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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-05-25 18:05:00 +0300
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-08-17 17:26:04 +0300
commit7e42776d5ed1fe9a941ed8876c5d15cd7cf5d89f (patch)
tree254e896f95ad0aa9e3084645c6779d6b866d6f96
parent8be6e1b15c54402106e6ba9bc706e685458b2d2d (diff)
downloadlinux-7e42776d5ed1fe9a941ed8876c5d15cd7cf5d89f.tar.xz
rcu: Drive TASKS_RCU directly off of PREEMPT
The actual use of TASKS_RCU is only when PREEMPT, otherwise RCU-sched is used instead. This commit therefore makes synchronize_rcu_tasks() and call_rcu_tasks() available always, but mapped to synchronize_sched() and call_rcu_sched(), respectively, when !PREEMPT. This approach also allows some #ifdefs to be removed from rcutorture. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--include/linux/rcupdate.h6
-rw-r--r--kernel/rcu/Kconfig3
-rw-r--r--kernel/rcu/rcutorture.c17
-rw-r--r--tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt2
4 files changed, 7 insertions, 21 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index f816fc72b51e..c3f380befdd7 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -58,8 +58,6 @@ void call_rcu(struct rcu_head *head, rcu_callback_t func);
void call_rcu_bh(struct rcu_head *head, rcu_callback_t func);
void call_rcu_sched(struct rcu_head *head, rcu_callback_t func);
void synchronize_sched(void);
-void call_rcu_tasks(struct rcu_head *head, rcu_callback_t func);
-void synchronize_rcu_tasks(void);
void rcu_barrier_tasks(void);
#ifdef CONFIG_PREEMPT_RCU
@@ -176,10 +174,14 @@ extern struct srcu_struct tasks_rcu_exit_srcu;
rcu_all_qs(); \
rcu_note_voluntary_context_switch_lite(t); \
} while (0)
+void call_rcu_tasks(struct rcu_head *head, rcu_callback_t func);
+void synchronize_rcu_tasks(void);
#else /* #ifdef CONFIG_TASKS_RCU */
#define TASKS_RCU(x) do { } while (0)
#define rcu_note_voluntary_context_switch_lite(t) do { } while (0)
#define rcu_note_voluntary_context_switch(t) rcu_all_qs()
+#define call_rcu_tasks call_rcu_sched
+#define synchronize_rcu_tasks synchronize_sched
#endif /* #else #ifdef CONFIG_TASKS_RCU */
/**
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index be90c945063f..9210379c0353 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -69,8 +69,7 @@ config TREE_SRCU
This option selects the full-fledged version of SRCU.
config TASKS_RCU
- bool
- default n
+ def_bool PREEMPT
select SRCU
help
This option enables a task-based RCU implementation that uses
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index b8f7f8ce8575..b284c861a511 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -696,8 +696,6 @@ static struct rcu_torture_ops sched_ops = {
.name = "sched"
};
-#ifdef CONFIG_TASKS_RCU
-
/*
* Definitions for RCU-tasks torture testing.
*/
@@ -735,24 +733,11 @@ static struct rcu_torture_ops tasks_ops = {
.name = "tasks"
};
-#define RCUTORTURE_TASKS_OPS &tasks_ops,
-
static bool __maybe_unused torturing_tasks(void)
{
return cur_ops == &tasks_ops;
}
-#else /* #ifdef CONFIG_TASKS_RCU */
-
-#define RCUTORTURE_TASKS_OPS
-
-static bool __maybe_unused torturing_tasks(void)
-{
- return false;
-}
-
-#endif /* #else #ifdef CONFIG_TASKS_RCU */
-
/*
* RCU torture priority-boost testing. Runs one real-time thread per
* CPU for moderate bursts, repeatedly registering RCU callbacks and
@@ -1749,7 +1734,7 @@ rcu_torture_init(void)
int firsterr = 0;
static struct rcu_torture_ops *torture_ops[] = {
&rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
- &sched_ops, RCUTORTURE_TASKS_OPS
+ &sched_ops, &tasks_ops,
};
if (!torture_init_begin(torture_type, verbose, &torture_runnable))
diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
index 9ad3f89c8dc7..af6fca03602f 100644
--- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
+++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
@@ -69,11 +69,11 @@ CONFIG_RCU_TORTURE_TEST_RUNNABLE
CONFIG_PREEMPT_RCU
CONFIG_TREE_RCU
CONFIG_TINY_RCU
+CONFIG_TASKS_RCU
These are controlled by CONFIG_PREEMPT and/or CONFIG_SMP.
CONFIG_SRCU
-CONFIG_TASKS_RCU
Selected by CONFIG_RCU_TORTURE_TEST, so cannot disable.