Messages in this thread | | | Date | Mon, 22 Sep 2014 10:01:49 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] rcu: Remove redundant CONFIG_PREEMPT_RCU option |
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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 >
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