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-rw-r--r--kernel/rcu/update.c155
1 files changed, 112 insertions, 43 deletions
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 84843adfd939..c912b594ba98 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -25,6 +25,7 @@
#include <linux/interrupt.h>
#include <linux/sched/signal.h>
#include <linux/sched/debug.h>
+#include <linux/torture.h>
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/percpu.h>
@@ -42,6 +43,7 @@
#include <linux/kprobes.h>
#include <linux/slab.h>
#include <linux/irq_work.h>
+#include <linux/rcupdate_trace.h>
#define CREATE_TRACE_POINTS
@@ -52,24 +54,13 @@
#endif
#define MODULE_PARAM_PREFIX "rcupdate."
-#ifndef data_race
-#define data_race(expr) \
- ({ \
- expr; \
- })
-#endif
-#ifndef ASSERT_EXCLUSIVE_WRITER
-#define ASSERT_EXCLUSIVE_WRITER(var) do { } while (0)
-#endif
-#ifndef ASSERT_EXCLUSIVE_ACCESS
-#define ASSERT_EXCLUSIVE_ACCESS(var) do { } while (0)
-#endif
-
#ifndef CONFIG_TINY_RCU
-module_param(rcu_expedited, int, 0);
-module_param(rcu_normal, int, 0);
-static int rcu_normal_after_boot;
-module_param(rcu_normal_after_boot, int, 0);
+module_param(rcu_expedited, int, 0444);
+module_param(rcu_normal, int, 0444);
+static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT);
+#if !defined(CONFIG_PREEMPT_RT) || defined(CONFIG_NO_HZ_FULL)
+module_param(rcu_normal_after_boot, int, 0444);
+#endif
#endif /* #ifndef CONFIG_TINY_RCU */
#ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -95,7 +86,7 @@ module_param(rcu_normal_after_boot, int, 0);
* and while lockdep is disabled.
*
* Note that if the CPU is in the idle loop from an RCU point of view (ie:
- * that we are in the section between rcu_idle_enter() and rcu_idle_exit())
+ * that we are in the section between ct_idle_enter() and ct_idle_exit())
* then rcu_read_lock_held() sets ``*ret`` to false even if the CPU did an
* rcu_read_lock(). The reason for this is that RCU ignores CPUs that are
* in such a section, considering these as in extended quiescent state,
@@ -154,8 +145,45 @@ bool rcu_gp_is_normal(void)
}
EXPORT_SYMBOL_GPL(rcu_gp_is_normal);
-static atomic_t rcu_expedited_nesting = ATOMIC_INIT(1);
+static atomic_t rcu_async_hurry_nesting = ATOMIC_INIT(1);
+/*
+ * Should call_rcu() callbacks be processed with urgency or are
+ * they OK being executed with arbitrary delays?
+ */
+bool rcu_async_should_hurry(void)
+{
+ return !IS_ENABLED(CONFIG_RCU_LAZY) ||
+ atomic_read(&rcu_async_hurry_nesting);
+}
+EXPORT_SYMBOL_GPL(rcu_async_should_hurry);
+/**
+ * rcu_async_hurry - Make future async RCU callbacks not lazy.
+ *
+ * After a call to this function, future calls to call_rcu()
+ * will be processed in a timely fashion.
+ */
+void rcu_async_hurry(void)
+{
+ if (IS_ENABLED(CONFIG_RCU_LAZY))
+ atomic_inc(&rcu_async_hurry_nesting);
+}
+EXPORT_SYMBOL_GPL(rcu_async_hurry);
+
+/**
+ * rcu_async_relax - Make future async RCU callbacks lazy.
+ *
+ * After a call to this function, future calls to call_rcu()
+ * will be processed in a lazy fashion.
+ */
+void rcu_async_relax(void)
+{
+ if (IS_ENABLED(CONFIG_RCU_LAZY))
+ atomic_dec(&rcu_async_hurry_nesting);
+}
+EXPORT_SYMBOL_GPL(rcu_async_relax);
+
+static atomic_t rcu_expedited_nesting = ATOMIC_INIT(1);
/*
* Should normal grace-period primitives be expedited? Intended for
* use within RCU. Note that this function takes the rcu_expedited
@@ -205,9 +233,10 @@ static bool rcu_boot_ended __read_mostly;
void rcu_end_inkernel_boot(void)
{
rcu_unexpedite_gp();
+ rcu_async_relax();
if (rcu_normal_after_boot)
WRITE_ONCE(rcu_normal, 1);
- rcu_boot_ended = 1;
+ rcu_boot_ended = true;
}
/*
@@ -230,11 +259,12 @@ void rcu_test_sync_prims(void)
{
if (!IS_ENABLED(CONFIG_PROVE_RCU))
return;
+ pr_info("Running RCU synchronous self tests\n");
synchronize_rcu();
synchronize_rcu_expedited();
}
-#if !defined(CONFIG_TINY_RCU) || defined(CONFIG_SRCU)
+#if !defined(CONFIG_TINY_RCU)
/*
* Switch to run-time mode once RCU has fully initialized.
@@ -249,7 +279,7 @@ static int __init rcu_set_runtime_mode(void)
}
core_initcall(rcu_set_runtime_mode);
-#endif /* #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_SRCU) */
+#endif /* #if !defined(CONFIG_TINY_RCU) */
#ifdef CONFIG_DEBUG_LOCK_ALLOC
static struct lock_class_key rcu_lock_key;
@@ -257,7 +287,7 @@ struct lockdep_map rcu_lock_map = {
.name = "rcu_read_lock",
.key = &rcu_lock_key,
.wait_type_outer = LD_WAIT_FREE,
- .wait_type_inner = LD_WAIT_CONFIG, /* XXX PREEMPT_RCU ? */
+ .wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_RT implies PREEMPT_RCU */
};
EXPORT_SYMBOL_GPL(rcu_lock_map);
@@ -266,7 +296,7 @@ struct lockdep_map rcu_bh_lock_map = {
.name = "rcu_read_lock_bh",
.key = &rcu_bh_lock_key,
.wait_type_outer = LD_WAIT_FREE,
- .wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_LOCK also makes BH preemptible */
+ .wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_RT makes BH preemptible. */
};
EXPORT_SYMBOL_GPL(rcu_bh_lock_map);
@@ -279,6 +309,7 @@ struct lockdep_map rcu_sched_lock_map = {
};
EXPORT_SYMBOL_GPL(rcu_sched_lock_map);
+// Tell lockdep when RCU callbacks are being invoked.
static struct lock_class_key rcu_callback_key;
struct lockdep_map rcu_callback_map =
STATIC_LOCKDEP_MAP_INIT("rcu_callback", &rcu_callback_key);
@@ -286,7 +317,7 @@ EXPORT_SYMBOL_GPL(rcu_callback_map);
noinstr int notrace debug_lockdep_rcu_enabled(void)
{
- return rcu_scheduler_active != RCU_SCHEDULER_INACTIVE && debug_locks &&
+ return rcu_scheduler_active != RCU_SCHEDULER_INACTIVE && READ_ONCE(debug_locks) &&
current->lockdep_recursion == 0;
}
EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled);
@@ -377,7 +408,7 @@ void wakeme_after_rcu(struct rcu_head *head)
}
EXPORT_SYMBOL_GPL(wakeme_after_rcu);
-void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
+void __wait_rcu_gp(bool checktiny, unsigned int state, int n, call_rcu_func_t *crcu_array,
struct rcu_synchronize *rs_array)
{
int i;
@@ -390,13 +421,14 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
might_sleep();
continue;
}
- init_rcu_head_on_stack(&rs_array[i].head);
- init_completion(&rs_array[i].completion);
for (j = 0; j < i; j++)
if (crcu_array[j] == crcu_array[i])
break;
- if (j == i)
+ if (j == i) {
+ init_rcu_head_on_stack(&rs_array[i].head);
+ init_completion(&rs_array[i].completion);
(crcu_array[i])(&rs_array[i].head, wakeme_after_rcu);
+ }
}
/* Wait for all callbacks to be invoked. */
@@ -407,13 +439,21 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
for (j = 0; j < i; j++)
if (crcu_array[j] == crcu_array[i])
break;
- if (j == i)
- wait_for_completion(&rs_array[i].completion);
- destroy_rcu_head_on_stack(&rs_array[i].head);
+ if (j == i) {
+ wait_for_completion_state(&rs_array[i].completion, state);
+ destroy_rcu_head_on_stack(&rs_array[i].head);
+ }
}
}
EXPORT_SYMBOL_GPL(__wait_rcu_gp);
+void finish_rcuwait(struct rcuwait *w)
+{
+ rcu_assign_pointer(w->task, NULL);
+ __set_current_state(TASK_RUNNING);
+}
+EXPORT_SYMBOL_GPL(finish_rcuwait);
+
#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
void init_rcu_head(struct rcu_head *head)
{
@@ -465,7 +505,7 @@ void destroy_rcu_head_on_stack(struct rcu_head *head)
}
EXPORT_SYMBOL_GPL(destroy_rcu_head_on_stack);
-struct debug_obj_descr rcuhead_debug_descr = {
+const struct debug_obj_descr rcuhead_debug_descr = {
.name = "rcu_head",
.is_static_object = rcuhead_is_static_object,
};
@@ -485,27 +525,39 @@ EXPORT_SYMBOL_GPL(do_trace_rcu_torture_read);
do { } while (0)
#endif
-#if IS_ENABLED(CONFIG_RCU_TORTURE_TEST) || IS_MODULE(CONFIG_RCU_TORTURE_TEST)
+#if IS_ENABLED(CONFIG_RCU_TORTURE_TEST) || IS_MODULE(CONFIG_RCU_TORTURE_TEST) || IS_ENABLED(CONFIG_LOCK_TORTURE_TEST) || IS_MODULE(CONFIG_LOCK_TORTURE_TEST)
/* Get rcutorture access to sched_setaffinity(). */
-long rcutorture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask, bool dowarn)
{
int ret;
ret = sched_setaffinity(pid, in_mask);
- WARN_ONCE(ret, "%s: sched_setaffinity() returned %d\n", __func__, ret);
+ WARN_ONCE(dowarn && ret, "%s: sched_setaffinity(%d) returned %d\n", __func__, pid, ret);
return ret;
}
-EXPORT_SYMBOL_GPL(rcutorture_sched_setaffinity);
+EXPORT_SYMBOL_GPL(torture_sched_setaffinity);
#endif
+int rcu_cpu_stall_notifiers __read_mostly; // !0 = provide stall notifiers (rarely useful)
+EXPORT_SYMBOL_GPL(rcu_cpu_stall_notifiers);
+
#ifdef CONFIG_RCU_STALL_COMMON
int rcu_cpu_stall_ftrace_dump __read_mostly;
module_param(rcu_cpu_stall_ftrace_dump, int, 0644);
+#ifdef CONFIG_RCU_CPU_STALL_NOTIFIER
+module_param(rcu_cpu_stall_notifiers, int, 0444);
+#endif // #ifdef CONFIG_RCU_CPU_STALL_NOTIFIER
int rcu_cpu_stall_suppress __read_mostly; // !0 = suppress stall warnings.
EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress);
module_param(rcu_cpu_stall_suppress, int, 0644);
int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
module_param(rcu_cpu_stall_timeout, int, 0644);
+int rcu_exp_cpu_stall_timeout __read_mostly = CONFIG_RCU_EXP_CPU_STALL_TIMEOUT;
+module_param(rcu_exp_cpu_stall_timeout, int, 0644);
+int rcu_cpu_stall_cputime __read_mostly = IS_ENABLED(CONFIG_RCU_CPU_STALL_CPUTIME);
+module_param(rcu_cpu_stall_cputime, int, 0644);
+bool rcu_exp_stall_task_details __read_mostly;
+module_param(rcu_exp_stall_task_details, bool, 0644);
#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
// Suppress boot-time RCU CPU stall warnings and rcutorture writer stall
@@ -514,6 +566,19 @@ int rcu_cpu_stall_suppress_at_boot __read_mostly; // !0 = suppress boot stalls.
EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress_at_boot);
module_param(rcu_cpu_stall_suppress_at_boot, int, 0444);
+/**
+ * get_completed_synchronize_rcu - Return a pre-completed polled state cookie
+ *
+ * Returns a value that will always be treated by functions like
+ * poll_state_synchronize_rcu() as a cookie whose grace period has already
+ * completed.
+ */
+unsigned long get_completed_synchronize_rcu(void)
+{
+ return RCU_GET_STATE_COMPLETED;
+}
+EXPORT_SYMBOL_GPL(get_completed_synchronize_rcu);
+
#ifdef CONFIG_PROVE_RCU
/*
@@ -531,6 +596,7 @@ static void test_callback(struct rcu_head *r)
}
DEFINE_STATIC_SRCU(early_srcu);
+static unsigned long early_srcu_cookie;
struct early_boot_kfree_rcu {
struct rcu_head rh;
@@ -539,12 +605,15 @@ struct early_boot_kfree_rcu {
static void early_boot_test_call_rcu(void)
{
static struct rcu_head head;
+ int idx;
static struct rcu_head shead;
struct early_boot_kfree_rcu *rhp;
+ idx = srcu_down_read(&early_srcu);
+ srcu_up_read(&early_srcu, idx);
call_rcu(&head, test_callback);
- if (IS_ENABLED(CONFIG_SRCU))
- call_srcu(&early_srcu, &shead, test_callback);
+ early_srcu_cookie = start_poll_synchronize_srcu(&early_srcu);
+ call_srcu(&early_srcu, &shead, test_callback);
rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
if (!WARN_ON_ONCE(!rhp))
kfree_rcu(rhp, rh);
@@ -567,10 +636,10 @@ static int rcu_verify_early_boot_tests(void)
if (rcu_self_test) {
early_boot_test_counter++;
rcu_barrier();
- if (IS_ENABLED(CONFIG_SRCU)) {
- early_boot_test_counter++;
- srcu_barrier(&early_srcu);
- }
+ early_boot_test_counter++;
+ srcu_barrier(&early_srcu);
+ WARN_ON_ONCE(!poll_state_synchronize_srcu(&early_srcu, early_srcu_cookie));
+ cleanup_srcu_struct(&early_srcu);
}
if (rcu_self_test_counter != early_boot_test_counter) {
WARN_ON(1);
generated by cgit (git 2.34.1) at 2025-07-24 06:50:11 +0000