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Diffstat (limited to 'kernel/rcu/tree_plugin.h')
-rw-r--r--kernel/rcu/tree_plugin.h144
1 files changed, 92 insertions, 52 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 387dd4599344..3ec85cb5d544 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -30,14 +30,24 @@
#include <linux/smpboot.h>
#include "../time/tick-internal.h"
-#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
-#endif
+
+/* rcuc/rcub kthread realtime priority */
+static int kthread_prio = CONFIG_RCU_KTHREAD_PRIO;
+module_param(kthread_prio, int, 0644);
+
+/*
+ * Control variables for per-CPU and per-rcu_node kthreads. These
+ * handle all flavors of RCU.
+ */
+static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task);
+DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
+DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
+DEFINE_PER_CPU(char, rcu_cpu_has_work);
+
+#endif /* #ifdef CONFIG_RCU_BOOST */
#ifdef CONFIG_RCU_NOCB_CPU
static cpumask_var_t rcu_nocb_mask; /* CPUs to have callbacks offloaded. */
@@ -72,9 +82,6 @@ static void __init rcu_bootup_announce_oddness(void)
#ifdef CONFIG_RCU_TORTURE_TEST_RUNNABLE
pr_info("\tRCU torture testing starts during boot.\n");
#endif
-#if defined(CONFIG_TREE_PREEMPT_RCU) && !defined(CONFIG_RCU_CPU_STALL_VERBOSE)
- pr_info("\tDump stacks of tasks blocking RCU-preempt GP.\n");
-#endif
#if defined(CONFIG_RCU_CPU_STALL_INFO)
pr_info("\tAdditional per-CPU info printed with stalls.\n");
#endif
@@ -85,9 +92,12 @@ static void __init rcu_bootup_announce_oddness(void)
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_RCU_BOOST
+ pr_info("\tRCU kthread priority: %d.\n", kthread_prio);
+#endif
}
-#ifdef CONFIG_TREE_PREEMPT_RCU
+#ifdef CONFIG_PREEMPT_RCU
RCU_STATE_INITIALIZER(rcu_preempt, 'p', call_rcu);
static struct rcu_state *rcu_state_p = &rcu_preempt_state;
@@ -156,7 +166,7 @@ static void rcu_preempt_qs(void)
*
* Caller must disable preemption.
*/
-static void rcu_preempt_note_context_switch(int cpu)
+static void rcu_preempt_note_context_switch(void)
{
struct task_struct *t = current;
unsigned long flags;
@@ -167,7 +177,7 @@ static void rcu_preempt_note_context_switch(int cpu)
!t->rcu_read_unlock_special.b.blocked) {
/* Possibly blocking in an RCU read-side critical section. */
- rdp = per_cpu_ptr(rcu_preempt_state.rda, cpu);
+ rdp = this_cpu_ptr(rcu_preempt_state.rda);
rnp = rdp->mynode;
raw_spin_lock_irqsave(&rnp->lock, flags);
smp_mb__after_unlock_lock();
@@ -415,8 +425,6 @@ void rcu_read_unlock_special(struct task_struct *t)
}
}
-#ifdef CONFIG_RCU_CPU_STALL_VERBOSE
-
/*
* Dump detailed information for all tasks blocking the current RCU
* grace period on the specified rcu_node structure.
@@ -451,14 +459,6 @@ static void rcu_print_detail_task_stall(struct rcu_state *rsp)
rcu_print_detail_task_stall_rnp(rnp);
}
-#else /* #ifdef CONFIG_RCU_CPU_STALL_VERBOSE */
-
-static void rcu_print_detail_task_stall(struct rcu_state *rsp)
-{
-}
-
-#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_VERBOSE */
-
#ifdef CONFIG_RCU_CPU_STALL_INFO
static void rcu_print_task_stall_begin(struct rcu_node *rnp)
@@ -621,7 +621,7 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp,
*
* Caller must disable hard irqs.
*/
-static void rcu_preempt_check_callbacks(int cpu)
+static void rcu_preempt_check_callbacks(void)
{
struct task_struct *t = current;
@@ -630,8 +630,8 @@ static void rcu_preempt_check_callbacks(int cpu)
return;
}
if (t->rcu_read_lock_nesting > 0 &&
- per_cpu(rcu_preempt_data, cpu).qs_pending &&
- !per_cpu(rcu_preempt_data, cpu).passed_quiesce)
+ __this_cpu_read(rcu_preempt_data.qs_pending) &&
+ !__this_cpu_read(rcu_preempt_data.passed_quiesce))
t->rcu_read_unlock_special.b.need_qs = true;
}
@@ -919,7 +919,7 @@ void exit_rcu(void)
__rcu_read_unlock();
}
-#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
+#else /* #ifdef CONFIG_PREEMPT_RCU */
static struct rcu_state *rcu_state_p = &rcu_sched_state;
@@ -945,7 +945,7 @@ EXPORT_SYMBOL_GPL(rcu_batches_completed);
* Because preemptible RCU does not exist, we never have to check for
* CPUs being in quiescent states.
*/
-static void rcu_preempt_note_context_switch(int cpu)
+static void rcu_preempt_note_context_switch(void)
{
}
@@ -1017,7 +1017,7 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp,
* Because preemptible RCU does not exist, it never has any callbacks
* to check.
*/
-static void rcu_preempt_check_callbacks(int cpu)
+static void rcu_preempt_check_callbacks(void)
{
}
@@ -1070,7 +1070,7 @@ void exit_rcu(void)
{
}
-#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
+#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
#ifdef CONFIG_RCU_BOOST
@@ -1326,7 +1326,7 @@ static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
smp_mb__after_unlock_lock();
rnp->boost_kthread_task = t;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
- sp.sched_priority = RCU_BOOST_PRIO;
+ sp.sched_priority = kthread_prio;
sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
wake_up_process(t); /* get to TASK_INTERRUPTIBLE quickly. */
return 0;
@@ -1343,7 +1343,7 @@ static void rcu_cpu_kthread_setup(unsigned int cpu)
{
struct sched_param sp;
- sp.sched_priority = RCU_KTHREAD_PRIO;
+ sp.sched_priority = kthread_prio;
sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
}
@@ -1512,10 +1512,10 @@ static void rcu_prepare_kthreads(int cpu)
* any flavor of RCU.
*/
#ifndef CONFIG_RCU_NOCB_CPU_ALL
-int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
+int rcu_needs_cpu(unsigned long *delta_jiffies)
{
*delta_jiffies = ULONG_MAX;
- return rcu_cpu_has_callbacks(cpu, NULL);
+ return rcu_cpu_has_callbacks(NULL);
}
#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
@@ -1523,7 +1523,7 @@ int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
* Because we do not have RCU_FAST_NO_HZ, don't bother cleaning up
* after it.
*/
-static void rcu_cleanup_after_idle(int cpu)
+static void rcu_cleanup_after_idle(void)
{
}
@@ -1531,7 +1531,7 @@ static void rcu_cleanup_after_idle(int cpu)
* Do the idle-entry grace-period work, which, because CONFIG_RCU_FAST_NO_HZ=n,
* is nothing.
*/
-static void rcu_prepare_for_idle(int cpu)
+static void rcu_prepare_for_idle(void)
{
}
@@ -1624,15 +1624,15 @@ static bool __maybe_unused 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)
+int rcu_needs_cpu(unsigned long *dj)
{
- struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
+ struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
/* Snapshot to detect later posting of non-lazy callback. */
rdtp->nonlazy_posted_snap = rdtp->nonlazy_posted;
/* If no callbacks, RCU doesn't need the CPU. */
- if (!rcu_cpu_has_callbacks(cpu, &rdtp->all_lazy)) {
+ if (!rcu_cpu_has_callbacks(&rdtp->all_lazy)) {
*dj = ULONG_MAX;
return 0;
}
@@ -1666,12 +1666,12 @@ int rcu_needs_cpu(int cpu, unsigned long *dj)
*
* The caller must have disabled interrupts.
*/
-static void rcu_prepare_for_idle(int cpu)
+static void rcu_prepare_for_idle(void)
{
#ifndef CONFIG_RCU_NOCB_CPU_ALL
bool needwake;
struct rcu_data *rdp;
- struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
+ struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
struct rcu_node *rnp;
struct rcu_state *rsp;
int tne;
@@ -1679,7 +1679,7 @@ static void rcu_prepare_for_idle(int cpu)
/* Handle nohz enablement switches conservatively. */
tne = ACCESS_ONCE(tick_nohz_active);
if (tne != rdtp->tick_nohz_enabled_snap) {
- if (rcu_cpu_has_callbacks(cpu, NULL))
+ if (rcu_cpu_has_callbacks(NULL))
invoke_rcu_core(); /* force nohz to see update. */
rdtp->tick_nohz_enabled_snap = tne;
return;
@@ -1688,7 +1688,7 @@ static void rcu_prepare_for_idle(int cpu)
return;
/* If this is a no-CBs CPU, no callbacks, just return. */
- if (rcu_is_nocb_cpu(cpu))
+ if (rcu_is_nocb_cpu(smp_processor_id()))
return;
/*
@@ -1712,7 +1712,7 @@ static void rcu_prepare_for_idle(int cpu)
return;
rdtp->last_accelerate = jiffies;
for_each_rcu_flavor(rsp) {
- rdp = per_cpu_ptr(rsp->rda, cpu);
+ rdp = this_cpu_ptr(rsp->rda);
if (!*rdp->nxttail[RCU_DONE_TAIL])
continue;
rnp = rdp->mynode;
@@ -1731,10 +1731,10 @@ static void rcu_prepare_for_idle(int cpu)
* any grace periods that elapsed while the CPU was idle, and if any
* callbacks are now ready to invoke, initiate invocation.
*/
-static void rcu_cleanup_after_idle(int cpu)
+static void rcu_cleanup_after_idle(void)
{
#ifndef CONFIG_RCU_NOCB_CPU_ALL
- if (rcu_is_nocb_cpu(cpu))
+ if (rcu_is_nocb_cpu(smp_processor_id()))
return;
if (rcu_try_advance_all_cbs())
invoke_rcu_core();
@@ -2050,6 +2050,33 @@ static void wake_nocb_leader(struct rcu_data *rdp, bool force)
}
/*
+ * Does the specified CPU need an RCU callback for the specified flavor
+ * of rcu_barrier()?
+ */
+static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu)
+{
+ struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
+ struct rcu_head *rhp;
+
+ /* No-CBs CPUs might have callbacks on any of three lists. */
+ rhp = ACCESS_ONCE(rdp->nocb_head);
+ if (!rhp)
+ rhp = ACCESS_ONCE(rdp->nocb_gp_head);
+ if (!rhp)
+ rhp = ACCESS_ONCE(rdp->nocb_follower_head);
+
+ /* Having no rcuo kthread but CBs after scheduler starts is bad! */
+ if (!ACCESS_ONCE(rdp->nocb_kthread) && rhp) {
+ /* RCU callback enqueued before CPU first came online??? */
+ pr_err("RCU: Never-onlined no-CBs CPU %d has CB %p\n",
+ cpu, rhp->func);
+ WARN_ON_ONCE(1);
+ }
+
+ return !!rhp;
+}
+
+/*
* 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
@@ -2546,9 +2573,13 @@ static void rcu_spawn_one_nocb_kthread(struct rcu_state *rsp, int cpu)
rdp->nocb_leader = rdp_spawn;
if (rdp_last && rdp != rdp_spawn)
rdp_last->nocb_next_follower = rdp;
- rdp_last = rdp;
- rdp = rdp->nocb_next_follower;
- rdp_last->nocb_next_follower = NULL;
+ if (rdp == rdp_spawn) {
+ rdp = rdp->nocb_next_follower;
+ } else {
+ rdp_last = rdp;
+ rdp = rdp->nocb_next_follower;
+ rdp_last->nocb_next_follower = NULL;
+ }
} while (rdp);
rdp_spawn->nocb_next_follower = rdp_old_leader;
}
@@ -2642,6 +2673,12 @@ static bool init_nocb_callback_list(struct rcu_data *rdp)
#else /* #ifdef CONFIG_RCU_NOCB_CPU */
+static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu)
+{
+ WARN_ON_ONCE(1); /* Should be dead code. */
+ return false;
+}
+
static void rcu_nocb_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp)
{
}
@@ -2728,9 +2765,10 @@ static int full_sysidle_state; /* Current system-idle state. */
* to detect full-system idle states, not RCU quiescent states and grace
* periods. The caller must have disabled interrupts.
*/
-static void rcu_sysidle_enter(struct rcu_dynticks *rdtp, int irq)
+static void rcu_sysidle_enter(int irq)
{
unsigned long j;
+ struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
/* If there are no nohz_full= CPUs, no need to track this. */
if (!tick_nohz_full_enabled())
@@ -2799,8 +2837,10 @@ void rcu_sysidle_force_exit(void)
* usermode execution does -not- count as idle here! The caller must
* have disabled interrupts.
*/
-static void rcu_sysidle_exit(struct rcu_dynticks *rdtp, int irq)
+static void rcu_sysidle_exit(int irq)
{
+ struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
+
/* If there are no nohz_full= CPUs, no need to track this. */
if (!tick_nohz_full_enabled())
return;
@@ -3094,11 +3134,11 @@ static void rcu_sysidle_init_percpu_data(struct rcu_dynticks *rdtp)
#else /* #ifdef CONFIG_NO_HZ_FULL_SYSIDLE */
-static void rcu_sysidle_enter(struct rcu_dynticks *rdtp, int irq)
+static void rcu_sysidle_enter(int irq)
{
}
-static void rcu_sysidle_exit(struct rcu_dynticks *rdtp, int irq)
+static void rcu_sysidle_exit(int irq)
{
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-20 20:15:16 +0300