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Message-ID: <1516694381-20333-8-git-send-email-lianglihao@huawei.com>
Date: Tue, 23 Jan 2018 15:59:32 +0800
From: <lianglihao@...wei.com>
To: <paulmck@...ux.vnet.ibm.com>
CC: <guohanjun@...wei.com>, <heng.z@...wei.com>, <hb.chen@...wei.com>,
<lihao.liang@...il.com>, <linux-kernel@...r.kernel.org>
Subject: [PATCH RFC 07/16] prcu: Implement call_prcu() API
From: Lihao Liang <lianglihao@...wei.com>
This is PRCU's counterpart of RCU's call_rcu() API.
Reviewed-by: Heng Zhang <heng.z@...wei.com>
Signed-off-by: Lihao Liang <lianglihao@...wei.com>
---
include/linux/prcu.h | 25 ++++++++++++++++++++
init/main.c | 2 ++
kernel/rcu/prcu.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++---
3 files changed, 91 insertions(+), 3 deletions(-)
diff --git a/include/linux/prcu.h b/include/linux/prcu.h
index 653b4633..e5e09c9b 100644
--- a/include/linux/prcu.h
+++ b/include/linux/prcu.h
@@ -2,15 +2,36 @@
#define __LINUX_PRCU_H
#include <linux/atomic.h>
+#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/wait.h>
#define CONFIG_PRCU
+struct prcu_version_head {
+ unsigned long long version;
+ struct prcu_version_head *next;
+};
+
+/* Simple unsegmented callback list for PRCU. */
+struct prcu_cblist {
+ struct rcu_head *head;
+ struct rcu_head **tail;
+ struct prcu_version_head *version_head;
+ struct prcu_version_head **version_tail;
+ long len;
+};
+
+#define PRCU_CBLIST_INITIALIZER(n) { \
+ .head = NULL, .tail = &n.head, \
+ .version_head = NULL, .version_tail = &n.version_head, \
+}
+
struct prcu_local_struct {
unsigned int locked;
unsigned int online;
unsigned long long version;
+ struct prcu_cblist cblist;
};
struct prcu_struct {
@@ -24,6 +45,8 @@ struct prcu_struct {
void prcu_read_lock(void);
void prcu_read_unlock(void);
void synchronize_prcu(void);
+void call_prcu(struct rcu_head *head, rcu_callback_t func);
+void prcu_init(void);
void prcu_note_context_switch(void);
#else /* #ifdef CONFIG_PRCU */
@@ -31,6 +54,8 @@ void prcu_note_context_switch(void);
#define prcu_read_lock() do {} while (0)
#define prcu_read_unlock() do {} while (0)
#define synchronize_prcu() do {} while (0)
+#define call_prcu() do {} while (0)
+#define prcu_init() do {} while (0)
#define prcu_note_context_switch() do {} while (0)
#endif /* #ifdef CONFIG_PRCU */
diff --git a/init/main.c b/init/main.c
index f8665104..4925964e 100644
--- a/init/main.c
+++ b/init/main.c
@@ -38,6 +38,7 @@
#include <linux/smp.h>
#include <linux/profile.h>
#include <linux/rcupdate.h>
+#include <linux/prcu.h>
#include <linux/moduleparam.h>
#include <linux/kallsyms.h>
#include <linux/writeback.h>
@@ -574,6 +575,7 @@ asmlinkage __visible void __init start_kernel(void)
workqueue_init_early();
rcu_init();
+ prcu_init();
/* Trace events are available after this */
trace_init();
diff --git a/kernel/rcu/prcu.c b/kernel/rcu/prcu.c
index a00b9420..f198285c 100644
--- a/kernel/rcu/prcu.c
+++ b/kernel/rcu/prcu.c
@@ -1,11 +1,12 @@
#include <linux/smp.h>
-#include <linux/prcu.h>
#include <linux/percpu.h>
-#include <linux/compiler.h>
+#include <linux/prcu.h>
#include <linux/sched.h>
-
+#include <linux/slab.h>
#include <asm/barrier.h>
+#include "rcu.h"
+
DEFINE_PER_CPU_SHARED_ALIGNED(struct prcu_local_struct, prcu_local);
struct prcu_struct global_prcu = {
@@ -16,6 +17,16 @@ struct prcu_struct global_prcu = {
};
struct prcu_struct *prcu = &global_prcu;
+/* Initialize simple callback list. */
+static void prcu_cblist_init(struct prcu_cblist *rclp)
+{
+ rclp->head = NULL;
+ rclp->tail = &rclp->head;
+ rclp->version_head = NULL;
+ rclp->version_tail = &rclp->version_head;
+ rclp->len = 0;
+}
+
static inline void prcu_report(struct prcu_local_struct *local)
{
unsigned long long global_version;
@@ -123,3 +134,53 @@ void prcu_note_context_switch(void)
prcu_report(local);
put_cpu_ptr(&prcu_local);
}
+
+void call_prcu(struct rcu_head *head, rcu_callback_t func)
+{
+ unsigned long flags;
+ struct prcu_local_struct *local;
+ struct prcu_cblist *rclp;
+ struct prcu_version_head *vhp;
+
+ debug_rcu_head_queue(head);
+
+ /* Use GFP_ATOMIC with IRQs disabled */
+ vhp = kmalloc(sizeof(struct prcu_version_head), GFP_ATOMIC);
+ if (!vhp)
+ return;
+
+ head->func = func;
+ head->next = NULL;
+ vhp->next = NULL;
+
+ local_irq_save(flags);
+ local = this_cpu_ptr(&prcu_local);
+ vhp->version = local->version;
+ rclp = &local->cblist;
+ rclp->len++;
+ *rclp->tail = head;
+ rclp->tail = &head->next;
+ *rclp->version_tail = vhp;
+ rclp->version_tail = &vhp->next;
+ local_irq_restore(flags);
+}
+EXPORT_SYMBOL(call_prcu);
+
+void prcu_init_local_struct(int cpu)
+{
+ struct prcu_local_struct *local;
+
+ local = per_cpu_ptr(&prcu_local, cpu);
+ local->locked = 0;
+ local->online = 0;
+ local->version = 0;
+ prcu_cblist_init(&local->cblist);
+}
+
+void __init prcu_init(void)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu)
+ prcu_init_local_struct(cpu);
+}
--
2.14.1.729.g59c0ea183
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