Messages in this thread | | | From | Pranith Kumar <> | Date | Mon, 22 Sep 2014 12:49:24 -0400 | Subject | Re: [PATCH] rcu: Remove redundant CONFIG_PREEMPT_RCU option |
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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
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