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>

diff --git a/arch/Kconfig b/arch/Kconfig
index a7b57dd..c7efbc0 100644 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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