
+ * been interrupted just as it was going to sleep, and just after the final
+ * pre-sleep check of the awaken condition. In this case, a wakeup really
+ * is required, and is therefore supplied.
*/
static void rcu_gp_kthread_wake(void)
{
- if (current == rcu_state.gp_kthread ||
+ if ((current == rcu_state.gp_kthread &&
+ !in_interrupt() && !in_serving_softirq()) ||
!READ_ONCE(rcu_state.gp_flags) ||
!rcu_state.gp_kthread)
return;
+ WRITE_ONCE(rcu_state.gp_wake_time, jiffies);
+ WRITE_ONCE(rcu_state.gp_wake_seq, READ_ONCE(rcu_state.gp_seq));
swake_up_one(&rcu_state.gp_wq);
}
@@ -1711,7 +1732,7 @@ static bool __note_gp_changes(struct rcu_node *rnp, struct rcu_data *rdp)
zero_cpu_stall_ticks(rdp);
}
rdp->gp_seq = rnp->gp_seq; /* Remember new grace-period state. */
- if (ULONG_CMP_GE(rnp->gp_seq_needed, rdp->gp_seq_needed) || rdp->gpwrap)
+ if (ULONG_CMP_LT(rdp->gp_seq_needed, rnp->gp_seq_needed) || rdp->gpwrap)
rdp->gp_seq_needed = rnp->gp_seq_needed;
WRITE_ONCE(rdp->gpwrap, false);
rcu_gpnum_ovf(rnp, rdp);
@@ -1939,7 +1960,7 @@ static void rcu_gp_fqs_loop(void)
if (!ret) {
rcu_state.jiffies_force_qs = jiffies + j;
WRITE_ONCE(rcu_state.jiffies_kick_kthreads,
- jiffies + 3 * j);
+ jiffies + (j ? 3 * j : 2));
}
trace_rcu_grace_period(rcu_state.name,
READ_ONCE(rcu_state.gp_seq),
@@ -2497,14 +2518,14 @@ static void rcu_do_batch(struct rcu_data *rdp)
}
/*
- * Check to see if this CPU is in a non-context-switch quiescent state
- * (user mode or idle loop for rcu, non-softirq execution for rcu_bh).
- * Also schedule RCU core processing.
- *
- * This function must be called from hardirq context. It is normally
- * invoked from the scheduling-clock interrupt.
+ * This function is invoked from each scheduling-clock interrupt,
+ * and checks to see if this CPU is in a non-context-switch quiescent
+ * state, for example, user mode or idle loop. It also schedules RCU
+ * core processing. If the current grace period has gone on too long,
+ * it will ask the scheduler to manufacture a context switch for the sole
+ * purpose of providing a providing the needed quiescent state.
*/
-void rcu_check_callbacks(int user)
+void rcu_sched_clock_irq(int user)
{
trace_rcu_utilization(TPS("Start scheduler-tick"));
raw_cpu_inc(rcu_data.ticks_this_gp);
@@ -2517,7 +2538,7 @@ void rcu_check_callbacks(int user)
}
__this_cpu_write(rcu_data.rcu_urgent_qs, false);
}
- rcu_flavor_check_callbacks(user);
+ rcu_flavor_sched_clock_irq(user);
if (rcu_pending())
invoke_rcu_core();
@@ -2578,7 +2599,7 @@ static void force_qs_rnp(int (*f)(struct rcu_data *rdp))
* Force quiescent states on reluctant CPUs, and also detect which
* CPUs are in dyntick-idle mode.
*/
-static void force_quiescent_state(void)
+void rcu_force_quiescent_state(void)
{
unsigned long flags;
bool ret;
@@ -2610,6 +2631,7 @@ static void force_quiescent_state(void)
raw_spin_unlock_irqrestore_rcu_node(rnp_old, flags);
rcu_gp_kthread_wake();
}
+EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);
/*
* This function checks for grace-period requests that fail to motivate
@@ -2657,16 +2679,11 @@ rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp,
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
}
- pr_alert("%s: g%ld->%ld gar:%lu ga:%lu f%#x gs:%d %s->state:%#lx\n",
- __func__, (long)READ_ONCE(rcu_state.gp_seq),
- (long)READ_ONCE(rnp_root->gp_seq_needed),
- j - rcu_state.gp_req_activity, j - rcu_state.gp_activity,
- rcu_state.gp_flags, rcu_state.gp_state, rcu_state.name,
- rcu_state.gp_kthread ? rcu_state.gp_kthread->state : 0x1ffffL);
WARN_ON(1);
if (rnp_root != rnp)
raw_spin_unlock_rcu_node(rnp_root);
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+ show_rcu_gp_kthreads();
}
/*
@@ -2711,12 +2728,8 @@ void rcu_fwd_progress_check(unsigned long j)
}
EXPORT_SYMBOL_GPL(rcu_fwd_progress_check);
-/*
- * This does the RCU core processing work for the specified rcu_data
- * structures. This may be called only from the CPU to whom the rdp
- * belongs.
- */
-static __latent_entropy void rcu_process_callbacks(struct softirq_action *unused)
+/* Perform RCU core processing work for the current CPU. */
+static __latent_entropy void rcu_core(struct softirq_action *unused)
{
unsigned long flags;
struct rcu_data *rdp = raw_cpu_ptr(&rcu_data);
@@ -2801,9 +2814,9 @@ static void __call_rcu_core(struct rcu_data *rdp, struct rcu_head *head,
/*
* Force the grace period if too many callbacks or too long waiting.
- * Enforce hysteresis, and don't invoke force_quiescent_state()
+ * Enforce hysteresis, and don't invoke rcu_force_quiescent_state()
* if some other CPU has recently done so. Also, don't bother
- * invoking force_quiescent_state() if the newly enqueued callback
+ * invoking rcu_force_quiescent_state() if the newly enqueued callback
* is the only one waiting for a grace period to complete.
*/
if (unlikely(rcu_segcblist_n_cbs(&rdp->cblist) >
@@ -2820,7 +2833,7 @@ static void __call_rcu_core(struct rcu_data *rdp, struct rcu_head *head,
rdp->blimit = LONG_MAX;
if (rcu_state.n_force_qs == rdp->n_force_qs_snap &&
rcu_segcblist_first_pend_cb(&rdp->cblist) != head)
- force_quiescent_state();
+ rcu_force_quiescent_state();
rdp->n_force_qs_snap = rcu_state.n_force_qs;
rdp->qlen_last_fqs_check = rcu_segcblist_n_cbs(&rdp->cblist);
}
@@ -2889,9 +2902,6 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func, int cpu, bool lazy)
rcu_segcblist_init(&rdp->cblist);
}
rcu_segcblist_enqueue(&rdp->cblist, head, lazy);
- if (!lazy)
- rcu_idle_count_callbacks_posted();
-
if (__is_kfree_rcu_offset((unsigned long)func))
trace_rcu_kfree_callback(rcu_state.name, head,
(unsigned long)func,
@@ -2961,6 +2971,79 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
}
EXPORT_SYMBOL_GPL(kfree_call_rcu);
+/*
+ * During early boot, any blocking grace-period wait automatically
+ * implies a grace period. Later on, this is never the case for PREEMPT.
+ *
+ * Howevr, because a context switch is a grace period for !PREEMPT, any
+ * blocking grace-period wait automatically implies a grace period if
+ * there is only one CPU online at any point time during execution of
+ * either synchronize_rcu() or synchronize_rcu_expedited(). It is OK to
+ * occasionally incorrectly indicate that there are multiple CPUs online
+ * when there was in fact only one the whole time, as this just adds some
+ * overhead: RCU still operates correctly.
+ */
+static int rcu_blocking_is_gp(void)
+{
+ int ret;
+
+ if (IS_ENABLED(CONFIG_PREEMPT))
+ return rcu_scheduler_active == RCU_SCHEDULER_INACTIVE;
+ might_sleep(); /* Check for RCU read-side critical section. */
+ preempt_disable();
+ ret = num_online_cpus() <= 1;
+ preempt_enable();
+ return ret;
+}
+
+/**
+ * synchronize_rcu - wait until a grace period has elapsed.
+ *
+ * Control will return to the caller some time after a full grace
+ * period has elapsed, in other words after all currently executing RCU
+ * read-side critical sections have completed. Note, however, that
+ * upon return from synchronize_rcu(), the caller might well be executing
+ * concurrently with new RCU read-side critical sections that began while
+ * synchronize_rcu() was waiting. RCU read-side critical sections are
+ * delimited by rcu_read_lock() and rcu_read_unlock(), and may be nested.
+ * In addition, regions of code across which interrupts, preemption, or
+ * softirqs have been disabled also serve as RCU read-side critical
+ * sections. This includes hardware interrupt handlers, softirq handlers,
+ * and NMI handlers.
+ *
+ * Note that this guarantee implies further memory-ordering guarantees.
+ * On systems with more than one CPU, when synchronize_rcu() returns,
+ * each CPU is guaranteed to have executed a full memory barrier since
+ * the end of its last RCU read-side critical section whose beginning
+ * preceded the call to synchronize_rcu(). In addition, each CPU having
+ * an RCU read-side critical section that extends beyond the return from
+ * synchronize_rcu() is guaranteed to have executed a full memory barrier
+ * after the beginning of synchronize_rcu() and before the beginning of
+ * that RCU read-side critical section. Note that these guarantees include
+ * CPUs that are offline, idle, or executing in user mode, as well as CPUs
+ * that are executing in the kernel.
+ *
+ * Furthermore, if CPU A invoked synchronize_rcu(), which returned
+ * to its caller on CPU B, then both CPU A and CPU B are guaranteed
+ * to have executed a full memory barrier during the execution of
+ * synchronize_rcu() -- even if CPU A and CPU B are the same CPU (but
+ * again only if the system has more than one CPU).
+ */
+void synchronize_rcu(void)
+{
+ RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+ lock_is_held(&rcu_lock_map) ||
+ lock_is_held(&rcu_sched_lock_map),
+ "Illegal synchronize_rcu() in RCU read-side critical section");
+ if (rcu_blocking_is_gp())
+ return;
+ if (rcu_gp_is_expedited())
+ synchronize_rcu_expedited();
+ else
+ wait_rcu_gp(call_rcu);
+}
+EXPORT_SYMBOL_GPL(synchronize_rcu);
+
/**
* get_state_synchronize_rcu - Snapshot current RCU state
*
@@ -3049,28 +3132,6 @@ static int rcu_pending(void)
}
/*
- * Return true if the specified CPU has any callback. If all_lazy is
- * non-NULL, store an indication of whether all callbacks are lazy.
- * (If there are no callbacks, all of them are deemed to be lazy.)
- */
-static bool rcu_cpu_has_callbacks(bool *all_lazy)
-{
- bool al = true;
- bool hc = false;
- struct rcu_data *rdp;
-
- rdp = this_cpu_ptr(&rcu_data);
- if (!rcu_segcblist_empty(&rdp->cblist)) {
- hc = true;
- if (rcu_segcblist_n_nonlazy_cbs(&rdp->cblist))
- al = false;
- }
- if (all_lazy)
- *all_lazy = al;
- return hc;
-}
-
-/*
* Helper function for rcu_barrier() tracing. If tracing is disabled,
* the compiler is expected to optimize this away.
*/
@@ -3299,7 +3360,7 @@ int rcutree_prepare_cpu(unsigned int cpu)
trace_rcu_grace_period(rcu_state.name, rdp->gp_seq, TPS("cpuonl"));
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
rcu_prepare_kthreads(cpu);
- rcu_spawn_all_nocb_kthreads(cpu);
+ rcu_spawn_cpu_nocb_kthread(cpu);
return 0;
}
@@ -3329,8 +3390,6 @@ int rcutree_online_cpu(unsigned int cpu)
raw_spin_lock_irqsave_rcu_node(rnp, flags);
rnp->ffmask |= rdp->grpmask;
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
- if (IS_ENABLED(CONFIG_TREE_SRCU))
- srcu_online_cpu(cpu);
if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
return 0; /* Too early in boot for scheduler work. */
sync_sched_exp_online_cleanup(cpu);
@@ -3355,8 +3414,6 @@ int rcutree_offline_cpu(unsigned int cpu)
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
rcutree_affinity_setting(cpu, cpu);
- if (IS_ENABLED(CONFIG_TREE_SRCU))
- srcu_offline_cpu(cpu);
return 0;
}
@@ -3777,7 +3834,7 @@ void __init rcu_init(void)
rcu_init_one();
if (dump_tree)
rcu_dump_rcu_node_tree();
- open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
+ open_softirq(RCU_SOFTIRQ, rcu_core);
/*
* We don't need protection against CPU-hotplug here because
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index d90b02b53c0e..bb4f995f2d3f 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -1,25 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Read-Copy Update mechanism for mutual exclusion (tree-based version)
* Internal non-public definitions.
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright IBM Corporation, 2008
*
* Author: Ingo Molnar <mingo@elte.hu>
- * Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+ * Paul E. McKenney <paulmck@linux.ibm.com>
*/
#include <linux/cache.h>
@@ -36,7 +23,6 @@
/* Communicate arguments to a workqueue handler. */
struct rcu_exp_work {
- smp_call_func_t rew_func;
unsigned long rew_s;
struct work_struct rew_work;
};
@@ -194,10 +180,7 @@ struct rcu_data {
bool rcu_need_heavy_qs; /* GP old, so heavy quiescent state! */
bool rcu_urgent_qs; /* GP old need light quiescent state. */
#ifdef CONFIG_RCU_FAST_NO_HZ
- bool all_lazy; /* Are all CPU's CBs lazy? */
- unsigned long nonlazy_posted; /* # times non-lazy CB posted to CPU. */
- unsigned long nonlazy_posted_snap;
- /* Nonlazy_posted snapshot. */
+ bool all_lazy; /* All CPU's CBs lazy at idle start? */
unsigned long last_accelerate; /* Last jiffy CBs were accelerated. */
unsigned long last_advance_all; /* Last jiffy CBs were all advanced. */
int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */
@@ -234,7 +217,13 @@ struct rcu_data {
/* Leader CPU takes GP-end wakeups. */
#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
- /* 6) Diagnostic data, including RCU CPU stall warnings. */
+ /* 6) RCU priority boosting. */
+ struct task_struct *rcu_cpu_kthread_task;
+ /* rcuc per-CPU kthread or NULL. */
+ unsigned int rcu_cpu_kthread_status;
+ char rcu_cpu_has_work;
+
+ /* 7) Diagnostic data, including RCU CPU stall warnings. */
unsigned int softirq_snap; /* Snapshot of softirq activity. */
/* ->rcu_iw* fields protected by leaf rcu_node ->lock. */
struct irq_work rcu_iw; /* Check for non-irq activity. */
@@ -303,6 +292,8 @@ struct rcu_state {
struct swait_queue_head gp_wq; /* Where GP task waits. */
short gp_flags; /* Commands for GP task. */
short gp_state; /* GP kthread sleep state. */
+ unsigned long gp_wake_time; /* Last GP kthread wake. */
+ unsigned long gp_wake_seq; /* ->gp_seq at ^^^. */
/* End of fields guarded by root rcu_node's lock. */
@@ -402,13 +393,6 @@ static const char *tp_rcu_varname __used __tracepoint_string = rcu_name;
int rcu_dynticks_snap(struct rcu_data *rdp);
-#ifdef CONFIG_RCU_BOOST
-DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
-DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu);
-DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
-DECLARE_PER_CPU(char, rcu_cpu_has_work);
-#endif /* #ifdef CONFIG_RCU_BOOST */
-
/* Forward declarations for rcutree_plugin.h */
static void rcu_bootup_announce(void);
static void rcu_qs(void);
@@ -420,7 +404,7 @@ static void rcu_print_detail_task_stall(void);
static int rcu_print_task_stall(struct rcu_node *rnp);
static int rcu_print_task_exp_stall(struct rcu_node *rnp);
static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp);
-static void rcu_flavor_check_callbacks(int user);
+static void rcu_flavor_sched_clock_irq(int user);
void call_rcu(struct rcu_head *head, rcu_callback_t func);
static void dump_blkd_tasks(struct rcu_node *rnp, int ncheck);
static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags);
@@ -431,7 +415,6 @@ static void __init rcu_spawn_boost_kthreads(void);
static void rcu_prepare_kthreads(int cpu);
static void rcu_cleanup_after_idle(void);
static void rcu_prepare_for_idle(void);
-static void rcu_idle_count_callbacks_posted(void);
static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
static bool rcu_preempt_need_deferred_qs(struct task_struct *t);
static void rcu_preempt_deferred_qs(struct task_struct *t);
@@ -451,7 +434,7 @@ static bool rcu_nocb_adopt_orphan_cbs(struct rcu_data *my_rdp,
static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp);
static void do_nocb_deferred_wakeup(struct rcu_data *rdp);
static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp);
-static void rcu_spawn_all_nocb_kthreads(int cpu);
+static void rcu_spawn_cpu_nocb_kthread(int cpu);
static void __init rcu_spawn_nocb_kthreads(void);
#ifdef CONFIG_RCU_NOCB_CPU
static void __init rcu_organize_nocb_kthreads(void);
@@ -462,11 +445,3 @@ static void rcu_bind_gp_kthread(void);
static bool rcu_nohz_full_cpu(void);
static void rcu_dynticks_task_enter(void);
static void rcu_dynticks_task_exit(void);
-
-#ifdef CONFIG_SRCU
-void srcu_online_cpu(unsigned int cpu);
-void srcu_offline_cpu(unsigned int cpu);
-#else /* #ifdef CONFIG_SRCU */
-void srcu_online_cpu(unsigned int cpu) { }
-void srcu_offline_cpu(unsigned int cpu) { }
-#endif /* #else #ifdef CONFIG_SRCU */
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 928fe5893a57..4c2a0189e748 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -1,27 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
/*
* RCU expedited grace periods
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright IBM Corporation, 2016
*
- * Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
*/
#include <linux/lockdep.h>
+static void rcu_exp_handler(void *unused);
+
/*
* Record the start of an expedited grace period.
*/
@@ -344,7 +333,6 @@ static void sync_rcu_exp_select_node_cpus(struct work_struct *wp)
{
int cpu;
unsigned long flags;
- smp_call_func_t func;
unsigned long mask_ofl_test;
unsigned long mask_ofl_ipi;
int ret;
@@ -352,7 +340,6 @@ static void sync_rcu_exp_select_node_cpus(struct work_struct *wp)
container_of(wp, struct rcu_exp_work, rew_work);
struct rcu_node *rnp = container_of(rewp, struct rcu_node, rew);
- func = rewp->rew_func;
raw_spin_lock_irqsave_rcu_node(rnp, flags);
/* Each pass checks a CPU for identity, offline, and idle. */
@@ -396,7 +383,7 @@ retry_ipi:
mask_ofl_test |= mask;
continue;
}
- ret = smp_call_function_single(cpu, func, NULL, 0);
+ ret = smp_call_function_single(cpu, rcu_exp_handler, NULL, 0);
if (!ret) {
mask_ofl_ipi &= ~mask;
continue;
@@ -426,7 +413,7 @@ retry_ipi:
* Select the nodes that the upcoming expedited grace period needs
* to wait for.
*/
-static void sync_rcu_exp_select_cpus(smp_call_func_t func)
+static void sync_rcu_exp_select_cpus(void)
{
int cpu;
struct rcu_node *rnp;
@@ -440,7 +427,6 @@ static void sync_rcu_exp_select_cpus(smp_call_func_t func)
rnp->exp_need_flush = false;
if (!READ_ONCE(rnp->expmask))
continue; /* Avoid early boot non-existent wq. */
- rnp->rew.rew_func = func;
if (!READ_ONCE(rcu_par_gp_wq) ||
rcu_scheduler_active != RCU_SCHEDULER_RUNNING ||
rcu_is_last_leaf_node(rnp)) {
@@ -449,7 +435,6 @@ static void sync_rcu_exp_select_cpus(smp_call_func_t func)
continue;
}
INIT_WORK(&rnp->rew.rew_work, sync_rcu_exp_select_node_cpus);
- preempt_disable();
cpu = find_next_bit(&rnp->ffmask, BITS_PER_LONG, -1);
/* If all offline, queue the work on an unbound CPU. */
if (unlikely(cpu > rnp->grphi - rnp->grplo))
@@ -457,7 +442,6 @@ static void sync_rcu_exp_select_cpus(smp_call_func_t func)
else
cpu += rnp->grplo;
queue_work_on(cpu, rcu_par_gp_wq, &rnp->rew.rew_work);
- preempt_enable();
rnp->exp_need_flush = true;
}
@@ -580,10 +564,10 @@ static void rcu_exp_wait_wake(unsigned long s)
* Common code to drive an expedited grace period forward, used by
* workqueues and mid-boot-time tasks.
*/
-static void rcu_exp_sel_wait_wake(smp_call_func_t func, unsigned long s)
+static void rcu_exp_sel_wait_wake(unsigned long s)
{
/* Initialize the rcu_node tree in preparation for the wait. */
- sync_rcu_exp_select_cpus(func);
+ sync_rcu_exp_select_cpus();
/* Wait and clean up, including waking everyone. */
rcu_exp_wait_wake(s);
@@ -597,52 +581,7 @@ static void wait_rcu_exp_gp(struct work_struct *wp)
struct rcu_exp_work *rewp;
rewp = container_of(wp, struct rcu_exp_work, rew_work);
- rcu_exp_sel_wait_wake(rewp->rew_func, rewp->rew_s);
-}
-
-/*
- * Given a smp_call_function() handler, kick off the specified
- * implementation of expedited grace period.
- */
-static void _synchronize_rcu_expedited(smp_call_func_t func)
-{
- struct rcu_data *rdp;
- struct rcu_exp_work rew;
- struct rcu_node *rnp;
- unsigned long s;
-
- /* If expedited grace periods are prohibited, fall back to normal. */
- if (rcu_gp_is_normal()) {
- wait_rcu_gp(call_rcu);
- return;
- }
-
- /* Take a snapshot of the sequence number. */
- s = rcu_exp_gp_seq_snap();
- if (exp_funnel_lock(s))
- return; /* Someone else did our work for us. */
-
- /* Ensure that load happens before action based on it. */
- if (unlikely(rcu_scheduler_active == RCU_SCHEDULER_INIT)) {
- /* Direct call during scheduler init and early_initcalls(). */
- rcu_exp_sel_wait_wake(func, s);
- } else {
- /* Marshall arguments & schedule the expedited grace period. */
- rew.rew_func = func;
- rew.rew_s = s;
- INIT_WORK_ONSTACK(&rew.rew_work, wait_rcu_exp_gp);
- queue_work(rcu_gp_wq, &rew.rew_work);
- }
-
- /* Wait for expedited grace period to complete. */
- rdp = per_cpu_ptr(&rcu_data, raw_smp_processor_id());
- rnp = rcu_get_root();
- wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3],
- sync_exp_work_done(s));
- smp_mb(); /* Workqueue actions happen before return. */
-
- /* Let the next expedited grace period start. */
- mutex_unlock(&rcu_state.exp_mutex);
+ rcu_exp_sel_wait_wake(rewp->rew_s);
}
#ifdef CONFIG_PREEMPT_RCU
@@ -654,7 +593,7 @@ static void _synchronize_rcu_expedited(smp_call_func_t func)
* ->expmask fields in the rcu_node tree. Otherwise, immediately
* report the quiescent state.
*/
-static void sync_rcu_exp_handler(void *unused)
+static void rcu_exp_handler(void *unused)
{
unsigned long flags;
struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
@@ -697,6 +636,7 @@ static void sync_rcu_exp_handler(void *unused)
WRITE_ONCE(t->rcu_read_unlock_special.b.exp_hint, true);
}
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+ return;
}
/*
@@ -730,43 +670,10 @@ static void sync_sched_exp_online_cleanup(int cpu)
{
}
-/**
- * synchronize_rcu_expedited - Brute-force RCU grace period
- *
- * Wait for an RCU-preempt grace period, but expedite it. The basic
- * idea is to IPI all non-idle non-nohz online CPUs. The IPI handler
- * checks whether the CPU is in an RCU-preempt critical section, and
- * if so, it sets a flag that causes the outermost rcu_read_unlock()
- * to report the quiescent state. On the other hand, if the CPU is
- * not in an RCU read-side critical section, the IPI handler reports
- * the quiescent state immediately.
- *
- * Although this is a greate improvement over previous expedited
- * implementations, it is still unfriendly to real-time workloads, so is
- * thus not recommended for any sort of common-case code. In fact, if
- * you are using synchronize_rcu_expedited() in a loop, please restructure
- * your code to batch your updates, and then Use a single synchronize_rcu()
- * instead.
- *
- * This has the same semantics as (but is more brutal than) synchronize_rcu().
- */
-void synchronize_rcu_expedited(void)
-{
- RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
- lock_is_held(&rcu_lock_map) ||
- lock_is_held(&rcu_sched_lock_map),
- "Illegal synchronize_rcu_expedited() in RCU read-side critical section");
-
- if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
- return;
- _synchronize_rcu_expedited(sync_rcu_exp_handler);
-}
-EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
-
#else /* #ifdef CONFIG_PREEMPT_RCU */
/* Invoked on each online non-idle CPU for expedited quiescent state. */
-static void sync_sched_exp_handler(void *unused)
+static void rcu_exp_handler(void *unused)
{
struct rcu_data *rdp;
struct rcu_node *rnp;
@@ -798,44 +705,78 @@ static void sync_sched_exp_online_cleanup(int cpu)
rnp = rdp->mynode;
if (!(READ_ONCE(rnp->expmask) & rdp->grpmask))
return;
- ret = smp_call_function_single(cpu, sync_sched_exp_handler, NULL, 0);
+ ret = smp_call_function_single(cpu, rcu_exp_handler, NULL, 0);
WARN_ON_ONCE(ret);
}
-/*
- * Because a context switch is a grace period for !PREEMPT, any
- * blocking grace-period wait automatically implies a grace period if
- * there is only one CPU online at any point time during execution of
- * either synchronize_rcu() or synchronize_rcu_expedited(). It is OK to
- * occasionally incorrectly indicate that there are multiple CPUs online
- * when there was in fact only one the whole time, as this just adds some
- * overhead: RCU still operates correctly.
- */
-static int rcu_blocking_is_gp(void)
-{
- int ret;
-
- might_sleep(); /* Check for RCU read-side critical section. */
- preempt_disable();
- ret = num_online_cpus() <= 1;
- preempt_enable();
- return ret;
-}
+#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
-/* PREEMPT=n implementation of synchronize_rcu_expedited(). */
+/**
+ * synchronize_rcu_expedited - Brute-force RCU grace period
+ *
+ * Wait for an RCU grace period, but expedite it. The basic idea is to
+ * IPI all non-idle non-nohz online CPUs. The IPI handler checks whether
+ * the CPU is in an RCU critical section, and if so, it sets a flag that
+ * causes the outermost rcu_read_unlock() to report the quiescent state
+ * for RCU-preempt or asks the scheduler for help for RCU-sched. On the
+ * other hand, if the CPU is not in an RCU read-side critical section,
+ * the IPI handler reports the quiescent state immediately.
+ *
+ * Although this is a greate improvement over previous expedited
+ * implementations, it is still unfriendly to real-time workloads, so is
+ * thus not recommended for any sort of common-case code. In fact, if
+ * you are using synchronize_rcu_expedited() in a loop, please restructure
+ * your code to batch your updates, and then Use a single synchronize_rcu()
+ * instead.
+ *
+ * This has the same semantics as (but is more brutal than) synchronize_rcu().
+ */
void synchronize_rcu_expedited(void)
{
+ struct rcu_data *rdp;
+ struct rcu_exp_work rew;
+ struct rcu_node *rnp;
+ unsigned long s;
+
RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
lock_is_held(&rcu_lock_map) ||
lock_is_held(&rcu_sched_lock_map),
"Illegal synchronize_rcu_expedited() in RCU read-side critical section");
- /* If only one CPU, this is automatically a grace period. */
+ /* Is the state is such that the call is a grace period? */
if (rcu_blocking_is_gp())
return;
- _synchronize_rcu_expedited(sync_sched_exp_handler);
+ /* If expedited grace periods are prohibited, fall back to normal. */
+ if (rcu_gp_is_normal()) {
+ wait_rcu_gp(call_rcu);
+ return;
+ }
+
+ /* Take a snapshot of the sequence number. */
+ s = rcu_exp_gp_seq_snap();
+ if (exp_funnel_lock(s))
+ return; /* Someone else did our work for us. */
+
+ /* Ensure that load happens before action based on it. */
+ if (unlikely(rcu_scheduler_active == RCU_SCHEDULER_INIT)) {
+ /* Direct call during scheduler init and early_initcalls(). */
+ rcu_exp_sel_wait_wake(s);
+ } else {
+ /* Marshall arguments & schedule the expedited grace period. */
+ rew.rew_s = s;
+ INIT_WORK_ONSTACK(&rew.rew_work, wait_rcu_exp_gp);
+ queue_work(rcu_gp_wq, &rew.rew_work);
+ }
+
+ /* Wait for expedited grace period to complete. */
+ rdp = per_cpu_ptr(&rcu_data, raw_smp_processor_id());
+ rnp = rcu_get_root();
+ wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3],
+ sync_exp_work_done(s));
+ smp_mb(); /* Workqueue actions happen before return. */
+
+ /* Let the next expedited grace period start. */
+ mutex_unlock(&rcu_state.exp_mutex);
}
EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
-
-#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 1b3dd2fc0cd6..97dba50f6fb2 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1,27 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Read-Copy Update mechanism for mutual exclusion (tree-based version)
* Internal non-public definitions that provide either classic
* or preemptible semantics.
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright Red Hat, 2009
* Copyright IBM Corporation, 2009
*
* Author: Ingo Molnar <mingo@elte.hu>
- * Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+ * Paul E. McKenney <paulmck@linux.ibm.com>
*/
#include <linux/delay.h>
@@ -34,17 +21,7 @@
#include "../time/tick-internal.h"
#ifdef CONFIG_RCU_BOOST
-
#include "../locking/rtmutex_common.h"
-
-/*
- * Control variables for per-CPU and per-rcu_node kthreads.
- */
-static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task);
-DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
-DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
-DEFINE_PER_CPU(char, rcu_cpu_has_work);
-
#else /* #ifdef CONFIG_RCU_BOOST */
/*
@@ -307,7 +284,7 @@ static void rcu_qs(void)
__this_cpu_read(rcu_data.gp_seq),
TPS("cpuqs"));
__this_cpu_write(rcu_data.cpu_no_qs.b.norm, false);
- barrier(); /* Coordinate with rcu_flavor_check_callbacks(). */
+ barrier(); /* Coordinate with rcu_flavor_sched_clock_irq(). */
current->rcu_read_unlock_special.b.need_qs = false;
}
}
@@ -788,13 +765,13 @@ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp)
}
/*
- * Check for a quiescent state from the current CPU. When a task blocks,
- * the task is recorded in the corresponding CPU's rcu_node structure,
- * which is checked elsewhere.
- *
- * Caller must disable hard irqs.
+ * Check for a quiescent state from the current CPU, including voluntary
+ * context switches for Tasks RCU. When a task blocks, the task is
+ * recorded in the corresponding CPU's rcu_node structure, which is checked
+ * elsewhere, hence this function need only check for quiescent states
+ * related to the current CPU, not to those related to tasks.
*/
-static void rcu_flavor_check_callbacks(int user)
+static void rcu_flavor_sched_clock_irq(int user)
{
struct task_struct *t = current;
@@ -825,54 +802,6 @@ static void rcu_flavor_check_callbacks(int user)
t->rcu_read_unlock_special.b.need_qs = true;
}
-/**
- * synchronize_rcu - wait until a grace period has elapsed.
- *
- * Control will return to the caller some time after a full grace
- * period has elapsed, in other words after all currently executing RCU
- * read-side critical sections have completed. Note, however, that
- * upon return from synchronize_rcu(), the caller might well be executing
- * concurrently with new RCU read-side critical sections that began while
- * synchronize_rcu() was waiting. RCU read-side critical sections are
- * delimited by rcu_read_lock() and rcu_read_unlock(), and may be nested.
- * In addition, regions of code across which interrupts, preemption, or
- * softirqs have been disabled also serve as RCU read-side critical
- * sections. This includes hardware interrupt handlers, softirq handlers,
- * and NMI handlers.
- *
- * Note that this guarantee implies further memory-ordering guarantees.
- * On systems with more than one CPU, when synchronize_rcu() returns,
- * each CPU is guaranteed to have executed a full memory barrier since
- * the end of its last RCU read-side critical section whose beginning
- * preceded the call to synchronize_rcu(). In addition, each CPU having
- * an RCU read-side critical section that extends beyond the return from
- * synchronize_rcu() is guaranteed to have executed a full memory barrier
- * after the beginning of synchronize_rcu() and before the beginning of
- * that RCU read-side critical section. Note that these guarantees include
- * CPUs that are offline, idle, or executing in user mode, as well as CPUs
- * that are executing in the kernel.
- *
- * Furthermore, if CPU A invoked synchronize_rcu(), which returned
- * to its caller on CPU B, then both CPU A and CPU B are guaranteed
- * to have executed a full memory barrier during the execution of
- * synchronize_rcu() -- even if CPU A and CPU B are the same CPU (but
- * again only if the system has more than one CPU).
- */
-void synchronize_rcu(void)
-{
- RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
- lock_is_held(&rcu_lock_map) ||
- lock_is_held(&rcu_sched_lock_map),
- "Illegal synchronize_rcu() in RCU read-side critical section");
- if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
- return;
- if (rcu_gp_is_expedited())
- synchronize_rcu_expedited();
- else
- wait_rcu_gp(call_rcu);
-}
-EXPORT_SYMBOL_GPL(synchronize_rcu);
-
/*
* Check for a task exiting while in a preemptible-RCU read-side
* critical section, clean up if so. No need to issue warnings,
@@ -1088,14 +1017,10 @@ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp)
}
/*
- * Check to see if this CPU is in a non-context-switch quiescent state
- * (user mode or idle loop for rcu, non-softirq execution for rcu_bh).
- * Also schedule RCU core processing.
- *
- * This function must be called from hardirq context. It is normally
- * invoked from the scheduling-clock interrupt.
+ * Check to see if this CPU is in a non-context-switch quiescent state,
+ * namely user mode and idle loop.
*/
-static void rcu_flavor_check_callbacks(int user)
+static void rcu_flavor_sched_clock_irq(int user)
{
if (user || rcu_is_cpu_rrupt_from_idle()) {
@@ -1115,22 +1040,6 @@ static void rcu_flavor_check_callbacks(int user)
}
}
-/* PREEMPT=n implementation of synchronize_rcu(). */
-void synchronize_rcu(void)
-{
- RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
- lock_is_held(&rcu_lock_map) ||
- lock_is_held(&rcu_sched_lock_map),
- "Illegal synchronize_rcu() in RCU read-side critical section");
- if (rcu_blocking_is_gp())
- return;
- if (rcu_gp_is_expedited())
- synchronize_rcu_expedited();
- else
- wait_rcu_gp(call_rcu);
-}
-EXPORT_SYMBOL_GPL(synchronize_rcu);
-
/*
* Because preemptible RCU does not exist, tasks cannot possibly exit
* while in preemptible RCU read-side critical sections.
@@ -1307,11 +1216,11 @@ static void invoke_rcu_callbacks_kthread(void)
unsigned long flags;
local_irq_save(flags);
- __this_cpu_write(rcu_cpu_has_work, 1);
- if (__this_cpu_read(rcu_cpu_kthread_task) != NULL &&
- current != __this_cpu_read(rcu_cpu_kthread_task)) {
- rcu_wake_cond(__this_cpu_read(rcu_cpu_kthread_task),
- __this_cpu_read(rcu_cpu_kthread_status));
+ __this_cpu_write(rcu_data.rcu_cpu_has_work, 1);
+ if (__this_cpu_read(rcu_data.rcu_cpu_kthread_task) != NULL &&
+ current != __this_cpu_read(rcu_data.rcu_cpu_kthread_task)) {
+ rcu_wake_cond(__this_cpu_read(rcu_data.rcu_cpu_kthread_task),
+ __this_cpu_read(rcu_data.rcu_cpu_kthread_status));
}
local_irq_restore(flags);
}
@@ -1322,7 +1231,7 @@ static void invoke_rcu_callbacks_kthread(void)
*/
static bool rcu_is_callbacks_kthread(void)
{
- return __this_cpu_read(rcu_cpu_kthread_task) == current;
+ return __this_cpu_read(rcu_data.rcu_cpu_kthread_task) == current;
}
#define RCU_BOOST_DELAY_JIFFIES DIV_ROUND_UP(CONFIG_RCU_BOOST_DELAY * HZ, 1000)
@@ -1369,11 +1278,6 @@ static int rcu_spawn_one_boost_kthread(struct rcu_node *rnp)
return 0;
}
-static void rcu_kthread_do_work(void)
-{
- rcu_do_batch(this_cpu_ptr(&rcu_data));
-}
-
static void rcu_cpu_kthread_setup(unsigned int cpu)
{
struct sched_param sp;
@@ -1384,12 +1288,12 @@ static void rcu_cpu_kthread_setup(unsigned int cpu)
static void rcu_cpu_kthread_park(unsigned int cpu)
{
- per_cpu(rcu_cpu_kthread_status, cpu) = RCU_KTHREAD_OFFCPU;
+ per_cpu(rcu_data.rcu_cpu_kthread_status, cpu) = RCU_KTHREAD_OFFCPU;
}
static int rcu_cpu_kthread_should_run(unsigned int cpu)
{
- return __this_cpu_read(rcu_cpu_has_work);
+ return __this_cpu_read(rcu_data.rcu_cpu_has_work);
}
/*
@@ -1399,21 +1303,20 @@ static int rcu_cpu_kthread_should_run(unsigned int cpu)
*/
static void rcu_cpu_kthread(unsigned int cpu)
{
- unsigned int *statusp = this_cpu_ptr(&rcu_cpu_kthread_status);
- char work, *workp = this_cpu_ptr(&rcu_cpu_has_work);
+ unsigned int *statusp = this_cpu_ptr(&rcu_data.rcu_cpu_kthread_status);
+ char work, *workp = this_cpu_ptr(&rcu_data.rcu_cpu_has_work);
int spincnt;
for (spincnt = 0; spincnt < 10; spincnt++) {
trace_rcu_utilization(TPS("Start CPU kthread@rcu_wait"));
local_bh_disable();
*statusp = RCU_KTHREAD_RUNNING;
- this_cpu_inc(rcu_cpu_kthread_loops);
local_irq_disable();
work = *workp;
*workp = 0;
local_irq_enable();
if (work)
- rcu_kthread_do_work();
+ rcu_do_batch(this_cpu_ptr(&rcu_data));
local_bh_enable();
if (*workp == 0) {
trace_rcu_utilization(TPS("End CPU kthread@rcu_wait"));
@@ -1459,7 +1362,7 @@ static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu)
}
static struct smp_hotplug_thread rcu_cpu_thread_spec = {
- .store = &rcu_cpu_kthread_task,
+ .store = &rcu_data.rcu_cpu_kthread_task,
.thread_should_run = rcu_cpu_kthread_should_run,
.thread_fn = rcu_cpu_kthread,
.thread_comm = "rcuc/%u",
@@ -1476,7 +1379,7 @@ static void __init rcu_spawn_boost_kthreads(void)
int cpu;
for_each_possible_cpu(cpu)
- per_cpu(rcu_cpu_has_work, cpu) = 0;
+ per_cpu(rcu_data.rcu_cpu_has_work, cpu) = 0;
if (WARN_ONCE(smpboot_register_percpu_thread(&rcu_cpu_thread_spec), "%s: Could not start rcub kthread, OOM is now expected behavior\n", __func__))
return;
rcu_for_each_leaf_node(rnp)
@@ -1543,7 +1446,7 @@ static void rcu_prepare_kthreads(int cpu)
int rcu_needs_cpu(u64 basemono, u64 *nextevt)
{
*nextevt = KTIME_MAX;
- return rcu_cpu_has_callbacks(NULL);
+ return !rcu_segcblist_empty(&this_cpu_ptr(&rcu_data)->cblist);
}
/*
@@ -1562,14 +1465,6 @@ static void rcu_prepare_for_idle(void)
{
}
-/*
- * Don't bother keeping a running count of the number of RCU callbacks
- * posted because CONFIG_RCU_FAST_NO_HZ=n.
- */
-static void rcu_idle_count_callbacks_posted(void)
-{
-}
-
#else /* #if !defined(CONFIG_RCU_FAST_NO_HZ) */
/*
@@ -1652,11 +1547,8 @@ int rcu_needs_cpu(u64 basemono, u64 *nextevt)
lockdep_assert_irqs_disabled();
- /* Snapshot to detect later posting of non-lazy callback. */
- rdp->nonlazy_posted_snap = rdp->nonlazy_posted;
-
/* If no callbacks, RCU doesn't need the CPU. */
- if (!rcu_cpu_has_callbacks(&rdp->all_lazy)) {
+ if (rcu_segcblist_empty(&rdp->cblist)) {
*nextevt = KTIME_MAX;
return 0;
}
@@ -1670,11 +1562,12 @@ int rcu_needs_cpu(u64 basemono, u64 *nextevt)
rdp->last_accelerate = jiffies;
/* Request timer delay depending on laziness, and round. */
- if (!rdp->all_lazy) {
+ rdp->all_lazy = !rcu_segcblist_n_nonlazy_cbs(&rdp->cblist);
+ if (rdp->all_lazy) {
+ dj = round_jiffies(rcu_idle_lazy_gp_delay + jiffies) - jiffies;
+ } else {
dj = round_up(rcu_idle_gp_delay + jiffies,
rcu_idle_gp_delay) - jiffies;
- } else {
- dj = round_jiffies(rcu_idle_lazy_gp_delay + jiffies) - jiffies;
}
*nextevt = basemono + dj * TICK_NSEC;
return 0;
@@ -1704,7 +1597,7 @@ static void rcu_prepare_for_idle(void)
/* Handle nohz enablement switches conservatively. */
tne = READ_ONCE(tick_nohz_active);
if (tne != rdp->tick_nohz_enabled_snap) {
- if (rcu_cpu_has_callbacks(NULL))
+ if (!rcu_segcblist_empty(&rdp->cblist))
invoke_rcu_core(); /* force nohz to see update. */
rdp->tick_nohz_enabled_snap = tne;
return;
@@ -1717,10 +1610,8 @@ static void rcu_prepare_for_idle(void)
* callbacks, invoke RCU core for the side-effect of recalculating
* idle duration on re-entry to idle.
*/
- if (rdp->all_lazy &&
- rdp->nonlazy_posted != rdp->nonlazy_posted_snap) {
+ if (rdp->all_lazy && rcu_segcblist_n_nonlazy_cbs(&rdp->cblist)) {
rdp->all_lazy = false;
- rdp->nonlazy_posted_snap = rdp->nonlazy_posted;
invoke_rcu_core();
return;
}
@@ -1756,19 +1647,6 @@ static void rcu_cleanup_after_idle(void)
invoke_rcu_core();
}
-/*
- * Keep a running count of the number of non-lazy callbacks posted
- * on this CPU. This running counter (which is never decremented) allows
- * rcu_prepare_for_idle() to detect when something out of the idle loop
- * posts a callback, even if an equal number of callbacks are invoked.
- * Of course, callbacks should only be posted from within a trace event
- * designed to be called from idle or from within RCU_NONIDLE().
- */
-static void rcu_idle_count_callbacks_posted(void)
-{
- __this_cpu_add(rcu_data.nonlazy_posted, 1);
-}
-
#endif /* #else #if !defined(CONFIG_RCU_FAST_NO_HZ) */
#ifdef CONFIG_RCU_FAST_NO_HZ
@@ -1776,13 +1654,12 @@ static void rcu_idle_count_callbacks_posted(void)
static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
{
struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
- unsigned long nlpd = rdp->nonlazy_posted - rdp->nonlazy_posted_snap;
- sprintf(cp, "last_accelerate: %04lx/%04lx, nonlazy_posted: %ld, %c%c",
+ sprintf(cp, "last_accelerate: %04lx/%04lx, Nonlazy posted: %c%c%c",
rdp->last_accelerate & 0xffff, jiffies & 0xffff,
- ulong2long(nlpd),
- rdp->all_lazy ? 'L' : '.',
- rdp->tick_nohz_enabled_snap ? '.' : 'D');
+ ".l"[rdp->all_lazy],
+ ".L"[!rcu_segcblist_n_nonlazy_cbs(&rdp->cblist)],
+ ".D"[!rdp->tick_nohz_enabled_snap]);
}
#else /* #ifdef CONFIG_RCU_FAST_NO_HZ */
@@ -1868,22 +1745,24 @@ static void zero_cpu_stall_ticks(struct rcu_data *rdp)
/*
* Offload callback processing from the boot-time-specified set of CPUs
- * specified by rcu_nocb_mask. For each CPU in the set, there is a
- * kthread created that pulls the callbacks from the corresponding CPU,
- * waits for a grace period to elapse, and invokes the callbacks.
- * The no-CBs CPUs do a wake_up() on their kthread when they insert
- * a callback into any empty list, unless the rcu_nocb_poll boot parameter
- * has been specified, in which case each kthread actively polls its
- * CPU. (Which isn't so great for energy efficiency, but which does
- * reduce RCU's overhead on that CPU.)
+ * specified by rcu_nocb_mask. For the CPUs in the set, there are kthreads
+ * created that pull the callbacks from the corresponding CPU, wait for
+ * a grace period to elapse, and invoke the callbacks. These kthreads
+ * are organized into leaders, which manage incoming callbacks, wait for
+ * grace periods, and awaken followers, and the followers, which only
+ * invoke callbacks. Each leader is its own follower. The no-CBs CPUs
+ * do a wake_up() on their kthread when they insert a callback into any
+ * empty list, unless the rcu_nocb_poll boot parameter has been specified,
+ * in which case each kthread actively polls its CPU. (Which isn't so great
+ * for energy efficiency, but which does reduce RCU's overhead on that CPU.)
*
* This is intended to be used in conjunction with Frederic Weisbecker's
* adaptive-idle work, which would seriously reduce OS jitter on CPUs
* running CPU-bound user-mode computations.
*
- * Offloading of callback processing could also in theory be used as
- * an energy-efficiency measure because CPUs with no RCU callbacks
- * queued are more aggressive about entering dyntick-idle mode.
+ * Offloading of callbacks can also be used as an energy-efficiency
+ * measure because CPUs with no RCU callbacks queued are more aggressive
+ * about entering dyntick-idle mode.
*/
@@ -1987,10 +1866,7 @@ static void wake_nocb_leader_defer(struct rcu_data *rdp, int waketype,
raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags);
}
-/*
- * Does the specified CPU need an RCU callback for this invocation
- * of rcu_barrier()?
- */
+/* Does rcu_barrier need to queue an RCU callback on the specified CPU? */
static bool rcu_nocb_cpu_needs_barrier(int cpu)
{
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
@@ -2006,8 +1882,8 @@ static bool rcu_nocb_cpu_needs_barrier(int cpu)
* callbacks would be posted. In the worst case, the first
* barrier in rcu_barrier() suffices (but the caller cannot
* necessarily rely on this, not a substitute for the caller
- * getting the concurrency design right!). There must also be
- * a barrier between the following load an posting of a callback
+ * getting the concurrency design right!). There must also be a
+ * barrier between the following load and posting of a callback
* (if a callback is in fact needed). This is associated with an
* atomic_inc() in the caller.
*/
@@ -2517,9 +2393,9 @@ static void rcu_spawn_one_nocb_kthread(int cpu)
/*
* If the specified CPU is a no-CBs CPU that does not already have its
- * rcuo kthreads, spawn them.
+ * rcuo kthread, spawn it.
*/
-static void rcu_spawn_all_nocb_kthreads(int cpu)
+static void rcu_spawn_cpu_nocb_kthread(int cpu)
{
if (rcu_scheduler_fully_active)
rcu_spawn_one_nocb_kthread(cpu);
@@ -2536,7 +2412,7 @@ static void __init rcu_spawn_nocb_kthreads(void)
int cpu;
for_each_online_cpu(cpu)
- rcu_spawn_all_nocb_kthreads(cpu);
+ rcu_spawn_cpu_nocb_kthread(cpu);
}
/* How many follower CPU IDs per leader? Default of -1 for sqrt(nr_cpu_ids). */
@@ -2670,7 +2546,7 @@ static void do_nocb_deferred_wakeup(struct rcu_data *rdp)
{
}
-static void rcu_spawn_all_nocb_kthreads(int cpu)
+static void rcu_spawn_cpu_nocb_kthread(int cpu)
{
}
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 1971869c4072..e3c6395c9b4c 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -1,26 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0+
/*
* Read-Copy Update mechanism for mutual exclusion
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright IBM Corporation, 2001
*
* Authors: Dipankar Sarma <dipankar@in.ibm.com>
* Manfred Spraul <manfred@colorfullife.com>
*
- * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
+ * Based on the original work by Paul McKenney <paulmck@linux.ibm.com>
* and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
* Papers:
* http://www.rdrop.com/users/paulmck/paper/rclockpdcsproof.pdf
diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c
index 22bd8980f32f..835671f0f917 100644
--- a/kernel/sched/cpufreq.c
+++ b/kernel/sched/cpufreq.c
@@ -48,8 +48,8 @@ EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook);
*
* Clear the update_util_data pointer for the given CPU.
*
- * Callers must use RCU-sched callbacks to free any memory that might be
- * accessed via the old update_util_data pointer or invoke synchronize_sched()
+ * Callers must use RCU callbacks to free any memory that might be
+ * accessed via the old update_util_data pointer or invoke synchronize_rcu()
* right after this function to avoid use-after-free.
*/
void cpufreq_remove_update_util_hook(int cpu)
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 033ec7c45f13..2efe629425be 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -859,7 +859,7 @@ static void sugov_stop(struct cpufreq_policy *policy)
for_each_cpu(cpu, policy->cpus)
cpufreq_remove_update_util_hook(cpu);
- synchronize_sched();
+ synchronize_rcu();
if (!policy->fast_switch_enabled) {
irq_work_sync(&sg_policy->irq_work);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index d04530bf251f..6665b9c02e2f 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1260,7 +1260,7 @@ extern void sched_ttwu_pending(void);
/*
* The domain tree (rq->sd) is protected by RCU's quiescent state transition.
- * See detach_destroy_domains: synchronize_sched for details.
+ * See destroy_sched_domains: call_rcu for details.
*
* The domain tree of any CPU may only be accessed from within
* preempt-disabled sections.
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 3f35ba1d8fde..7d905f55e7fa 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -442,7 +442,7 @@ void rq_attach_root(struct rq *rq, struct root_domain *rd)
raw_spin_unlock_irqrestore(&rq->lock, flags);
if (old_rd)
- call_rcu_sched(&old_rd->rcu, free_rootdomain);
+ call_rcu(&old_rd->rcu, free_rootdomain);
}
void sched_get_rd(struct root_domain *rd)
@@ -455,7 +455,7 @@ void sched_put_rd(struct root_domain *rd)
if (!atomic_dec_and_test(&rd->refcount))
return;
- call_rcu_sched(&rd->rcu, free_rootdomain);
+ call_rcu(&rd->rcu, free_rootdomain);
}
static int init_rootdomain(struct root_domain *rd)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 167e71f9ed3c..2fce056f8a49 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1632,7 +1632,7 @@ void update_process_times(int user_tick)
/* Note: this timer irq context must be accounted for as well. */
account_process_tick(p, user_tick);
run_local_timers();
- rcu_check_callbacks(user_tick);
+ rcu_sched_clock_irq(user_tick);
#ifdef CONFIG_IRQ_WORK
if (in_irq())
irq_work_tick();
diff --git a/kernel/torture.c b/kernel/torture.c
index bbf6d473e50c..8faa1a9aaeb9 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -1,23 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0+
/*
* Common functions for in-kernel torture tests.
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright (C) IBM Corporation, 2014
*
- * Author: Paul E. McKenney <paulmck@us.ibm.com>
+ * Author: Paul E. McKenney <paulmck@linux.ibm.com>
* Based on kernel/rcu/torture.c.
*/
@@ -53,7 +40,7 @@
#include "rcu/rcu.h"
MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
static char *torture_type;
static int verbose;
@@ -75,6 +62,7 @@ static DEFINE_MUTEX(fullstop_mutex);
static struct task_struct *onoff_task;
static long onoff_holdoff;
static long onoff_interval;
+static torture_ofl_func *onoff_f;
static long n_offline_attempts;
static long n_offline_successes;
static unsigned long sum_offline;
@@ -118,6 +106,8 @@ bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
pr_alert("%s" TORTURE_FLAG
"torture_onoff task: offlined %d\n",
torture_type, cpu);
+ if (onoff_f)
+ onoff_f();
(*n_offl_successes)++;
delta = jiffies - starttime;
*sum_offl += delta;
@@ -243,11 +233,12 @@ stop:
/*
* Initiate online-offline handling.
*/
-int torture_onoff_init(long ooholdoff, long oointerval)
+int torture_onoff_init(long ooholdoff, long oointerval, torture_ofl_func *f)
{
#ifdef CONFIG_HOTPLUG_CPU
onoff_holdoff = ooholdoff;
onoff_interval = oointerval;
+ onoff_f = f;
if (onoff_interval <= 0)
return 0;
return torture_create_kthread(torture_onoff, NULL, onoff_task);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-12 07:31:22 +0000