DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
DEFINE_PER_CPU(char, rcu_cpu_has_work);
-#endif /* #ifdef CONFIG_RCU_BOOST */
+#else /* #ifdef CONFIG_RCU_BOOST */
+
+/*
+ * Some architectures do not define rt_mutexes, but if !CONFIG_RCU_BOOST,
+ * all uses are in dead code. Provide a definition to keep the compiler
+ * happy, but add WARN_ON_ONCE() to complain if used in the wrong place.
+ * This probably needs to be excluded from -rt builds.
+ */
+#define rt_mutex_owner(a) ({ WARN_ON_ONCE(1); NULL; })
+
+#endif /* #else #ifdef CONFIG_RCU_BOOST */
#ifdef CONFIG_RCU_NOCB_CPU
static cpumask_var_t rcu_nocb_mask; /* CPUs to have callbacks offloaded. */
{
if (IS_ENABLED(CONFIG_RCU_TRACE))
pr_info("\tRCU debugfs-based tracing is enabled.\n");
- if ((IS_ENABLED(CONFIG_64BIT) && CONFIG_RCU_FANOUT != 64) ||
- (!IS_ENABLED(CONFIG_64BIT) && CONFIG_RCU_FANOUT != 32))
+ if ((IS_ENABLED(CONFIG_64BIT) && RCU_FANOUT != 64) ||
+ (!IS_ENABLED(CONFIG_64BIT) && RCU_FANOUT != 32))
pr_info("\tCONFIG_RCU_FANOUT set to non-default value of %d\n",
- CONFIG_RCU_FANOUT);
- if (IS_ENABLED(CONFIG_RCU_FANOUT_EXACT))
+ RCU_FANOUT);
+ if (rcu_fanout_exact)
pr_info("\tHierarchical RCU autobalancing is disabled.\n");
if (IS_ENABLED(CONFIG_RCU_FAST_NO_HZ))
pr_info("\tRCU dyntick-idle grace-period acceleration is enabled.\n");
pr_info("\tAdditional per-CPU info printed with stalls.\n");
if (NUM_RCU_LVL_4 != 0)
pr_info("\tFour-level hierarchy is enabled.\n");
- if (CONFIG_RCU_FANOUT_LEAF != 16)
+ if (RCU_FANOUT_LEAF != 16)
pr_info("\tBuild-time adjustment of leaf fanout to %d.\n",
- CONFIG_RCU_FANOUT_LEAF);
- if (rcu_fanout_leaf != CONFIG_RCU_FANOUT_LEAF)
+ RCU_FANOUT_LEAF);
+ if (rcu_fanout_leaf != RCU_FANOUT_LEAF)
pr_info("\tBoot-time adjustment of leaf fanout to %d.\n", rcu_fanout_leaf);
if (nr_cpu_ids != NR_CPUS)
pr_info("\tRCU restricting CPUs from NR_CPUS=%d to nr_cpu_ids=%d.\n", NR_CPUS, nr_cpu_ids);
#ifdef CONFIG_PREEMPT_RCU
RCU_STATE_INITIALIZER(rcu_preempt, 'p', call_rcu);
-static struct rcu_state *rcu_state_p = &rcu_preempt_state;
+static struct rcu_state *const rcu_state_p = &rcu_preempt_state;
+static struct rcu_data __percpu *const rcu_data_p = &rcu_preempt_data;
static int rcu_preempted_readers_exp(struct rcu_node *rnp);
static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
*/
static void rcu_preempt_qs(void)
{
- if (!__this_cpu_read(rcu_preempt_data.passed_quiesce)) {
+ if (!__this_cpu_read(rcu_data_p->passed_quiesce)) {
trace_rcu_grace_period(TPS("rcu_preempt"),
- __this_cpu_read(rcu_preempt_data.gpnum),
+ __this_cpu_read(rcu_data_p->gpnum),
TPS("cpuqs"));
- __this_cpu_write(rcu_preempt_data.passed_quiesce, 1);
+ __this_cpu_write(rcu_data_p->passed_quiesce, 1);
barrier(); /* Coordinate with rcu_preempt_check_callbacks(). */
current->rcu_read_unlock_special.b.need_qs = false;
}
!t->rcu_read_unlock_special.b.blocked) {
/* Possibly blocking in an RCU read-side critical section. */
- rdp = this_cpu_ptr(rcu_preempt_state.rda);
+ rdp = this_cpu_ptr(rcu_state_p->rda);
rnp = rdp->mynode;
raw_spin_lock_irqsave(&rnp->lock, flags);
smp_mb__after_unlock_lock();
if ((rnp->qsmask & rdp->grpmask) && rnp->gp_tasks != NULL) {
list_add(&t->rcu_node_entry, rnp->gp_tasks->prev);
rnp->gp_tasks = &t->rcu_node_entry;
-#ifdef CONFIG_RCU_BOOST
- if (rnp->boost_tasks != NULL)
+ if (IS_ENABLED(CONFIG_RCU_BOOST) &&
+ rnp->boost_tasks != NULL)
rnp->boost_tasks = rnp->gp_tasks;
-#endif /* #ifdef CONFIG_RCU_BOOST */
} else {
list_add(&t->rcu_node_entry, &rnp->blkd_tasks);
if (rnp->qsmask & rdp->grpmask)
bool empty_exp_now;
unsigned long flags;
struct list_head *np;
-#ifdef CONFIG_RCU_BOOST
bool drop_boost_mutex = false;
-#endif /* #ifdef CONFIG_RCU_BOOST */
struct rcu_node *rnp;
union rcu_special special;
t->rcu_read_unlock_special.b.blocked = false;
/*
- * Remove this task from the list it blocked on. The
- * task can migrate while we acquire the lock, but at
- * most one time. So at most two passes through loop.
+ * Remove this task from the list it blocked on. The task
+ * now remains queued on the rcu_node corresponding to
+ * the CPU it first blocked on, so the first attempt to
+ * acquire the task's rcu_node's ->lock will succeed.
+ * Keep the loop and add a WARN_ON() out of sheer paranoia.
*/
for (;;) {
rnp = t->rcu_blocked_node;
smp_mb__after_unlock_lock();
if (rnp == t->rcu_blocked_node)
break;
+ WARN_ON_ONCE(1);
raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
}
empty_norm = !rcu_preempt_blocked_readers_cgp(rnp);
rnp->gp_tasks = np;
if (&t->rcu_node_entry == rnp->exp_tasks)
rnp->exp_tasks = np;
-#ifdef CONFIG_RCU_BOOST
- if (&t->rcu_node_entry == rnp->boost_tasks)
- rnp->boost_tasks = np;
- /* Snapshot ->boost_mtx ownership with rcu_node lock held. */
- drop_boost_mutex = rt_mutex_owner(&rnp->boost_mtx) == t;
-#endif /* #ifdef CONFIG_RCU_BOOST */
+ if (IS_ENABLED(CONFIG_RCU_BOOST)) {
+ if (&t->rcu_node_entry == rnp->boost_tasks)
+ rnp->boost_tasks = np;
+ /* Snapshot ->boost_mtx ownership w/rnp->lock held. */
+ drop_boost_mutex = rt_mutex_owner(&rnp->boost_mtx) == t;
+ }
/*
* If this was the last task on the current list, and if
rnp->grplo,
rnp->grphi,
!!rnp->gp_tasks);
- rcu_report_unblock_qs_rnp(&rcu_preempt_state,
- rnp, flags);
+ rcu_report_unblock_qs_rnp(rcu_state_p, rnp, flags);
} else {
raw_spin_unlock_irqrestore(&rnp->lock, flags);
}
-#ifdef CONFIG_RCU_BOOST
/* Unboost if we were boosted. */
- if (drop_boost_mutex)
+ if (IS_ENABLED(CONFIG_RCU_BOOST) && drop_boost_mutex)
rt_mutex_unlock(&rnp->boost_mtx);
-#endif /* #ifdef CONFIG_RCU_BOOST */
/*
* If this was the last task on the expedited lists,
* then we need to report up the rcu_node hierarchy.
*/
if (!empty_exp && empty_exp_now)
- rcu_report_exp_rnp(&rcu_preempt_state, rnp, true);
+ rcu_report_exp_rnp(rcu_state_p, rnp, true);
} else {
local_irq_restore(flags);
}
raw_spin_unlock_irqrestore(&rnp->lock, flags);
return;
}
- t = list_entry(rnp->gp_tasks,
+ t = list_entry(rnp->gp_tasks->prev,
struct task_struct, rcu_node_entry);
list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry)
sched_show_task(t);
if (!rcu_preempt_blocked_readers_cgp(rnp))
return 0;
rcu_print_task_stall_begin(rnp);
- t = list_entry(rnp->gp_tasks,
+ t = list_entry(rnp->gp_tasks->prev,
struct task_struct, rcu_node_entry);
list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) {
pr_cont(" P%d", t->pid);
return;
}
if (t->rcu_read_lock_nesting > 0 &&
- __this_cpu_read(rcu_preempt_data.qs_pending) &&
- !__this_cpu_read(rcu_preempt_data.passed_quiesce))
+ __this_cpu_read(rcu_data_p->qs_pending) &&
+ !__this_cpu_read(rcu_data_p->passed_quiesce))
t->rcu_read_unlock_special.b.need_qs = true;
}
static void rcu_preempt_do_callbacks(void)
{
- rcu_do_batch(&rcu_preempt_state, this_cpu_ptr(&rcu_preempt_data));
+ rcu_do_batch(rcu_state_p, this_cpu_ptr(rcu_data_p));
}
#endif /* #ifdef CONFIG_RCU_BOOST */
*/
void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
{
- __call_rcu(head, func, &rcu_preempt_state, -1, 0);
+ __call_rcu(head, func, rcu_state_p, -1, 0);
}
EXPORT_SYMBOL_GPL(call_rcu);
void synchronize_rcu_expedited(void)
{
struct rcu_node *rnp;
- struct rcu_state *rsp = &rcu_preempt_state;
+ struct rcu_state *rsp = rcu_state_p;
unsigned long snap;
int trycount = 0;
*/
void rcu_barrier(void)
{
- _rcu_barrier(&rcu_preempt_state);
+ _rcu_barrier(rcu_state_p);
}
EXPORT_SYMBOL_GPL(rcu_barrier);
*/
static void __init __rcu_init_preempt(void)
{
- rcu_init_one(&rcu_preempt_state, &rcu_preempt_data);
+ rcu_init_one(rcu_state_p, rcu_data_p);
}
/*
#else /* #ifdef CONFIG_PREEMPT_RCU */
-static struct rcu_state *rcu_state_p = &rcu_sched_state;
+static struct rcu_state *const rcu_state_p = &rcu_sched_state;
+static struct rcu_data __percpu *const rcu_data_p = &rcu_sched_data;
/*
* Tell them what RCU they are running.
struct sched_param sp;
struct task_struct *t;
- if (&rcu_preempt_state != rsp)
+ if (rcu_state_p != rsp)
return 0;
if (!rcu_scheduler_fully_active || rcu_rnp_online_cpus(rnp) == 0)
* 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(unsigned long *delta_jiffies)
{
*delta_jiffies = ULONG_MAX;
- return rcu_cpu_has_callbacks(NULL);
+ return IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL)
+ ? 0 : rcu_cpu_has_callbacks(NULL);
}
-#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
/*
* Because we do not have RCU_FAST_NO_HZ, don't bother cleaning up
*
* The caller must have disabled interrupts.
*/
-#ifndef CONFIG_RCU_NOCB_CPU_ALL
int rcu_needs_cpu(unsigned long *dj)
{
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
+ if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL)) {
+ *dj = ULONG_MAX;
+ return 0;
+ }
+
/* Snapshot to detect later posting of non-lazy callback. */
rdtp->nonlazy_posted_snap = rdtp->nonlazy_posted;
}
return 0;
}
-#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
/*
* Prepare a CPU for idle from an RCU perspective. The first major task
*/
static void rcu_prepare_for_idle(void)
{
-#ifndef CONFIG_RCU_NOCB_CPU_ALL
bool needwake;
struct rcu_data *rdp;
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
struct rcu_state *rsp;
int tne;
+ if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL))
+ return;
+
/* Handle nohz enablement switches conservatively. */
tne = READ_ONCE(tick_nohz_active);
if (tne != rdtp->tick_nohz_enabled_snap) {
if (needwake)
rcu_gp_kthread_wake(rsp);
}
-#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
}
/*
*/
static void rcu_cleanup_after_idle(void)
{
-#ifndef CONFIG_RCU_NOCB_CPU_ALL
- if (rcu_is_nocb_cpu(smp_processor_id()))
+ if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL) ||
+ rcu_is_nocb_cpu(smp_processor_id()))
return;
if (rcu_try_advance_all_cbs())
invoke_rcu_core();
-#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
}
/*
if (tick_nohz_full_cpu(smp_processor_id()) &&
(!rcu_gp_in_progress(rsp) ||
ULONG_CMP_LT(jiffies, READ_ONCE(rsp->gp_start) + HZ)))
- return 1;
+ return true;
#endif /* #ifdef CONFIG_NO_HZ_FULL */
- return 0;
+ return false;
}
/*
projects / mirror_ubuntu-bionic-kernel.git / blobdiff