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-rw-r--r--Documentation/RCU/RTFP.txt4
-rw-r--r--Documentation/RCU/rcuref.txt9
-rw-r--r--Documentation/kernel-parameters.txt7
-rw-r--r--Documentation/memory-barriers.txt27
-rw-r--r--MAINTAINERS18
-rw-r--r--include/linux/init_task.h9
-rw-r--r--include/linux/rcupdate.h45
-rw-r--r--include/linux/sched.h6
-rw-r--r--include/linux/tick.h20
-rw-r--r--init/Kconfig6
-rw-r--r--kernel/rcu/rcu.h8
-rw-r--r--kernel/rcu/srcu.c4
-rw-r--r--kernel/rcu/tree.c59
-rw-r--r--kernel/rcu/tree.h36
-rw-r--r--kernel/rcu/tree_plugin.h302
-rw-r--r--kernel/rcu/update.c3
-rw-r--r--kernel/signal.c4
-rw-r--r--kernel/time/tick-sched.c10
-rw-r--r--kernel/torture.c2
-rw-r--r--lib/Kconfig.debug14
-rwxr-xr-xscripts/get_maintainer.pl22
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm-recheck.sh8
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh9
-rw-r--r--tools/testing/selftests/rcutorture/bin/kvm.sh21
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE011
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE021
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE02-T1
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE031
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE041
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE051
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE061
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE071
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE081
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE08-T1
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE091
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/v0.0/P5-U-T-NH-sd-SMP-hp1
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/v3.12/P5-U-T-NH-sd-SMP-hp1
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/v3.3/P5-U-T-NH-sd-SMP-hp1
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/v3.5/P5-U-T-NH-sd-SMP-hp1
-rw-r--r--tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt1
40 files changed, 492 insertions, 177 deletions
diff --git a/Documentation/RCU/RTFP.txt b/Documentation/RCU/RTFP.txt
index 2f0fcb2112d..f29bcbc463e 100644
--- a/Documentation/RCU/RTFP.txt
+++ b/Documentation/RCU/RTFP.txt
@@ -2451,8 +2451,8 @@ lot of {Linux} into your technology!!!"
,month="February"
,year="2010"
,note="Available:
-\url{http://kerneltrap.com/mailarchive/linux-netdev/2010/2/26/6270589}
-[Viewed March 20, 2011]"
+\url{http://thread.gmane.org/gmane.linux.network/153338}
+[Viewed June 9, 2014]"
,annotation={
Use a pair of list_head structures to support RCU-protected
resizable hash tables.
diff --git a/Documentation/RCU/rcuref.txt b/Documentation/RCU/rcuref.txt
index 141d531aa14..613033ff2b9 100644
--- a/Documentation/RCU/rcuref.txt
+++ b/Documentation/RCU/rcuref.txt
@@ -1,5 +1,14 @@
Reference-count design for elements of lists/arrays protected by RCU.
+
+Please note that the percpu-ref feature is likely your first
+stop if you need to combine reference counts and RCU. Please see
+include/linux/percpu-refcount.h for more information. However, in
+those unusual cases where percpu-ref would consume too much memory,
+please read on.
+
+------------------------------------------------------------------------
+
Reference counting on elements of lists which are protected by traditional
reader/writer spinlocks or semaphores are straightforward:
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 45fbea7c329..90f6139608f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2813,6 +2813,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
quiescent states. Units are jiffies, minimum
value is one, and maximum value is HZ.
+ rcutree.rcu_nocb_leader_stride= [KNL]
+ Set the number of NOCB kthread groups, which
+ defaults to the square root of the number of
+ CPUs. Larger numbers reduces the wakeup overhead
+ on the per-CPU grace-period kthreads, but increases
+ that same overhead on each group's leader.
+
rcutree.qhimark= [KNL]
Set threshold of queued RCU callbacks beyond which
batch limiting is disabled.
diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt
index f1dc4a21559..a4de88fb55f 100644
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -757,10 +757,14 @@ SMP BARRIER PAIRING
When dealing with CPU-CPU interactions, certain types of memory barrier should
always be paired. A lack of appropriate pairing is almost certainly an error.
-A write barrier should always be paired with a data dependency barrier or read
-barrier, though a general barrier would also be viable. Similarly a read
-barrier or a data dependency barrier should always be paired with at least an
-write barrier, though, again, a general barrier is viable:
+General barriers pair with each other, though they also pair with
+most other types of barriers, albeit without transitivity. An acquire
+barrier pairs with a release barrier, but both may also pair with other
+barriers, including of course general barriers. A write barrier pairs
+with a data dependency barrier, an acquire barrier, a release barrier,
+a read barrier, or a general barrier. Similarly a read barrier or a
+data dependency barrier pairs with a write barrier, an acquire barrier,
+a release barrier, or a general barrier:
CPU 1 CPU 2
=============== ===============
@@ -1893,6 +1897,21 @@ between the STORE to indicate the event and the STORE to set TASK_RUNNING:
<general barrier> STORE current->state
LOAD event_indicated
+To repeat, this write memory barrier is present if and only if something
+is actually awakened. To see this, consider the following sequence of
+events, where X and Y are both initially zero:
+
+ CPU 1 CPU 2
+ =============================== ===============================
+ X = 1; STORE event_indicated
+ smp_mb(); wake_up();
+ Y = 1; wait_event(wq, Y == 1);
+ wake_up(); load from Y sees 1, no memory barrier
+ load from X might see 0
+
+In contrast, if a wakeup does occur, CPU 2's load from X would be guaranteed
+to see 1.
+
The available waker functions include:
complete();
diff --git a/MAINTAINERS b/MAINTAINERS
index e4cf1f63f48..1acc624ecfd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -70,6 +70,8 @@ Descriptions of section entries:
P: Person (obsolete)
M: Mail patches to: FullName <address@domain>
+ R: Designated reviewer: FullName <address@domain>
+ These reviewers should be CCed on patches.
L: Mailing list that is relevant to this area
W: Web-page with status/info
Q: Patchwork web based patch tracking system site
@@ -7443,10 +7445,14 @@ L: linux-kernel@vger.kernel.org
S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
F: Documentation/RCU/torture.txt
-F: kernel/rcu/torture.c
+F: kernel/rcu/rcutorture.c
RCUTORTURE TEST FRAMEWORK
M: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
+M: Josh Triplett <josh@joshtriplett.org>
+R: Steven Rostedt <rostedt@goodmis.org>
+R: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+R: Lai Jiangshan <laijs@cn.fujitsu.com>
L: linux-kernel@vger.kernel.org
S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
@@ -7469,8 +7475,11 @@ S: Supported
F: net/rds/
READ-COPY UPDATE (RCU)
-M: Dipankar Sarma <dipankar@in.ibm.com>
M: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
+M: Josh Triplett <josh@joshtriplett.org>
+R: Steven Rostedt <rostedt@goodmis.org>
+R: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+R: Lai Jiangshan <laijs@cn.fujitsu.com>
L: linux-kernel@vger.kernel.org
W: http://www.rdrop.com/users/paulmck/RCU/
S: Supported
@@ -7480,7 +7489,7 @@ X: Documentation/RCU/torture.txt
F: include/linux/rcu*
X: include/linux/srcu.h
F: kernel/rcu/
-X: kernel/rcu/torture.c
+X: kernel/torture.c
REAL TIME CLOCK (RTC) SUBSYSTEM
M: Alessandro Zummo <a.zummo@towertech.it>
@@ -8263,6 +8272,9 @@ F: mm/sl?b*
SLEEPABLE READ-COPY UPDATE (SRCU)
M: Lai Jiangshan <laijs@cn.fujitsu.com>
M: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
+M: Josh Triplett <josh@joshtriplett.org>
+R: Steven Rostedt <rostedt@goodmis.org>
+R: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
L: linux-kernel@vger.kernel.org
W: http://www.rdrop.com/users/paulmck/RCU/
S: Supported
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 6df7f9fe0d0..2bb4c4f3531 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -102,12 +102,6 @@ extern struct group_info init_groups;
#define INIT_IDS
#endif
-#ifdef CONFIG_RCU_BOOST
-#define INIT_TASK_RCU_BOOST() \
- .rcu_boost_mutex = NULL,
-#else
-#define INIT_TASK_RCU_BOOST()
-#endif
#ifdef CONFIG_TREE_PREEMPT_RCU
#define INIT_TASK_RCU_TREE_PREEMPT() \
.rcu_blocked_node = NULL,
@@ -119,8 +113,7 @@ extern struct group_info init_groups;
.rcu_read_lock_nesting = 0, \
.rcu_read_unlock_special = 0, \
.rcu_node_entry = LIST_HEAD_INIT(tsk.rcu_node_entry), \
- INIT_TASK_RCU_TREE_PREEMPT() \
- INIT_TASK_RCU_BOOST()
+ INIT_TASK_RCU_TREE_PREEMPT()
#else
#define INIT_TASK_RCU_PREEMPT(tsk)
#endif
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 6a94cc8b1ca..d231aa17b1d 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -826,15 +826,14 @@ static inline void rcu_preempt_sleep_check(void)
* read-side critical section that would block in a !PREEMPT kernel.
* But if you want the full story, read on!
*
- * In non-preemptible RCU implementations (TREE_RCU and TINY_RCU), it
- * is illegal to block while in an RCU read-side critical section. In
- * preemptible RCU implementations (TREE_PREEMPT_RCU and TINY_PREEMPT_RCU)
- * in CONFIG_PREEMPT kernel builds, RCU read-side critical sections may
- * be preempted, but explicit blocking is illegal. Finally, in preemptible
- * RCU implementations in real-time (with -rt patchset) kernel builds,
- * RCU read-side critical sections may be preempted and they may also
- * block, but only when acquiring spinlocks that are subject to priority
- * inheritance.
+ * In non-preemptible RCU implementations (TREE_RCU and TINY_RCU),
+ * it is illegal to block while in an RCU read-side critical section.
+ * In preemptible RCU implementations (TREE_PREEMPT_RCU) in CONFIG_PREEMPT
+ * kernel builds, RCU read-side critical sections may be preempted,
+ * but explicit blocking is illegal. Finally, in preemptible RCU
+ * implementations in real-time (with -rt patchset) kernel builds, RCU
+ * read-side critical sections may be preempted and they may also block, but
+ * only when acquiring spinlocks that are subject to priority inheritance.
*/
static inline void rcu_read_lock(void)
{
@@ -858,6 +857,34 @@ static inline void rcu_read_lock(void)
/**
* rcu_read_unlock() - marks the end of an RCU read-side critical section.
*
+ * In most situations, rcu_read_unlock() is immune from deadlock.
+ * However, in kernels built with CONFIG_RCU_BOOST, rcu_read_unlock()
+ * is responsible for deboosting, which it does via rt_mutex_unlock().
+ * Unfortunately, this function acquires the scheduler's runqueue and
+ * priority-inheritance spinlocks. This means that deadlock could result
+ * if the caller of rcu_read_unlock() already holds one of these locks or
+ * any lock that is ever acquired while holding them.
+ *
+ * That said, RCU readers are never priority boosted unless they were
+ * preempted. Therefore, one way to avoid deadlock is to make sure
+ * that preemption never happens within any RCU read-side critical
+ * section whose outermost rcu_read_unlock() is called with one of
+ * rt_mutex_unlock()'s locks held. Such preemption can be avoided in
+ * a number of ways, for example, by invoking preempt_disable() before
+ * critical section's outermost rcu_read_lock().
+ *
+ * Given that the set of locks acquired by rt_mutex_unlock() might change
+ * at any time, a somewhat more future-proofed approach is to make sure
+ * that that preemption never happens within any RCU read-side critical
+ * section whose outermost rcu_read_unlock() is called with irqs disabled.
+ * This approach relies on the fact that rt_mutex_unlock() currently only
+ * acquires irq-disabled locks.
+ *
+ * The second of these two approaches is best in most situations,
+ * however, the first approach can also be useful, at least to those
+ * developers willing to keep abreast of the set of locks acquired by
+ * rt_mutex_unlock().
+ *
* See rcu_read_lock() for more information.
*/
static inline void rcu_read_unlock(void)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0376b054a0d..b39a671cfd5 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1270,9 +1270,6 @@ struct task_struct {
#ifdef CONFIG_TREE_PREEMPT_RCU
struct rcu_node *rcu_blocked_node;
#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
-#ifdef CONFIG_RCU_BOOST
- struct rt_mutex *rcu_boost_mutex;
-#endif /* #ifdef CONFIG_RCU_BOOST */
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
struct sched_info sched_info;
@@ -2009,9 +2006,6 @@ static inline void rcu_copy_process(struct task_struct *p)
#ifdef CONFIG_TREE_PREEMPT_RCU
p->rcu_blocked_node = NULL;
#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
-#ifdef CONFIG_RCU_BOOST
- p->rcu_boost_mutex = NULL;
-#endif /* #ifdef CONFIG_RCU_BOOST */
INIT_LIST_HEAD(&p->rcu_node_entry);
}
diff --git a/include/linux/tick.h b/include/linux/tick.h
index b84773cb9f4..06cc093ab7a 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -12,6 +12,7 @@
#include <linux/hrtimer.h>
#include <linux/context_tracking_state.h>
#include <linux/cpumask.h>
+#include <linux/sched.h>
#ifdef CONFIG_GENERIC_CLOCKEVENTS
@@ -162,6 +163,7 @@ static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
#ifdef CONFIG_NO_HZ_FULL
extern bool tick_nohz_full_running;
extern cpumask_var_t tick_nohz_full_mask;
+extern cpumask_var_t housekeeping_mask;
static inline bool tick_nohz_full_enabled(void)
{
@@ -194,6 +196,24 @@ static inline void tick_nohz_full_kick_all(void) { }
static inline void __tick_nohz_task_switch(struct task_struct *tsk) { }
#endif
+static inline bool is_housekeeping_cpu(int cpu)
+{
+#ifdef CONFIG_NO_HZ_FULL
+ if (tick_nohz_full_enabled())
+ return cpumask_test_cpu(cpu, housekeeping_mask);
+#endif
+ return true;
+}
+
+static inline void housekeeping_affine(struct task_struct *t)
+{
+#ifdef CONFIG_NO_HZ_FULL
+ if (tick_nohz_full_enabled())
+ set_cpus_allowed_ptr(t, housekeeping_mask);
+
+#endif
+}
+
static inline void tick_nohz_full_check(void)
{
if (tick_nohz_full_enabled())
diff --git a/init/Kconfig b/init/Kconfig
index 9d76b99af1b..41066e49e88 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -505,7 +505,7 @@ config PREEMPT_RCU
def_bool TREE_PREEMPT_RCU
help
This option enables preemptible-RCU code that is common between
- the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
+ TREE_PREEMPT_RCU and, in the old days, TINY_PREEMPT_RCU.
config RCU_STALL_COMMON
def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
@@ -737,7 +737,7 @@ choice
config RCU_NOCB_CPU_NONE
bool "No build_forced no-CBs CPUs"
- depends on RCU_NOCB_CPU && !NO_HZ_FULL
+ depends on RCU_NOCB_CPU && !NO_HZ_FULL_ALL
help
This option does not force any of the CPUs to be no-CBs CPUs.
Only CPUs designated by the rcu_nocbs= boot parameter will be
@@ -751,7 +751,7 @@ config RCU_NOCB_CPU_NONE
config RCU_NOCB_CPU_ZERO
bool "CPU 0 is a build_forced no-CBs CPU"
- depends on RCU_NOCB_CPU && !NO_HZ_FULL
+ depends on RCU_NOCB_CPU && !NO_HZ_FULL_ALL
help
This option forces CPU 0 to be a no-CBs CPU, so that its RCU
callbacks are invoked by a per-CPU kthread whose name begins
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index bfda2726ca4..ff1a6de62f1 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -99,6 +99,10 @@ static inline void debug_rcu_head_unqueue(struct rcu_head *head)
void kfree(const void *);
+/*
+ * Reclaim the specified callback, either by invoking it (non-lazy case)
+ * or freeing it directly (lazy case). Return true if lazy, false otherwise.
+ */
static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
{
unsigned long offset = (unsigned long)head->func;
@@ -108,12 +112,12 @@ static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset));
kfree((void *)head - offset);
rcu_lock_release(&rcu_callback_map);
- return 1;
+ return true;
} else {
RCU_TRACE(trace_rcu_invoke_callback(rn, head));
head->func(head);
rcu_lock_release(&rcu_callback_map);
- return 0;
+ return false;
}
}
diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c
index c639556f3fa..e037f3eb2f7 100644
--- a/kernel/rcu/srcu.c
+++ b/kernel/rcu/srcu.c
@@ -298,9 +298,9 @@ int __srcu_read_lock(struct srcu_struct *sp)
idx = ACCESS_ONCE(sp->completed) & 0x1;
preempt_disable();
- ACCESS_ONCE(this_cpu_ptr(sp->per_cpu_ref)->c[idx]) += 1;
+ __this_cpu_inc(sp->per_cpu_ref->c[idx]);
smp_mb(); /* B */ /* Avoid leaking the critical section. */
- ACCESS_ONCE(this_cpu_ptr(sp->per_cpu_ref)->seq[idx]) += 1;
+ __this_cpu_inc(sp->per_cpu_ref->seq[idx]);
preempt_enable();
return idx;
}
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 625d0b0cd75..1b70cb6fbe3 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1013,10 +1013,7 @@ static void record_gp_stall_check_time(struct rcu_state *rsp)
}
/*
- * Dump stacks of all tasks running on stalled CPUs. This is a fallback
- * for architectures that do not implement trigger_all_cpu_backtrace().
- * The NMI-triggered stack traces are more accurate because they are
- * printed by the target CPU.
+ * Dump stacks of all tasks running on stalled CPUs.
*/
static void rcu_dump_cpu_stacks(struct rcu_state *rsp)
{
@@ -1094,7 +1091,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
(long)rsp->gpnum, (long)rsp->completed, totqlen);
if (ndetected == 0)
pr_err("INFO: Stall ended before state dump start\n");
- else if (!trigger_all_cpu_backtrace())
+ else
rcu_dump_cpu_stacks(rsp);
/* Complain about tasks blocking the grace period. */
@@ -1125,8 +1122,7 @@ static void print_cpu_stall(struct rcu_state *rsp)
pr_cont(" (t=%lu jiffies g=%ld c=%ld q=%lu)\n",
jiffies - rsp->gp_start,
(long)rsp->gpnum, (long)rsp->completed, totqlen);
- if (!trigger_all_cpu_backtrace())
- dump_stack();
+ rcu_dump_cpu_stacks(rsp);
raw_spin_lock_irqsave(&rnp->lock, flags);
if (ULONG_CMP_GE(jiffies, ACCESS_ONCE(rsp->jiffies_stall)))
@@ -1305,10 +1301,16 @@ rcu_start_future_gp(struct rcu_node *rnp, struct rcu_data *rdp,
* believe that a grace period is in progress, then we must wait
* for the one following, which is in "c". Because our request
* will be noticed at the end of the current grace period, we don't
- * need to explicitly start one.
+ * need to explicitly start one. We only do the lockless check
+ * of rnp_root's fields if the current rcu_node structure thinks
+ * there is no grace period in flight, and because we hold rnp->lock,
+ * the only possible change is when rnp_root's two fields are
+ * equal, in which case rnp_root->gpnum might be concurrently
+ * incremented. But that is OK, as it will just result in our
+ * doing some extra useless work.
*/
if (rnp->gpnum != rnp->completed ||
- ACCESS_ONCE(rnp->gpnum) != ACCESS_ONCE(rnp->completed)) {
+ ACCESS_ONCE(rnp_root->gpnum) != ACCESS_ONCE(rnp_root->completed)) {
rnp->need_future_gp[c & 0x1]++;
trace_rcu_future_gp(rnp, rdp, c, TPS("Startedleaf"));
goto out;
@@ -1645,11 +1647,6 @@ static int rcu_gp_init(struct rcu_state *rsp)
rnp->level, rnp->grplo,
rnp->grphi, rnp->qsmask);
raw_spin_unlock_irq(&rnp->lock);
-#ifdef CONFIG_PROVE_RCU_DELAY
- if ((prandom_u32() % (rcu_num_nodes + 1)) == 0 &&
- system_state == SYSTEM_RUNNING)
- udelay(200);
-#endif /* #ifdef CONFIG_PROVE_RCU_DELAY */
cond_resched();
}
@@ -2347,7 +2344,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
}
smp_mb(); /* List handling before counting for rcu_barrier(). */
rdp->qlen_lazy -= count_lazy;
- ACCESS_ONCE(rdp->qlen) -= count;
+ ACCESS_ONCE(rdp->qlen) = rdp->qlen - count;
rdp->n_cbs_invoked += count;
/* Reinstate batch limit if we have worked down the excess. */
@@ -2485,14 +2482,14 @@ static void force_quiescent_state(struct rcu_state *rsp)
struct rcu_node *rnp_old = NULL;
/* Funnel through hierarchy to reduce memory contention. */
- rnp = per_cpu_ptr(rsp->rda, raw_smp_processor_id())->mynode;
+ rnp = __this_cpu_read(rsp->rda->mynode);
for (; rnp != NULL; rnp = rnp->parent) {
ret = (ACCESS_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) ||
!raw_spin_trylock(&rnp->fqslock);
if (rnp_old != NULL)
raw_spin_unlock(&rnp_old->fqslock);
if (ret) {
- ACCESS_ONCE(rsp->n_force_qs_lh)++;
+ rsp->n_force_qs_lh++;
return;
}
rnp_old = rnp;
@@ -2504,7 +2501,7 @@ 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) {
- ACCESS_ONCE(rsp->n_force_qs_lh)++;
+ rsp->n_force_qs_lh++;
raw_spin_unlock_irqrestore(&rnp_old->lock, flags);
return; /* Someone beat us to it. */
}
@@ -2662,7 +2659,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu),
unsigned long flags;
struct rcu_data *rdp;
- WARN_ON_ONCE((unsigned long)head & 0x3); /* Misaligned rcu_head! */
+ WARN_ON_ONCE((unsigned long)head & 0x1); /* Misaligned rcu_head! */
if (debug_rcu_head_queue(head)) {
/* Probable double call_rcu(), so leak the callback. */
ACCESS_ONCE(head->func) = rcu_leak_callback;
@@ -2693,7 +2690,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu),
local_irq_restore(flags);
return;
}
- ACCESS_ONCE(rdp->qlen)++;
+ ACCESS_ONCE(rdp->qlen) = rdp->qlen + 1;
if (lazy)
rdp->qlen_lazy++;
else
@@ -3257,7 +3254,7 @@ static void _rcu_barrier(struct rcu_state *rsp)
* ACCESS_ONCE() to prevent the compiler from speculating
* the increment to precede the early-exit check.
*/
- ACCESS_ONCE(rsp->n_barrier_done)++;
+ ACCESS_ONCE(rsp->n_barrier_done) = rsp->n_barrier_done + 1;
WARN_ON_ONCE((rsp->n_barrier_done & 0x1) != 1);
_rcu_barrier_trace(rsp, "Inc1", -1, rsp->n_barrier_done);
smp_mb(); /* Order ->n_barrier_done increment with below mechanism. */
@@ -3307,7 +3304,7 @@ static void _rcu_barrier(struct rcu_state *rsp)
/* Increment ->n_barrier_done to prevent duplicate work. */
smp_mb(); /* Keep increment after above mechanism. */
- ACCESS_ONCE(rsp->n_barrier_done)++;
+ ACCESS_ONCE(rsp->n_barrier_done) = rsp->n_barrier_done + 1;
WARN_ON_ONCE((rsp->n_barrier_done & 0x1) != 0);
_rcu_barrier_trace(rsp, "Inc2", -1, rsp->n_barrier_done);
smp_mb(); /* Keep increment before caller's subsequent code. */
@@ -3564,14 +3561,16 @@ static void __init rcu_init_levelspread(struct rcu_state *rsp)
static void __init rcu_init_one(struct rcu_state *rsp,
struct rcu_data __percpu *rda)
{
- static char *buf[] = { "rcu_node_0",
- "rcu_node_1",
- "rcu_node_2",
- "rcu_node_3" }; /* Match MAX_RCU_LVLS */
- static char *fqs[] = { "rcu_node_fqs_0",
- "rcu_node_fqs_1",
- "rcu_node_fqs_2",
- "rcu_node_fqs_3" }; /* Match MAX_RCU_LVLS */
+ static const char * const buf[] = {
+ "rcu_node_0",
+ "rcu_node_1",
+ "rcu_node_2",
+ "rcu_node_3" }; /* Match MAX_RCU_LVLS */
+ static const char * const fqs[] = {
+ "rcu_node_fqs_0",
+ "rcu_node_fqs_1",
+ "rcu_node_fqs_2",
+ "rcu_node_fqs_3" }; /* Match MAX_RCU_LVLS */
static u8 fl_mask = 0x1;
int cpustride = 1;
int i;
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 0f69a79c5b7..71e64c718f7 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -172,6 +172,14 @@ struct rcu_node {
/* queued on this rcu_node structure that */
/* are blocking the current grace period, */
/* there can be no such task. */
+ struct completion boost_completion;
+ /* Used to ensure that the rt_mutex used */
+ /* to carry out the boosting is fully */
+ /* released with no future boostee accesses */
+ /* before that rt_mutex is re-initialized. */
+ struct rt_mutex boost_mtx;
+ /* Used only for the priority-boosting */
+ /* side effect, not as a lock. */
unsigned long boost_time;
/* When to start boosting (jiffies). */
struct task_struct *boost_kthread_task;
@@ -334,11 +342,29 @@ struct rcu_data {
struct rcu_head **nocb_tail;
atomic_long_t nocb_q_count; /* # CBs waiting for kthread */
atomic_long_t nocb_q_count_lazy; /* (approximate). */
+ struct rcu_head *nocb_follower_head; /* CBs ready to invoke. */
+ struct rcu_head **nocb_follower_tail;
+ atomic_long_t nocb_follower_count; /* # CBs ready to invoke. */
+ atomic_long_t nocb_follower_count_lazy; /* (approximate). */
int nocb_p_count; /* # CBs being invoked by kthread */
int nocb_p_count_lazy; /* (approximate). */
wait_queue_head_t nocb_wq; /* For nocb kthreads to sleep on. */
struct task_struct *nocb_kthread;
bool nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */
+
+ /* The following fields are used by the leader, hence own cacheline. */
+ struct rcu_head *nocb_gp_head ____cacheline_internodealigned_in_smp;
+ /* CBs waiting for GP. */
+ struct rcu_head **nocb_gp_tail;
+ long nocb_gp_count;
+ long nocb_gp_count_lazy;
+ bool nocb_leader_wake; /* Is the nocb leader thread awake? */
+ struct rcu_data *nocb_next_follower;
+ /* Next follower in wakeup chain. */
+
+ /* The following fields are used by the follower, hence new cachline. */
+ struct rcu_data *nocb_leader ____cacheline_internodealigned_in_smp;
+ /* Leader CPU takes GP-end wakeups. */
#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
/* 8) RCU CPU stall data. */
@@ -587,8 +613,14 @@ static bool rcu_nohz_full_cpu(struct rcu_state *rsp);
/* Sum up queue lengths for tracing. */
static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
{
- *ql = atomic_long_read(&rdp->nocb_q_count) + rdp->nocb_p_count;
- *qll = atomic_long_read(&rdp->nocb_q_count_lazy) + rdp->nocb_p_count_lazy;
+ *ql = atomic_long_read(&rdp->nocb_q_count) +
+ rdp->nocb_p_count +
+ atomic_long_read(&rdp->nocb_follower_count) +
+ rdp->nocb_p_count + rdp->nocb_gp_count;
+ *qll = atomic_long_read(&rdp->nocb_q_count_lazy) +
+ rdp->nocb_p_count_lazy +
+ atomic_long_read(&rdp->nocb_follower_count_lazy) +
+ rdp->nocb_p_count_lazy + rdp->nocb_gp_count_lazy;
}
#else /* #ifdef CONFIG_RCU_NOCB_CPU */
static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 02ac0fb186b..00dc411e967 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -33,6 +33,7 @@
#define RCU_KTHREAD_PRIO 1
#ifdef CONFIG_RCU_BOOST
+#include "../locking/rtmutex_common.h"
#define RCU_BOOST_PRIO CONFIG_RCU_BOOST_PRIO
#else
#define RCU_BOOST_PRIO RCU_KTHREAD_PRIO
@@ -336,7 +337,7 @@ void rcu_read_unlock_special(struct task_struct *t)
unsigned long flags;
struct list_head *np;
#ifdef CONFIG_RCU_BOOST
- struct rt_mutex *rbmp = NULL;
+ bool drop_boost_mutex = false;
#endif /* #ifdef CONFIG_RCU_BOOST */
struct rcu_node *rnp;
int special;
@@ -398,11 +399,8 @@ void rcu_read_unlock_special(struct task_struct *t)
#ifdef CONFIG_RCU_BOOST
if (&t->rcu_node_entry == rnp->boost_tasks)
rnp->boost_tasks = np;
- /* Snapshot/clear ->rcu_boost_mutex with rcu_node lock held. */
- if (t->rcu_boost_mutex) {
- rbmp = t->rcu_boost_mutex;
- t->rcu_boost_mutex = NULL;
- }
+ /* Snapshot ->boost_mtx ownership with rcu_node lock held. */
+ drop_boost_mutex = rt_mutex_owner(&rnp->boost_mtx) == t;
#endif /* #ifdef CONFIG_RCU_BOOST */
/*
@@ -427,8 +425,10 @@ void rcu_read_unlock_special(struct task_struct *t)
#ifdef CONFIG_RCU_BOOST
/* Unboost if we were boosted. */
- if (rbmp)
- rt_mutex_unlock(rbmp);
+ if (drop_boost_mutex) {
+ rt_mutex_unlock(&rnp->boost_mtx);
+ complete(&rnp->boost_completion);
+ }
#endif /* #ifdef CONFIG_RCU_BOOST */
/*
@@ -988,6 +988,7 @@ static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp)
/* Because preemptible RCU does not exist, no quieting of tasks. */
static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags)
+ __releases(rnp->lock)
{
raw_spin_unlock_irqrestore(&rnp->lock, flags);
}
@@ -1149,7 +1150,6 @@ static void rcu_wake_cond(struct task_struct *t, int status)
static int rcu_boost(struct rcu_node *rnp)
{
unsigned long flags;
- struct rt_mutex mtx;
struct task_struct *t;
struct list_head *tb;
@@ -1200,11 +1200,15 @@ static int rcu_boost(struct rcu_node *rnp)
* section.
*/
t = container_of(tb, struct task_struct, rcu_node_entry);
- rt_mutex_init_proxy_locked(&mtx, t);
- t->rcu_boost_mutex = &mtx;
+ rt_mutex_init_proxy_locked(&rnp->boost_mtx, t);
+ init_completion(&rnp->boost_completion);
raw_spin_unlock_irqrestore(&rnp->lock, flags);
- rt_mutex_lock(&mtx); /* Side effect: boosts task t's priority. */
- rt_mutex_unlock(&mtx); /* Keep lockdep happy. */
+ /* Lock only for side effect: boosts task t's priority. */
+ rt_mutex_lock(&rnp->boost_mtx);
+ rt_mutex_unlock(&rnp->boost_mtx); /* Then keep lockdep happy. */
+
+ /* Wait for boostee to be done w/boost_mtx before reinitializing. */
+ wait_for_completion(&rnp->boost_completion);
return ACCESS_ONCE(rnp->exp_tasks) != NULL ||
ACCESS_ONCE(rnp->boost_tasks) != NULL;
@@ -1256,6 +1260,7 @@ static int rcu_boost_kthread(void *arg)
* about it going away.
*/
static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
+ __releases(rnp->lock)
{
struct task_struct *t;
@@ -1491,6 +1496,7 @@ static void rcu_prepare_kthreads(int cpu)
#else /* #ifdef CONFIG_RCU_BOOST */
static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
+ __releases(rnp->lock)
{
raw_spin_unlock_irqrestore(&rnp->lock, flags);
}
@@ -2060,6 +2066,22 @@ bool rcu_is_nocb_cpu(int cpu)
#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
/*
+ * Kick the leader kthread for this NOCB group.
+ */
+static void wake_nocb_leader(struct rcu_data *rdp, bool force)
+{
+ struct rcu_data *rdp_leader = rdp->nocb_leader;
+
+ if (!ACCESS_ONCE(rdp_leader->nocb_kthread))
+ return;
+ if (!ACCESS_ONCE(rdp_leader->nocb_leader_wake) || force) {
+ /* Prior xchg orders against prior callback enqueue. */
+ ACCESS_ONCE(rdp_leader->nocb_leader_wake) = true;
+ wake_up(&rdp_leader->nocb_wq);
+ }
+}
+
+/*
* Enqueue the specified string of rcu_head structures onto the specified
* CPU's no-CBs lists. The CPU is specified by rdp, the head of the
* string by rhp, and the tail of the string by rhtp. The non-lazy/lazy
@@ -2093,7 +2115,8 @@ static void __call_rcu_nocb_enqueue(struct rcu_data *rdp,
len = atomic_long_read(&rdp->nocb_q_count);
if (old_rhpp == &rdp->nocb_head) {
if (!irqs_disabled_flags(flags)) {
- wake_up(&rdp->nocb_wq); /* ... if queue was empty ... */
+ /* ... if queue was empty ... */
+ wake_nocb_leader(rdp, false);
trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
TPS("WakeEmpty"));
} else {
@@ -2103,7 +2126,8 @@ static void __call_rcu_nocb_enqueue(struct rcu_data *rdp,
}
rdp->qlen_last_fqs_check = 0;
} else if (len > rdp->qlen_last_fqs_check + qhimark) {
- wake_up_process(t); /* ... or if many callbacks queued. */
+ /* ... or if many callbacks queued. */
+ wake_nocb_leader(rdp, true);
rdp->qlen_last_fqs_check = LONG_MAX / 2;
trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WakeOvf"));
} else {
@@ -2213,13 +2237,150 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp)
}
/*
+ * Leaders come here to wait for additional callbacks to show up.
+ * This function does not return until callbacks appear.
+ */
+static void nocb_leader_wait(struct rcu_data *my_rdp)
+{
+ bool firsttime = true;
+ bool gotcbs;
+ struct rcu_data *rdp;
+ struct rcu_head **tail;
+
+wait_again:
+
+ /* Wait for callbacks to appear. */
+ if (!rcu_nocb_poll) {
+ trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "Sleep");
+ wait_event_interruptible(my_rdp->nocb_wq,
+ ACCESS_ONCE(my_rdp->nocb_leader_wake));
+ /* Memory barrier handled by smp_mb() calls below and repoll. */
+ } else if (firsttime) {
+ firsttime = false; /* Don't drown trace log with "Poll"! */
+ trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "Poll");
+ }
+
+ /*
+ * Each pass through the following loop checks a follower for CBs.
+ * We are our own first follower. Any CBs found are moved to
+ * nocb_gp_head, where they await a grace period.
+ */
+ gotcbs = false;
+ for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower) {
+ rdp->nocb_gp_head = ACCESS_ONCE(rdp->nocb_head);
+ if (!rdp->nocb_gp_head)
+ continue; /* No CBs here, try next follower. */
+
+ /* Move callbacks to wait-for-GP list, which is empty. */
+ ACCESS_ONCE(rdp->nocb_head) = NULL;
+ rdp->nocb_gp_tail = xchg(&rdp->nocb_tail, &rdp->nocb_head);
+ rdp->nocb_gp_count = atomic_long_xchg(&rdp->nocb_q_count, 0);
+ rdp->nocb_gp_count_lazy =
+ atomic_long_xchg(&rdp->nocb_q_count_lazy, 0);
+ gotcbs = true;
+ }
+
+ /*
+ * If there were no callbacks, sleep a bit, rescan after a
+ * memory barrier, and go retry.
+ */
+ if (unlikely(!gotcbs)) {
+ if (!rcu_nocb_poll)
+ trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu,
+ "WokeEmpty");
+ flush_signals(current);
+ schedule_timeout_interruptible(1);
+
+ /* Rescan in case we were a victim of memory ordering. */
+ my_rdp->nocb_leader_wake = false;
+ smp_mb(); /* Ensure _wake false before scan. */
+ for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower)
+ if (ACCESS_ONCE(rdp->nocb_head)) {
+ /* Found CB, so short-circuit next wait. */
+ my_rdp->nocb_leader_wake = true;
+ break;
+ }
+ goto wait_again;
+ }
+
+ /* Wait for one grace period. */
+ rcu_nocb_wait_gp(my_rdp);
+
+ /*
+ * We left ->nocb_leader_wake set to reduce cache thrashing.
+ * We clear it now, but recheck for new callbacks while
+ * traversing our follower list.
+ */
+ my_rdp->nocb_leader_wake = false;
+ smp_mb(); /* Ensure _wake false before scan of ->nocb_head. */
+
+ /* Each pass through the following loop wakes a follower, if needed. */
+ for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower) {
+ if (ACCESS_ONCE(rdp->nocb_head))
+ my_rdp->nocb_leader_wake = true; /* No need to wait. */
+ if (!rdp->nocb_gp_head)
+ continue; /* No CBs, so no need to wake follower. */
+
+ /* Append callbacks to follower's "done" list. */
+ tail = xchg(&rdp->nocb_follower_tail, rdp->nocb_gp_tail);
+ *tail = rdp->nocb_gp_head;
+ atomic_long_add(rdp->nocb_gp_count, &rdp->nocb_follower_count);
+ atomic_long_add(rdp->nocb_gp_count_lazy,
+ &rdp->nocb_follower_count_lazy);
+ if (rdp != my_rdp && tail == &rdp->nocb_follower_head) {
+ /*
+ * List was empty, wake up the follower.
+ * Memory barriers supplied by atomic_long_add().
+ */
+ wake_up(&rdp->nocb_wq);
+ }
+ }
+
+ /* If we (the leader) don't have CBs, go wait some more. */
+ if (!my_rdp->nocb_follower_head)
+ goto wait_again;
+}
+
+/*
+ * Followers come here to wait for additional callbacks to show up.
+ * This function does not return until callbacks appear.
+ */
+static void nocb_follower_wait(struct rcu_data *rdp)
+{
+ bool firsttime = true;
+
+ for (;;) {
+ if (!rcu_nocb_poll) {
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
+ "FollowerSleep");
+ wait_event_interruptible(rdp->nocb_wq,
+ ACCESS_ONCE(rdp->nocb_follower_head));
+ } else if (firsttime) {
+ /* Don't drown trace log with "Poll"! */
+ firsttime = false;
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "Poll");
+ }
+ if (smp_load_acquire(&rdp->nocb_follower_head)) {
+ /* ^^^ Ensure CB invocation follows _head test. */
+ return;
+ }
+ if (!rcu_nocb_poll)
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
+ "WokeEmpty");
+ flush_signals(current);
+ schedule_timeout_interruptible(1);
+ }
+}
+
+/*
* Per-rcu_data kthread, but only for no-CBs CPUs. Each kthread invokes
- * callbacks queued by the corresponding no-CBs CPU.
+ * callbacks queued by the corresponding no-CBs CPU, however, there is
+ * an optional leader-follower relationship so that the grace-period
+ * kthreads don't have to do quite so many wakeups.
*/
static int rcu_nocb_kthread(void *arg)
{
int c, cl;
- bool firsttime = 1;
struct rcu_head *list;
struct rcu_head *next;
struct rcu_head **tail;
@@ -2227,41 +2388,22 @@ static int rcu_nocb_kthread(void *arg)
/* Each pass through this loop invokes one batch of callbacks */
for (;;) {
- /* If not polling, wait for next batch of callbacks. */
- if (!rcu_nocb_poll) {
- trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
- TPS("Sleep"));
- wait_event_interruptible(rdp->nocb_wq, rdp->nocb_head);
- /* Memory barrier provide by xchg() below. */
- } else if (firsttime) {
- firsttime = 0;
- trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
- TPS("Poll"));
- }
- list = ACCESS_ONCE(rdp->nocb_head);
- if (!list) {
- if (!rcu_nocb_poll)
- trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
- TPS("WokeEmpty"));
- schedule_timeout_interruptible(1);
- flush_signals(current);
- continue;
- }
- firsttime = 1;
- trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
- TPS("WokeNonEmpty"));
-
- /*
- * Extract queued callbacks, update counts, and wait
- * for a grace period to elapse.
- */
- ACCESS_ONCE(rdp->nocb_head) = NULL;
- tail = xchg(&rdp->nocb_tail, &rdp->nocb_head);
- c = atomic_long_xchg(&rdp->nocb_q_count, 0);
- cl = atomic_long_xchg(&rdp->nocb_q_count_lazy, 0);
- ACCESS_ONCE(rdp->nocb_p_count) += c;
- ACCESS_ONCE(rdp->nocb_p_count_lazy) += cl;
- rcu_nocb_wait_gp(rdp);
+ /* Wait for callbacks. */
+ if (rdp->nocb_leader == rdp)
+ nocb_leader_wait(rdp);
+ else
+ nocb_follower_wait(rdp);
+
+ /* Pull the ready-to-invoke callbacks onto local list. */
+ list = ACCESS_ONCE(rdp->nocb_follower_head);
+ BUG_ON(!list);
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "WokeNonEmpty");
+ ACCESS_ONCE(rdp->nocb_follower_head) = NULL;
+ tail = xchg(&rdp->nocb_follower_tail, &rdp->nocb_follower_head);
+ c = atomic_long_xchg(&rdp->nocb_follower_count, 0);
+ cl = atomic_long_xchg(&rdp->nocb_follower_count_lazy, 0);
+ rdp->nocb_p_count += c;
+ rdp->nocb_p_count_lazy += cl;
/* Each pass through the following loop invokes a callback. */
trace_rcu_batch_start(rdp->rsp->name, cl, c, -1);
@@ -2305,7 +2447,7 @@ static void do_nocb_deferred_wakeup(struct rcu_data *rdp)
if (!rcu_nocb_need_deferred_wakeup(rdp))
return;
ACCESS_ONCE(rdp->nocb_defer_wakeup) = false;
- wake_up(&rdp->nocb_wq);
+ wake_nocb_leader(rdp, false);
trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("DeferredWakeEmpty"));
}
@@ -2314,19 +2456,57 @@ static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp)
{
rdp->nocb_tail = &rdp->nocb_head;
init_waitqueue_head(&rdp->nocb_wq);
+ rdp->nocb_follower_tail = &rdp->nocb_follower_head;
}
-/* Create a kthread for each RCU flavor for each no-CBs CPU. */
+/* How many follower CPU IDs per leader? Default of -1 for sqrt(nr_cpu_ids). */
+static int rcu_nocb_leader_stride = -1;
+module_param(rcu_nocb_leader_stride, int, 0444);
+
+/*
+ * Create a kthread for each RCU flavor for each no-CBs CPU.
+ * Also initialize leader-follower relationships.
+ */
static void __init rcu_spawn_nocb_kthreads(struct rcu_state *rsp)
{
int cpu;
+ int ls = rcu_nocb_leader_stride;
+ int nl = 0; /* Next leader. */
struct rcu_data *rdp;
+ struct rcu_data *rdp_leader = NULL; /* Suppress misguided gcc warn. */
+ struct rcu_data *rdp_prev = NULL;
struct task_struct *t;
if (rcu_nocb_mask == NULL)
return;
+#if defined(CONFIG_NO_HZ_FULL) && !defined(CONFIG_NO_HZ_FULL_ALL)
+ if (tick_nohz_full_running)
+ cpumask_or(rcu_nocb_mask, rcu_nocb_mask, tick_nohz_full_mask);
+#endif /* #if defined(CONFIG_NO_HZ_FULL) && !defined(CONFIG_NO_HZ_FULL_ALL) */
+ if (ls == -1) {
+ ls = int_sqrt(nr_cpu_ids);
+ rcu_nocb_leader_stride = ls;
+ }
+
+ /*
+ * Each pass through this loop sets up one rcu_data structure and
+ * spawns one rcu_nocb_kthread().
+ */
for_each_cpu(cpu, rcu_nocb_mask) {
rdp = per_cpu_ptr(rsp->rda, cpu);
+ if (rdp->cpu >= nl) {
+ /* New leader, set up for followers & next leader. */
+ nl = DIV_ROUND_UP(rdp->cpu + 1, ls) * ls;
+ rdp->nocb_leader = rdp;
+ rdp_leader = rdp;
+ } else {
+ /* Another follower, link to previous leader. */
+ rdp->nocb_leader = rdp_leader;
+ rdp_prev->nocb_next_follower = rdp;
+ }
+ rdp_prev = rdp;
+
+ /* Spawn the kthread for this CPU. */
t = kthread_run(rcu_nocb_kthread, rdp,
"rcuo%c/%d", rsp->abbr, cpu);
BUG_ON(IS_ERR(t));
@@ -2843,12 +3023,16 @@ static bool rcu_nohz_full_cpu(struct rcu_state *rsp)
*/
static void rcu_bind_gp_kthread(void)
{
-#ifdef CONFIG_NO_HZ_FULL
- int cpu = ACCESS_ONCE(tick_do_timer_cpu);
+ int __maybe_unused cpu;
- if (cpu < 0 || cpu >= nr_cpu_ids)
+ if (!tick_nohz_full_enabled())
return;
- if (raw_smp_processor_id() != cpu)
+#ifdef CONFIG_NO_HZ_FULL_SYSIDLE
+ cpu = tick_do_timer_cpu;
+ if (cpu >= 0 && cpu < nr_cpu_ids && raw_smp_processor_id() != cpu)
set_cpus_allowed_ptr(current, cpumask_of(cpu));
-#endif /* #ifdef CONFIG_NO_HZ_FULL */
+#else /* #ifdef CONFIG_NO_HZ_FULL_SYSIDLE */
+ if (!is_housekeeping_cpu(raw_smp_processor_id()))
+ housekeeping_affine(current);
+#endif /* #else #ifdef CONFIG_NO_HZ_FULL_SYSIDLE */
}
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index bc788357053..4056d7992a6 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -90,9 +90,6 @@ void __rcu_read_unlock(void)
} else {
barrier(); /* critical section before exit code. */
t->rcu_read_lock_nesting = INT_MIN;
-#ifdef CONFIG_PROVE_RCU_DELAY
- udelay(10); /* Make preemption more probable. */
-#endif /* #ifdef CONFIG_PROVE_RCU_DELAY */
barrier(); /* assign before ->rcu_read_unlock_special load */
if (unlikely(ACCESS_ONCE(t->rcu_read_unlock_special)))
rcu_read_unlock_special(t);
diff --git a/kernel/signal.c b/kernel/signal.c
index a4077e90f19..40b76e351e6 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1263,6 +1263,10 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
struct sighand_struct *sighand;
for (;;) {
+ /*
+ * Disable interrupts early to avoid deadlocks.
+ * See rcu_read_unlock() comment header for details.
+ */
local_irq_save(*flags);
rcu_read_lock();
sighand = rcu_dereference(tsk->sighand);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 6558b7ac112..f784d83e29f 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -154,6 +154,7 @@ static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
#ifdef CONFIG_NO_HZ_FULL
cpumask_var_t tick_nohz_full_mask;
+cpumask_var_t housekeeping_mask;
bool tick_nohz_full_running;
static bool can_stop_full_tick(void)
@@ -281,6 +282,7 @@ static int __init tick_nohz_full_setup(char *str)
int cpu;
alloc_bootmem_cpumask_var(&tick_nohz_full_mask);
+ alloc_bootmem_cpumask_var(&housekeeping_mask);
if (cpulist_parse(str, tick_nohz_full_mask) < 0) {
pr_warning("NOHZ: Incorrect nohz_full cpumask\n");
return 1;
@@ -291,6 +293,8 @@ static int __init tick_nohz_full_setup(char *str)
pr_warning("NO_HZ: Clearing %d from nohz_full range for timekeeping\n", cpu);
cpumask_clear_cpu(cpu, tick_nohz_full_mask);
}
+ cpumask_andnot(housekeeping_mask,
+ cpu_possible_mask, tick_nohz_full_mask);
tick_nohz_full_running = true;
return 1;
@@ -332,9 +336,15 @@ static int tick_nohz_init_all(void)
pr_err("NO_HZ: Can't allocate full dynticks cpumask\n");
return err;
}
+ if (!alloc_cpumask_var(&housekeeping_mask, GFP_KERNEL)) {
+ pr_err("NO_HZ: Can't allocate not-full dynticks cpumask\n");
+ return err;
+ }
err = 0;
cpumask_setall(tick_nohz_full_mask);
cpumask_clear_cpu(smp_processor_id(), tick_nohz_full_mask);
+ cpumask_clear(housekeeping_mask);
+ cpumask_set_cpu(smp_processor_id(), housekeeping_mask);
tick_nohz_full_running = true;
#endif
return err;
diff --git a/kernel/torture.c b/kernel/torture.c
index 40bb511cca4..d600af21f02 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -708,7 +708,7 @@ int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
int ret = 0;
VERBOSE_TOROUT_STRING(m);
- *tp = kthread_run(fn, arg, s);
+ *tp = kthread_run(fn, arg, "%s", s);
if (IS_ERR(*tp)) {
ret = PTR_ERR(*tp);
VERBOSE_TOROUT_ERRSTRING(f);
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 7a638aa3545..12132e433e3 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1131,20 +1131,6 @@ config PROVE_RCU_REPEATEDLY
Say N if you are unsure.
-config PROVE_RCU_DELAY
- bool "RCU debugging: preemptible RCU race provocation"
- depends on DEBUG_KERNEL && PREEMPT_RCU
- default n
- help
- There is a class of races that involve an unlikely preemption
- of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
- been set to INT_MIN. This feature inserts a delay at that
- point to increase the probability of these races.
-
- Say Y to increase probability of preemption of __rcu_read_unlock().
-
- Say N if you are unsure.
-
config SPARSE_RCU_POINTER
bool "RCU debugging: sparse-based checks for pointer usage"
default n
diff --git a/scripts/get_maintainer.pl b/scripts/get_maintainer.pl
index 41987885bd3..d7016279ec2 100755
--- a/scripts/get_maintainer.pl
+++ b/scripts/get_maintainer.pl
@@ -21,6 +21,7 @@ my $lk_path = "./";
my $email = 1;
my $email_usename = 1;
my $email_maintainer = 1;
+my $email_reviewer = 1;
my $email_list = 1;
my $email_subscriber_list = 0;
my $email_git_penguin_chiefs = 0;
@@ -202,6 +203,7 @@ if (!GetOptions(
'remove-duplicates!' => \$email_remove_duplicates,
'mailmap!' => \$email_use_mailmap,
'm!' => \$email_maintainer,
+ 'r!' => \$email_reviewer,
'n!' => \$email_usename,
'l!' => \$email_list,
's!' => \$email_subscriber_list,
@@ -260,7 +262,8 @@ if ($sections) {
}
if ($email &&
- ($email_maintainer + $email_list + $email_subscriber_list +
+ ($email_maintainer + $email_reviewer +
+ $email_list + $email_subscriber_list +
$email_git + $email_git_penguin_chiefs + $email_git_blame) == 0) {
die "$P: Please select at least 1 email option\n";
}
@@ -750,6 +753,7 @@ MAINTAINER field selection options:
--hg-since => hg history to use (default: $email_hg_since)
--interactive => display a menu (mostly useful if used with the --git option)
--m => include maintainer(s) if any
+ --r => include reviewer(s) if any
--n => include name 'Full Name <addr\@domain.tld>'
--l => include list(s) if any
--s => include subscriber only list(s) if any
@@ -1064,6 +1068,22 @@ sub add_categories {
my $role = get_maintainer_role($i);
push_email_addresses($pvalue, $role);
}
+ } elsif ($ptype eq "R") {
+ my ($name, $address) = parse_email($pvalue);
+ if ($name eq "") {
+ if ($i > 0) {
+ my $tv = $typevalue[$i - 1];
+ if ($tv =~ m/^(\C):\s*(.*)/) {
+ if ($1 eq "P") {
+ $name = $2;
+ $pvalue = format_email($name, $address, $email_usename);
+ }
+ }
+ }
+ }
+ if ($email_reviewer) {
+ push_email_addresses($pvalue, 'reviewer');
+ }
} elsif ($ptype eq "T") {
push(@scm, $pvalue);
} elsif ($ptype eq "W") {
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh b/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
index ee1f6cae3d7..3f6c9b78d17 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
@@ -54,10 +54,16 @@ do
if test -f "$i/qemu-cmd"
then
print_bug qemu failed
+ echo " $i"
+ elif test -f "$i/buildonly"
+ then
+ echo Build-only run, no boot/test
+ configcheck.sh $i/.config $i/ConfigFragment
+ parse-build.sh $i/Make.out $configfile
else
print_bug Build failed
+ echo " $i"
fi
- echo " $i"
fi
done
done
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
index 27e544e2951..0f69dcbf9de 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
@@ -42,6 +42,7 @@ grace=120
T=/tmp/kvm-test-1-run.sh.$$
trap 'rm -rf $T' 0
+touch $T
. $KVM/bin/functions.sh
. $KVPATH/ver_functions.sh
@@ -131,7 +132,10 @@ boot_args=$6
cd $KVM
kstarttime=`awk 'BEGIN { print systime() }' < /dev/null`
-echo ' ---' `date`: Starting kernel
+if test -z "$TORTURE_BUILDONLY"
+then
+ echo ' ---' `date`: Starting kernel
+fi
# Generate -smp qemu argument.
qemu_args="-nographic $qemu_args"
@@ -157,12 +161,13 @@ boot_args="`configfrag_boot_params "$boot_args" "$config_template"`"
# Generate kernel-version-specific boot parameters
boot_args="`per_version_boot_params "$boot_args" $builddir/.config $seconds`"
-echo $QEMU $qemu_args -m 512 -kernel $builddir/$BOOT_IMAGE -append \"$qemu_append $boot_args\" > $resdir/qemu-cmd
if test -n "$TORTURE_BUILDONLY"
then
echo Build-only run specified, boot/test omitted.
+ touch $resdir/buildonly
exit 0
fi
+echo $QEMU $qemu_args -m 512 -kernel $builddir/$BOOT_IMAGE -append \"$qemu_append $boot_args\" > $resdir/qemu-cmd
( $QEMU $qemu_args -m 512 -kernel $builddir/$BOOT_IMAGE -append "$qemu_append $boot_args"; echo $? > $resdir/qemu-retval ) &
qemu_pid=$!
commandcompleted=0
diff --git a/tools/testing/selftests/rcutorture/bin/kvm.sh b/tools/testing/selftests/rcutorture/bin/kvm.sh
index 40285c58653..589e9c38413 100644
--- a/tools/testing/selftests/rcutorture/bin/kvm.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm.sh
@@ -340,12 +340,18 @@ function dump(first, pastlast)
for (j = 1; j < jn; j++) {
builddir=KVM "/b" j
print "rm -f " builddir ".ready"
- print "echo ----", cfr[j], cpusr[j] ovf ": Starting kernel. `date`";
- print "echo ----", cfr[j], cpusr[j] ovf ": Starting kernel. `date` >> " rd "/log";
+ print "if test -z \"$TORTURE_BUILDONLY\""
+ print "then"
+ print "\techo ----", cfr[j], cpusr[j] ovf ": Starting kernel. `date`";
+ print "\techo ----", cfr[j], cpusr[j] ovf ": Starting kernel. `date` >> " rd "/log";
+ print "fi"
}
print "wait"
- print "echo ---- All kernel runs complete. `date`";
- print "echo ---- All kernel runs complete. `date` >> " rd "/log";
+ print "if test -z \"$TORTURE_BUILDONLY\""
+ print "then"
+ print "\techo ---- All kernel runs complete. `date`";
+ print "\techo ---- All kernel runs complete. `date` >> " rd "/log";
+ print "fi"
for (j = 1; j < jn; j++) {
builddir=KVM "/b" j
print "echo ----", cfr[j], cpusr[j] ovf ": Build/run results:";
@@ -385,10 +391,7 @@ echo
echo
echo " --- `date` Test summary:"
echo Results directory: $resdir/$ds
-if test -z "$TORTURE_BUILDONLY"
-then
- kvm-recheck.sh $resdir/$ds
-fi
+kvm-recheck.sh $resdir/$ds
___EOF___
if test "$dryrun" = script
@@ -403,7 +406,7 @@ then
sed -e 's/:.*$//' -e 's/^echo //'
exit 0
else
- # Not a dryru, so run the script.
+ # Not a dryrun, so run the script.
sh $T/script
fi
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE01 b/tools/testing/selftests/rcutorture/configs/rcu/TREE01
index 9c827ec59a9..063b7079c62 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE01
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE01
@@ -15,7 +15,6 @@ CONFIG_RCU_FANOUT_EXACT=n
CONFIG_RCU_NOCB_CPU=y
CONFIG_RCU_NOCB_CPU_ZERO=y
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_PROVE_RCU_DELAY=n
CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_CPU_STALL_VERBOSE=n
CONFIG_RCU_BOOST=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE02 b/tools/testing/selftests/rcutorture/configs/rcu/TREE02
index 1a777b5f68b..ea119ba2f7d 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE02
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE02
@@ -18,7 +18,6 @@ CONFIG_RCU_FANOUT_EXACT=n
CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_PROVE_LOCKING=n
-CONFIG_PROVE_RCU_DELAY=n
CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_CPU_STALL_VERBOSE=y
CONFIG_RCU_BOOST=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T b/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T
index 61c8d9ce5bb..19cf9485f48 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T
@@ -18,7 +18,6 @@ CONFIG_RCU_FANOUT_EXACT=n
CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_PROVE_LOCKING=n
-CONFIG_PROVE_RCU_DELAY=n
CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_CPU_STALL_VERBOSE=y
CONFIG_RCU_BOOST=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE03 b/tools/testing/selftests/rcutorture/configs/rcu/TREE03
index c1f111c1561..f4567fb3e33 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE03
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE03
@@ -14,7 +14,6 @@ CONFIG_RCU_FANOUT_LEAF=4
CONFIG_RCU_FANOUT_EXACT=n
CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_PROVE_RCU_DELAY=n
CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_CPU_STALL_VERBOSE=n
CONFIG_RCU_BOOST=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE04 b/tools/testing/selftests/rcutorture/configs/rcu/TREE04
index 7dbd27ce17a..0a262fbb0c1 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE04
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE04
@@ -18,7 +18,6 @@ CONFIG_RCU_FANOUT_LEAF=2
CONFIG_RCU_FANOUT_EXACT=n
CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_PROVE_RCU_DELAY=n
CONFIG_RCU_CPU_STALL_INFO=y
CONFIG_RCU_CPU_STALL_VERBOSE=y
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE05 b/tools/testing/selftests/rcutorture/configs/rcu/TREE05
index d0f32e57474..3a06b97e9a7 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE05
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE05
@@ -18,7 +18,6 @@ CONFIG_RCU_NOCB_CPU_NONE=y
CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_PROVE_LOCKING=y
CONFIG_PROVE_RCU=y
-CONFIG_PROVE_RCU_DELAY=y
CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_CPU_STALL_VERBOSE=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE06 b/tools/testing/selftests/rcutorture/configs/rcu/TREE06
index 2e477dfb9c5..8f084cca91b 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE06
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE06
@@ -19,7 +19,6 @@ CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_PROVE_LOCKING=y
CONFIG_PROVE_RCU=y
-CONFIG_PROVE_RCU_DELAY=n
CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_CPU_STALL_VERBOSE=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE07 b/tools/testing/selftests/rcutorture/configs/rcu/TREE07
index 042f86ef362..ab622550690 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE07
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE07
@@ -17,7 +17,6 @@ CONFIG_RCU_FANOUT_LEAF=2
CONFIG_RCU_FANOUT_EXACT=n
CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_PROVE_RCU_DELAY=n
CONFIG_RCU_CPU_STALL_INFO=y
CONFIG_RCU_CPU_STALL_VERBOSE=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE08 b/tools/testing/selftests/rcutorture/configs/rcu/TREE08
index 3438cee1e3c..69a2e255bf9 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE08
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE08
@@ -18,7 +18,6 @@ CONFIG_RCU_FANOUT_LEAF=2
CONFIG_RCU_NOCB_CPU=y
CONFIG_RCU_NOCB_CPU_ALL=y
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_PROVE_RCU_DELAY=n
CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_CPU_STALL_VERBOSE=n
CONFIG_RCU_BOOST=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T b/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T
index bf4523d3e44..a0f32fb8f17 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T
@@ -18,7 +18,6 @@ CONFIG_RCU_FANOUT_LEAF=2
CONFIG_RCU_NOCB_CPU=y
CONFIG_RCU_NOCB_CPU_ALL=y
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_PROVE_RCU_DELAY=n
CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_CPU_STALL_VERBOSE=n
CONFIG_RCU_BOOST=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE09 b/tools/testing/selftests/rcutorture/configs/rcu/TREE09
index 81e4f7c0bf0..b7a62a540ad 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE09
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE09
@@ -13,7 +13,6 @@ CONFIG_SUSPEND=n
CONFIG_HIBERNATION=n
CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_PROVE_RCU_DELAY=n
CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_CPU_STALL_VERBOSE=n
CONFIG_RCU_BOOST=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/v0.0/P5-U-T-NH-sd-SMP-hp b/tools/testing/selftests/rcutorture/configs/rcu/v0.0/P5-U-T-NH-sd-SMP-hp
index ef624ce73d8..a55c00877fe 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/v0.0/P5-U-T-NH-sd-SMP-hp
+++ b/tools/testing/selftests/rcutorture/configs/rcu/v0.0/P5-U-T-NH-sd-SMP-hp
@@ -13,7 +13,6 @@ CONFIG_PREEMPT_VOLUNTARY=n
CONFIG_PREEMPT=y
#CHECK#CONFIG_TREE_PREEMPT_RCU=y
CONFIG_DEBUG_KERNEL=y
-CONFIG_PROVE_RCU_DELAY=y
CONFIG_DEBUG_OBJECTS=y
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
CONFIG_RT_MUTEXES=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/v3.12/P5-U-T-NH-sd-SMP-hp b/tools/testing/selftests/rcutorture/configs/rcu/v3.12/P5-U-T-NH-sd-SMP-hp
index ef624ce73d8..a55c00877fe 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/v3.12/P5-U-T-NH-sd-SMP-hp
+++ b/tools/testing/selftests/rcutorture/configs/rcu/v3.12/P5-U-T-NH-sd-SMP-hp
@@ -13,7 +13,6 @@ CONFIG_PREEMPT_VOLUNTARY=n
CONFIG_PREEMPT=y
#CHECK#CONFIG_TREE_PREEMPT_RCU=y
CONFIG_DEBUG_KERNEL=y
-CONFIG_PROVE_RCU_DELAY=y
CONFIG_DEBUG_OBJECTS=y
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
CONFIG_RT_MUTEXES=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/v3.3/P5-U-T-NH-sd-SMP-hp b/tools/testing/selftests/rcutorture/configs/rcu/v3.3/P5-U-T-NH-sd-SMP-hp
index ef624ce73d8..a55c00877fe 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/v3.3/P5-U-T-NH-sd-SMP-hp
+++ b/tools/testing/selftests/rcutorture/configs/rcu/v3.3/P5-U-T-NH-sd-SMP-hp
@@ -13,7 +13,6 @@ CONFIG_PREEMPT_VOLUNTARY=n
CONFIG_PREEMPT=y
#CHECK#CONFIG_TREE_PREEMPT_RCU=y
CONFIG_DEBUG_KERNEL=y
-CONFIG_PROVE_RCU_DELAY=y
CONFIG_DEBUG_OBJECTS=y
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
CONFIG_RT_MUTEXES=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/v3.5/P5-U-T-NH-sd-SMP-hp b/tools/testing/selftests/rcutorture/configs/rcu/v3.5/P5-U-T-NH-sd-SMP-hp
index ef624ce73d8..a55c00877fe 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/v3.5/P5-U-T-NH-sd-SMP-hp
+++ b/tools/testing/selftests/rcutorture/configs/rcu/v3.5/P5-U-T-NH-sd-SMP-hp
@@ -13,7 +13,6 @@ CONFIG_PREEMPT_VOLUNTARY=n
CONFIG_PREEMPT=y
#CHECK#CONFIG_TREE_PREEMPT_RCU=y
CONFIG_DEBUG_KERNEL=y
-CONFIG_PROVE_RCU_DELAY=y
CONFIG_DEBUG_OBJECTS=y
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
CONFIG_RT_MUTEXES=y
diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
index adbb76cffb4..3e588db86a1 100644
--- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
+++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
@@ -14,7 +14,6 @@ CONFIG_NO_HZ_FULL_SYSIDLE -- Do one.
CONFIG_PREEMPT -- Do half. (First three and #8.)
CONFIG_PROVE_LOCKING -- Do all but two, covering CONFIG_PROVE_RCU and not.
CONFIG_PROVE_RCU -- Do all but one under CONFIG_PROVE_LOCKING.
-CONFIG_PROVE_RCU_DELAY -- Do one.
CONFIG_RCU_BOOST -- one of TREE_PREEMPT_RCU.
CONFIG_RCU_BOOST_PRIO -- set to 2 for _BOOST testing.
CONFIG_RCU_CPU_STALL_INFO -- do one with and without _VERBOSE.