On Thu, Sep 03, 2020 at 08:19:38AM -0700, Guenter Roeck wrote:
> This doesn't compile for me - there is no "name" parameter in __DO_TRACE().
>
> Error log:
> In file included from ./include/linux/rculist.h:11,
> from ./include/linux/pid.h:5,
> from ./include/linux/sched.h:14,
> from ./include/linux/sched/numa_balancing.h:10,
> from ./include/trace/events/sched.h:8,
> from kernel/sched/core.c:10:
> ./include/trace/events/sched.h: In function 'trace_sched_kthread_stop':
> ./include/linux/tracepoint.h:175:26: error: '__tracepoint_name' undeclared
>
> I applied your patch on top of v5.9-rc3-75-gfc3abb53250a. Are you using
> a different branch ?
Argh, I was on tip/master... easy fix though.
---
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 7d9c1c0e149c..878bac893e41 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -27,17 +27,20 @@
* SOFTIRQ_MASK: 0x0000ff00
* HARDIRQ_MASK: 0x000f0000
* NMI_MASK: 0x00f00000
+ * RCUIDLE_MASK: 0x01000000
* PREEMPT_NEED_RESCHED: 0x80000000
*/
#define PREEMPT_BITS 8
#define SOFTIRQ_BITS 8
#define HARDIRQ_BITS 4
#define NMI_BITS 4
+#define RCUIDLE_BITS 1
#define PREEMPT_SHIFT 0
#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
#define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS)
+#define RCUIDLE_SHIFT (NMI_SHIFT + NMI_BITS)
#define __IRQ_MASK(x) ((1UL << (x))-1)
@@ -45,11 +48,13 @@
#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
#define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT)
+#define RCUIDLE_MASK (__IRQ_MASK(RCUIDLE_BITS) << RCUIDLE_SHIFT)
#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
#define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
#define NMI_OFFSET (1UL << NMI_SHIFT)
+#define RCUIDLE_OFFSET (1UL << RCUIDLE_SHIFT)
#define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET)
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 598fec9f9dbf..0469bc1c24fc 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -164,12 +164,18 @@ static inline struct tracepoint
*tracepoint_ptr_deref(tracepoint_ptr_t *p)
void *__data; \
int __maybe_unused __idx = 0; \
\
- if (!(cond)) \
+ if (!(cond) || (preempt_count() & RCUIDLE_MASK)) \
return; \
\
/* srcu can't be used from NMI */ \
WARN_ON_ONCE(rcuidle && in_nmi()); \
\
+ if (IS_ENABLED(CONFIG_LOCKDEP) && !(rcuidle)) { \
+ rcu_read_lock_sched_notrace(); \
+ rcu_dereference_sched((tp)->funcs); \
+ rcu_read_unlock_sched_notrace(); \
+ } \
+ \
/* keep srcu and sched-rcu usage consistent */ \
preempt_disable_notrace(); \
\
@@ -235,11 +241,6 @@ static inline struct tracepoint
*tracepoint_ptr_deref(tracepoint_ptr_t *p)
TP_PROTO(data_proto), \
TP_ARGS(data_args), \
TP_CONDITION(cond), 0); \
- if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \
- rcu_read_lock_sched_notrace(); \
- rcu_dereference_sched(__tracepoint_##name.funcs);\
- rcu_read_unlock_sched_notrace(); \
- } \
} \
__DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args), \
PARAMS(cond), PARAMS(data_proto), PARAMS(data_args)) \
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8ce77d9ac716..ad9fb4f12c63 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -269,6 +269,8 @@ static noinstr void rcu_dynticks_eqs_enter(void)
/* Better not have special action (TLB flush) pending! */
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) &&
(seq & RCU_DYNTICK_CTRL_MASK));
+
+ __preempt_count_add(RCUIDLE_OFFSET);
}
/*
@@ -281,6 +283,8 @@ static noinstr void rcu_dynticks_eqs_exit(void)
struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
int seq;
+ __preempt_count_sub(RCUIDLE_OFFSET);
+
/*
* CPUs seeing atomic_add_return() must see prior idle sojourns,
* and we also must force ordering with the next RCU read-side
