From 01b1d88b09824bea1a75b0bac04dcf50d9893875 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 26 Jul 2019 23:19:38 +0200 Subject: [PATCH] rcu: Use CONFIG_PREEMPTION CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same functionality which today depends on CONFIG_PREEMPT. Switch the conditionals in RCU to use CONFIG_PREEMPTION. That's the first step towards RCU on RT. The further tweaks are work in progress. This neither touches the selftest bits which need a closer look by Paul. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Paolo Bonzini Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Steven Rostedt Link: http://lkml.kernel.org/r/20190726212124.210156346@linutronix.de Signed-off-by: Ingo Molnar --- arch/Kconfig | 2 +- include/linux/rcupdate.h | 2 +- include/linux/rcutree.h | 2 +- include/linux/torture.h | 2 +- kernel/rcu/Kconfig | 8 ++++---- kernel/rcu/tree.c | 6 +++--- kernel/rcu/tree_stall.h | 6 +++--- kernel/trace/Kconfig | 2 +- 8 files changed, 15 insertions(+), 15 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index a7b57dd..c7efbc0 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -103,7 +103,7 @@ config STATIC_KEYS_SELFTEST config OPTPROBES def_bool y depends on KPROBES && HAVE_OPTPROBES - select TASKS_RCU if PREEMPT + select TASKS_RCU if PREEMPTION config KPROBES_ON_FTRACE def_bool y diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 8f71674..c4f76a3 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -578,7 +578,7 @@ do { \ * * In non-preemptible RCU implementations (TREE_RCU and TINY_RCU), * it is illegal to block while in an RCU read-side critical section. - * In preemptible RCU implementations (PREEMPT_RCU) in CONFIG_PREEMPT + * In preemptible RCU implementations (PREEMPT_RCU) in CONFIG_PREEMPTION * kernel builds, RCU read-side critical sections may be preempted, * but explicit blocking is illegal. Finally, in preemptible RCU * implementations in real-time (with -rt patchset) kernel builds, RCU diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 735601a..18b1ed9 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -53,7 +53,7 @@ void rcu_scheduler_starting(void); extern int rcu_scheduler_active __read_mostly; void rcu_end_inkernel_boot(void); bool rcu_is_watching(void); -#ifndef CONFIG_PREEMPT +#ifndef CONFIG_PREEMPTION void rcu_all_qs(void); #endif diff --git a/include/linux/torture.h b/include/linux/torture.h index a620118..6241f59 100644 --- a/include/linux/torture.h +++ b/include/linux/torture.h @@ -86,7 +86,7 @@ void _torture_stop_kthread(char *m, struct task_struct **tp); #define torture_stop_kthread(n, tp) \ _torture_stop_kthread("Stopping " #n " task", &(tp)) -#ifdef CONFIG_PREEMPT +#ifdef CONFIG_PREEMPTION #define torture_preempt_schedule() preempt_schedule() #else #define torture_preempt_schedule() diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig index 480edf3..7644eda 100644 --- a/kernel/rcu/Kconfig +++ b/kernel/rcu/Kconfig @@ -7,7 +7,7 @@ menu "RCU Subsystem" config TREE_RCU bool - default y if !PREEMPT && SMP + default y if !PREEMPTION && SMP help This option selects the RCU implementation that is designed for very large SMP system with hundreds or @@ -16,7 +16,7 @@ config TREE_RCU config PREEMPT_RCU bool - default y if PREEMPT + default y if PREEMPTION help This option selects the RCU implementation that is designed for very large SMP systems with hundreds or @@ -28,7 +28,7 @@ config PREEMPT_RCU config TINY_RCU bool - default y if !PREEMPT && !SMP + default y if !PREEMPTION && !SMP help This option selects the RCU implementation that is designed for UP systems from which real-time response @@ -70,7 +70,7 @@ config TREE_SRCU This option selects the full-fledged version of SRCU. config TASKS_RCU - def_bool PREEMPT + def_bool PREEMPTION select SRCU help This option enables a task-based RCU implementation that uses diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index a14e5fb..5962636 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1881,7 +1881,7 @@ rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) struct rcu_node *rnp_p; raw_lockdep_assert_held_rcu_node(rnp); - if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT)) || + if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPTION)) || WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)) || rnp->qsmask != 0) { raw_spin_unlock_irqrestore_rcu_node(rnp, flags); @@ -2205,7 +2205,7 @@ static void force_qs_rnp(int (*f)(struct rcu_data *rdp)) mask = 0; raw_spin_lock_irqsave_rcu_node(rnp, flags); if (rnp->qsmask == 0) { - if (!IS_ENABLED(CONFIG_PREEMPT) || + if (!IS_ENABLED(CONFIG_PREEMPTION) || rcu_preempt_blocked_readers_cgp(rnp)) { /* * No point in scanning bits because they @@ -2622,7 +2622,7 @@ static int rcu_blocking_is_gp(void) { int ret; - if (IS_ENABLED(CONFIG_PREEMPT)) + if (IS_ENABLED(CONFIG_PREEMPTION)) return rcu_scheduler_active == RCU_SCHEDULER_INACTIVE; might_sleep(); /* Check for RCU read-side critical section. */ preempt_disable(); diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 0651833..9b92bf1 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -163,7 +163,7 @@ static void rcu_iw_handler(struct irq_work *iwp) // // Printing RCU CPU stall warnings -#ifdef CONFIG_PREEMPT +#ifdef CONFIG_PREEMPTION /* * Dump detailed information for all tasks blocking the current RCU @@ -215,7 +215,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp) return ndetected; } -#else /* #ifdef CONFIG_PREEMPT */ +#else /* #ifdef CONFIG_PREEMPTION */ /* * Because preemptible RCU does not exist, we never have to check for @@ -233,7 +233,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp) { return 0; } -#endif /* #else #ifdef CONFIG_PREEMPT */ +#endif /* #else #ifdef CONFIG_PREEMPTION */ /* * Dump stacks of all tasks running on stalled CPUs. First try using diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 98da899..d2c1fe0 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -146,7 +146,7 @@ config FUNCTION_TRACER select GENERIC_TRACER select CONTEXT_SWITCH_TRACER select GLOB - select TASKS_RCU if PREEMPT + select TASKS_RCU if PREEMPTION help Enable the kernel to trace every kernel function. This is done by using a compiler feature to insert a small, 5-byte No-Operation -- 2.7.4