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-rw-r--r--include/linux/srcutiny.h2
-rw-r--r--include/linux/srcutree.h14
-rw-r--r--kernel/rcu/rcu.h6
-rw-r--r--kernel/rcu/srcutiny.c29
-rw-r--r--kernel/rcu/srcutree.c26
-rw-r--r--kernel/rcu/tiny.c1
-rw-r--r--kernel/rcu/tree.c1
-rw-r--r--kernel/rcu/update.c9
8 files changed, 78 insertions, 10 deletions
diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h
index f41d2fb09f87..2b5c0822e683 100644
--- a/include/linux/srcutiny.h
+++ b/include/linux/srcutiny.h
@@ -36,6 +36,7 @@ struct srcu_struct {
struct rcu_head *srcu_cb_head; /* Pending callbacks: Head. */
struct rcu_head **srcu_cb_tail; /* Pending callbacks: Tail. */
struct work_struct srcu_work; /* For driving grace periods. */
+ struct list_head srcu_boot_entry; /* Early-boot callbacks. */
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
@@ -48,6 +49,7 @@ void srcu_drive_gp(struct work_struct *wp);
.srcu_wq = __SWAIT_QUEUE_HEAD_INITIALIZER(name.srcu_wq), \
.srcu_cb_tail = &name.srcu_cb_head, \
.srcu_work = __WORK_INITIALIZER(name.srcu_work, srcu_drive_gp), \
+ .srcu_boot_entry = LIST_HEAD_INIT(name.srcu_boot_entry), \
__SRCU_DEP_MAP_INIT(name) \
}
diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
index 745d4ca4dd50..9cfa4610113a 100644
--- a/include/linux/srcutree.h
+++ b/include/linux/srcutree.h
@@ -94,6 +94,7 @@ struct srcu_struct {
/* callback for the barrier */
/* operation. */
struct delayed_work work;
+ struct list_head srcu_boot_entry; /* Early-boot callbacks. */
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
@@ -105,12 +106,13 @@ struct srcu_struct {
#define SRCU_STATE_SCAN2 2
#define __SRCU_STRUCT_INIT(name, pcpu_name) \
- { \
- .sda = &pcpu_name, \
- .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
- .srcu_gp_seq_needed = 0 - 1, \
- __SRCU_DEP_MAP_INIT(name) \
- }
+{ \
+ .sda = &pcpu_name, \
+ .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
+ .srcu_gp_seq_needed = -1UL, \
+ .srcu_boot_entry = LIST_HEAD_INIT(name.srcu_boot_entry), \
+ __SRCU_DEP_MAP_INIT(name) \
+}
/*
* Define and initialize a srcu struct at build time.
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 4d04683c31b2..e1b5aec5ec1c 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -435,6 +435,12 @@ do { \
#endif /* #if defined(SRCU) || !defined(TINY_RCU) */
+#ifdef CONFIG_SRCU
+void srcu_init(void);
+#else /* #ifdef CONFIG_SRCU */
+static inline void srcu_init(void) { }
+#endif /* #else #ifdef CONFIG_SRCU */
+
#ifdef CONFIG_TINY_RCU
/* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */
static inline bool rcu_gp_is_normal(void) { return true; }
diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
index 04fc2ed71af8..d233f0c63f6f 100644
--- a/kernel/rcu/srcutiny.c
+++ b/kernel/rcu/srcutiny.c
@@ -34,6 +34,8 @@
#include "rcu.h"
int rcu_scheduler_active __read_mostly;
+static LIST_HEAD(srcu_boot_list);
+static bool srcu_init_done;
static int init_srcu_struct_fields(struct srcu_struct *sp)
{
@@ -46,6 +48,7 @@ static int init_srcu_struct_fields(struct srcu_struct *sp)
sp->srcu_gp_waiting = false;
sp->srcu_idx = 0;
INIT_WORK(&sp->srcu_work, srcu_drive_gp);
+ INIT_LIST_HEAD(&sp->srcu_boot_entry);
return 0;
}
@@ -179,8 +182,12 @@ void call_srcu(struct srcu_struct *sp, struct rcu_head *rhp,
*sp->srcu_cb_tail = rhp;
sp->srcu_cb_tail = &rhp->next;
local_irq_restore(flags);
- if (!READ_ONCE(sp->srcu_gp_running))
- schedule_work(&sp->srcu_work);
+ if (!READ_ONCE(sp->srcu_gp_running)) {
+ if (likely(srcu_init_done))
+ schedule_work(&sp->srcu_work);
+ else if (list_empty(&sp->srcu_boot_entry))
+ list_add(&sp->srcu_boot_entry, &srcu_boot_list);
+ }
}
EXPORT_SYMBOL_GPL(call_srcu);
@@ -204,3 +211,21 @@ void __init rcu_scheduler_starting(void)
{
rcu_scheduler_active = RCU_SCHEDULER_RUNNING;
}
+
+/*
+ * Queue work for srcu_struct structures with early boot callbacks.
+ * The work won't actually execute until the workqueue initialization
+ * phase that takes place after the scheduler starts.
+ */
+void __init srcu_init(void)
+{
+ struct srcu_struct *sp;
+
+ srcu_init_done = true;
+ while (!list_empty(&srcu_boot_list)) {
+ sp = list_first_entry(&srcu_boot_list,
+ struct srcu_struct, srcu_boot_entry);
+ list_del_init(&sp->srcu_boot_entry);
+ schedule_work(&sp->srcu_work);
+ }
+}
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 6c9866a854b1..2e7f6b460150 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -51,6 +51,10 @@ module_param(exp_holdoff, ulong, 0444);
static ulong counter_wrap_check = (ULONG_MAX >> 2);
module_param(counter_wrap_check, ulong, 0444);
+/* Early-boot callback-management, so early that no lock is required! */
+static LIST_HEAD(srcu_boot_list);
+static bool __read_mostly srcu_init_done;
+
static void srcu_invoke_callbacks(struct work_struct *work);
static void srcu_reschedule(struct srcu_struct *sp, unsigned long delay);
static void process_srcu(struct work_struct *work);
@@ -182,6 +186,7 @@ static int init_srcu_struct_fields(struct srcu_struct *sp, bool is_static)
mutex_init(&sp->srcu_barrier_mutex);
atomic_set(&sp->srcu_barrier_cpu_cnt, 0);
INIT_DELAYED_WORK(&sp->work, process_srcu);
+ INIT_LIST_HEAD(&sp->srcu_boot_entry);
if (!is_static)
sp->sda = alloc_percpu(struct srcu_data);
init_srcu_struct_nodes(sp, is_static);
@@ -235,7 +240,6 @@ static void check_init_srcu_struct(struct srcu_struct *sp)
{
unsigned long flags;
- WARN_ON_ONCE(rcu_scheduler_active == RCU_SCHEDULER_INIT);
/* The smp_load_acquire() pairs with the smp_store_release(). */
if (!rcu_seq_state(smp_load_acquire(&sp->srcu_gp_seq_needed))) /*^^^*/
return; /* Already initialized. */
@@ -701,7 +705,11 @@ static void srcu_funnel_gp_start(struct srcu_struct *sp, struct srcu_data *sdp,
rcu_seq_state(sp->srcu_gp_seq) == SRCU_STATE_IDLE) {
WARN_ON_ONCE(ULONG_CMP_GE(sp->srcu_gp_seq, sp->srcu_gp_seq_needed));
srcu_gp_start(sp);
- queue_delayed_work(rcu_gp_wq, &sp->work, srcu_get_delay(sp));
+ if (likely(srcu_init_done))
+ queue_delayed_work(rcu_gp_wq, &sp->work,
+ srcu_get_delay(sp));
+ else if (list_empty(&sp->srcu_boot_entry))
+ list_add(&sp->srcu_boot_entry, &srcu_boot_list);
}
spin_unlock_irqrestore_rcu_node(sp, flags);
}
@@ -1308,3 +1316,17 @@ static int __init srcu_bootup_announce(void)
return 0;
}
early_initcall(srcu_bootup_announce);
+
+void __init srcu_init(void)
+{
+ struct srcu_struct *sp;
+
+ srcu_init_done = true;
+ while (!list_empty(&srcu_boot_list)) {
+ sp = list_first_entry(&srcu_boot_list,
+ struct srcu_struct, srcu_boot_entry);
+ check_init_srcu_struct(sp);
+ list_del_init(&sp->srcu_boot_entry);
+ queue_work(rcu_gp_wq, &sp->work.work);
+ }
+}
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index befc9321a89c..101ed5bb836c 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -236,4 +236,5 @@ void __init rcu_init(void)
{
open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
rcu_early_boot_tests();
+ srcu_init();
}
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 0b760c1369f7..43c806291208 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -4164,6 +4164,7 @@ void __init rcu_init(void)
WARN_ON(!rcu_gp_wq);
rcu_par_gp_wq = alloc_workqueue("rcu_par_gp", WQ_MEM_RECLAIM, 0);
WARN_ON(!rcu_par_gp_wq);
+ srcu_init();
}
#include "tree_exp.h"
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 39cb23d22109..7d057d0aaec4 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -888,11 +888,16 @@ static void test_callback(struct rcu_head *r)
pr_info("RCU test callback executed %d\n", rcu_self_test_counter);
}
+DEFINE_STATIC_SRCU(early_srcu);
+
static void early_boot_test_call_rcu(void)
{
static struct rcu_head head;
+ static struct rcu_head shead;
call_rcu(&head, test_callback);
+ if (IS_ENABLED(CONFIG_SRCU))
+ call_srcu(&early_srcu, &shead, test_callback);
}
static void early_boot_test_call_rcu_bh(void)
@@ -930,6 +935,10 @@ 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);
+ }
}
if (rcu_self_test_bh) {
early_boot_test_counter++;
generated by cgit (git 2.34.1) at 2024-05-28 09:33:22 +0000