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-rw-r--r--kernel/rcuclassic.c4
-rw-r--r--kernel/rcupdate.c12
-rw-r--r--kernel/rcupreempt.c3
-rw-r--r--kernel/rcutree.c4
-rw-r--r--kernel/sched.c9
-rw-r--r--kernel/seccomp.c7
6 files changed, 31 insertions, 8 deletions
diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c
index bd5a9003497c..654c640a6b9c 100644
--- a/kernel/rcuclassic.c
+++ b/kernel/rcuclassic.c
@@ -679,8 +679,8 @@ int rcu_needs_cpu(int cpu)
void rcu_check_callbacks(int cpu, int user)
{
if (user ||
- (idle_cpu(cpu) && !in_softirq() &&
- hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
+ (idle_cpu(cpu) && rcu_scheduler_active &&
+ !in_softirq() && hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
/*
* Get here if this CPU took its interrupt from user
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index d92a76a881aa..cae8a059cf47 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -44,6 +44,7 @@
#include <linux/cpu.h>
#include <linux/mutex.h>
#include <linux/module.h>
+#include <linux/kernel_stat.h>
enum rcu_barrier {
RCU_BARRIER_STD,
@@ -55,6 +56,7 @@ static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL};
static atomic_t rcu_barrier_cpu_count;
static DEFINE_MUTEX(rcu_barrier_mutex);
static struct completion rcu_barrier_completion;
+int rcu_scheduler_active __read_mostly;
/*
* Awaken the corresponding synchronize_rcu() instance now that a
@@ -80,6 +82,10 @@ void wakeme_after_rcu(struct rcu_head *head)
void synchronize_rcu(void)
{
struct rcu_synchronize rcu;
+
+ if (rcu_blocking_is_gp())
+ return;
+
init_completion(&rcu.completion);
/* Will wake me after RCU finished. */
call_rcu(&rcu.head, wakeme_after_rcu);
@@ -175,3 +181,9 @@ void __init rcu_init(void)
__rcu_init();
}
+void rcu_scheduler_starting(void)
+{
+ WARN_ON(num_online_cpus() != 1);
+ WARN_ON(nr_context_switches() > 0);
+ rcu_scheduler_active = 1;
+}
diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c
index 33cfc50781f9..5d59e850fb71 100644
--- a/kernel/rcupreempt.c
+++ b/kernel/rcupreempt.c
@@ -1181,6 +1181,9 @@ void __synchronize_sched(void)
{
struct rcu_synchronize rcu;
+ if (num_online_cpus() == 1)
+ return; /* blocking is gp if only one CPU! */
+
init_completion(&rcu.completion);
/* Will wake me after RCU finished. */
call_rcu_sched(&rcu.head, wakeme_after_rcu);
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index b2fd602a6f6f..97ce31579ec0 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -948,8 +948,8 @@ static void rcu_do_batch(struct rcu_data *rdp)
void rcu_check_callbacks(int cpu, int user)
{
if (user ||
- (idle_cpu(cpu) && !in_softirq() &&
- hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
+ (idle_cpu(cpu) && rcu_scheduler_active &&
+ !in_softirq() && hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
/*
* Get here if this CPU took its interrupt from user
diff --git a/kernel/sched.c b/kernel/sched.c
index 9fe8e17574af..8b92f40c147d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4148,6 +4148,11 @@ static void run_rebalance_domains(struct softirq_action *h)
#endif
}
+static inline int on_null_domain(int cpu)
+{
+ return !rcu_dereference(cpu_rq(cpu)->sd);
+}
+
/*
* Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
*
@@ -4205,7 +4210,9 @@ static inline void trigger_load_balance(struct rq *rq, int cpu)
cpumask_test_cpu(cpu, nohz.cpu_mask))
return;
#endif
- if (time_after_eq(jiffies, rq->next_balance))
+ /* Don't need to rebalance while attached to NULL domain */
+ if (time_after_eq(jiffies, rq->next_balance) &&
+ likely(!on_null_domain(cpu)))
raise_softirq(SCHED_SOFTIRQ);
}
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index ad64fcb731f2..57d4b13b631d 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -8,6 +8,7 @@
#include <linux/seccomp.h>
#include <linux/sched.h>
+#include <linux/compat.h>
/* #define SECCOMP_DEBUG 1 */
#define NR_SECCOMP_MODES 1
@@ -22,7 +23,7 @@ static int mode1_syscalls[] = {
0, /* null terminated */
};
-#ifdef TIF_32BIT
+#ifdef CONFIG_COMPAT
static int mode1_syscalls_32[] = {
__NR_seccomp_read_32, __NR_seccomp_write_32, __NR_seccomp_exit_32, __NR_seccomp_sigreturn_32,
0, /* null terminated */
@@ -37,8 +38,8 @@ void __secure_computing(int this_syscall)
switch (mode) {
case 1:
syscall = mode1_syscalls;
-#ifdef TIF_32BIT
- if (test_thread_flag(TIF_32BIT))
+#ifdef CONFIG_COMPAT
+ if (is_compat_task())
syscall = mode1_syscalls_32;
#endif
do {