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Message-Id: <12487185672198-git-send-email->
Date: Mon, 27 Jul 2009 11:16:05 -0700
From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: mingo@...e.hu, laijs@...fujitsu.com, dipankar@...ibm.com,
akpm@...ux-foundation.org, mathieu.desnoyers@...ymtl.ca,
josht@...ux.vnet.ibm.com, dvhltc@...ibm.com, niv@...ibm.com,
tglx@...utronix.de, peterz@...radead.org, rostedt@...dmis.org,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH RFC -tip 2/4] v2 Renamings to increase RCU clarity.
From: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
Make RCU-sched, RCU-bh, and RCU-preempt be underlying implementations,
with "RCU" defined in terms of one of the three. Update the outdated
rcu_qsctr_inc() names, as these functions no longer increment anything.
Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
---
Documentation/RCU/trace.txt | 7 ++--
include/linux/rcupdate.h | 21 +++++++++---
include/linux/rcupreempt.h | 4 +-
include/linux/rcutree.h | 8 +++--
kernel/rcupreempt.c | 8 ++--
kernel/rcutree.c | 78 +++++++++++++++++++++++++++----------------
kernel/rcutree.h | 4 +-
kernel/rcutree_trace.c | 20 +++++-----
kernel/sched.c | 2 +-
kernel/softirq.c | 4 +-
10 files changed, 94 insertions(+), 62 deletions(-)
diff --git a/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt
index 02cced1..187bbf1 100644
--- a/Documentation/RCU/trace.txt
+++ b/Documentation/RCU/trace.txt
@@ -191,8 +191,7 @@ rcu/rcuhier (which displays the struct rcu_node hierarchy).
The output of "cat rcu/rcudata" looks as follows:
-rcu:
-rcu:
+rcu_sched:
0 c=17829 g=17829 pq=1 pqc=17829 qp=0 dt=10951/1 dn=0 df=1101 of=0 ri=36 ql=0 b=10
1 c=17829 g=17829 pq=1 pqc=17829 qp=0 dt=16117/1 dn=0 df=1015 of=0 ri=0 ql=0 b=10
2 c=17829 g=17829 pq=1 pqc=17829 qp=0 dt=1445/1 dn=0 df=1839 of=0 ri=0 ql=0 b=10
@@ -306,7 +305,7 @@ comma-separated-variable spreadsheet format.
The output of "cat rcu/rcugp" looks as follows:
-rcu: completed=33062 gpnum=33063
+rcu_sched: completed=33062 gpnum=33063
rcu_bh: completed=464 gpnum=464
Again, this output is for both "rcu" and "rcu_bh". The fields are
@@ -413,7 +412,7 @@ o Each element of the form "1/1 0:127 ^0" represents one struct
The output of "cat rcu/rcu_pending" looks as follows:
-rcu:
+rcu_sched:
0 np=255892 qsp=53936 cbr=0 cng=14417 gpc=10033 gps=24320 nf=6445 nn=146741
1 np=261224 qsp=54638 cbr=0 cng=25723 gpc=16310 gps=2849 nf=5912 nn=155792
2 np=237496 qsp=49664 cbr=0 cng=2762 gpc=45478 gps=1762 nf=1201 nn=136629
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 3c89d6a..e920f0f 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -157,17 +157,28 @@ extern int rcu_scheduler_active;
* - call_rcu_sched() and rcu_barrier_sched()
* on the write-side to insure proper synchronization.
*/
-#define rcu_read_lock_sched() preempt_disable()
-#define rcu_read_lock_sched_notrace() preempt_disable_notrace()
+static inline void rcu_read_lock_sched(void)
+{
+ preempt_disable();
+}
+static inline void rcu_read_lock_sched_notrace(void)
+{
+ preempt_disable_notrace();
+}
/*
* rcu_read_unlock_sched - marks the end of a RCU-classic critical section
*
* See rcu_read_lock_sched for more information.
*/
-#define rcu_read_unlock_sched() preempt_enable()
-#define rcu_read_unlock_sched_notrace() preempt_enable_notrace()
-
+static inline void rcu_read_unlock_sched(void)
+{
+ preempt_enable();
+}
+static inline void rcu_read_unlock_sched_notrace(void)
+{
+ preempt_enable_notrace();
+}
/**
diff --git a/include/linux/rcupreempt.h b/include/linux/rcupreempt.h
index f164ac9..2963f08 100644
--- a/include/linux/rcupreempt.h
+++ b/include/linux/rcupreempt.h
@@ -40,8 +40,8 @@
#include <linux/cpumask.h>
#include <linux/seqlock.h>
-extern void rcu_qsctr_inc(int cpu);
-static inline void rcu_bh_qsctr_inc(int cpu) { }
+extern void rcu_sched_qs(int cpu);
+static inline void rcu_bh_qs(int cpu) { }
/*
* Someone might want to pass call_rcu_bh as a function pointer.
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index e37d5e2..a0852d0 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -30,8 +30,8 @@
#ifndef __LINUX_RCUTREE_H
#define __LINUX_RCUTREE_H
-extern void rcu_qsctr_inc(int cpu);
-extern void rcu_bh_qsctr_inc(int cpu);
+extern void rcu_sched_qs(int cpu);
+extern void rcu_bh_qs(int cpu);
extern int rcu_pending(int cpu);
extern int rcu_needs_cpu(int cpu);
@@ -73,7 +73,8 @@ static inline void __rcu_read_unlock_bh(void)
#define __synchronize_sched() synchronize_rcu()
-#define call_rcu_sched(head, func) call_rcu(head, func)
+extern void call_rcu_sched(struct rcu_head *head,
+ void (*func)(struct rcu_head *rcu));
static inline void synchronize_rcu_expedited(void)
{
@@ -91,6 +92,7 @@ extern void rcu_restart_cpu(int cpu);
extern long rcu_batches_completed(void);
extern long rcu_batches_completed_bh(void);
+extern long rcu_batches_completed_sched(void);
static inline void rcu_init_sched(void)
{
diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c
index 4300212..788a7ed 100644
--- a/kernel/rcupreempt.c
+++ b/kernel/rcupreempt.c
@@ -159,7 +159,7 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_dyntick_sched, rcu_dyntick_sched
.dynticks = 1,
};
-void rcu_qsctr_inc(int cpu)
+void rcu_sched_qs(int cpu)
{
struct rcu_dyntick_sched *rdssp = &per_cpu(rcu_dyntick_sched, cpu);
@@ -967,12 +967,12 @@ void rcu_check_callbacks(int cpu, int user)
* If this CPU took its interrupt from user mode or from the
* idle loop, and this is not a nested interrupt, then
* this CPU has to have exited all prior preept-disable
- * sections of code. So increment the counter to note this.
+ * sections of code. So invoke rcu_sched_qs() to note this.
*
* The memory barrier is needed to handle the case where
* writes from a preempt-disable section of code get reordered
* into schedule() by this CPU's write buffer. So the memory
- * barrier makes sure that the rcu_qsctr_inc() is seen by other
+ * barrier makes sure that the rcu_sched_qs() is seen by other
* CPUs to happen after any such write.
*/
@@ -980,7 +980,7 @@ void rcu_check_callbacks(int cpu, int user)
(idle_cpu(cpu) && !in_softirq() &&
hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
smp_mb(); /* Guard against aggressive schedule(). */
- rcu_qsctr_inc(cpu);
+ rcu_sched_qs(cpu);
}
rcu_check_mb(cpu);
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index e4b5d01..47817f7 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -74,26 +74,25 @@ EXPORT_SYMBOL_GPL(rcu_lock_map);
.n_force_qs_ngp = 0, \
}
-struct rcu_state rcu_state = RCU_STATE_INITIALIZER(rcu_state);
-DEFINE_PER_CPU(struct rcu_data, rcu_data);
+struct rcu_state rcu_sched_state = RCU_STATE_INITIALIZER(rcu_sched_state);
+DEFINE_PER_CPU(struct rcu_data, rcu_sched_data);
struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state);
DEFINE_PER_CPU(struct rcu_data, rcu_bh_data);
/*
- * Increment the quiescent state counter.
- * The counter is a bit degenerated: We do not need to know
+ * Note a quiescent state. Because we do not need to know
* how many quiescent states passed, just if there was at least
- * one since the start of the grace period. Thus just a flag.
+ * one since the start of the grace period, this just sets a flag.
*/
-void rcu_qsctr_inc(int cpu)
+void rcu_sched_qs(int cpu)
{
- struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
+ struct rcu_data *rdp = &per_cpu(rcu_sched_data, cpu);
rdp->passed_quiesc = 1;
rdp->passed_quiesc_completed = rdp->completed;
}
-void rcu_bh_qsctr_inc(int cpu)
+void rcu_bh_qs(int cpu)
{
struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu);
rdp->passed_quiesc = 1;
@@ -114,11 +113,21 @@ static int qlowmark = 100; /* Once only this many pending, use blimit. */
static void force_quiescent_state(struct rcu_state *rsp, int relaxed);
/*
+ * Return the number of RCU-sched batches processed thus far for debug & stats.
+ */
+long rcu_batches_completed_sched(void)
+{
+ return rcu_sched_state.completed;
+}
+EXPORT_SYMBOL_GPL(rcu_batches_completed_sched);
+
+/*
* Return the number of RCU batches processed thus far for debug & stats.
+ * @@@ placeholder, maps to rcu_batches_completed_sched().
*/
long rcu_batches_completed(void)
{
- return rcu_state.completed;
+ return rcu_batches_completed_sched();
}
EXPORT_SYMBOL_GPL(rcu_batches_completed);
@@ -310,7 +319,7 @@ void rcu_irq_exit(void)
WARN_ON_RATELIMIT(rdtp->dynticks & 0x1, &rcu_rs);
/* If the interrupt queued a callback, get out of dyntick mode. */
- if (__get_cpu_var(rcu_data).nxtlist ||
+ if (__get_cpu_var(rcu_sched_data).nxtlist ||
__get_cpu_var(rcu_bh_data).nxtlist)
set_need_resched();
}
@@ -847,7 +856,7 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp)
/*
* Move callbacks from the outgoing CPU to the running CPU.
* Note that the outgoing CPU is now quiscent, so it is now
- * (uncharacteristically) safe to access it rcu_data structure.
+ * (uncharacteristically) safe to access its rcu_data structure.
* Note also that we must carefully retain the order of the
* outgoing CPU's callbacks in order for rcu_barrier() to work
* correctly. Finally, note that we start all the callbacks
@@ -878,7 +887,7 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp)
*/
static void rcu_offline_cpu(int cpu)
{
- __rcu_offline_cpu(cpu, &rcu_state);
+ __rcu_offline_cpu(cpu, &rcu_sched_state);
__rcu_offline_cpu(cpu, &rcu_bh_state);
}
@@ -973,17 +982,16 @@ void rcu_check_callbacks(int cpu, int user)
* Get here if this CPU took its interrupt from user
* mode or from the idle loop, and if this is not a
* nested interrupt. In this case, the CPU is in
- * a quiescent state, so count it.
+ * a quiescent state, so note it.
*
* No memory barrier is required here because both
- * rcu_qsctr_inc() and rcu_bh_qsctr_inc() reference
- * only CPU-local variables that other CPUs neither
- * access nor modify, at least not while the corresponding
- * CPU is online.
+ * rcu_sched_qs() and rcu_bh_qs() reference only CPU-local
+ * variables that other CPUs neither access nor modify,
+ * at least not while the corresponding CPU is online.
*/
- rcu_qsctr_inc(cpu);
- rcu_bh_qsctr_inc(cpu);
+ rcu_sched_qs(cpu);
+ rcu_bh_qs(cpu);
} else if (!in_softirq()) {
@@ -991,10 +999,10 @@ void rcu_check_callbacks(int cpu, int user)
* Get here if this CPU did not take its interrupt from
* softirq, in other words, if it is not interrupting
* a rcu_bh read-side critical section. This is an _bh
- * critical section, so count it.
+ * critical section, so note it.
*/
- rcu_bh_qsctr_inc(cpu);
+ rcu_bh_qs(cpu);
}
raise_softirq(RCU_SOFTIRQ);
}
@@ -1172,7 +1180,8 @@ static void rcu_process_callbacks(struct softirq_action *unused)
*/
smp_mb(); /* See above block comment. */
- __rcu_process_callbacks(&rcu_state, &__get_cpu_var(rcu_data));
+ __rcu_process_callbacks(&rcu_sched_state,
+ &__get_cpu_var(rcu_sched_data));
__rcu_process_callbacks(&rcu_bh_state, &__get_cpu_var(rcu_bh_data));
/*
@@ -1229,14 +1238,25 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu),
}
/*
- * Queue an RCU callback for invocation after a grace period.
+ * Queue an RCU-sched callback for invocation after a grace period.
+ */
+void call_rcu_sched(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
+{
+ __call_rcu(head, func, &rcu_sched_state);
+}
+EXPORT_SYMBOL_GPL(call_rcu_sched);
+
+/*
+ * @@@ Queue an RCU callback for invocation after a grace period.
+ * @@@ Placeholder pending rcutree_plugin.h.
*/
void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
{
- __call_rcu(head, func, &rcu_state);
+ call_rcu_sched(head, func);
}
EXPORT_SYMBOL_GPL(call_rcu);
+
/*
* Queue an RCU for invocation after a quicker grace period.
*/
@@ -1309,7 +1329,7 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
*/
int rcu_pending(int cpu)
{
- return __rcu_pending(&rcu_state, &per_cpu(rcu_data, cpu)) ||
+ return __rcu_pending(&rcu_sched_state, &per_cpu(rcu_sched_data, cpu)) ||
__rcu_pending(&rcu_bh_state, &per_cpu(rcu_bh_data, cpu));
}
@@ -1322,7 +1342,7 @@ int rcu_pending(int cpu)
int rcu_needs_cpu(int cpu)
{
/* RCU callbacks either ready or pending? */
- return per_cpu(rcu_data, cpu).nxtlist ||
+ return per_cpu(rcu_sched_data, cpu).nxtlist ||
per_cpu(rcu_bh_data, cpu).nxtlist;
}
@@ -1407,7 +1427,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
static void __cpuinit rcu_online_cpu(int cpu)
{
- rcu_init_percpu_data(cpu, &rcu_state);
+ rcu_init_percpu_data(cpu, &rcu_sched_state);
rcu_init_percpu_data(cpu, &rcu_bh_state);
}
@@ -1534,8 +1554,8 @@ void __init __rcu_init(void)
#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n");
#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
- rcu_init_one(&rcu_state);
- RCU_DATA_PTR_INIT(&rcu_state, rcu_data);
+ rcu_init_one(&rcu_sched_state);
+ RCU_DATA_PTR_INIT(&rcu_sched_state, rcu_sched_data);
rcu_init_one(&rcu_bh_state);
RCU_DATA_PTR_INIT(&rcu_bh_state, rcu_bh_data);
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index 7cc830a..0024e5d 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -238,8 +238,8 @@ struct rcu_state {
/*
* RCU implementation internal declarations:
*/
-extern struct rcu_state rcu_state;
-DECLARE_PER_CPU(struct rcu_data, rcu_data);
+extern struct rcu_state rcu_sched_state;
+DECLARE_PER_CPU(struct rcu_data, rcu_sched_data);
extern struct rcu_state rcu_bh_state;
DECLARE_PER_CPU(struct rcu_data, rcu_bh_data);
diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c
index 0cb52b8..236c050 100644
--- a/kernel/rcutree_trace.c
+++ b/kernel/rcutree_trace.c
@@ -77,8 +77,8 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
static int show_rcudata(struct seq_file *m, void *unused)
{
- seq_puts(m, "rcu:\n");
- PRINT_RCU_DATA(rcu_data, print_one_rcu_data, m);
+ seq_puts(m, "rcu_sched:\n");
+ PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data, m);
seq_puts(m, "rcu_bh:\n");
PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data, m);
return 0;
@@ -125,8 +125,8 @@ static int show_rcudata_csv(struct seq_file *m, void *unused)
seq_puts(m, "\"dt\",\"dt nesting\",\"dn\",\"df\",");
#endif /* #ifdef CONFIG_NO_HZ */
seq_puts(m, "\"of\",\"ri\",\"ql\",\"b\"\n");
- seq_puts(m, "\"rcu:\"\n");
- PRINT_RCU_DATA(rcu_data, print_one_rcu_data_csv, m);
+ seq_puts(m, "\"rcu_sched:\"\n");
+ PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data_csv, m);
seq_puts(m, "\"rcu_bh:\"\n");
PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data_csv, m);
return 0;
@@ -172,8 +172,8 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
static int show_rcuhier(struct seq_file *m, void *unused)
{
- seq_puts(m, "rcu:\n");
- print_one_rcu_state(m, &rcu_state);
+ seq_puts(m, "rcu_sched:\n");
+ print_one_rcu_state(m, &rcu_sched_state);
seq_puts(m, "rcu_bh:\n");
print_one_rcu_state(m, &rcu_bh_state);
return 0;
@@ -194,8 +194,8 @@ static struct file_operations rcuhier_fops = {
static int show_rcugp(struct seq_file *m, void *unused)
{
- seq_printf(m, "rcu: completed=%ld gpnum=%ld\n",
- rcu_state.completed, rcu_state.gpnum);
+ seq_printf(m, "rcu_sched: completed=%ld gpnum=%ld\n",
+ rcu_sched_state.completed, rcu_sched_state.gpnum);
seq_printf(m, "rcu_bh: completed=%ld gpnum=%ld\n",
rcu_bh_state.completed, rcu_bh_state.gpnum);
return 0;
@@ -244,8 +244,8 @@ static void print_rcu_pendings(struct seq_file *m, struct rcu_state *rsp)
static int show_rcu_pending(struct seq_file *m, void *unused)
{
- seq_puts(m, "rcu:\n");
- print_rcu_pendings(m, &rcu_state);
+ seq_puts(m, "rcu_sched:\n");
+ print_rcu_pendings(m, &rcu_sched_state);
seq_puts(m, "rcu_bh:\n");
print_rcu_pendings(m, &rcu_bh_state);
return 0;
diff --git a/kernel/sched.c b/kernel/sched.c
index 9ae80be..8251654 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5302,7 +5302,7 @@ need_resched:
preempt_disable();
cpu = smp_processor_id();
rq = cpu_rq(cpu);
- rcu_qsctr_inc(cpu);
+ rcu_sched_qs(cpu);
prev = rq->curr;
switch_count = &prev->nivcsw;
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 3a94905..0aedd87 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -227,7 +227,7 @@ restart:
preempt_count() = prev_count;
}
- rcu_bh_qsctr_inc(cpu);
+ rcu_bh_qs(cpu);
}
h++;
pending >>= 1;
@@ -659,7 +659,7 @@ static int ksoftirqd(void * __bind_cpu)
preempt_enable_no_resched();
cond_resched();
preempt_disable();
- rcu_qsctr_inc((long)__bind_cpu);
+ rcu_sched_qs((long)__bind_cpu);
}
preempt_enable();
set_current_state(TASK_INTERRUPTIBLE);
--
1.5.2.5
--
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