From 3660c2813fb6d0ba48ee44bcbf9feddf7218c11d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 3 Dec 2013 09:24:02 -0800 Subject: rcu: Add ACCESS_ONCE() to ->n_force_qs_lh accesses The ->n_force_qs_lh field is accessed without the benefit of any synchronization, so this commit adds the needed ACCESS_ONCE() wrappers. Yes, increments to ->n_force_qs_lh can be lost, but contention should be low and the field is strictly statistical in nature, so this is not a problem. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcu/tree.c | 4 ++-- kernel/rcu/tree_trace.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index b3d116cd072d..e64157798624 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2304,7 +2304,7 @@ static void force_quiescent_state(struct rcu_state *rsp) if (rnp_old != NULL) raw_spin_unlock(&rnp_old->fqslock); if (ret) { - rsp->n_force_qs_lh++; + ACCESS_ONCE(rsp->n_force_qs_lh)++; return; } rnp_old = rnp; @@ -2316,7 +2316,7 @@ static void force_quiescent_state(struct rcu_state *rsp) smp_mb__after_unlock_lock(); raw_spin_unlock(&rnp_old->fqslock); if (ACCESS_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) { - rsp->n_force_qs_lh++; + ACCESS_ONCE(rsp->n_force_qs_lh)++; raw_spin_unlock_irqrestore(&rnp_old->lock, flags); return; /* Someone beat us to it. */ } diff --git a/kernel/rcu/tree_trace.c b/kernel/rcu/tree_trace.c index 4def475336d4..d1f1e64a6d72 100644 --- a/kernel/rcu/tree_trace.c +++ b/kernel/rcu/tree_trace.c @@ -273,7 +273,7 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n", rsp->n_force_qs, rsp->n_force_qs_ngp, rsp->n_force_qs - rsp->n_force_qs_ngp, - rsp->n_force_qs_lh, rsp->qlen_lazy, rsp->qlen); + ACCESS_ONCE(rsp->n_force_qs_lh), rsp->qlen_lazy, rsp->qlen); for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) { if (rnp->level != level) { seq_puts(m, "\n"); -- cgit v1.2.2 From 87de1cfdc55b16b794e245b07322340725149d62 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 3 Dec 2013 10:02:52 -0800 Subject: rcu: Stop tracking FSF's postal address All of the RCU source files have the usual GPL header, which contains a long-obsolete postal address for FSF. To avoid the need to track the FSF office's movements, this commit substitutes the URL where GPL may be found. Reported-by: Greg KH Reported-by: Steven Rostedt Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcu/rcu.h | 4 ++-- kernel/rcu/srcu.c | 4 ++-- kernel/rcu/tiny.c | 4 ++-- kernel/rcu/tiny_plugin.h | 4 ++-- kernel/rcu/torture.c | 4 ++-- kernel/rcu/tree.c | 4 ++-- kernel/rcu/tree.h | 4 ++-- kernel/rcu/tree_plugin.h | 4 ++-- kernel/rcu/tree_trace.c | 4 ++-- kernel/rcu/update.c | 4 ++-- 10 files changed, 20 insertions(+), 20 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 79c3877e9c5b..1bd787fddcb2 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -12,8 +12,8 @@ * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * 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 * diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c index 3318d8284384..5db7e9272d37 100644 --- a/kernel/rcu/srcu.c +++ b/kernel/rcu/srcu.c @@ -12,8 +12,8 @@ * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * 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 diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c index 1254f312d024..53b95bbf4abb 100644 --- a/kernel/rcu/tiny.c +++ b/kernel/rcu/tiny.c @@ -12,8 +12,8 @@ * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * 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 * diff --git a/kernel/rcu/tiny_plugin.h b/kernel/rcu/tiny_plugin.h index 280d06cae352..431528520562 100644 --- a/kernel/rcu/tiny_plugin.h +++ b/kernel/rcu/tiny_plugin.h @@ -14,8 +14,8 @@ * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * along with this program; if not, you can access it online at + * http://www.gnu.org/licenses/gpl-2.0.html. * * Copyright (c) 2010 Linaro * diff --git a/kernel/rcu/torture.c b/kernel/rcu/torture.c index 732f8ae3086a..ab7dd192a50b 100644 --- a/kernel/rcu/torture.c +++ b/kernel/rcu/torture.c @@ -12,8 +12,8 @@ * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * 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 * diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index e64157798624..321feef0f5c0 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -12,8 +12,8 @@ * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * 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 * diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 8c19873f1ac9..75dc3c39a02a 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -13,8 +13,8 @@ * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * 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 * diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 6e2ef4b2b920..f9b9cdd36c8d 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -14,8 +14,8 @@ * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * 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 diff --git a/kernel/rcu/tree_trace.c b/kernel/rcu/tree_trace.c index d1f1e64a6d72..5cdc62e1beeb 100644 --- a/kernel/rcu/tree_trace.c +++ b/kernel/rcu/tree_trace.c @@ -12,8 +12,8 @@ * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * 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 * diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index c54609faf233..fd0d5b5b8e7c 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -12,8 +12,8 @@ * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * 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 * -- cgit v1.2.2 From cb1e78cfa267453bb19e7edafd214c03834b664c Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 4 Dec 2013 18:42:03 -0800 Subject: rcu: Remove ACCESS_ONCE() from jiffies Because jiffies is one of a very few variables marked "volatile", there is no need to use ACCESS_ONCE() when accessing it. This commit therefore removes the redundant ACCESS_ONCE() wrappers. Reported by: Eric Dumazet Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcu/torture.c | 4 ++-- kernel/rcu/tree.c | 6 +++--- 2 files changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/torture.c b/kernel/rcu/torture.c index ab7dd192a50b..022c5312b725 100644 --- a/kernel/rcu/torture.c +++ b/kernel/rcu/torture.c @@ -1352,7 +1352,7 @@ rcu_torture_shutdown(void *arg) unsigned long jiffies_snap; VERBOSE_PRINTK_STRING("rcu_torture_shutdown task started"); - jiffies_snap = ACCESS_ONCE(jiffies); + jiffies_snap = jiffies; while (ULONG_CMP_LT(jiffies_snap, shutdown_time) && !kthread_should_stop()) { delta = shutdown_time - jiffies_snap; @@ -1361,7 +1361,7 @@ rcu_torture_shutdown(void *arg) "rcu_torture_shutdown task: %lu jiffies remaining\n", torture_type, delta); schedule_timeout_interruptible(delta); - jiffies_snap = ACCESS_ONCE(jiffies); + jiffies_snap = jiffies; } if (kthread_should_stop()) { VERBOSE_PRINTK_STRING("rcu_torture_shutdown task stopping"); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 321feef0f5c0..73c3cd2b87ac 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -837,7 +837,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp, * to the next. Only do this for the primary flavor of RCU. */ if (rdp->rsp == rcu_state && - ULONG_CMP_GE(ACCESS_ONCE(jiffies), rdp->rsp->jiffies_resched)) { + ULONG_CMP_GE(jiffies, rdp->rsp->jiffies_resched)) { rdp->rsp->jiffies_resched += 5; resched_cpu(rdp->cpu); } @@ -847,7 +847,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp, static void record_gp_stall_check_time(struct rcu_state *rsp) { - unsigned long j = ACCESS_ONCE(jiffies); + unsigned long j = jiffies; unsigned long j1; rsp->gp_start = j; @@ -1005,7 +1005,7 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) if (rcu_cpu_stall_suppress || !rcu_gp_in_progress(rsp)) return; - j = ACCESS_ONCE(jiffies); + j = jiffies; /* * Lots of memory barriers to reject false positives. -- cgit v1.2.2 From 52e2bb958ac4f9b3c4bdd78606d279852fd72922 Mon Sep 17 00:00:00 2001 From: Paul Bolle Date: Sun, 9 Feb 2014 14:35:11 +0100 Subject: rcu: Disambiguate CONFIG_RCU_NOCB_CPUs This commit fixes a grammar issue in the rcu_nohz_full_cpu() comment header, so that it is clear that the plural is CPUs not Kconfig options. Signed-off-by: Paul Bolle Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcu/tree_plugin.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index f9b9cdd36c8d..fffe4178a23d 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2893,7 +2893,7 @@ static void rcu_sysidle_init_percpu_data(struct rcu_dynticks *rdtp) * CPU unless the grace period has extended for too long. * * This code relies on the fact that all NO_HZ_FULL CPUs are also - * CONFIG_RCU_NOCB_CPUs. + * CONFIG_RCU_NOCB_CPU CPUs. */ static bool rcu_nohz_full_cpu(struct rcu_state *rsp) { -- cgit v1.2.2 From ae1670339c95c3ff96ab10582506cf827c5fecc8 Mon Sep 17 00:00:00 2001 From: Shaibal Dutta Date: Fri, 31 Jan 2014 11:53:06 -0800 Subject: rcu: Move SRCU grace period work to power efficient workqueue For better use of CPU idle time, allow the scheduler to select the CPU on which the SRCU grace period work would be scheduled. This improves idle residency time and conserves power. This functionality is enabled when CONFIG_WQ_POWER_EFFICIENT is selected. Cc: Lai Jiangshan Cc: "Paul E. McKenney" Cc: Dipankar Sarma Signed-off-by: Shaibal Dutta [zoran.markovic@linaro.org: Rebased to latest kernel version. Added commit message. Fixed code alignment.] Signed-off-by: Zoran Markovic Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcu/srcu.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c index 5db7e9272d37..2359779e1daa 100644 --- a/kernel/rcu/srcu.c +++ b/kernel/rcu/srcu.c @@ -398,7 +398,7 @@ void call_srcu(struct srcu_struct *sp, struct rcu_head *head, rcu_batch_queue(&sp->batch_queue, head); if (!sp->running) { sp->running = true; - schedule_delayed_work(&sp->work, 0); + queue_delayed_work(system_power_efficient_wq, &sp->work, 0); } spin_unlock_irqrestore(&sp->queue_lock, flags); } @@ -674,7 +674,8 @@ static void srcu_reschedule(struct srcu_struct *sp) } if (pending) - schedule_delayed_work(&sp->work, SRCU_INTERVAL); + queue_delayed_work(system_power_efficient_wq, + &sp->work, SRCU_INTERVAL); } /* -- cgit v1.2.2 From 2f33b512a5460578f6cf11d7b7867bed53157c7c Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 17 Nov 2013 18:25:48 -0800 Subject: rcu: Optimize rcu_is_nocb_cpu() for RCU_NOCB_CPU_ALL If CONFIG_RCU_NOCB_CPU_ALL=y, then rcu_is_nocb_cpu() will always return true, however, the current version nevertheless checks rcu_nocb_mask. This commit therefore creates a static inline implementation of rcu_is_nocb_cpu() that unconditionally returns true when CONFIG_RCU_NOCB_CPU_ALL=y. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcu/tree_plugin.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 6e2ef4b2b920..39a50b918bff 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2101,6 +2101,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp) init_waitqueue_head(&rnp->nocb_gp_wq[1]); } +#ifndef CONFIG_RCU_NOCB_CPU_ALL /* Is the specified CPU a no-CPUs CPU? */ bool rcu_is_nocb_cpu(int cpu) { @@ -2108,6 +2109,7 @@ bool rcu_is_nocb_cpu(int cpu) return cpumask_test_cpu(cpu, rcu_nocb_mask); return false; } +#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */ /* * Enqueue the specified string of rcu_head structures onto the specified -- cgit v1.2.2 From ffa83fb565fbc397cbafb4b71fd1cce276d4c3b6 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 17 Nov 2013 19:27:16 -0800 Subject: rcu: Optimize rcu_needs_cpu() for RCU_NOCB_CPU_ALL If CONFIG_RCU_NOCB_CPU_ALL=y, then rcu_needs_cpu() will always return false, however, the current version nevertheless checks for RCU callbacks. This commit therefore creates a static inline implementation of rcu_needs_cpu() that unconditionally returns false when CONFIG_RCU_NOCB_CPU_ALL=y. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcu/tree.c | 2 +- kernel/rcu/tree_plugin.h | 4 ++++ 2 files changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index b3d116cd072d..c2c8234a0291 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2880,7 +2880,7 @@ static int rcu_pending(int cpu) * 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 int rcu_cpu_has_callbacks(int cpu, bool *all_lazy) +static int __maybe_unused rcu_cpu_has_callbacks(int cpu, bool *all_lazy) { bool al = true; bool hc = false; diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 39a50b918bff..820b06aefbee 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -1586,11 +1586,13 @@ static void rcu_prepare_kthreads(int cpu) * Because we not have RCU_FAST_NO_HZ, just check whether this CPU needs * any flavor of RCU. */ +#ifndef CONFIG_RCU_NOCB_CPU_ALL int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies) { *delta_jiffies = ULONG_MAX; return rcu_cpu_has_callbacks(cpu, NULL); } +#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */ /* * Because we do not have RCU_FAST_NO_HZ, don't bother cleaning up @@ -1696,6 +1698,7 @@ static bool rcu_try_advance_all_cbs(void) * * The caller must have disabled interrupts. */ +#ifndef CONFIG_RCU_NOCB_CPU_ALL int rcu_needs_cpu(int cpu, unsigned long *dj) { struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu); @@ -1726,6 +1729,7 @@ int rcu_needs_cpu(int cpu, unsigned long *dj) } return 0; } +#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */ /* * Prepare a CPU for idle from an RCU perspective. The first major task -- cgit v1.2.2 From f1f399d1281ea339a08469f7e58193624992f620 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 17 Nov 2013 21:08:07 -0800 Subject: rcu: Optimize RCU_FAST_NO_HZ for RCU_NOCB_CPU_ALL If CONFIG_RCU_NOCB_CPU_ALL=y, then no CPU will ever have RCU callbacks because these callbacks will instead be handled by the rcuo kthreads. However, the current version of RCU_FAST_NO_HZ nevertheless checks for RCU callbacks. This commit therefore creates static inline implementations of rcu_prepare_for_idle() and rcu_cleanup_after_idle() that are no-ops when CONFIG_RCU_NOCB_CPU_ALL=y. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcu/tree_plugin.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 820b06aefbee..41afc3fbfb6c 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -1658,7 +1658,7 @@ extern int tick_nohz_active; * only if it has been awhile since the last time we did so. Afterwards, * if there are any callbacks ready for immediate invocation, return true. */ -static bool rcu_try_advance_all_cbs(void) +static bool __maybe_unused rcu_try_advance_all_cbs(void) { bool cbs_ready = false; struct rcu_data *rdp; @@ -1743,6 +1743,7 @@ int rcu_needs_cpu(int cpu, unsigned long *dj) */ static void rcu_prepare_for_idle(int cpu) { +#ifndef CONFIG_RCU_NOCB_CPU_ALL struct rcu_data *rdp; struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu); struct rcu_node *rnp; @@ -1794,6 +1795,7 @@ static void rcu_prepare_for_idle(int cpu) rcu_accelerate_cbs(rsp, rnp, rdp); raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ } +#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */ } /* @@ -1803,11 +1805,12 @@ static void rcu_prepare_for_idle(int cpu) */ static void rcu_cleanup_after_idle(int cpu) { - +#ifndef CONFIG_RCU_NOCB_CPU_ALL if (rcu_is_nocb_cpu(cpu)) return; if (rcu_try_advance_all_cbs()) invoke_rcu_core(); +#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */ } /* -- cgit v1.2.2 From 806274c018e9858320a27b785df761f45c33a56c Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 17 Feb 2014 13:13:05 -0800 Subject: rcutorture: Fix checkpatch complaint This commit does a code-style cleanup so that the first curly brace of an initializer does not appear at the beginning of a line. Signed-off-by: Paul E. McKenney --- kernel/rcu/torture.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/torture.c b/kernel/rcu/torture.c index 732f8ae3086a..dad67238d086 100644 --- a/kernel/rcu/torture.c +++ b/kernel/rcu/torture.c @@ -170,10 +170,10 @@ static struct rcu_torture __rcu *rcu_torture_current; static unsigned long rcu_torture_current_version; static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; static DEFINE_SPINLOCK(rcu_torture_lock); -static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) = - { 0 }; -static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) = - { 0 }; +static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], + rcu_torture_count) = { 0 }; +static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], + rcu_torture_batch) = { 0 }; static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; static atomic_t n_rcu_torture_alloc; static atomic_t n_rcu_torture_alloc_fail; -- cgit v1.2.2 From 51b1130eb5823ddb90a9ad07d243031d8cb7ecf2 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 27 Jan 2014 11:49:39 -0800 Subject: rcutorture: Abstract rcu_torture_random() Because rcu_torture_random() will be used by the locking equivalent to rcutorture, pull it out into its own module. This new module cannot be separately configured, instead, use the Kconfig "select" statement from the Kconfig options of tests depending on it. Suggested-by: Rusty Russell Signed-off-by: Paul E. McKenney --- kernel/Makefile | 1 + kernel/rcu/Makefile | 2 +- kernel/rcu/rcutorture.c | 2125 ++++++++++++++++++++++++++++++++++++++++++++++ kernel/rcu/torture.c | 2148 ----------------------------------------------- kernel/torture.c | 71 ++ 5 files changed, 2198 insertions(+), 2149 deletions(-) create mode 100644 kernel/rcu/rcutorture.c delete mode 100644 kernel/rcu/torture.c create mode 100644 kernel/torture.c (limited to 'kernel') diff --git a/kernel/Makefile b/kernel/Makefile index bc010ee272b6..5c0e7666811d 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -93,6 +93,7 @@ obj-$(CONFIG_PADATA) += padata.o obj-$(CONFIG_CRASH_DUMP) += crash_dump.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o +obj-$(CONFIG_TORTURE_TEST) += torture.o $(obj)/configs.o: $(obj)/config_data.h diff --git a/kernel/rcu/Makefile b/kernel/rcu/Makefile index 01e9ec37a3e3..807ccfbf69b3 100644 --- a/kernel/rcu/Makefile +++ b/kernel/rcu/Makefile @@ -1,5 +1,5 @@ obj-y += update.o srcu.o -obj-$(CONFIG_RCU_TORTURE_TEST) += torture.o +obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o obj-$(CONFIG_TREE_RCU) += tree.o obj-$(CONFIG_TREE_PREEMPT_RCU) += tree.o obj-$(CONFIG_TREE_RCU_TRACE) += tree_trace.o diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c new file mode 100644 index 000000000000..94b1cd8b214c --- /dev/null +++ b/kernel/rcu/rcutorture.c @@ -0,0 +1,2125 @@ +/* + * 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, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) IBM Corporation, 2005, 2006 + * + * Authors: Paul E. McKenney + * Josh Triplett + * + * See also: Documentation/RCU/torture.txt + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Paul E. McKenney and Josh Triplett "); + +MODULE_ALIAS("rcutorture"); +#ifdef MODULE_PARAM_PREFIX +#undef MODULE_PARAM_PREFIX +#endif +#define MODULE_PARAM_PREFIX "rcutorture." + +static int fqs_duration; +module_param(fqs_duration, int, 0444); +MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us), 0 to disable"); +static int fqs_holdoff; +module_param(fqs_holdoff, int, 0444); +MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)"); +static int fqs_stutter = 3; +module_param(fqs_stutter, int, 0444); +MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)"); +static bool gp_exp; +module_param(gp_exp, bool, 0444); +MODULE_PARM_DESC(gp_exp, "Use expedited GP wait primitives"); +static bool gp_normal; +module_param(gp_normal, bool, 0444); +MODULE_PARM_DESC(gp_normal, "Use normal (non-expedited) GP wait primitives"); +static int irqreader = 1; +module_param(irqreader, int, 0444); +MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers"); +static int n_barrier_cbs; +module_param(n_barrier_cbs, int, 0444); +MODULE_PARM_DESC(n_barrier_cbs, "# of callbacks/kthreads for barrier testing"); +static int nfakewriters = 4; +module_param(nfakewriters, int, 0444); +MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads"); +static int nreaders = -1; +module_param(nreaders, int, 0444); +MODULE_PARM_DESC(nreaders, "Number of RCU reader threads"); +static int object_debug; +module_param(object_debug, int, 0444); +MODULE_PARM_DESC(object_debug, "Enable debug-object double call_rcu() testing"); +static int onoff_holdoff; +module_param(onoff_holdoff, int, 0444); +MODULE_PARM_DESC(onoff_holdoff, "Time after boot before CPU hotplugs (s)"); +static int onoff_interval; +module_param(onoff_interval, int, 0444); +MODULE_PARM_DESC(onoff_interval, "Time between CPU hotplugs (s), 0=disable"); +static int shuffle_interval = 3; +module_param(shuffle_interval, int, 0444); +MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles"); +static int shutdown_secs; +module_param(shutdown_secs, int, 0444); +MODULE_PARM_DESC(shutdown_secs, "Shutdown time (s), <= zero to disable."); +static int stall_cpu; +module_param(stall_cpu, int, 0444); +MODULE_PARM_DESC(stall_cpu, "Stall duration (s), zero to disable."); +static int stall_cpu_holdoff = 10; +module_param(stall_cpu_holdoff, int, 0444); +MODULE_PARM_DESC(stall_cpu_holdoff, "Time to wait before starting stall (s)."); +static int stat_interval = 60; +module_param(stat_interval, int, 0644); +MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s"); +static int stutter = 5; +module_param(stutter, int, 0444); +MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test"); +static int test_boost = 1; +module_param(test_boost, int, 0444); +MODULE_PARM_DESC(test_boost, "Test RCU prio boost: 0=no, 1=maybe, 2=yes."); +static int test_boost_duration = 4; +module_param(test_boost_duration, int, 0444); +MODULE_PARM_DESC(test_boost_duration, "Duration of each boost test, seconds."); +static int test_boost_interval = 7; +module_param(test_boost_interval, int, 0444); +MODULE_PARM_DESC(test_boost_interval, "Interval between boost tests, seconds."); +static bool test_no_idle_hz = true; +module_param(test_no_idle_hz, bool, 0444); +MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs"); +static char *torture_type = "rcu"; +module_param(torture_type, charp, 0444); +MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)"); +static bool verbose; +module_param(verbose, bool, 0444); +MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s"); + +#define TORTURE_FLAG "-torture:" +#define PRINTK_STRING(s) \ + do { pr_alert("%s" TORTURE_FLAG s "\n", torture_type); } while (0) +#define VERBOSE_PRINTK_STRING(s) \ + do { if (verbose) pr_alert("%s" TORTURE_FLAG s "\n", torture_type); } while (0) +#define VERBOSE_PRINTK_ERRSTRING(s) \ + do { if (verbose) pr_alert("%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0) + +static int nrealreaders; +static struct task_struct *writer_task; +static struct task_struct **fakewriter_tasks; +static struct task_struct **reader_tasks; +static struct task_struct *stats_task; +static struct task_struct *shuffler_task; +static struct task_struct *stutter_task; +static struct task_struct *fqs_task; +static struct task_struct *boost_tasks[NR_CPUS]; +static struct task_struct *shutdown_task; +#ifdef CONFIG_HOTPLUG_CPU +static struct task_struct *onoff_task; +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ +static struct task_struct *stall_task; +static struct task_struct **barrier_cbs_tasks; +static struct task_struct *barrier_task; + +#define RCU_TORTURE_PIPE_LEN 10 + +struct rcu_torture { + struct rcu_head rtort_rcu; + int rtort_pipe_count; + struct list_head rtort_free; + int rtort_mbtest; +}; + +static LIST_HEAD(rcu_torture_freelist); +static struct rcu_torture __rcu *rcu_torture_current; +static unsigned long rcu_torture_current_version; +static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; +static DEFINE_SPINLOCK(rcu_torture_lock); +static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], + rcu_torture_count) = { 0 }; +static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], + rcu_torture_batch) = { 0 }; +static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; +static atomic_t n_rcu_torture_alloc; +static atomic_t n_rcu_torture_alloc_fail; +static atomic_t n_rcu_torture_free; +static atomic_t n_rcu_torture_mberror; +static atomic_t n_rcu_torture_error; +static long n_rcu_torture_barrier_error; +static long n_rcu_torture_boost_ktrerror; +static long n_rcu_torture_boost_rterror; +static long n_rcu_torture_boost_failure; +static long n_rcu_torture_boosts; +static long n_rcu_torture_timers; +static long n_offline_attempts; +static long n_offline_successes; +static unsigned long sum_offline; +static int min_offline = -1; +static int max_offline; +static long n_online_attempts; +static long n_online_successes; +static unsigned long sum_online; +static int min_online = -1; +static int max_online; +static long n_barrier_attempts; +static long n_barrier_successes; +static struct list_head rcu_torture_removed; +static cpumask_var_t shuffle_tmp_mask; + +static int stutter_pause_test; + +#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE) +#define RCUTORTURE_RUNNABLE_INIT 1 +#else +#define RCUTORTURE_RUNNABLE_INIT 0 +#endif +int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT; +module_param(rcutorture_runnable, int, 0444); +MODULE_PARM_DESC(rcutorture_runnable, "Start rcutorture at boot"); + +#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) +#define rcu_can_boost() 1 +#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ +#define rcu_can_boost() 0 +#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ + +#ifdef CONFIG_RCU_TRACE +static u64 notrace rcu_trace_clock_local(void) +{ + u64 ts = trace_clock_local(); + unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC); + return ts; +} +#else /* #ifdef CONFIG_RCU_TRACE */ +static u64 notrace rcu_trace_clock_local(void) +{ + return 0ULL; +} +#endif /* #else #ifdef CONFIG_RCU_TRACE */ + +static unsigned long shutdown_time; /* jiffies to system shutdown. */ +static unsigned long boost_starttime; /* jiffies of next boost test start. */ +DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ + /* and boost task create/destroy. */ +static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */ +static bool barrier_phase; /* Test phase. */ +static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */ +static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */ +static DECLARE_WAIT_QUEUE_HEAD(barrier_wq); + +/* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */ + +#define FULLSTOP_DONTSTOP 0 /* Normal operation. */ +#define FULLSTOP_SHUTDOWN 1 /* System shutdown with rcutorture running. */ +#define FULLSTOP_RMMOD 2 /* Normal rmmod of rcutorture. */ +static int fullstop = FULLSTOP_RMMOD; +/* + * Protect fullstop transitions and spawning of kthreads. + */ +static DEFINE_MUTEX(fullstop_mutex); + +/* Forward reference. */ +static void rcu_torture_cleanup(void); + +/* + * Detect and respond to a system shutdown. + */ +static int +rcutorture_shutdown_notify(struct notifier_block *unused1, + unsigned long unused2, void *unused3) +{ + mutex_lock(&fullstop_mutex); + if (fullstop == FULLSTOP_DONTSTOP) + fullstop = FULLSTOP_SHUTDOWN; + else + pr_warn(/* but going down anyway, so... */ + "Concurrent 'rmmod rcutorture' and shutdown illegal!\n"); + mutex_unlock(&fullstop_mutex); + return NOTIFY_DONE; +} + +/* + * Absorb kthreads into a kernel function that won't return, so that + * they won't ever access module text or data again. + */ +static void rcutorture_shutdown_absorb(const char *title) +{ + if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) { + pr_notice( + "rcutorture thread %s parking due to system shutdown\n", + title); + schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT); + } +} + +/* + * Allocate an element from the rcu_tortures pool. + */ +static struct rcu_torture * +rcu_torture_alloc(void) +{ + struct list_head *p; + + spin_lock_bh(&rcu_torture_lock); + if (list_empty(&rcu_torture_freelist)) { + atomic_inc(&n_rcu_torture_alloc_fail); + spin_unlock_bh(&rcu_torture_lock); + return NULL; + } + atomic_inc(&n_rcu_torture_alloc); + p = rcu_torture_freelist.next; + list_del_init(p); + spin_unlock_bh(&rcu_torture_lock); + return container_of(p, struct rcu_torture, rtort_free); +} + +/* + * Free an element to the rcu_tortures pool. + */ +static void +rcu_torture_free(struct rcu_torture *p) +{ + atomic_inc(&n_rcu_torture_free); + spin_lock_bh(&rcu_torture_lock); + list_add_tail(&p->rtort_free, &rcu_torture_freelist); + spin_unlock_bh(&rcu_torture_lock); +} + +static void +rcu_stutter_wait(const char *title) +{ + while (stutter_pause_test || !rcutorture_runnable) { + if (rcutorture_runnable) + schedule_timeout_interruptible(1); + else + schedule_timeout_interruptible(round_jiffies_relative(HZ)); + rcutorture_shutdown_absorb(title); + } +} + +/* + * Operations vector for selecting different types of tests. + */ + +struct rcu_torture_ops { + void (*init)(void); + int (*readlock)(void); + void (*read_delay)(struct torture_random_state *rrsp); + void (*readunlock)(int idx); + int (*completed)(void); + void (*deferred_free)(struct rcu_torture *p); + void (*sync)(void); + void (*exp_sync)(void); + void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); + void (*cb_barrier)(void); + void (*fqs)(void); + void (*stats)(char *page); + int irq_capable; + int can_boost; + const char *name; +}; + +static struct rcu_torture_ops *cur_ops; + +/* + * Definitions for rcu torture testing. + */ + +static int rcu_torture_read_lock(void) __acquires(RCU) +{ + rcu_read_lock(); + return 0; +} + +static void rcu_read_delay(struct torture_random_state *rrsp) +{ + const unsigned long shortdelay_us = 200; + const unsigned long longdelay_ms = 50; + + /* We want a short delay sometimes to make a reader delay the grace + * period, and we want a long delay occasionally to trigger + * force_quiescent_state. */ + + if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) + mdelay(longdelay_ms); + if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) + udelay(shortdelay_us); +#ifdef CONFIG_PREEMPT + if (!preempt_count() && + !(torture_random(rrsp) % (nrealreaders * 20000))) + preempt_schedule(); /* No QS if preempt_disable() in effect */ +#endif +} + +static void rcu_torture_read_unlock(int idx) __releases(RCU) +{ + rcu_read_unlock(); +} + +static int rcu_torture_completed(void) +{ + return rcu_batches_completed(); +} + +static void +rcu_torture_cb(struct rcu_head *p) +{ + int i; + struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); + + if (fullstop != FULLSTOP_DONTSTOP) { + /* Test is ending, just drop callbacks on the floor. */ + /* The next initialization will pick up the pieces. */ + return; + } + i = rp->rtort_pipe_count; + if (i > RCU_TORTURE_PIPE_LEN) + i = RCU_TORTURE_PIPE_LEN; + atomic_inc(&rcu_torture_wcount[i]); + if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { + rp->rtort_mbtest = 0; + rcu_torture_free(rp); + } else { + cur_ops->deferred_free(rp); + } +} + +static int rcu_no_completed(void) +{ + return 0; +} + +static void rcu_torture_deferred_free(struct rcu_torture *p) +{ + call_rcu(&p->rtort_rcu, rcu_torture_cb); +} + +static void rcu_sync_torture_init(void) +{ + INIT_LIST_HEAD(&rcu_torture_removed); +} + +static struct rcu_torture_ops rcu_ops = { + .init = rcu_sync_torture_init, + .readlock = rcu_torture_read_lock, + .read_delay = rcu_read_delay, + .readunlock = rcu_torture_read_unlock, + .completed = rcu_torture_completed, + .deferred_free = rcu_torture_deferred_free, + .sync = synchronize_rcu, + .exp_sync = synchronize_rcu_expedited, + .call = call_rcu, + .cb_barrier = rcu_barrier, + .fqs = rcu_force_quiescent_state, + .stats = NULL, + .irq_capable = 1, + .can_boost = rcu_can_boost(), + .name = "rcu" +}; + +/* + * Definitions for rcu_bh torture testing. + */ + +static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH) +{ + rcu_read_lock_bh(); + return 0; +} + +static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH) +{ + rcu_read_unlock_bh(); +} + +static int rcu_bh_torture_completed(void) +{ + return rcu_batches_completed_bh(); +} + +static void rcu_bh_torture_deferred_free(struct rcu_torture *p) +{ + call_rcu_bh(&p->rtort_rcu, rcu_torture_cb); +} + +static struct rcu_torture_ops rcu_bh_ops = { + .init = rcu_sync_torture_init, + .readlock = rcu_bh_torture_read_lock, + .read_delay = rcu_read_delay, /* just reuse rcu's version. */ + .readunlock = rcu_bh_torture_read_unlock, + .completed = rcu_bh_torture_completed, + .deferred_free = rcu_bh_torture_deferred_free, + .sync = synchronize_rcu_bh, + .exp_sync = synchronize_rcu_bh_expedited, + .call = call_rcu_bh, + .cb_barrier = rcu_barrier_bh, + .fqs = rcu_bh_force_quiescent_state, + .stats = NULL, + .irq_capable = 1, + .name = "rcu_bh" +}; + +/* + * Definitions for srcu torture testing. + */ + +DEFINE_STATIC_SRCU(srcu_ctl); + +static int srcu_torture_read_lock(void) __acquires(&srcu_ctl) +{ + return srcu_read_lock(&srcu_ctl); +} + +static void srcu_read_delay(struct torture_random_state *rrsp) +{ + long delay; + const long uspertick = 1000000 / HZ; + const long longdelay = 10; + + /* We want there to be long-running readers, but not all the time. */ + + delay = torture_random(rrsp) % + (nrealreaders * 2 * longdelay * uspertick); + if (!delay) + schedule_timeout_interruptible(longdelay); + else + rcu_read_delay(rrsp); +} + +static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl) +{ + srcu_read_unlock(&srcu_ctl, idx); +} + +static int srcu_torture_completed(void) +{ + return srcu_batches_completed(&srcu_ctl); +} + +static void srcu_torture_deferred_free(struct rcu_torture *rp) +{ + call_srcu(&srcu_ctl, &rp->rtort_rcu, rcu_torture_cb); +} + +static void srcu_torture_synchronize(void) +{ + synchronize_srcu(&srcu_ctl); +} + +static void srcu_torture_call(struct rcu_head *head, + void (*func)(struct rcu_head *head)) +{ + call_srcu(&srcu_ctl, head, func); +} + +static void srcu_torture_barrier(void) +{ + srcu_barrier(&srcu_ctl); +} + +static void srcu_torture_stats(char *page) +{ + int cpu; + int idx = srcu_ctl.completed & 0x1; + + page += sprintf(page, "%s%s per-CPU(idx=%d):", + torture_type, TORTURE_FLAG, idx); + for_each_possible_cpu(cpu) { + page += sprintf(page, " %d(%lu,%lu)", cpu, + per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx], + per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]); + } + sprintf(page, "\n"); +} + +static void srcu_torture_synchronize_expedited(void) +{ + synchronize_srcu_expedited(&srcu_ctl); +} + +static struct rcu_torture_ops srcu_ops = { + .init = rcu_sync_torture_init, + .readlock = srcu_torture_read_lock, + .read_delay = srcu_read_delay, + .readunlock = srcu_torture_read_unlock, + .completed = srcu_torture_completed, + .deferred_free = srcu_torture_deferred_free, + .sync = srcu_torture_synchronize, + .exp_sync = srcu_torture_synchronize_expedited, + .call = srcu_torture_call, + .cb_barrier = srcu_torture_barrier, + .stats = srcu_torture_stats, + .name = "srcu" +}; + +/* + * Definitions for sched torture testing. + */ + +static int sched_torture_read_lock(void) +{ + preempt_disable(); + return 0; +} + +static void sched_torture_read_unlock(int idx) +{ + preempt_enable(); +} + +static void rcu_sched_torture_deferred_free(struct rcu_torture *p) +{ + call_rcu_sched(&p->rtort_rcu, rcu_torture_cb); +} + +static struct rcu_torture_ops sched_ops = { + .init = rcu_sync_torture_init, + .readlock = sched_torture_read_lock, + .read_delay = rcu_read_delay, /* just reuse rcu's version. */ + .readunlock = sched_torture_read_unlock, + .completed = rcu_no_completed, + .deferred_free = rcu_sched_torture_deferred_free, + .sync = synchronize_sched, + .exp_sync = synchronize_sched_expedited, + .call = call_rcu_sched, + .cb_barrier = rcu_barrier_sched, + .fqs = rcu_sched_force_quiescent_state, + .stats = NULL, + .irq_capable = 1, + .name = "sched" +}; + +/* + * RCU torture priority-boost testing. Runs one real-time thread per + * CPU for moderate bursts, repeatedly registering RCU callbacks and + * spinning waiting for them to be invoked. If a given callback takes + * too long to be invoked, we assume that priority inversion has occurred. + */ + +struct rcu_boost_inflight { + struct rcu_head rcu; + int inflight; +}; + +static void rcu_torture_boost_cb(struct rcu_head *head) +{ + struct rcu_boost_inflight *rbip = + container_of(head, struct rcu_boost_inflight, rcu); + + smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */ + rbip->inflight = 0; +} + +static int rcu_torture_boost(void *arg) +{ + unsigned long call_rcu_time; + unsigned long endtime; + unsigned long oldstarttime; + struct rcu_boost_inflight rbi = { .inflight = 0 }; + struct sched_param sp; + + VERBOSE_PRINTK_STRING("rcu_torture_boost started"); + + /* Set real-time priority. */ + sp.sched_priority = 1; + if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) { + VERBOSE_PRINTK_STRING("rcu_torture_boost RT prio failed!"); + n_rcu_torture_boost_rterror++; + } + + init_rcu_head_on_stack(&rbi.rcu); + /* Each pass through the following loop does one boost-test cycle. */ + do { + /* Wait for the next test interval. */ + oldstarttime = boost_starttime; + while (ULONG_CMP_LT(jiffies, oldstarttime)) { + schedule_timeout_interruptible(oldstarttime - jiffies); + rcu_stutter_wait("rcu_torture_boost"); + if (kthread_should_stop() || + fullstop != FULLSTOP_DONTSTOP) + goto checkwait; + } + + /* Do one boost-test interval. */ + endtime = oldstarttime + test_boost_duration * HZ; + call_rcu_time = jiffies; + while (ULONG_CMP_LT(jiffies, endtime)) { + /* If we don't have a callback in flight, post one. */ + if (!rbi.inflight) { + smp_mb(); /* RCU core before ->inflight = 1. */ + rbi.inflight = 1; + call_rcu(&rbi.rcu, rcu_torture_boost_cb); + if (jiffies - call_rcu_time > + test_boost_duration * HZ - HZ / 2) { + VERBOSE_PRINTK_STRING("rcu_torture_boost boosting failed"); + n_rcu_torture_boost_failure++; + } + call_rcu_time = jiffies; + } + cond_resched(); + rcu_stutter_wait("rcu_torture_boost"); + if (kthread_should_stop() || + fullstop != FULLSTOP_DONTSTOP) + goto checkwait; + } + + /* + * Set the start time of the next test interval. + * Yes, this is vulnerable to long delays, but such + * delays simply cause a false negative for the next + * interval. Besides, we are running at RT priority, + * so delays should be relatively rare. + */ + while (oldstarttime == boost_starttime && + !kthread_should_stop()) { + if (mutex_trylock(&boost_mutex)) { + boost_starttime = jiffies + + test_boost_interval * HZ; + n_rcu_torture_boosts++; + mutex_unlock(&boost_mutex); + break; + } + schedule_timeout_uninterruptible(1); + } + + /* Go do the stutter. */ +checkwait: rcu_stutter_wait("rcu_torture_boost"); + } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); + + /* Clean up and exit. */ + VERBOSE_PRINTK_STRING("rcu_torture_boost task stopping"); + rcutorture_shutdown_absorb("rcu_torture_boost"); + while (!kthread_should_stop() || rbi.inflight) + schedule_timeout_uninterruptible(1); + smp_mb(); /* order accesses to ->inflight before stack-frame death. */ + destroy_rcu_head_on_stack(&rbi.rcu); + return 0; +} + +/* + * RCU torture force-quiescent-state kthread. Repeatedly induces + * bursts of calls to force_quiescent_state(), increasing the probability + * of occurrence of some important types of race conditions. + */ +static int +rcu_torture_fqs(void *arg) +{ + unsigned long fqs_resume_time; + int fqs_burst_remaining; + + VERBOSE_PRINTK_STRING("rcu_torture_fqs task started"); + do { + fqs_resume_time = jiffies + fqs_stutter * HZ; + while (ULONG_CMP_LT(jiffies, fqs_resume_time) && + !kthread_should_stop()) { + schedule_timeout_interruptible(1); + } + fqs_burst_remaining = fqs_duration; + while (fqs_burst_remaining > 0 && + !kthread_should_stop()) { + cur_ops->fqs(); + udelay(fqs_holdoff); + fqs_burst_remaining -= fqs_holdoff; + } + rcu_stutter_wait("rcu_torture_fqs"); + } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); + VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping"); + rcutorture_shutdown_absorb("rcu_torture_fqs"); + while (!kthread_should_stop()) + schedule_timeout_uninterruptible(1); + return 0; +} + +/* + * RCU torture writer kthread. Repeatedly substitutes a new structure + * for that pointed to by rcu_torture_current, freeing the old structure + * after a series of grace periods (the "pipeline"). + */ +static int +rcu_torture_writer(void *arg) +{ + bool exp; + int i; + struct rcu_torture *rp; + struct rcu_torture *rp1; + struct rcu_torture *old_rp; + static DEFINE_TORTURE_RANDOM(rand); + + VERBOSE_PRINTK_STRING("rcu_torture_writer task started"); + set_user_nice(current, 19); + + do { + schedule_timeout_uninterruptible(1); + rp = rcu_torture_alloc(); + if (rp == NULL) + continue; + rp->rtort_pipe_count = 0; + udelay(torture_random(&rand) & 0x3ff); + old_rp = rcu_dereference_check(rcu_torture_current, + current == writer_task); + rp->rtort_mbtest = 1; + rcu_assign_pointer(rcu_torture_current, rp); + smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */ + if (old_rp) { + i = old_rp->rtort_pipe_count; + if (i > RCU_TORTURE_PIPE_LEN) + i = RCU_TORTURE_PIPE_LEN; + atomic_inc(&rcu_torture_wcount[i]); + old_rp->rtort_pipe_count++; + if (gp_normal == gp_exp) + exp = !!(torture_random(&rand) & 0x80); + else + exp = gp_exp; + if (!exp) { + cur_ops->deferred_free(old_rp); + } else { + cur_ops->exp_sync(); + list_add(&old_rp->rtort_free, + &rcu_torture_removed); + list_for_each_entry_safe(rp, rp1, + &rcu_torture_removed, + rtort_free) { + i = rp->rtort_pipe_count; + if (i > RCU_TORTURE_PIPE_LEN) + i = RCU_TORTURE_PIPE_LEN; + atomic_inc(&rcu_torture_wcount[i]); + if (++rp->rtort_pipe_count >= + RCU_TORTURE_PIPE_LEN) { + rp->rtort_mbtest = 0; + list_del(&rp->rtort_free); + rcu_torture_free(rp); + } + } + } + } + rcutorture_record_progress(++rcu_torture_current_version); + rcu_stutter_wait("rcu_torture_writer"); + } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); + VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping"); + rcutorture_shutdown_absorb("rcu_torture_writer"); + while (!kthread_should_stop()) + schedule_timeout_uninterruptible(1); + return 0; +} + +/* + * RCU torture fake writer kthread. Repeatedly calls sync, with a random + * delay between calls. + */ +static int +rcu_torture_fakewriter(void *arg) +{ + DEFINE_TORTURE_RANDOM(rand); + + VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started"); + set_user_nice(current, 19); + + do { + schedule_timeout_uninterruptible(1 + torture_random(&rand)%10); + udelay(torture_random(&rand) & 0x3ff); + if (cur_ops->cb_barrier != NULL && + torture_random(&rand) % (nfakewriters * 8) == 0) { + cur_ops->cb_barrier(); + } else if (gp_normal == gp_exp) { + if (torture_random(&rand) & 0x80) + cur_ops->sync(); + else + cur_ops->exp_sync(); + } else if (gp_normal) { + cur_ops->sync(); + } else { + cur_ops->exp_sync(); + } + rcu_stutter_wait("rcu_torture_fakewriter"); + } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); + + VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping"); + rcutorture_shutdown_absorb("rcu_torture_fakewriter"); + while (!kthread_should_stop()) + schedule_timeout_uninterruptible(1); + return 0; +} + +void rcutorture_trace_dump(void) +{ + static atomic_t beenhere = ATOMIC_INIT(0); + + if (atomic_read(&beenhere)) + return; + if (atomic_xchg(&beenhere, 1) != 0) + return; + ftrace_dump(DUMP_ALL); +} + +/* + * RCU torture reader from timer handler. Dereferences rcu_torture_current, + * incrementing the corresponding element of the pipeline array. The + * counter in the element should never be greater than 1, otherwise, the + * RCU implementation is broken. + */ +static void rcu_torture_timer(unsigned long unused) +{ + int idx; + int completed; + int completed_end; + static DEFINE_TORTURE_RANDOM(rand); + static DEFINE_SPINLOCK(rand_lock); + struct rcu_torture *p; + int pipe_count; + unsigned long long ts; + + idx = cur_ops->readlock(); + completed = cur_ops->completed(); + ts = rcu_trace_clock_local(); + p = rcu_dereference_check(rcu_torture_current, + rcu_read_lock_bh_held() || + rcu_read_lock_sched_held() || + srcu_read_lock_held(&srcu_ctl)); + if (p == NULL) { + /* Leave because rcu_torture_writer is not yet underway */ + cur_ops->readunlock(idx); + return; + } + if (p->rtort_mbtest == 0) + atomic_inc(&n_rcu_torture_mberror); + spin_lock(&rand_lock); + cur_ops->read_delay(&rand); + n_rcu_torture_timers++; + spin_unlock(&rand_lock); + preempt_disable(); + pipe_count = p->rtort_pipe_count; + if (pipe_count > RCU_TORTURE_PIPE_LEN) { + /* Should not happen, but... */ + pipe_count = RCU_TORTURE_PIPE_LEN; + } + completed_end = cur_ops->completed(); + if (pipe_count > 1) { + do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts, + completed, completed_end); + rcutorture_trace_dump(); + } + __this_cpu_inc(rcu_torture_count[pipe_count]); + completed = completed_end - completed; + if (completed > RCU_TORTURE_PIPE_LEN) { + /* Should not happen, but... */ + completed = RCU_TORTURE_PIPE_LEN; + } + __this_cpu_inc(rcu_torture_batch[completed]); + preempt_enable(); + cur_ops->readunlock(idx); +} + +/* + * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, + * incrementing the corresponding element of the pipeline array. The + * counter in the element should never be greater than 1, otherwise, the + * RCU implementation is broken. + */ +static int +rcu_torture_reader(void *arg) +{ + int completed; + int completed_end; + int idx; + DEFINE_TORTURE_RANDOM(rand); + struct rcu_torture *p; + int pipe_count; + struct timer_list t; + unsigned long long ts; + + VERBOSE_PRINTK_STRING("rcu_torture_reader task started"); + set_user_nice(current, 19); + if (irqreader && cur_ops->irq_capable) + setup_timer_on_stack(&t, rcu_torture_timer, 0); + + do { + if (irqreader && cur_ops->irq_capable) { + if (!timer_pending(&t)) + mod_timer(&t, jiffies + 1); + } + idx = cur_ops->readlock(); + completed = cur_ops->completed(); + ts = rcu_trace_clock_local(); + p = rcu_dereference_check(rcu_torture_current, + rcu_read_lock_bh_held() || + rcu_read_lock_sched_held() || + srcu_read_lock_held(&srcu_ctl)); + if (p == NULL) { + /* Wait for rcu_torture_writer to get underway */ + cur_ops->readunlock(idx); + schedule_timeout_interruptible(HZ); + continue; + } + if (p->rtort_mbtest == 0) + atomic_inc(&n_rcu_torture_mberror); + cur_ops->read_delay(&rand); + preempt_disable(); + pipe_count = p->rtort_pipe_count; + if (pipe_count > RCU_TORTURE_PIPE_LEN) { + /* Should not happen, but... */ + pipe_count = RCU_TORTURE_PIPE_LEN; + } + completed_end = cur_ops->completed(); + if (pipe_count > 1) { + do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, + ts, completed, completed_end); + rcutorture_trace_dump(); + } + __this_cpu_inc(rcu_torture_count[pipe_count]); + completed = completed_end - completed; + if (completed > RCU_TORTURE_PIPE_LEN) { + /* Should not happen, but... */ + completed = RCU_TORTURE_PIPE_LEN; + } + __this_cpu_inc(rcu_torture_batch[completed]); + preempt_enable(); + cur_ops->readunlock(idx); + schedule(); + rcu_stutter_wait("rcu_torture_reader"); + } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); + VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping"); + rcutorture_shutdown_absorb("rcu_torture_reader"); + if (irqreader && cur_ops->irq_capable) + del_timer_sync(&t); + while (!kthread_should_stop()) + schedule_timeout_uninterruptible(1); + return 0; +} + +/* + * Create an RCU-torture statistics message in the specified buffer. + */ +static void +rcu_torture_printk(char *page) +{ + int cpu; + int i; + long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; + long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; + + for_each_possible_cpu(cpu) { + for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { + pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i]; + batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i]; + } + } + for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { + if (pipesummary[i] != 0) + break; + } + page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG); + page += sprintf(page, + "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", + rcu_torture_current, + rcu_torture_current_version, + list_empty(&rcu_torture_freelist), + atomic_read(&n_rcu_torture_alloc), + atomic_read(&n_rcu_torture_alloc_fail), + atomic_read(&n_rcu_torture_free)); + page += sprintf(page, "rtmbe: %d rtbke: %ld rtbre: %ld ", + atomic_read(&n_rcu_torture_mberror), + n_rcu_torture_boost_ktrerror, + n_rcu_torture_boost_rterror); + page += sprintf(page, "rtbf: %ld rtb: %ld nt: %ld ", + n_rcu_torture_boost_failure, + n_rcu_torture_boosts, + n_rcu_torture_timers); + page += sprintf(page, + "onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ", + n_online_successes, n_online_attempts, + n_offline_successes, n_offline_attempts, + min_online, max_online, + min_offline, max_offline, + sum_online, sum_offline, HZ); + page += sprintf(page, "barrier: %ld/%ld:%ld", + n_barrier_successes, + n_barrier_attempts, + n_rcu_torture_barrier_error); + page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG); + if (atomic_read(&n_rcu_torture_mberror) != 0 || + n_rcu_torture_barrier_error != 0 || + n_rcu_torture_boost_ktrerror != 0 || + n_rcu_torture_boost_rterror != 0 || + n_rcu_torture_boost_failure != 0 || + i > 1) { + page += sprintf(page, "!!! "); + atomic_inc(&n_rcu_torture_error); + WARN_ON_ONCE(1); + } + page += sprintf(page, "Reader Pipe: "); + for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) + page += sprintf(page, " %ld", pipesummary[i]); + page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG); + page += sprintf(page, "Reader Batch: "); + for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) + page += sprintf(page, " %ld", batchsummary[i]); + page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG); + page += sprintf(page, "Free-Block Circulation: "); + for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { + page += sprintf(page, " %d", + atomic_read(&rcu_torture_wcount[i])); + } + page += sprintf(page, "\n"); + if (cur_ops->stats) + cur_ops->stats(page); +} + +/* + * Print torture statistics. Caller must ensure that there is only + * one call to this function at a given time!!! This is normally + * accomplished by relying on the module system to only have one copy + * of the module loaded, and then by giving the rcu_torture_stats + * kthread full control (or the init/cleanup functions when rcu_torture_stats + * thread is not running). + */ +static void +rcu_torture_stats_print(void) +{ + int size = nr_cpu_ids * 200 + 8192; + char *buf; + + buf = kmalloc(size, GFP_KERNEL); + if (!buf) { + pr_err("rcu-torture: Out of memory, need: %d", size); + return; + } + rcu_torture_printk(buf); + pr_alert("%s", buf); + kfree(buf); +} + +/* + * Periodically prints torture statistics, if periodic statistics printing + * was specified via the stat_interval module parameter. + * + * No need to worry about fullstop here, since this one doesn't reference + * volatile state or register callbacks. + */ +static int +rcu_torture_stats(void *arg) +{ + VERBOSE_PRINTK_STRING("rcu_torture_stats task started"); + do { + schedule_timeout_interruptible(stat_interval * HZ); + rcu_torture_stats_print(); + rcutorture_shutdown_absorb("rcu_torture_stats"); + } while (!kthread_should_stop()); + VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping"); + return 0; +} + +static int rcu_idle_cpu; /* Force all torture tasks off this CPU */ + +/* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case + * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs. + */ +static void rcu_torture_shuffle_tasks(void) +{ + int i; + + cpumask_setall(shuffle_tmp_mask); + get_online_cpus(); + + /* No point in shuffling if there is only one online CPU (ex: UP) */ + if (num_online_cpus() == 1) { + put_online_cpus(); + return; + } + + if (rcu_idle_cpu != -1) + cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask); + + set_cpus_allowed_ptr(current, shuffle_tmp_mask); + + if (reader_tasks) { + for (i = 0; i < nrealreaders; i++) + if (reader_tasks[i]) + set_cpus_allowed_ptr(reader_tasks[i], + shuffle_tmp_mask); + } + if (fakewriter_tasks) { + for (i = 0; i < nfakewriters; i++) + if (fakewriter_tasks[i]) + set_cpus_allowed_ptr(fakewriter_tasks[i], + shuffle_tmp_mask); + } + if (writer_task) + set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask); + if (stats_task) + set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask); + if (stutter_task) + set_cpus_allowed_ptr(stutter_task, shuffle_tmp_mask); + if (fqs_task) + set_cpus_allowed_ptr(fqs_task, shuffle_tmp_mask); + if (shutdown_task) + set_cpus_allowed_ptr(shutdown_task, shuffle_tmp_mask); +#ifdef CONFIG_HOTPLUG_CPU + if (onoff_task) + set_cpus_allowed_ptr(onoff_task, shuffle_tmp_mask); +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ + if (stall_task) + set_cpus_allowed_ptr(stall_task, shuffle_tmp_mask); + if (barrier_cbs_tasks) + for (i = 0; i < n_barrier_cbs; i++) + if (barrier_cbs_tasks[i]) + set_cpus_allowed_ptr(barrier_cbs_tasks[i], + shuffle_tmp_mask); + if (barrier_task) + set_cpus_allowed_ptr(barrier_task, shuffle_tmp_mask); + + if (rcu_idle_cpu == -1) + rcu_idle_cpu = num_online_cpus() - 1; + else + rcu_idle_cpu--; + + put_online_cpus(); +} + +/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the + * system to become idle at a time and cut off its timer ticks. This is meant + * to test the support for such tickless idle CPU in RCU. + */ +static int +rcu_torture_shuffle(void *arg) +{ + VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started"); + do { + schedule_timeout_interruptible(shuffle_interval * HZ); + rcu_torture_shuffle_tasks(); + rcutorture_shutdown_absorb("rcu_torture_shuffle"); + } while (!kthread_should_stop()); + VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping"); + return 0; +} + +/* Cause the rcutorture test to "stutter", starting and stopping all + * threads periodically. + */ +static int +rcu_torture_stutter(void *arg) +{ + VERBOSE_PRINTK_STRING("rcu_torture_stutter task started"); + do { + schedule_timeout_interruptible(stutter * HZ); + stutter_pause_test = 1; + if (!kthread_should_stop()) + schedule_timeout_interruptible(stutter * HZ); + stutter_pause_test = 0; + rcutorture_shutdown_absorb("rcu_torture_stutter"); + } while (!kthread_should_stop()); + VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping"); + return 0; +} + +static inline void +rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) +{ + pr_alert("%s" TORTURE_FLAG + "--- %s: nreaders=%d nfakewriters=%d " + "stat_interval=%d verbose=%d test_no_idle_hz=%d " + "shuffle_interval=%d stutter=%d irqreader=%d " + "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d " + "test_boost=%d/%d test_boost_interval=%d " + "test_boost_duration=%d shutdown_secs=%d " + "stall_cpu=%d stall_cpu_holdoff=%d " + "n_barrier_cbs=%d " + "onoff_interval=%d onoff_holdoff=%d\n", + torture_type, tag, nrealreaders, nfakewriters, + stat_interval, verbose, test_no_idle_hz, shuffle_interval, + stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, + test_boost, cur_ops->can_boost, + test_boost_interval, test_boost_duration, shutdown_secs, + stall_cpu, stall_cpu_holdoff, + n_barrier_cbs, + onoff_interval, onoff_holdoff); +} + +static struct notifier_block rcutorture_shutdown_nb = { + .notifier_call = rcutorture_shutdown_notify, +}; + +static void rcutorture_booster_cleanup(int cpu) +{ + struct task_struct *t; + + if (boost_tasks[cpu] == NULL) + return; + mutex_lock(&boost_mutex); + VERBOSE_PRINTK_STRING("Stopping rcu_torture_boost task"); + t = boost_tasks[cpu]; + boost_tasks[cpu] = NULL; + mutex_unlock(&boost_mutex); + + /* This must be outside of the mutex, otherwise deadlock! */ + kthread_stop(t); + boost_tasks[cpu] = NULL; +} + +static int rcutorture_booster_init(int cpu) +{ + int retval; + + if (boost_tasks[cpu] != NULL) + return 0; /* Already created, nothing more to do. */ + + /* Don't allow time recalculation while creating a new task. */ + mutex_lock(&boost_mutex); + VERBOSE_PRINTK_STRING("Creating rcu_torture_boost task"); + boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL, + cpu_to_node(cpu), + "rcu_torture_boost"); + if (IS_ERR(boost_tasks[cpu])) { + retval = PTR_ERR(boost_tasks[cpu]); + VERBOSE_PRINTK_STRING("rcu_torture_boost task create failed"); + n_rcu_torture_boost_ktrerror++; + boost_tasks[cpu] = NULL; + mutex_unlock(&boost_mutex); + return retval; + } + kthread_bind(boost_tasks[cpu], cpu); + wake_up_process(boost_tasks[cpu]); + mutex_unlock(&boost_mutex); + return 0; +} + +/* + * Cause the rcutorture test to shutdown the system after the test has + * run for the time specified by the shutdown_secs module parameter. + */ +static int +rcu_torture_shutdown(void *arg) +{ + long delta; + unsigned long jiffies_snap; + + VERBOSE_PRINTK_STRING("rcu_torture_sh