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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 <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20190726212124.210156346@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Thomas Gleixner 2019-07-26 23:19:38 +02:00 committed by Ingo Molnar
parent c1a280b68d
commit 01b1d88b09
8 changed files with 15 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/Kconfig
View File

@ -103,7 +103,7 @@ config STATIC_KEYS_SELFTEST
config OPTPROBES config OPTPROBES
def_bool y def_bool y
depends on KPROBES && HAVE_OPTPROBES depends on KPROBES && HAVE_OPTPROBES
select TASKS_RCU if PREEMPT select TASKS_RCU if PREEMPTION
config KPROBES_ON_FTRACE config KPROBES_ON_FTRACE
def_bool y def_bool y

2
include/linux/rcupdate.h
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@ -578,7 +578,7 @@ do { \
* *
* In non-preemptible RCU implementations (TREE_RCU and TINY_RCU), * In non-preemptible RCU implementations (TREE_RCU and TINY_RCU),
* it is illegal to block while in an RCU read-side critical section. * 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, * kernel builds, RCU read-side critical sections may be preempted,
* but explicit blocking is illegal. Finally, in preemptible RCU * but explicit blocking is illegal. Finally, in preemptible RCU
* implementations in real-time (with -rt patchset) kernel builds, RCU * implementations in real-time (with -rt patchset) kernel builds, RCU

2
include/linux/rcutree.h
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@ -53,7 +53,7 @@ void rcu_scheduler_starting(void);
extern int rcu_scheduler_active __read_mostly; extern int rcu_scheduler_active __read_mostly;
void rcu_end_inkernel_boot(void); void rcu_end_inkernel_boot(void);
bool rcu_is_watching(void); bool rcu_is_watching(void);
#ifndef CONFIG_PREEMPT #ifndef CONFIG_PREEMPTION
void rcu_all_qs(void); void rcu_all_qs(void);
#endif #endif

2
include/linux/torture.h
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@ -86,7 +86,7 @@ void _torture_stop_kthread(char *m, struct task_struct **tp);
#define torture_stop_kthread(n, tp) \ #define torture_stop_kthread(n, tp) \
_torture_stop_kthread("Stopping " #n " task", &(tp)) _torture_stop_kthread("Stopping " #n " task", &(tp))
#ifdef CONFIG_PREEMPT #ifdef CONFIG_PREEMPTION
#define torture_preempt_schedule() preempt_schedule() #define torture_preempt_schedule() preempt_schedule()
#else #else
#define torture_preempt_schedule() #define torture_preempt_schedule()

8
kernel/rcu/Kconfig
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@ -7,7 +7,7 @@ menu "RCU Subsystem"
config TREE_RCU config TREE_RCU
bool bool
default y if !PREEMPT && SMP default y if !PREEMPTION && SMP
help help
This option selects the RCU implementation that is This option selects the RCU implementation that is
designed for very large SMP system with hundreds or designed for very large SMP system with hundreds or
@ -16,7 +16,7 @@ config TREE_RCU
config PREEMPT_RCU config PREEMPT_RCU
bool bool
default y if PREEMPT default y if PREEMPTION
help help
This option selects the RCU implementation that is This option selects the RCU implementation that is
designed for very large SMP systems with hundreds or designed for very large SMP systems with hundreds or
@ -28,7 +28,7 @@ config PREEMPT_RCU
config TINY_RCU config TINY_RCU
bool bool
default y if !PREEMPT && !SMP default y if !PREEMPTION && !SMP
help help
This option selects the RCU implementation that is This option selects the RCU implementation that is
designed for UP systems from which real-time response 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. This option selects the full-fledged version of SRCU.
config TASKS_RCU config TASKS_RCU
def_bool PREEMPT def_bool PREEMPTION
select SRCU select SRCU
help help
This option enables a task-based RCU implementation that uses This option enables a task-based RCU implementation that uses

6
kernel/rcu/tree.c
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@ -1881,7 +1881,7 @@ rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags)
struct rcu_node *rnp_p; struct rcu_node *rnp_p;
raw_lockdep_assert_held_rcu_node(rnp); 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)) || WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)) ||
rnp->qsmask != 0) { rnp->qsmask != 0) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); 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; mask = 0;
raw_spin_lock_irqsave_rcu_node(rnp, flags); raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rnp->qsmask == 0) { if (rnp->qsmask == 0) {
if (!IS_ENABLED(CONFIG_PREEMPT) || if (!IS_ENABLED(CONFIG_PREEMPTION) ||
rcu_preempt_blocked_readers_cgp(rnp)) { rcu_preempt_blocked_readers_cgp(rnp)) {
/* /*
* No point in scanning bits because they * No point in scanning bits because they
@ -2622,7 +2622,7 @@ static int rcu_blocking_is_gp(void)
{ {
int ret; int ret;
if (IS_ENABLED(CONFIG_PREEMPT)) if (IS_ENABLED(CONFIG_PREEMPTION))
return rcu_scheduler_active == RCU_SCHEDULER_INACTIVE; return rcu_scheduler_active == RCU_SCHEDULER_INACTIVE;
might_sleep(); /* Check for RCU read-side critical section. */ might_sleep(); /* Check for RCU read-side critical section. */
preempt_disable(); preempt_disable();

6
kernel/rcu/tree_stall.h
View File

@ -163,7 +163,7 @@ static void rcu_iw_handler(struct irq_work *iwp)
// //
// Printing RCU CPU stall warnings // Printing RCU CPU stall warnings
#ifdef CONFIG_PREEMPT #ifdef CONFIG_PREEMPTION
/* /*
* Dump detailed information for all tasks blocking the current RCU * 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; return ndetected;
} }
#else /* #ifdef CONFIG_PREEMPT */ #else /* #ifdef CONFIG_PREEMPTION */
/* /*
* Because preemptible RCU does not exist, we never have to check for * 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; return 0;
} }
#endif /* #else #ifdef CONFIG_PREEMPT */ #endif /* #else #ifdef CONFIG_PREEMPTION */
/* /*
* Dump stacks of all tasks running on stalled CPUs. First try using * Dump stacks of all tasks running on stalled CPUs. First try using

2
kernel/trace/Kconfig
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@ -146,7 +146,7 @@ config FUNCTION_TRACER
select GENERIC_TRACER select GENERIC_TRACER
select CONTEXT_SWITCH_TRACER select CONTEXT_SWITCH_TRACER
select GLOB select GLOB
select TASKS_RCU if PREEMPT select TASKS_RCU if PREEMPTION
help help
Enable the kernel to trace every kernel function. This is done Enable the kernel to trace every kernel function. This is done
by using a compiler feature to insert a small, 5-byte No-Operation by using a compiler feature to insert a small, 5-byte No-Operation