* [PATCH] rcu: Remove redundant CONFIG_PREEMPT_RCU option
@ 2014-09-21 16:49 Pranith Kumar
2014-09-22 16:25 ` Josh Triplett
0 siblings, 1 reply; 6+ messages in thread
From: Pranith Kumar @ 2014-09-21 16:49 UTC (permalink / raw)
To: Paul E. McKenney, Josh Triplett, Steven Rostedt,
Mathieu Desnoyers, Lai Jiangshan, open list
PREEMPT_RCU and TREE_PREEMPT_RCU serve the same function after TINY_PREEMPT_RCU
has been removed. This patch removes CONFIG_PREEMPT_RCU and uses
CONFIG_TREE_PREEMPT_RCU in its place.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
---
arch/xtensa/configs/s6105_defconfig | 2 +-
include/linux/init_task.h | 2 +-
include/linux/rcupdate.h | 16 ++++++++--------
include/linux/sched.h | 10 +++++-----
init/Kconfig | 6 ------
kernel/rcu/update.c | 4 ++--
tools/testing/selftests/rcutorture/doc/TINY_RCU.txt | 2 +-
.../selftests/rcutorture/doc/TREE_RCU-kconfig.txt | 2 +-
8 files changed, 19 insertions(+), 25 deletions(-)
diff --git a/arch/xtensa/configs/s6105_defconfig b/arch/xtensa/configs/s6105_defconfig
index 12a492a..dab1a99 100644
--- a/arch/xtensa/configs/s6105_defconfig
+++ b/arch/xtensa/configs/s6105_defconfig
@@ -35,7 +35,7 @@ CONFIG_SYSVIPC_SYSCTL=y
#
# CONFIG_CLASSIC_RCU is not set
# CONFIG_TREE_RCU is not set
-CONFIG_PREEMPT_RCU=y
+CONFIG_TREE_PREEMPT_RCU=y
# CONFIG_RCU_TRACE is not set
# CONFIG_TREE_RCU_TRACE is not set
# CONFIG_PREEMPT_RCU_TRACE is not set
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 77fc43f..39600f4 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -108,7 +108,7 @@ extern struct group_info init_groups;
#else
#define INIT_TASK_RCU_TREE_PREEMPT(tsk)
#endif
-#ifdef CONFIG_PREEMPT_RCU
+#ifdef CONFIG_TREE_PREEMPT_RCU
#define INIT_TASK_RCU_PREEMPT(tsk) \
.rcu_read_lock_nesting = 0, \
.rcu_read_unlock_special.s = 0, \
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index a4a819f..17a15d5 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -103,7 +103,7 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
/* Exported common interfaces */
-#ifdef CONFIG_PREEMPT_RCU
+#ifdef CONFIG_TREE_PREEMPT_RCU
/**
* call_rcu() - Queue an RCU callback for invocation after a grace period.
@@ -140,12 +140,12 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
void call_rcu(struct rcu_head *head,
void (*func)(struct rcu_head *head));
-#else /* #ifdef CONFIG_PREEMPT_RCU */
+#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
/* In classic RCU, call_rcu() is just call_rcu_sched(). */
#define call_rcu call_rcu_sched
-#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
/**
* call_rcu_bh() - Queue an RCU for invocation after a quicker grace period.
@@ -217,7 +217,7 @@ void call_rcu_tasks(struct rcu_head *head, void (*func)(struct rcu_head *head));
void synchronize_rcu_tasks(void);
void rcu_barrier_tasks(void);
-#ifdef CONFIG_PREEMPT_RCU
+#ifdef CONFIG_TREE_PREEMPT_RCU
void __rcu_read_lock(void);
void __rcu_read_unlock(void);
@@ -227,12 +227,12 @@ void synchronize_rcu(void);
/*
* Defined as a macro as it is a very low level header included from
* areas that don't even know about current. This gives the rcu_read_lock()
- * nesting depth, but makes sense only if CONFIG_PREEMPT_RCU -- in other
+ * nesting depth, but makes sense only if CONFIG_TREE_PREEMPT_RCU -- in other
* types of kernel builds, the rcu_read_lock() nesting depth is unknowable.
*/
#define rcu_preempt_depth() (current->rcu_read_lock_nesting)
-#else /* #ifdef CONFIG_PREEMPT_RCU */
+#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
static inline void __rcu_read_lock(void)
{
@@ -254,7 +254,7 @@ static inline int rcu_preempt_depth(void)
return 0;
}
-#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
/* Internal to kernel */
void rcu_init(void);
@@ -530,7 +530,7 @@ static inline int rcu_read_lock_sched_held(void)
} \
} while (0)
-#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_PREEMPT_RCU)
+#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_TREE_PREEMPT_RCU)
static inline void rcu_preempt_sleep_check(void)
{
rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 42888d7..6acaa30 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1269,11 +1269,11 @@ struct task_struct {
int nr_cpus_allowed;
cpumask_t cpus_allowed;
-#ifdef CONFIG_PREEMPT_RCU
+#ifdef CONFIG_TREE_PREEMPT_RCU
int rcu_read_lock_nesting;
union rcu_special rcu_read_unlock_special;
struct list_head rcu_node_entry;
-#endif /* #ifdef CONFIG_PREEMPT_RCU */
+#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
#ifdef CONFIG_TREE_PREEMPT_RCU
struct rcu_node *rcu_blocked_node;
#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
@@ -2014,12 +2014,12 @@ extern void task_clear_jobctl_pending(struct task_struct *task,
static inline void rcu_copy_process(struct task_struct *p)
{
-#ifdef CONFIG_PREEMPT_RCU
+#ifdef CONFIG_TREE_PREEMPT_RCU
p->rcu_read_lock_nesting = 0;
p->rcu_read_unlock_special.s = 0;
p->rcu_blocked_node = NULL;
INIT_LIST_HEAD(&p->rcu_node_entry);
-#endif /* #ifdef CONFIG_PREEMPT_RCU */
+#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
#ifdef CONFIG_TASKS_RCU
p->rcu_tasks_holdout = false;
INIT_LIST_HEAD(&p->rcu_tasks_holdout_list);
@@ -2752,7 +2752,7 @@ extern int __cond_resched_softirq(void);
static inline void cond_resched_rcu(void)
{
-#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
+#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_TREE_PREEMPT_RCU)
rcu_read_unlock();
cond_resched();
rcu_read_lock();
diff --git a/init/Kconfig b/init/Kconfig
index 8a2b97c..27ad03c 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -501,12 +501,6 @@ config TINY_RCU
endchoice
-config PREEMPT_RCU
- def_bool TREE_PREEMPT_RCU
- help
- This option enables preemptible-RCU code that is common between
- TREE_PREEMPT_RCU and, in the old days, TINY_PREEMPT_RCU.
-
config TASKS_RCU
bool "Task_based RCU implementation using voluntary context switch"
default n
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 3ef8ba5..8848a32 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -62,7 +62,7 @@ MODULE_ALIAS("rcupdate");
module_param(rcu_expedited, int, 0);
-#ifdef CONFIG_PREEMPT_RCU
+#ifdef CONFIG_TREE_PREEMPT_RCU
/*
* Preemptible RCU implementation for rcu_read_lock().
@@ -108,7 +108,7 @@ void __rcu_read_unlock(void)
}
EXPORT_SYMBOL_GPL(__rcu_read_unlock);
-#endif /* #ifdef CONFIG_PREEMPT_RCU */
+#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
#ifdef CONFIG_DEBUG_LOCK_ALLOC
static struct lock_class_key rcu_lock_key;
diff --git a/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt b/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
index 28db67b..4fea92d 100644
--- a/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
+++ b/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
@@ -31,7 +31,7 @@ CONFIG_RCU_TORTURE_TEST
CONFIG_HOTPLUG_CPU
CONFIG_PREEMPT
-CONFIG_PREEMPT_RCU
+CONFIG_TREE_PREEMPT_RCU
CONFIG_SMP
CONFIG_TINY_RCU
CONFIG_TREE_PREEMPT_RCU
diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
index f85c45e..081dece 100644
--- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
+++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
@@ -62,7 +62,7 @@ CONFIG_NO_HZ_FULL_SYSIDLE_SMALL
Defer until Frederic uses this.
CONFIG_PREEMPT_COUNT
-CONFIG_PREEMPT_RCU
+CONFIG_TREE_PREEMPT_RCU
Redundant with CONFIG_PREEMPT, ignore.
--
2.1.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] rcu: Remove redundant CONFIG_PREEMPT_RCU option
2014-09-21 16:49 [PATCH] rcu: Remove redundant CONFIG_PREEMPT_RCU option Pranith Kumar
@ 2014-09-22 16:25 ` Josh Triplett
2014-09-22 16:44 ` Paul E. McKenney
2014-09-22 16:49 ` Pranith Kumar
0 siblings, 2 replies; 6+ messages in thread
From: Josh Triplett @ 2014-09-22 16:25 UTC (permalink / raw)
To: Pranith Kumar
Cc: Paul E. McKenney, Steven Rostedt, Mathieu Desnoyers,
Lai Jiangshan, open list
On Sun, Sep 21, 2014 at 12:49:54PM -0400, Pranith Kumar wrote:
> PREEMPT_RCU and TREE_PREEMPT_RCU serve the same function after TINY_PREEMPT_RCU
> has been removed. This patch removes CONFIG_PREEMPT_RCU and uses
> CONFIG_TREE_PREEMPT_RCU in its place.
>
> Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
I think it would actually make more sense to do this the other way
around, if at all: drop TREE_PREEMPT_RCU in favor of PREEMPT_RCU. The
instances shown here don't care about *which* preemptible RCU
implementation the kernel uses, they just need to behave differently
when preemptible. Let's also not assume that no new RCU implementation
will ever arise superceding TREE_PREEMPT_RCU.
- Josh Triplett
> arch/xtensa/configs/s6105_defconfig | 2 +-
> include/linux/init_task.h | 2 +-
> include/linux/rcupdate.h | 16 ++++++++--------
> include/linux/sched.h | 10 +++++-----
> init/Kconfig | 6 ------
> kernel/rcu/update.c | 4 ++--
> tools/testing/selftests/rcutorture/doc/TINY_RCU.txt | 2 +-
> .../selftests/rcutorture/doc/TREE_RCU-kconfig.txt | 2 +-
> 8 files changed, 19 insertions(+), 25 deletions(-)
>
> diff --git a/arch/xtensa/configs/s6105_defconfig b/arch/xtensa/configs/s6105_defconfig
> index 12a492a..dab1a99 100644
> --- a/arch/xtensa/configs/s6105_defconfig
> +++ b/arch/xtensa/configs/s6105_defconfig
> @@ -35,7 +35,7 @@ CONFIG_SYSVIPC_SYSCTL=y
> #
> # CONFIG_CLASSIC_RCU is not set
> # CONFIG_TREE_RCU is not set
> -CONFIG_PREEMPT_RCU=y
> +CONFIG_TREE_PREEMPT_RCU=y
> # CONFIG_RCU_TRACE is not set
> # CONFIG_TREE_RCU_TRACE is not set
> # CONFIG_PREEMPT_RCU_TRACE is not set
> diff --git a/include/linux/init_task.h b/include/linux/init_task.h
> index 77fc43f..39600f4 100644
> --- a/include/linux/init_task.h
> +++ b/include/linux/init_task.h
> @@ -108,7 +108,7 @@ extern struct group_info init_groups;
> #else
> #define INIT_TASK_RCU_TREE_PREEMPT(tsk)
> #endif
> -#ifdef CONFIG_PREEMPT_RCU
> +#ifdef CONFIG_TREE_PREEMPT_RCU
> #define INIT_TASK_RCU_PREEMPT(tsk) \
> .rcu_read_lock_nesting = 0, \
> .rcu_read_unlock_special.s = 0, \
> diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
> index a4a819f..17a15d5 100644
> --- a/include/linux/rcupdate.h
> +++ b/include/linux/rcupdate.h
> @@ -103,7 +103,7 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
>
> /* Exported common interfaces */
>
> -#ifdef CONFIG_PREEMPT_RCU
> +#ifdef CONFIG_TREE_PREEMPT_RCU
>
> /**
> * call_rcu() - Queue an RCU callback for invocation after a grace period.
> @@ -140,12 +140,12 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
> void call_rcu(struct rcu_head *head,
> void (*func)(struct rcu_head *head));
>
> -#else /* #ifdef CONFIG_PREEMPT_RCU */
> +#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
>
> /* In classic RCU, call_rcu() is just call_rcu_sched(). */
> #define call_rcu call_rcu_sched
>
> -#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
> +#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
>
> /**
> * call_rcu_bh() - Queue an RCU for invocation after a quicker grace period.
> @@ -217,7 +217,7 @@ void call_rcu_tasks(struct rcu_head *head, void (*func)(struct rcu_head *head));
> void synchronize_rcu_tasks(void);
> void rcu_barrier_tasks(void);
>
> -#ifdef CONFIG_PREEMPT_RCU
> +#ifdef CONFIG_TREE_PREEMPT_RCU
>
> void __rcu_read_lock(void);
> void __rcu_read_unlock(void);
> @@ -227,12 +227,12 @@ void synchronize_rcu(void);
> /*
> * Defined as a macro as it is a very low level header included from
> * areas that don't even know about current. This gives the rcu_read_lock()
> - * nesting depth, but makes sense only if CONFIG_PREEMPT_RCU -- in other
> + * nesting depth, but makes sense only if CONFIG_TREE_PREEMPT_RCU -- in other
> * types of kernel builds, the rcu_read_lock() nesting depth is unknowable.
> */
> #define rcu_preempt_depth() (current->rcu_read_lock_nesting)
>
> -#else /* #ifdef CONFIG_PREEMPT_RCU */
> +#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
>
> static inline void __rcu_read_lock(void)
> {
> @@ -254,7 +254,7 @@ static inline int rcu_preempt_depth(void)
> return 0;
> }
>
> -#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
> +#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
>
> /* Internal to kernel */
> void rcu_init(void);
> @@ -530,7 +530,7 @@ static inline int rcu_read_lock_sched_held(void)
> } \
> } while (0)
>
> -#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_PREEMPT_RCU)
> +#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_TREE_PREEMPT_RCU)
> static inline void rcu_preempt_sleep_check(void)
> {
> rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 42888d7..6acaa30 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -1269,11 +1269,11 @@ struct task_struct {
> int nr_cpus_allowed;
> cpumask_t cpus_allowed;
>
> -#ifdef CONFIG_PREEMPT_RCU
> +#ifdef CONFIG_TREE_PREEMPT_RCU
> int rcu_read_lock_nesting;
> union rcu_special rcu_read_unlock_special;
> struct list_head rcu_node_entry;
> -#endif /* #ifdef CONFIG_PREEMPT_RCU */
> +#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> #ifdef CONFIG_TREE_PREEMPT_RCU
> struct rcu_node *rcu_blocked_node;
> #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> @@ -2014,12 +2014,12 @@ extern void task_clear_jobctl_pending(struct task_struct *task,
>
> static inline void rcu_copy_process(struct task_struct *p)
> {
> -#ifdef CONFIG_PREEMPT_RCU
> +#ifdef CONFIG_TREE_PREEMPT_RCU
> p->rcu_read_lock_nesting = 0;
> p->rcu_read_unlock_special.s = 0;
> p->rcu_blocked_node = NULL;
> INIT_LIST_HEAD(&p->rcu_node_entry);
> -#endif /* #ifdef CONFIG_PREEMPT_RCU */
> +#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> #ifdef CONFIG_TASKS_RCU
> p->rcu_tasks_holdout = false;
> INIT_LIST_HEAD(&p->rcu_tasks_holdout_list);
> @@ -2752,7 +2752,7 @@ extern int __cond_resched_softirq(void);
>
> static inline void cond_resched_rcu(void)
> {
> -#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
> +#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_TREE_PREEMPT_RCU)
> rcu_read_unlock();
> cond_resched();
> rcu_read_lock();
> diff --git a/init/Kconfig b/init/Kconfig
> index 8a2b97c..27ad03c 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -501,12 +501,6 @@ config TINY_RCU
>
> endchoice
>
> -config PREEMPT_RCU
> - def_bool TREE_PREEMPT_RCU
> - help
> - This option enables preemptible-RCU code that is common between
> - TREE_PREEMPT_RCU and, in the old days, TINY_PREEMPT_RCU.
> -
> config TASKS_RCU
> bool "Task_based RCU implementation using voluntary context switch"
> default n
> diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
> index 3ef8ba5..8848a32 100644
> --- a/kernel/rcu/update.c
> +++ b/kernel/rcu/update.c
> @@ -62,7 +62,7 @@ MODULE_ALIAS("rcupdate");
>
> module_param(rcu_expedited, int, 0);
>
> -#ifdef CONFIG_PREEMPT_RCU
> +#ifdef CONFIG_TREE_PREEMPT_RCU
>
> /*
> * Preemptible RCU implementation for rcu_read_lock().
> @@ -108,7 +108,7 @@ void __rcu_read_unlock(void)
> }
> EXPORT_SYMBOL_GPL(__rcu_read_unlock);
>
> -#endif /* #ifdef CONFIG_PREEMPT_RCU */
> +#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
>
> #ifdef CONFIG_DEBUG_LOCK_ALLOC
> static struct lock_class_key rcu_lock_key;
> diff --git a/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt b/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
> index 28db67b..4fea92d 100644
> --- a/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
> +++ b/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
> @@ -31,7 +31,7 @@ CONFIG_RCU_TORTURE_TEST
>
> CONFIG_HOTPLUG_CPU
> CONFIG_PREEMPT
> -CONFIG_PREEMPT_RCU
> +CONFIG_TREE_PREEMPT_RCU
> CONFIG_SMP
> CONFIG_TINY_RCU
> CONFIG_TREE_PREEMPT_RCU
> diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
> index f85c45e..081dece 100644
> --- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
> +++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
> @@ -62,7 +62,7 @@ CONFIG_NO_HZ_FULL_SYSIDLE_SMALL
> Defer until Frederic uses this.
>
> CONFIG_PREEMPT_COUNT
> -CONFIG_PREEMPT_RCU
> +CONFIG_TREE_PREEMPT_RCU
>
> Redundant with CONFIG_PREEMPT, ignore.
>
> --
> 2.1.0
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] rcu: Remove redundant CONFIG_PREEMPT_RCU option
2014-09-22 16:25 ` Josh Triplett
@ 2014-09-22 16:44 ` Paul E. McKenney
2014-09-22 16:49 ` Pranith Kumar
1 sibling, 0 replies; 6+ messages in thread
From: Paul E. McKenney @ 2014-09-22 16:44 UTC (permalink / raw)
To: Josh Triplett
Cc: Pranith Kumar, Steven Rostedt, Mathieu Desnoyers, Lai Jiangshan,
open list
On Mon, Sep 22, 2014 at 09:25:34AM -0700, Josh Triplett wrote:
> On Sun, Sep 21, 2014 at 12:49:54PM -0400, Pranith Kumar wrote:
> > PREEMPT_RCU and TREE_PREEMPT_RCU serve the same function after TINY_PREEMPT_RCU
> > has been removed. This patch removes CONFIG_PREEMPT_RCU and uses
> > CONFIG_TREE_PREEMPT_RCU in its place.
> >
> > Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
>
> I think it would actually make more sense to do this the other way
> around, if at all: drop TREE_PREEMPT_RCU in favor of PREEMPT_RCU. The
> instances shown here don't care about *which* preemptible RCU
> implementation the kernel uses, they just need to behave differently
> when preemptible. Let's also not assume that no new RCU implementation
> will ever arise superceding TREE_PREEMPT_RCU.
Given that there has thus far been no fewer than three distinct
implementations of PREEMPT_RCU (one in -rt, the first in mainline, and the
current one in mainline), it would indeed be quite wise to avoid assuming
that there never will be some new PREEMPT_RCU implementation. ;-)
Thanx, Paul
> - Josh Triplett
>
> > arch/xtensa/configs/s6105_defconfig | 2 +-
> > include/linux/init_task.h | 2 +-
> > include/linux/rcupdate.h | 16 ++++++++--------
> > include/linux/sched.h | 10 +++++-----
> > init/Kconfig | 6 ------
> > kernel/rcu/update.c | 4 ++--
> > tools/testing/selftests/rcutorture/doc/TINY_RCU.txt | 2 +-
> > .../selftests/rcutorture/doc/TREE_RCU-kconfig.txt | 2 +-
> > 8 files changed, 19 insertions(+), 25 deletions(-)
> >
> > diff --git a/arch/xtensa/configs/s6105_defconfig b/arch/xtensa/configs/s6105_defconfig
> > index 12a492a..dab1a99 100644
> > --- a/arch/xtensa/configs/s6105_defconfig
> > +++ b/arch/xtensa/configs/s6105_defconfig
> > @@ -35,7 +35,7 @@ CONFIG_SYSVIPC_SYSCTL=y
> > #
> > # CONFIG_CLASSIC_RCU is not set
> > # CONFIG_TREE_RCU is not set
> > -CONFIG_PREEMPT_RCU=y
> > +CONFIG_TREE_PREEMPT_RCU=y
> > # CONFIG_RCU_TRACE is not set
> > # CONFIG_TREE_RCU_TRACE is not set
> > # CONFIG_PREEMPT_RCU_TRACE is not set
> > diff --git a/include/linux/init_task.h b/include/linux/init_task.h
> > index 77fc43f..39600f4 100644
> > --- a/include/linux/init_task.h
> > +++ b/include/linux/init_task.h
> > @@ -108,7 +108,7 @@ extern struct group_info init_groups;
> > #else
> > #define INIT_TASK_RCU_TREE_PREEMPT(tsk)
> > #endif
> > -#ifdef CONFIG_PREEMPT_RCU
> > +#ifdef CONFIG_TREE_PREEMPT_RCU
> > #define INIT_TASK_RCU_PREEMPT(tsk) \
> > .rcu_read_lock_nesting = 0, \
> > .rcu_read_unlock_special.s = 0, \
> > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
> > index a4a819f..17a15d5 100644
> > --- a/include/linux/rcupdate.h
> > +++ b/include/linux/rcupdate.h
> > @@ -103,7 +103,7 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
> >
> > /* Exported common interfaces */
> >
> > -#ifdef CONFIG_PREEMPT_RCU
> > +#ifdef CONFIG_TREE_PREEMPT_RCU
> >
> > /**
> > * call_rcu() - Queue an RCU callback for invocation after a grace period.
> > @@ -140,12 +140,12 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
> > void call_rcu(struct rcu_head *head,
> > void (*func)(struct rcu_head *head));
> >
> > -#else /* #ifdef CONFIG_PREEMPT_RCU */
> > +#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> >
> > /* In classic RCU, call_rcu() is just call_rcu_sched(). */
> > #define call_rcu call_rcu_sched
> >
> > -#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
> > +#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
> >
> > /**
> > * call_rcu_bh() - Queue an RCU for invocation after a quicker grace period.
> > @@ -217,7 +217,7 @@ void call_rcu_tasks(struct rcu_head *head, void (*func)(struct rcu_head *head));
> > void synchronize_rcu_tasks(void);
> > void rcu_barrier_tasks(void);
> >
> > -#ifdef CONFIG_PREEMPT_RCU
> > +#ifdef CONFIG_TREE_PREEMPT_RCU
> >
> > void __rcu_read_lock(void);
> > void __rcu_read_unlock(void);
> > @@ -227,12 +227,12 @@ void synchronize_rcu(void);
> > /*
> > * Defined as a macro as it is a very low level header included from
> > * areas that don't even know about current. This gives the rcu_read_lock()
> > - * nesting depth, but makes sense only if CONFIG_PREEMPT_RCU -- in other
> > + * nesting depth, but makes sense only if CONFIG_TREE_PREEMPT_RCU -- in other
> > * types of kernel builds, the rcu_read_lock() nesting depth is unknowable.
> > */
> > #define rcu_preempt_depth() (current->rcu_read_lock_nesting)
> >
> > -#else /* #ifdef CONFIG_PREEMPT_RCU */
> > +#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> >
> > static inline void __rcu_read_lock(void)
> > {
> > @@ -254,7 +254,7 @@ static inline int rcu_preempt_depth(void)
> > return 0;
> > }
> >
> > -#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
> > +#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
> >
> > /* Internal to kernel */
> > void rcu_init(void);
> > @@ -530,7 +530,7 @@ static inline int rcu_read_lock_sched_held(void)
> > } \
> > } while (0)
> >
> > -#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_PREEMPT_RCU)
> > +#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_TREE_PREEMPT_RCU)
> > static inline void rcu_preempt_sleep_check(void)
> > {
> > rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
> > diff --git a/include/linux/sched.h b/include/linux/sched.h
> > index 42888d7..6acaa30 100644
> > --- a/include/linux/sched.h
> > +++ b/include/linux/sched.h
> > @@ -1269,11 +1269,11 @@ struct task_struct {
> > int nr_cpus_allowed;
> > cpumask_t cpus_allowed;
> >
> > -#ifdef CONFIG_PREEMPT_RCU
> > +#ifdef CONFIG_TREE_PREEMPT_RCU
> > int rcu_read_lock_nesting;
> > union rcu_special rcu_read_unlock_special;
> > struct list_head rcu_node_entry;
> > -#endif /* #ifdef CONFIG_PREEMPT_RCU */
> > +#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> > #ifdef CONFIG_TREE_PREEMPT_RCU
> > struct rcu_node *rcu_blocked_node;
> > #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> > @@ -2014,12 +2014,12 @@ extern void task_clear_jobctl_pending(struct task_struct *task,
> >
> > static inline void rcu_copy_process(struct task_struct *p)
> > {
> > -#ifdef CONFIG_PREEMPT_RCU
> > +#ifdef CONFIG_TREE_PREEMPT_RCU
> > p->rcu_read_lock_nesting = 0;
> > p->rcu_read_unlock_special.s = 0;
> > p->rcu_blocked_node = NULL;
> > INIT_LIST_HEAD(&p->rcu_node_entry);
> > -#endif /* #ifdef CONFIG_PREEMPT_RCU */
> > +#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> > #ifdef CONFIG_TASKS_RCU
> > p->rcu_tasks_holdout = false;
> > INIT_LIST_HEAD(&p->rcu_tasks_holdout_list);
> > @@ -2752,7 +2752,7 @@ extern int __cond_resched_softirq(void);
> >
> > static inline void cond_resched_rcu(void)
> > {
> > -#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
> > +#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_TREE_PREEMPT_RCU)
> > rcu_read_unlock();
> > cond_resched();
> > rcu_read_lock();
> > diff --git a/init/Kconfig b/init/Kconfig
> > index 8a2b97c..27ad03c 100644
> > --- a/init/Kconfig
> > +++ b/init/Kconfig
> > @@ -501,12 +501,6 @@ config TINY_RCU
> >
> > endchoice
> >
> > -config PREEMPT_RCU
> > - def_bool TREE_PREEMPT_RCU
> > - help
> > - This option enables preemptible-RCU code that is common between
> > - TREE_PREEMPT_RCU and, in the old days, TINY_PREEMPT_RCU.
> > -
> > config TASKS_RCU
> > bool "Task_based RCU implementation using voluntary context switch"
> > default n
> > diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
> > index 3ef8ba5..8848a32 100644
> > --- a/kernel/rcu/update.c
> > +++ b/kernel/rcu/update.c
> > @@ -62,7 +62,7 @@ MODULE_ALIAS("rcupdate");
> >
> > module_param(rcu_expedited, int, 0);
> >
> > -#ifdef CONFIG_PREEMPT_RCU
> > +#ifdef CONFIG_TREE_PREEMPT_RCU
> >
> > /*
> > * Preemptible RCU implementation for rcu_read_lock().
> > @@ -108,7 +108,7 @@ void __rcu_read_unlock(void)
> > }
> > EXPORT_SYMBOL_GPL(__rcu_read_unlock);
> >
> > -#endif /* #ifdef CONFIG_PREEMPT_RCU */
> > +#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> >
> > #ifdef CONFIG_DEBUG_LOCK_ALLOC
> > static struct lock_class_key rcu_lock_key;
> > diff --git a/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt b/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
> > index 28db67b..4fea92d 100644
> > --- a/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
> > +++ b/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
> > @@ -31,7 +31,7 @@ CONFIG_RCU_TORTURE_TEST
> >
> > CONFIG_HOTPLUG_CPU
> > CONFIG_PREEMPT
> > -CONFIG_PREEMPT_RCU
> > +CONFIG_TREE_PREEMPT_RCU
> > CONFIG_SMP
> > CONFIG_TINY_RCU
> > CONFIG_TREE_PREEMPT_RCU
> > diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
> > index f85c45e..081dece 100644
> > --- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
> > +++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
> > @@ -62,7 +62,7 @@ CONFIG_NO_HZ_FULL_SYSIDLE_SMALL
> > Defer until Frederic uses this.
> >
> > CONFIG_PREEMPT_COUNT
> > -CONFIG_PREEMPT_RCU
> > +CONFIG_TREE_PREEMPT_RCU
> >
> > Redundant with CONFIG_PREEMPT, ignore.
> >
> > --
> > 2.1.0
> >
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] rcu: Remove redundant CONFIG_PREEMPT_RCU option
2014-09-22 16:25 ` Josh Triplett
2014-09-22 16:44 ` Paul E. McKenney
@ 2014-09-22 16:49 ` Pranith Kumar
2014-09-22 17:01 ` Paul E. McKenney
1 sibling, 1 reply; 6+ messages in thread
From: Pranith Kumar @ 2014-09-22 16:49 UTC (permalink / raw)
To: Josh Triplett
Cc: Paul E. McKenney, Steven Rostedt, Mathieu Desnoyers,
Lai Jiangshan, open list
On Mon, Sep 22, 2014 at 12:25 PM, Josh Triplett <josh@joshtriplett.org> wrote:
> On Sun, Sep 21, 2014 at 12:49:54PM -0400, Pranith Kumar wrote:
>> PREEMPT_RCU and TREE_PREEMPT_RCU serve the same function after TINY_PREEMPT_RCU
>> has been removed. This patch removes CONFIG_PREEMPT_RCU and uses
>> CONFIG_TREE_PREEMPT_RCU in its place.
>>
>> Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
>
> I think it would actually make more sense to do this the other way
> around, if at all: drop TREE_PREEMPT_RCU in favor of PREEMPT_RCU. The
> instances shown here don't care about *which* preemptible RCU
> implementation the kernel uses, they just need to behave differently
> when preemptible. Let's also not assume that no new RCU implementation
> will ever arise superceding TREE_PREEMPT_RCU.
That is exactly what I did first and got the following changelog:
51 files changed, 77 insertions(+), 83 deletions(-)
compared to
8 files changed, 19 insertions(+), 25 deletions(-)
for the current one. Hence my patch opting for the latter. I will go
ahead and send the other patch.
>> 8 files changed, 19 insertions(+), 25 deletions(-)
>>
>> diff --git a/arch/xtensa/configs/s6105_defconfig b/arch/xtensa/configs/s6105_defconfig
>> index 12a492a..dab1a99 100644
>> --- a/arch/xtensa/configs/s6105_defconfig
>> +++ b/arch/xtensa/configs/s6105_defconfig
>> @@ -35,7 +35,7 @@ CONFIG_SYSVIPC_SYSCTL=y
>> #
>> # CONFIG_CLASSIC_RCU is not set
>> # CONFIG_TREE_RCU is not set
>> -CONFIG_PREEMPT_RCU=y
>> +CONFIG_TREE_PREEMPT_RCU=y
>> # CONFIG_RCU_TRACE is not set
>> # CONFIG_TREE_RCU_TRACE is not set
>> # CONFIG_PREEMPT_RCU_TRACE is not set
>> diff --git a/include/linux/init_task.h b/include/linux/init_task.h
>> index 77fc43f..39600f4 100644
>> --- a/include/linux/init_task.h
>> +++ b/include/linux/init_task.h
>> @@ -108,7 +108,7 @@ extern struct group_info init_groups;
>> #else
>> #define INIT_TASK_RCU_TREE_PREEMPT(tsk)
>> #endif
>> -#ifdef CONFIG_PREEMPT_RCU
>> +#ifdef CONFIG_TREE_PREEMPT_RCU
>> #define INIT_TASK_RCU_PREEMPT(tsk) \
>> .rcu_read_lock_nesting = 0, \
>> .rcu_read_unlock_special.s = 0, \
>> diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
>> index a4a819f..17a15d5 100644
>> --- a/include/linux/rcupdate.h
>> +++ b/include/linux/rcupdate.h
>> @@ -103,7 +103,7 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
>>
>> /* Exported common interfaces */
>>
>> -#ifdef CONFIG_PREEMPT_RCU
>> +#ifdef CONFIG_TREE_PREEMPT_RCU
>>
>> /**
>> * call_rcu() - Queue an RCU callback for invocation after a grace period.
>> @@ -140,12 +140,12 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
>> void call_rcu(struct rcu_head *head,
>> void (*func)(struct rcu_head *head));
>>
>> -#else /* #ifdef CONFIG_PREEMPT_RCU */
>> +#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
>>
>> /* In classic RCU, call_rcu() is just call_rcu_sched(). */
>> #define call_rcu call_rcu_sched
>>
>> -#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
>> +#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
>>
>> /**
>> * call_rcu_bh() - Queue an RCU for invocation after a quicker grace period.
>> @@ -217,7 +217,7 @@ void call_rcu_tasks(struct rcu_head *head, void (*func)(struct rcu_head *head));
>> void synchronize_rcu_tasks(void);
>> void rcu_barrier_tasks(void);
>>
>> -#ifdef CONFIG_PREEMPT_RCU
>> +#ifdef CONFIG_TREE_PREEMPT_RCU
>>
>> void __rcu_read_lock(void);
>> void __rcu_read_unlock(void);
>> @@ -227,12 +227,12 @@ void synchronize_rcu(void);
>> /*
>> * Defined as a macro as it is a very low level header included from
>> * areas that don't even know about current. This gives the rcu_read_lock()
>> - * nesting depth, but makes sense only if CONFIG_PREEMPT_RCU -- in other
>> + * nesting depth, but makes sense only if CONFIG_TREE_PREEMPT_RCU -- in other
>> * types of kernel builds, the rcu_read_lock() nesting depth is unknowable.
>> */
>> #define rcu_preempt_depth() (current->rcu_read_lock_nesting)
>>
>> -#else /* #ifdef CONFIG_PREEMPT_RCU */
>> +#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
>>
>> static inline void __rcu_read_lock(void)
>> {
>> @@ -254,7 +254,7 @@ static inline int rcu_preempt_depth(void)
>> return 0;
>> }
>>
>> -#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
>> +#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
>>
>> /* Internal to kernel */
>> void rcu_init(void);
>> @@ -530,7 +530,7 @@ static inline int rcu_read_lock_sched_held(void)
>> } \
>> } while (0)
>>
>> -#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_PREEMPT_RCU)
>> +#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_TREE_PREEMPT_RCU)
>> static inline void rcu_preempt_sleep_check(void)
>> {
>> rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
>> diff --git a/include/linux/sched.h b/include/linux/sched.h
>> index 42888d7..6acaa30 100644
>> --- a/include/linux/sched.h
>> +++ b/include/linux/sched.h
>> @@ -1269,11 +1269,11 @@ struct task_struct {
>> int nr_cpus_allowed;
>> cpumask_t cpus_allowed;
>>
>> -#ifdef CONFIG_PREEMPT_RCU
>> +#ifdef CONFIG_TREE_PREEMPT_RCU
>> int rcu_read_lock_nesting;
>> union rcu_special rcu_read_unlock_special;
>> struct list_head rcu_node_entry;
>> -#endif /* #ifdef CONFIG_PREEMPT_RCU */
>> +#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
>> #ifdef CONFIG_TREE_PREEMPT_RCU
>> struct rcu_node *rcu_blocked_node;
>> #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
>> @@ -2014,12 +2014,12 @@ extern void task_clear_jobctl_pending(struct task_struct *task,
>>
>> static inline void rcu_copy_process(struct task_struct *p)
>> {
>> -#ifdef CONFIG_PREEMPT_RCU
>> +#ifdef CONFIG_TREE_PREEMPT_RCU
>> p->rcu_read_lock_nesting = 0;
>> p->rcu_read_unlock_special.s = 0;
>> p->rcu_blocked_node = NULL;
>> INIT_LIST_HEAD(&p->rcu_node_entry);
>> -#endif /* #ifdef CONFIG_PREEMPT_RCU */
>> +#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
>> #ifdef CONFIG_TASKS_RCU
>> p->rcu_tasks_holdout = false;
>> INIT_LIST_HEAD(&p->rcu_tasks_holdout_list);
>> @@ -2752,7 +2752,7 @@ extern int __cond_resched_softirq(void);
>>
>> static inline void cond_resched_rcu(void)
>> {
>> -#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
>> +#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_TREE_PREEMPT_RCU)
>> rcu_read_unlock();
>> cond_resched();
>> rcu_read_lock();
>> diff --git a/init/Kconfig b/init/Kconfig
>> index 8a2b97c..27ad03c 100644
>> --- a/init/Kconfig
>> +++ b/init/Kconfig
>> @@ -501,12 +501,6 @@ config TINY_RCU
>>
>> endchoice
>>
>> -config PREEMPT_RCU
>> - def_bool TREE_PREEMPT_RCU
>> - help
>> - This option enables preemptible-RCU code that is common between
>> - TREE_PREEMPT_RCU and, in the old days, TINY_PREEMPT_RCU.
>> -
>> config TASKS_RCU
>> bool "Task_based RCU implementation using voluntary context switch"
>> default n
>> diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
>> index 3ef8ba5..8848a32 100644
>> --- a/kernel/rcu/update.c
>> +++ b/kernel/rcu/update.c
>> @@ -62,7 +62,7 @@ MODULE_ALIAS("rcupdate");
>>
>> module_param(rcu_expedited, int, 0);
>>
>> -#ifdef CONFIG_PREEMPT_RCU
>> +#ifdef CONFIG_TREE_PREEMPT_RCU
>>
>> /*
>> * Preemptible RCU implementation for rcu_read_lock().
>> @@ -108,7 +108,7 @@ void __rcu_read_unlock(void)
>> }
>> EXPORT_SYMBOL_GPL(__rcu_read_unlock);
>>
>> -#endif /* #ifdef CONFIG_PREEMPT_RCU */
>> +#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
>>
>> #ifdef CONFIG_DEBUG_LOCK_ALLOC
>> static struct lock_class_key rcu_lock_key;
>> diff --git a/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt b/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
>> index 28db67b..4fea92d 100644
>> --- a/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
>> +++ b/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
>> @@ -31,7 +31,7 @@ CONFIG_RCU_TORTURE_TEST
>>
>> CONFIG_HOTPLUG_CPU
>> CONFIG_PREEMPT
>> -CONFIG_PREEMPT_RCU
>> +CONFIG_TREE_PREEMPT_RCU
>> CONFIG_SMP
>> CONFIG_TINY_RCU
>> CONFIG_TREE_PREEMPT_RCU
>> diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
>> index f85c45e..081dece 100644
>> --- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
>> +++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
>> @@ -62,7 +62,7 @@ CONFIG_NO_HZ_FULL_SYSIDLE_SMALL
>> Defer until Frederic uses this.
>>
>> CONFIG_PREEMPT_COUNT
>> -CONFIG_PREEMPT_RCU
>> +CONFIG_TREE_PREEMPT_RCU
>>
>> Redundant with CONFIG_PREEMPT, ignore.
>>
>> --
>> 2.1.0
>>
--
Pranith
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] rcu: Remove redundant CONFIG_PREEMPT_RCU option
2014-09-22 16:49 ` Pranith Kumar
@ 2014-09-22 17:01 ` Paul E. McKenney
2014-09-22 17:44 ` Pranith Kumar
0 siblings, 1 reply; 6+ messages in thread
From: Paul E. McKenney @ 2014-09-22 17:01 UTC (permalink / raw)
To: Pranith Kumar
Cc: Josh Triplett, Steven Rostedt, Mathieu Desnoyers, Lai Jiangshan,
open list
On Mon, Sep 22, 2014 at 12:49:24PM -0400, Pranith Kumar wrote:
> On Mon, Sep 22, 2014 at 12:25 PM, Josh Triplett <josh@joshtriplett.org> wrote:
> > On Sun, Sep 21, 2014 at 12:49:54PM -0400, Pranith Kumar wrote:
> >> PREEMPT_RCU and TREE_PREEMPT_RCU serve the same function after TINY_PREEMPT_RCU
> >> has been removed. This patch removes CONFIG_PREEMPT_RCU and uses
> >> CONFIG_TREE_PREEMPT_RCU in its place.
> >>
> >> Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
> >
> > I think it would actually make more sense to do this the other way
> > around, if at all: drop TREE_PREEMPT_RCU in favor of PREEMPT_RCU. The
> > instances shown here don't care about *which* preemptible RCU
> > implementation the kernel uses, they just need to behave differently
> > when preemptible. Let's also not assume that no new RCU implementation
> > will ever arise superceding TREE_PREEMPT_RCU.
>
> That is exactly what I did first and got the following changelog:
>
> 51 files changed, 77 insertions(+), 83 deletions(-)
>
> compared to
>
> 8 files changed, 19 insertions(+), 25 deletions(-)
Were the bulk of the files defconfig files? These need not be changed,
the architecture maintainers handle them.
Thanx, Paul
> for the current one. Hence my patch opting for the latter. I will go
> ahead and send the other patch.
>
> >> 8 files changed, 19 insertions(+), 25 deletions(-)
> >>
> >> diff --git a/arch/xtensa/configs/s6105_defconfig b/arch/xtensa/configs/s6105_defconfig
> >> index 12a492a..dab1a99 100644
> >> --- a/arch/xtensa/configs/s6105_defconfig
> >> +++ b/arch/xtensa/configs/s6105_defconfig
> >> @@ -35,7 +35,7 @@ CONFIG_SYSVIPC_SYSCTL=y
> >> #
> >> # CONFIG_CLASSIC_RCU is not set
> >> # CONFIG_TREE_RCU is not set
> >> -CONFIG_PREEMPT_RCU=y
> >> +CONFIG_TREE_PREEMPT_RCU=y
> >> # CONFIG_RCU_TRACE is not set
> >> # CONFIG_TREE_RCU_TRACE is not set
> >> # CONFIG_PREEMPT_RCU_TRACE is not set
> >> diff --git a/include/linux/init_task.h b/include/linux/init_task.h
> >> index 77fc43f..39600f4 100644
> >> --- a/include/linux/init_task.h
> >> +++ b/include/linux/init_task.h
> >> @@ -108,7 +108,7 @@ extern struct group_info init_groups;
> >> #else
> >> #define INIT_TASK_RCU_TREE_PREEMPT(tsk)
> >> #endif
> >> -#ifdef CONFIG_PREEMPT_RCU
> >> +#ifdef CONFIG_TREE_PREEMPT_RCU
> >> #define INIT_TASK_RCU_PREEMPT(tsk) \
> >> .rcu_read_lock_nesting = 0, \
> >> .rcu_read_unlock_special.s = 0, \
> >> diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
> >> index a4a819f..17a15d5 100644
> >> --- a/include/linux/rcupdate.h
> >> +++ b/include/linux/rcupdate.h
> >> @@ -103,7 +103,7 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
> >>
> >> /* Exported common interfaces */
> >>
> >> -#ifdef CONFIG_PREEMPT_RCU
> >> +#ifdef CONFIG_TREE_PREEMPT_RCU
> >>
> >> /**
> >> * call_rcu() - Queue an RCU callback for invocation after a grace period.
> >> @@ -140,12 +140,12 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
> >> void call_rcu(struct rcu_head *head,
> >> void (*func)(struct rcu_head *head));
> >>
> >> -#else /* #ifdef CONFIG_PREEMPT_RCU */
> >> +#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> >>
> >> /* In classic RCU, call_rcu() is just call_rcu_sched(). */
> >> #define call_rcu call_rcu_sched
> >>
> >> -#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
> >> +#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
> >>
> >> /**
> >> * call_rcu_bh() - Queue an RCU for invocation after a quicker grace period.
> >> @@ -217,7 +217,7 @@ void call_rcu_tasks(struct rcu_head *head, void (*func)(struct rcu_head *head));
> >> void synchronize_rcu_tasks(void);
> >> void rcu_barrier_tasks(void);
> >>
> >> -#ifdef CONFIG_PREEMPT_RCU
> >> +#ifdef CONFIG_TREE_PREEMPT_RCU
> >>
> >> void __rcu_read_lock(void);
> >> void __rcu_read_unlock(void);
> >> @@ -227,12 +227,12 @@ void synchronize_rcu(void);
> >> /*
> >> * Defined as a macro as it is a very low level header included from
> >> * areas that don't even know about current. This gives the rcu_read_lock()
> >> - * nesting depth, but makes sense only if CONFIG_PREEMPT_RCU -- in other
> >> + * nesting depth, but makes sense only if CONFIG_TREE_PREEMPT_RCU -- in other
> >> * types of kernel builds, the rcu_read_lock() nesting depth is unknowable.
> >> */
> >> #define rcu_preempt_depth() (current->rcu_read_lock_nesting)
> >>
> >> -#else /* #ifdef CONFIG_PREEMPT_RCU */
> >> +#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> >>
> >> static inline void __rcu_read_lock(void)
> >> {
> >> @@ -254,7 +254,7 @@ static inline int rcu_preempt_depth(void)
> >> return 0;
> >> }
> >>
> >> -#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
> >> +#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
> >>
> >> /* Internal to kernel */
> >> void rcu_init(void);
> >> @@ -530,7 +530,7 @@ static inline int rcu_read_lock_sched_held(void)
> >> } \
> >> } while (0)
> >>
> >> -#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_PREEMPT_RCU)
> >> +#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_TREE_PREEMPT_RCU)
> >> static inline void rcu_preempt_sleep_check(void)
> >> {
> >> rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
> >> diff --git a/include/linux/sched.h b/include/linux/sched.h
> >> index 42888d7..6acaa30 100644
> >> --- a/include/linux/sched.h
> >> +++ b/include/linux/sched.h
> >> @@ -1269,11 +1269,11 @@ struct task_struct {
> >> int nr_cpus_allowed;
> >> cpumask_t cpus_allowed;
> >>
> >> -#ifdef CONFIG_PREEMPT_RCU
> >> +#ifdef CONFIG_TREE_PREEMPT_RCU
> >> int rcu_read_lock_nesting;
> >> union rcu_special rcu_read_unlock_special;
> >> struct list_head rcu_node_entry;
> >> -#endif /* #ifdef CONFIG_PREEMPT_RCU */
> >> +#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> >> #ifdef CONFIG_TREE_PREEMPT_RCU
> >> struct rcu_node *rcu_blocked_node;
> >> #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> >> @@ -2014,12 +2014,12 @@ extern void task_clear_jobctl_pending(struct task_struct *task,
> >>
> >> static inline void rcu_copy_process(struct task_struct *p)
> >> {
> >> -#ifdef CONFIG_PREEMPT_RCU
> >> +#ifdef CONFIG_TREE_PREEMPT_RCU
> >> p->rcu_read_lock_nesting = 0;
> >> p->rcu_read_unlock_special.s = 0;
> >> p->rcu_blocked_node = NULL;
> >> INIT_LIST_HEAD(&p->rcu_node_entry);
> >> -#endif /* #ifdef CONFIG_PREEMPT_RCU */
> >> +#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> >> #ifdef CONFIG_TASKS_RCU
> >> p->rcu_tasks_holdout = false;
> >> INIT_LIST_HEAD(&p->rcu_tasks_holdout_list);
> >> @@ -2752,7 +2752,7 @@ extern int __cond_resched_softirq(void);
> >>
> >> static inline void cond_resched_rcu(void)
> >> {
> >> -#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
> >> +#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_TREE_PREEMPT_RCU)
> >> rcu_read_unlock();
> >> cond_resched();
> >> rcu_read_lock();
> >> diff --git a/init/Kconfig b/init/Kconfig
> >> index 8a2b97c..27ad03c 100644
> >> --- a/init/Kconfig
> >> +++ b/init/Kconfig
> >> @@ -501,12 +501,6 @@ config TINY_RCU
> >>
> >> endchoice
> >>
> >> -config PREEMPT_RCU
> >> - def_bool TREE_PREEMPT_RCU
> >> - help
> >> - This option enables preemptible-RCU code that is common between
> >> - TREE_PREEMPT_RCU and, in the old days, TINY_PREEMPT_RCU.
> >> -
> >> config TASKS_RCU
> >> bool "Task_based RCU implementation using voluntary context switch"
> >> default n
> >> diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
> >> index 3ef8ba5..8848a32 100644
> >> --- a/kernel/rcu/update.c
> >> +++ b/kernel/rcu/update.c
> >> @@ -62,7 +62,7 @@ MODULE_ALIAS("rcupdate");
> >>
> >> module_param(rcu_expedited, int, 0);
> >>
> >> -#ifdef CONFIG_PREEMPT_RCU
> >> +#ifdef CONFIG_TREE_PREEMPT_RCU
> >>
> >> /*
> >> * Preemptible RCU implementation for rcu_read_lock().
> >> @@ -108,7 +108,7 @@ void __rcu_read_unlock(void)
> >> }
> >> EXPORT_SYMBOL_GPL(__rcu_read_unlock);
> >>
> >> -#endif /* #ifdef CONFIG_PREEMPT_RCU */
> >> +#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
> >>
> >> #ifdef CONFIG_DEBUG_LOCK_ALLOC
> >> static struct lock_class_key rcu_lock_key;
> >> diff --git a/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt b/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
> >> index 28db67b..4fea92d 100644
> >> --- a/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
> >> +++ b/tools/testing/selftests/rcutorture/doc/TINY_RCU.txt
> >> @@ -31,7 +31,7 @@ CONFIG_RCU_TORTURE_TEST
> >>
> >> CONFIG_HOTPLUG_CPU
> >> CONFIG_PREEMPT
> >> -CONFIG_PREEMPT_RCU
> >> +CONFIG_TREE_PREEMPT_RCU
> >> CONFIG_SMP
> >> CONFIG_TINY_RCU
> >> CONFIG_TREE_PREEMPT_RCU
> >> diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
> >> index f85c45e..081dece 100644
> >> --- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
> >> +++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
> >> @@ -62,7 +62,7 @@ CONFIG_NO_HZ_FULL_SYSIDLE_SMALL
> >> Defer until Frederic uses this.
> >>
> >> CONFIG_PREEMPT_COUNT
> >> -CONFIG_PREEMPT_RCU
> >> +CONFIG_TREE_PREEMPT_RCU
> >>
> >> Redundant with CONFIG_PREEMPT, ignore.
> >>
> >> --
> >> 2.1.0
> >>
>
>
>
> --
> Pranith
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] rcu: Remove redundant CONFIG_PREEMPT_RCU option
2014-09-22 17:01 ` Paul E. McKenney
@ 2014-09-22 17:44 ` Pranith Kumar
0 siblings, 0 replies; 6+ messages in thread
From: Pranith Kumar @ 2014-09-22 17:44 UTC (permalink / raw)
To: Paul McKenney
Cc: Josh Triplett, Steven Rostedt, Mathieu Desnoyers, Lai Jiangshan,
open list
On Mon, Sep 22, 2014 at 1:01 PM, Paul E. McKenney
<paulmck@linux.vnet.ibm.com> wrote:
> On Mon, Sep 22, 2014 at 12:49:24PM -0400, Pranith Kumar wrote:
>> On Mon, Sep 22, 2014 at 12:25 PM, Josh Triplett <josh@joshtriplett.org> wrote:
>> >
>> > I think it would actually make more sense to do this the other way
>> > around, if at all: drop TREE_PREEMPT_RCU in favor of PREEMPT_RCU. The
>> > instances shown here don't care about *which* preemptible RCU
>> > implementation the kernel uses, they just need to behave differently
>> > when preemptible. Let's also not assume that no new RCU implementation
>> > will ever arise superceding TREE_PREEMPT_RCU.
>>
>> That is exactly what I did first and got the following changelog:
>>
>> 51 files changed, 77 insertions(+), 83 deletions(-)
>>
>> compared to
>>
>> 8 files changed, 19 insertions(+), 25 deletions(-)
>
> Were the bulk of the files defconfig files? These need not be changed,
> the architecture maintainers handle them.
>
There are only two defconfig files in there. I removed them now. Most
of them are rcutorture config files. I guess that should be fine. I am
sending the patch now.
--
Pranith
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2014-09-22 17:44 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-09-21 16:49 [PATCH] rcu: Remove redundant CONFIG_PREEMPT_RCU option Pranith Kumar
2014-09-22 16:25 ` Josh Triplett
2014-09-22 16:44 ` Paul E. McKenney
2014-09-22 16:49 ` Pranith Kumar
2014-09-22 17:01 ` Paul E. McKenney
2014-09-22 17:44 ` Pranith Kumar
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).