This patch detaches the preemptirq tracepoints from the tracers and
keeps it separate. With this, several ifdefs are cleaner, and lockdep
and other users can use the preemptirq tracepoints by registering probes
onto them. This makes it much cleaner, but not just that: PROVE_LOCKING
and CONFIG_IRQSOFF_TRACER can be enabled now at the same time and we
get rid of all the horrific ifdeferry around PROVE_LOCKING.
In the patch we introduce a new CONFIG option PREEMPTIRQ_TRACEPOINTS
as a single point for registering probes onto the tracepoints. With this,
the web of config options for preempt/irq toggle tracepoints and its
users becomes:
PREEMPT_TRACER PREEMPTIRQ_EVENTS IRQSOFF_TRACER PROVE_LOCKING
| | \ | |
\ (selects) / \ \ (selects) /
TRACE_PREEMPT_TOGGLE ----> TRACE_IRQFLAGS
\ /
\ (depends on) /
PREEMPTIRQ_TRACEPOINTS
Three user's of the tracepoints exist after this: lockdep, the
preemptirq tracers and preemptirq trace events. I did sanity testing on
all of these to see expected results.
Cc: Steven Rostedt <[email protected]>
Cc: Peter Zilstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Tom Zanussi <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: [email protected]
Signed-off-by: Joel Fernandes <[email protected]>
---
include/linux/ftrace.h | 11 +-
include/linux/irqflags.h | 11 +-
include/linux/lockdep.h | 6 +-
include/linux/preempt.h | 2 +-
include/trace/events/preemptirq.h | 23 +++--
init/main.c | 2 +-
kernel/locking/lockdep.c | 30 ++----
kernel/sched/core.c | 2 +-
kernel/trace/Kconfig | 19 +++-
kernel/trace/Makefile | 2 +-
kernel/trace/trace_irqsoff.c | 206 +++++++++-----------------------------
kernel/trace/trace_preemptirq.c | 70 +++++++++++++
12 files changed, 169 insertions(+), 215 deletions(-)
create mode 100644 kernel/trace/trace_preemptirq.c
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 3319df9727aa..7488ada6e4e3 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -709,16 +709,7 @@ static inline unsigned long get_lock_parent_ip(void)
return CALLER_ADDR2;
}
-#ifdef CONFIG_IRQSOFF_TRACER
- extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
- extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
-#else
- static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
- static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
-#endif
-
-#if defined(CONFIG_PREEMPT_TRACER) || \
- (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
+#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
extern void trace_preempt_on(unsigned long a0, unsigned long a1);
extern void trace_preempt_off(unsigned long a0, unsigned long a1);
#else
diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
index 1b3996ff3f16..9d72181d4a94 100644
--- a/include/linux/irqflags.h
+++ b/include/linux/irqflags.h
@@ -15,9 +15,16 @@
#include <linux/typecheck.h>
#include <asm/irqflags.h>
-#ifdef CONFIG_TRACE_IRQFLAGS
+/* Currently trace_softirqs_on/off is used only by lockdep */
+#ifdef CONFIG_PROVE_LOCKING
extern void trace_softirqs_on(unsigned long ip);
extern void trace_softirqs_off(unsigned long ip);
+#else
+# define trace_softirqs_on(ip) do { } while (0)
+# define trace_softirqs_off(ip) do { } while (0)
+#endif
+
+#ifdef CONFIG_TRACE_IRQFLAGS
extern void trace_hardirqs_on(void);
extern void trace_hardirqs_off(void);
# define trace_hardirq_context(p) ((p)->hardirq_context)
@@ -44,8 +51,6 @@ do { \
#else
# define trace_hardirqs_on() do { } while (0)
# define trace_hardirqs_off() do { } while (0)
-# define trace_softirqs_on(ip) do { } while (0)
-# define trace_softirqs_off(ip) do { } while (0)
# define trace_hardirq_context(p) 0
# define trace_softirq_context(p) 0
# define trace_hardirqs_enabled(p) 0
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 3251d9c0d313..1a6dcc95bba8 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -266,7 +266,7 @@ struct held_lock {
/*
* Initialization, self-test and debugging-output methods:
*/
-extern void lockdep_info(void);
+extern void lockdep_init(void);
extern void lockdep_reset(void);
extern void lockdep_reset_lock(struct lockdep_map *lock);
extern void lockdep_free_key_range(void *start, unsigned long size);
@@ -408,7 +408,7 @@ static inline void lockdep_on(void)
# define lock_downgrade(l, i) do { } while (0)
# define lock_set_class(l, n, k, s, i) do { } while (0)
# define lock_set_subclass(l, s, i) do { } while (0)
-# define lockdep_info() do { } while (0)
+# define lockdep_init() do { } while (0)
# define lockdep_init_map(lock, name, key, sub) \
do { (void)(name); (void)(key); } while (0)
# define lockdep_set_class(lock, key) do { (void)(key); } while (0)
@@ -535,7 +535,7 @@ do { \
#endif /* CONFIG_LOCKDEP */
-#ifdef CONFIG_TRACE_IRQFLAGS
+#ifdef CONFIG_PROVE_LOCKING
extern void print_irqtrace_events(struct task_struct *curr);
#else
static inline void print_irqtrace_events(struct task_struct *curr)
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 5bd3f151da78..c01813c3fbe9 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -150,7 +150,7 @@
*/
#define in_atomic_preempt_off() (preempt_count() != PREEMPT_DISABLE_OFFSET)
-#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)
+#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_TRACE_PREEMPT_TOGGLE)
extern void preempt_count_add(int val);
extern void preempt_count_sub(int val);
#define preempt_count_dec_and_test() \
diff --git a/include/trace/events/preemptirq.h b/include/trace/events/preemptirq.h
index 9c4eb33c5a1d..9a0d4ceeb166 100644
--- a/include/trace/events/preemptirq.h
+++ b/include/trace/events/preemptirq.h
@@ -1,4 +1,4 @@
-#ifdef CONFIG_PREEMPTIRQ_EVENTS
+#ifdef CONFIG_PREEMPTIRQ_TRACEPOINTS
#undef TRACE_SYSTEM
#define TRACE_SYSTEM preemptirq
@@ -32,7 +32,7 @@ DECLARE_EVENT_CLASS(preemptirq_template,
(void *)((unsigned long)(_stext) + __entry->parent_offs))
);
-#ifndef CONFIG_PROVE_LOCKING
+#ifdef CONFIG_TRACE_IRQFLAGS
DEFINE_EVENT(preemptirq_template, irq_disable,
TP_PROTO(unsigned long ip, unsigned long parent_ip),
TP_ARGS(ip, parent_ip));
@@ -40,9 +40,14 @@ DEFINE_EVENT(preemptirq_template, irq_disable,
DEFINE_EVENT(preemptirq_template, irq_enable,
TP_PROTO(unsigned long ip, unsigned long parent_ip),
TP_ARGS(ip, parent_ip));
+#else
+#define trace_irq_enable(...)
+#define trace_irq_disable(...)
+#define trace_irq_enable_rcuidle(...)
+#define trace_irq_disable_rcuidle(...)
#endif
-#ifdef CONFIG_DEBUG_PREEMPT
+#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
DEFINE_EVENT(preemptirq_template, preempt_disable,
TP_PROTO(unsigned long ip, unsigned long parent_ip),
TP_ARGS(ip, parent_ip));
@@ -50,22 +55,22 @@ DEFINE_EVENT(preemptirq_template, preempt_disable,
DEFINE_EVENT(preemptirq_template, preempt_enable,
TP_PROTO(unsigned long ip, unsigned long parent_ip),
TP_ARGS(ip, parent_ip));
+#else
+#define trace_preempt_enable(...)
+#define trace_preempt_disable(...)
+#define trace_preempt_enable_rcuidle(...)
+#define trace_preempt_disable_rcuidle(...)
#endif
#endif /* _TRACE_PREEMPTIRQ_H */
#include <trace/define_trace.h>
-#endif /* !CONFIG_PREEMPTIRQ_EVENTS */
-
-#if !defined(CONFIG_PREEMPTIRQ_EVENTS) || defined(CONFIG_PROVE_LOCKING)
+#else /* !CONFIG_PREEMPTIRQ_TRACEPOINTS */
#define trace_irq_enable(...)
#define trace_irq_disable(...)
#define trace_irq_enable_rcuidle(...)
#define trace_irq_disable_rcuidle(...)
-#endif
-
-#if !defined(CONFIG_PREEMPTIRQ_EVENTS) || !defined(CONFIG_DEBUG_PREEMPT)
#define trace_preempt_enable(...)
#define trace_preempt_disable(...)
#define trace_preempt_enable_rcuidle(...)
diff --git a/init/main.c b/init/main.c
index a8100b954839..33f1b998f82e 100644
--- a/init/main.c
+++ b/init/main.c
@@ -643,7 +643,7 @@ asmlinkage __visible void __init start_kernel(void)
panic("Too many boot %s vars at `%s'", panic_later,
panic_param);
- lockdep_info();
+ lockdep_init();
/*
* Need to run this when irqs are enabled, because it wants
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 521659044719..70d5e3fee887 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -55,6 +55,7 @@
#include "lockdep_internals.h"
+#include <trace/events/preemptirq.h>
#define CREATE_TRACE_POINTS
#include <trace/events/lock.h>
@@ -2837,10 +2838,9 @@ static void __trace_hardirqs_on_caller(unsigned long ip)
debug_atomic_inc(hardirqs_on_events);
}
-__visible void trace_hardirqs_on_caller(unsigned long ip)
+static void lockdep_hardirqs_on(void *none, unsigned long ignore,
+ unsigned long ip)
{
- time_hardirqs_on(CALLER_ADDR0, ip);
-
if (unlikely(!debug_locks || current->lockdep_recursion))
return;
@@ -2879,23 +2879,15 @@ __visible void trace_hardirqs_on_caller(unsigned long ip)
__trace_hardirqs_on_caller(ip);
current->lockdep_recursion = 0;
}
-EXPORT_SYMBOL(trace_hardirqs_on_caller);
-
-void trace_hardirqs_on(void)
-{
- trace_hardirqs_on_caller(CALLER_ADDR0);
-}
-EXPORT_SYMBOL(trace_hardirqs_on);
/*
* Hardirqs were disabled:
*/
-__visible void trace_hardirqs_off_caller(unsigned long ip)
+static void lockdep_hardirqs_off(void *none, unsigned long ignore,
+ unsigned long ip)
{
struct task_struct *curr = current;
- time_hardirqs_off(CALLER_ADDR0, ip);
-
if (unlikely(!debug_locks || current->lockdep_recursion))
return;
@@ -2917,13 +2909,6 @@ __visible void trace_hardirqs_off_caller(unsigned long ip)
} else
debug_atomic_inc(redundant_hardirqs_off);
}
-EXPORT_SYMBOL(trace_hardirqs_off_caller);
-
-void trace_hardirqs_off(void)
-{
- trace_hardirqs_off_caller(CALLER_ADDR0);
-}
-EXPORT_SYMBOL(trace_hardirqs_off);
/*
* Softirqs will be enabled:
@@ -4329,8 +4314,11 @@ void lockdep_reset_lock(struct lockdep_map *lock)
raw_local_irq_restore(flags);
}
-void __init lockdep_info(void)
+void __init lockdep_init(void)
{
+ register_trace_irq_disable(lockdep_hardirqs_off, NULL);
+ register_trace_irq_enable(lockdep_hardirqs_on, NULL);
+
printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index a7bf32aabfda..35944d21a527 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3065,7 +3065,7 @@ u64 scheduler_tick_max_deferment(void)
#endif
#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
- defined(CONFIG_PREEMPT_TRACER))
+ defined(CONFIG_TRACE_PREEMPT_TOGGLE))
/*
* If the value passed in is equal to the current preempt count
* then we just disabled preemption. Start timing the latency.
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index f54dc62b599c..b5c0817a4163 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -159,18 +159,28 @@ config FUNCTION_GRAPH_TRACER
the return value. This is done by setting the current return
address on the current task structure into a stack of calls.
+config TRACE_PREEMPT_TOGGLE
+ bool
+ help
+ Enables hooks which will be called when preemption is first disabled,
+ and last enabled.
+
+config PREEMPTIRQ_TRACEPOINTS
+ bool
+ depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS
+ default y
+ help
+ Create preempt/irq toggle tracepoints if needed, so that other parts
+ of the kernel can use them to generate or add hooks to them.
config PREEMPTIRQ_EVENTS
bool "Enable trace events for preempt and irq disable/enable"
select TRACE_IRQFLAGS
- depends on DEBUG_PREEMPT || !PROVE_LOCKING
+ select TRACE_PREEMPT_TOGGLE if PREEMPT
depends on TRACING
default n
help
Enable tracing of disable and enable events for preemption and irqs.
- For tracing preempt disable/enable events, DEBUG_PREEMPT must be
- enabled. For tracing irq disable/enable events, PROVE_LOCKING must
- be disabled.
config IRQSOFF_TRACER
bool "Interrupts-off Latency Tracer"
@@ -207,6 +217,7 @@ config PREEMPT_TRACER
select RING_BUFFER_ALLOW_SWAP
select TRACER_SNAPSHOT
select TRACER_SNAPSHOT_PER_CPU_SWAP
+ select TRACE_PREEMPT_TOGGLE
help
This option measures the time spent in preemption-off critical
sections, with microsecond accuracy.
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index e2538c7638d4..84a0cb222f20 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -35,7 +35,7 @@ obj-$(CONFIG_TRACING) += trace_printk.o
obj-$(CONFIG_TRACING_MAP) += tracing_map.o
obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
-obj-$(CONFIG_PREEMPTIRQ_EVENTS) += trace_irqsoff.o
+obj-$(CONFIG_PREEMPTIRQ_TRACEPOINTS) += trace_preemptirq.o
obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 03ecb4465ee4..e3cec13dd935 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -16,7 +16,6 @@
#include "trace.h"
-#define CREATE_TRACE_POINTS
#include <trace/events/preemptirq.h>
#if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER)
@@ -450,66 +449,6 @@ void stop_critical_timings(void)
}
EXPORT_SYMBOL_GPL(stop_critical_timings);
-#ifdef CONFIG_IRQSOFF_TRACER
-#ifdef CONFIG_PROVE_LOCKING
-void time_hardirqs_on(unsigned long a0, unsigned long a1)
-{
- if (!preempt_trace() && irq_trace())
- stop_critical_timing(a0, a1);
-}
-
-void time_hardirqs_off(unsigned long a0, unsigned long a1)
-{
- if (!preempt_trace() && irq_trace())
- start_critical_timing(a0, a1);
-}
-
-#else /* !CONFIG_PROVE_LOCKING */
-
-/*
- * We are only interested in hardirq on/off events:
- */
-static inline void tracer_hardirqs_on(void)
-{
- if (!preempt_trace() && irq_trace())
- stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
-}
-
-static inline void tracer_hardirqs_off(void)
-{
- if (!preempt_trace() && irq_trace())
- start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
-}
-
-static inline void tracer_hardirqs_on_caller(unsigned long caller_addr)
-{
- if (!preempt_trace() && irq_trace())
- stop_critical_timing(CALLER_ADDR0, caller_addr);
-}
-
-static inline void tracer_hardirqs_off_caller(unsigned long caller_addr)
-{
- if (!preempt_trace() && irq_trace())
- start_critical_timing(CALLER_ADDR0, caller_addr);
-}
-
-#endif /* CONFIG_PROVE_LOCKING */
-#endif /* CONFIG_IRQSOFF_TRACER */
-
-#ifdef CONFIG_PREEMPT_TRACER
-static inline void tracer_preempt_on(unsigned long a0, unsigned long a1)
-{
- if (preempt_trace() && !irq_trace())
- stop_critical_timing(a0, a1);
-}
-
-static inline void tracer_preempt_off(unsigned long a0, unsigned long a1)
-{
- if (preempt_trace() && !irq_trace())
- start_critical_timing(a0, a1);
-}
-#endif /* CONFIG_PREEMPT_TRACER */
-
#ifdef CONFIG_FUNCTION_TRACER
static bool function_enabled;
@@ -659,10 +598,28 @@ static void irqsoff_tracer_stop(struct trace_array *tr)
}
#ifdef CONFIG_IRQSOFF_TRACER
+/*
+ * We are only interested in hardirq on/off events:
+ */
+static void tracer_hardirqs_on(void *none, unsigned long a0, unsigned long a1)
+{
+ if (!preempt_trace() && irq_trace())
+ stop_critical_timing(a0, a1);
+}
+
+static void tracer_hardirqs_off(void *none, unsigned long a0, unsigned long a1)
+{
+ if (!preempt_trace() && irq_trace())
+ start_critical_timing(a0, a1);
+}
+
static int irqsoff_tracer_init(struct trace_array *tr)
{
trace_type = TRACER_IRQS_OFF;
+ register_trace_irq_disable(tracer_hardirqs_off, NULL);
+ register_trace_irq_enable(tracer_hardirqs_on, NULL);
+
return __irqsoff_tracer_init(tr);
}
static struct tracer irqsoff_tracer __read_mostly =
@@ -686,14 +643,31 @@ static struct tracer irqsoff_tracer __read_mostly =
};
# define register_irqsoff(trace) register_tracer(&trace)
#else
+static inline void tracer_hardirqs_on(unsigned long a0, unsigned long a1) { }
+static inline void tracer_hardirqs_off(unsigned long a0, unsigned long a1) { }
# define register_irqsoff(trace) do { } while (0)
-#endif
+#endif /* CONFIG_IRQSOFF_TRACER */
#ifdef CONFIG_PREEMPT_TRACER
+static void tracer_preempt_on(void *none, unsigned long a0, unsigned long a1)
+{
+ if (preempt_trace() && !irq_trace())
+ stop_critical_timing(a0, a1);
+}
+
+static void tracer_preempt_off(void *none, unsigned long a0, unsigned long a1)
+{
+ if (preempt_trace() && !irq_trace())
+ start_critical_timing(a0, a1);
+}
+
static int preemptoff_tracer_init(struct trace_array *tr)
{
trace_type = TRACER_PREEMPT_OFF;
+ register_trace_preempt_disable(tracer_preempt_off, NULL);
+ register_trace_preempt_enable(tracer_preempt_on, NULL);
+
return __irqsoff_tracer_init(tr);
}
@@ -718,16 +692,22 @@ static struct tracer preemptoff_tracer __read_mostly =
};
# define register_preemptoff(trace) register_tracer(&trace)
#else
+static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { }
+static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) { }
# define register_preemptoff(trace) do { } while (0)
-#endif
+#endif /* CONFIG_PREEMPT_TRACER */
-#if defined(CONFIG_IRQSOFF_TRACER) && \
- defined(CONFIG_PREEMPT_TRACER)
+#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
static int preemptirqsoff_tracer_init(struct trace_array *tr)
{
trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
+ register_trace_irq_disable(tracer_hardirqs_off, NULL);
+ register_trace_irq_enable(tracer_hardirqs_on, NULL);
+ register_trace_preempt_disable(tracer_preempt_off, NULL);
+ register_trace_preempt_enable(tracer_preempt_on, NULL);
+
return __irqsoff_tracer_init(tr);
}
@@ -766,99 +746,3 @@ __init static int init_irqsoff_tracer(void)
}
core_initcall(init_irqsoff_tracer);
#endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */
-
-#ifndef CONFIG_IRQSOFF_TRACER
-static inline void tracer_hardirqs_on(void) { }
-static inline void tracer_hardirqs_off(void) { }
-static inline void tracer_hardirqs_on_caller(unsigned long caller_addr) { }
-static inline void tracer_hardirqs_off_caller(unsigned long caller_addr) { }
-#endif
-
-#ifndef CONFIG_PREEMPT_TRACER
-static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { }
-static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) { }
-#endif
-
-#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PROVE_LOCKING)
-/* Per-cpu variable to prevent redundant calls when IRQs already off */
-static DEFINE_PER_CPU(int, tracing_irq_cpu);
-
-void trace_hardirqs_on(void)
-{
- if (!this_cpu_read(tracing_irq_cpu))
- return;
-
- trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
- tracer_hardirqs_on();
-
- this_cpu_write(tracing_irq_cpu, 0);
-}
-EXPORT_SYMBOL(trace_hardirqs_on);
-
-void trace_hardirqs_off(void)
-{
- if (this_cpu_read(tracing_irq_cpu))
- return;
-
- this_cpu_write(tracing_irq_cpu, 1);
-
- trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
- tracer_hardirqs_off();
-}
-EXPORT_SYMBOL(trace_hardirqs_off);
-
-__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
-{
- if (!this_cpu_read(tracing_irq_cpu))
- return;
-
- trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
- tracer_hardirqs_on_caller(caller_addr);
-
- this_cpu_write(tracing_irq_cpu, 0);
-}
-EXPORT_SYMBOL(trace_hardirqs_on_caller);
-
-__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
-{
- if (this_cpu_read(tracing_irq_cpu))
- return;
-
- this_cpu_write(tracing_irq_cpu, 1);
-
- trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
- tracer_hardirqs_off_caller(caller_addr);
-}
-EXPORT_SYMBOL(trace_hardirqs_off_caller);
-
-/*
- * Stubs:
- */
-
-void trace_softirqs_on(unsigned long ip)
-{
-}
-
-void trace_softirqs_off(unsigned long ip)
-{
-}
-
-inline void print_irqtrace_events(struct task_struct *curr)
-{
-}
-#endif
-
-#if defined(CONFIG_PREEMPT_TRACER) || \
- (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
-void trace_preempt_on(unsigned long a0, unsigned long a1)
-{
- trace_preempt_enable_rcuidle(a0, a1);
- tracer_preempt_on(a0, a1);
-}
-
-void trace_preempt_off(unsigned long a0, unsigned long a1)
-{
- trace_preempt_disable_rcuidle(a0, a1);
- tracer_preempt_off(a0, a1);
-}
-#endif
diff --git a/kernel/trace/trace_preemptirq.c b/kernel/trace/trace_preemptirq.c
new file mode 100644
index 000000000000..bec9926acb00
--- /dev/null
+++ b/kernel/trace/trace_preemptirq.c
@@ -0,0 +1,70 @@
+/*
+ * preemptoff and irqoff tracepoints
+ *
+ * Copyright (C) 2017 Joel Fernandes <[email protected]>
+ */
+
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/preemptirq.h>
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+/* Per-cpu variable to prevent redundant calls when IRQs already off */
+static DEFINE_PER_CPU(int, tracing_irq_cpu);
+
+void trace_hardirqs_on(void)
+{
+ if (!this_cpu_read(tracing_irq_cpu))
+ return;
+
+ trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+ this_cpu_write(tracing_irq_cpu, 0);
+}
+EXPORT_SYMBOL(trace_hardirqs_on);
+
+void trace_hardirqs_off(void)
+{
+ if (this_cpu_read(tracing_irq_cpu))
+ return;
+
+ this_cpu_write(tracing_irq_cpu, 1);
+ trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+}
+EXPORT_SYMBOL(trace_hardirqs_off);
+
+__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
+{
+ if (!this_cpu_read(tracing_irq_cpu))
+ return;
+
+ trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
+ this_cpu_write(tracing_irq_cpu, 0);
+}
+EXPORT_SYMBOL(trace_hardirqs_on_caller);
+
+__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
+{
+ if (this_cpu_read(tracing_irq_cpu))
+ return;
+
+ this_cpu_write(tracing_irq_cpu, 1);
+ trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
+}
+EXPORT_SYMBOL(trace_hardirqs_off_caller);
+#endif /* CONFIG_TRACE_IRQFLAGS */
+
+#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
+void trace_preempt_on(unsigned long a0, unsigned long a1)
+{
+ trace_preempt_enable_rcuidle(a0, a1);
+}
+
+void trace_preempt_off(unsigned long a0, unsigned long a1)
+{
+ trace_preempt_disable_rcuidle(a0, a1);
+}
+#endif
--
2.16.0.rc1.238.g530d649a79-goog
On Mon, Feb 5, 2018 at 6:39 PM, Joel Fernandes <[email protected]> wrote:
> This patch detaches the preemptirq tracepoints from the tracers and
> keeps it separate. With this, several ifdefs are cleaner, and lockdep
> and other users can use the preemptirq tracepoints by registering probes
> onto them. This makes it much cleaner, but not just that: PROVE_LOCKING
> and CONFIG_IRQSOFF_TRACER can be enabled now at the same time and we
> get rid of all the horrific ifdeferry around PROVE_LOCKING.
>
Sorry for the misstatement, irqsoff tracer and PROVE_LOCKING can still
be used at the same time (without this patch). I will correct the
commit message in the next rev. However this patch avoids the
complication that arises when enabling the 2 together, by eliminating
time_hardirqs_on/off.
thanks,
- Joel
On Mon, 5 Feb 2018 23:15:32 -0800
Joel Fernandes <[email protected]> wrote:
> On Mon, Feb 5, 2018 at 6:39 PM, Joel Fernandes <[email protected]> wrote:
> > This patch detaches the preemptirq tracepoints from the tracers and
> > keeps it separate. With this, several ifdefs are cleaner, and lockdep
> > and other users can use the preemptirq tracepoints by registering probes
> > onto them. This makes it much cleaner, but not just that: PROVE_LOCKING
> > and CONFIG_IRQSOFF_TRACER can be enabled now at the same time and we
> > get rid of all the horrific ifdeferry around PROVE_LOCKING.
> >
>
> Sorry for the misstatement, irqsoff tracer and PROVE_LOCKING can still
> be used at the same time (without this patch). I will correct the
> commit message in the next rev. However this patch avoids the
> complication that arises when enabling the 2 together, by eliminating
> time_hardirqs_on/off.
>
Hi Joel,
This looks nice, but I currently don't have time to look at it. Please
ping me again if you don't hear from me by beginning of next week.
-- Steve
FYI, we noticed the following commit (built with gcc-7):
commit: 8e130b0d9284a0a01ca1d6ecf8f0896cfc28b112 ("tracing: Improve design of preemptirq tracepoints and its users")
url: https://github.com/0day-ci/linux/commits/Joel-Fernandes/tracing-Improve-design-of-preemptirq-tracepoints-and-its-users/20180207-195707
in testcase: boot
on test machine: qemu-system-x86_64 -enable-kvm -m 512M
caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
+----------------------------------------------------+------------+------------+
| | e4c1091cb4 | 8e130b0d92 |
+----------------------------------------------------+------------+------------+
| boot_successes | 1 | 0 |
| boot_failures | 0 | 43 |
| WARNING:at_kernel/rcu/tree.c:#rcu_irq_exit | 0 | 43 |
| RIP:rcu_irq_exit | 0 | 43 |
| WARNING:at_kernel/rcu/tree.c:#rcu_irq_enter | 0 | 43 |
| RIP:rcu_irq_enter | 0 | 43 |
| WARNING:at_kernel/rcu/tree.c:#rcu_eqs_enter_common | 0 | 43 |
| RIP:rcu_eqs_enter_common | 0 | 43 |
+----------------------------------------------------+------------+------------+
[ 0.001000] WARNING: CPU: 0 PID: 0 at kernel/rcu/tree.c:892 rcu_irq_exit+0x4d/0x19a
[ 0.001000] Modules linked in:
[ 0.001000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc7-00430-g8e130b0 #35
[ 0.001000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[ 0.001000] RIP: 0010:rcu_irq_exit+0x4d/0x19a
[ 0.001000] RSP: 0000:ffffffff92803e18 EFLAGS: 00010082
[ 0.001000] RAX: 000000000000001d RBX: 0000000000000082 RCX: 70a3d70a3d70a3e0
[ 0.001000] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000046
[ 0.001000] RBP: ffffffff910fa412 R08: 00000000c5610c9a R09: 0000000000000004
[ 0.001000] R10: 0000000000000001 R11: ffffffff93dc0469 R12: 0000000000000000
[ 0.001000] R13: ffffffff93dc0880 R14: 0000000000000002 R15: 0000000000000048
[ 0.001000] FS: 0000000000000000(0000) GS:ffff8bfa5f600000(0000) knlGS:0000000000000000
[ 0.001000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.001000] CR2: 00000000ffffffff CR3: 0000000009824000 CR4: 00000000000006b0
[ 0.001000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 0.001000] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 0.001000] Call Trace:
[ 0.001000] ? vprintk_emit+0x26c/0x29c
[ 0.001000] rcu_irq_exit_irqson+0x21/0x48
[ 0.001000] trace_hardirqs_on+0xc2/0xd0
[ 0.001000] vprintk_emit+0x26c/0x29c
[ 0.001000] printk+0x43/0x4b
[ 0.001000] lockdep_init+0x36/0xcf
[ 0.001000] start_kernel+0x2fd/0x416
[ 0.001000] secondary_startup_64+0xa5/0xb0
[ 0.001000] Code: 08 00 00 00 75 27 83 b8 88 08 00 00 00 74 1e 80 3d ef 68 8c 01 00 75 15 48 c7 c7 a9 e3 5e 92 c6 05 df 68 8c 01 01 e8 31 9d f8 ff <0f> ff 48 c7 c5 a0 9d 1d 00 65 48 03 2d 70 cf ef 6e 83 7d 08 00
[ 0.001000] ---[ end trace 2507864299958132 ]---
To reproduce:
git clone https://github.com/intel/lkp-tests.git
cd lkp-tests
bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email
Thanks,
lkp
FYI, we noticed the following commit (built with gcc-7):
commit: 8e130b0d9284a0a01ca1d6ecf8f0896cfc28b112 ("tracing: Improve design of preemptirq tracepoints and its users")
url: https://github.com/0day-ci/linux/commits/Joel-Fernandes/tracing-Improve-design-of-preemptirq-tracepoints-and-its-users/20180207-195707
in testcase: boot
on test machine: qemu-system-x86_64 -enable-kvm -m 512M
caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
+----------------------------------------------------+------------+------------+
| | e4c1091cb4 | 8e130b0d92 |
+----------------------------------------------------+------------+------------+
| boot_successes | 1 | 0 |
| boot_failures | 0 | 43 |
| WARNING:at_kernel/rcu/tree.c:#rcu_irq_exit | 0 | 43 |
| RIP:rcu_irq_exit | 0 | 43 |
| WARNING:at_kernel/rcu/tree.c:#rcu_irq_enter | 0 | 43 |
| RIP:rcu_irq_enter | 0 | 43 |
| WARNING:at_kernel/rcu/tree.c:#rcu_eqs_enter_common | 0 | 43 |
| RIP:rcu_eqs_enter_common | 0 | 43 |
+----------------------------------------------------+------------+------------+
[ 0.001000] WARNING: CPU: 0 PID: 0 at kernel/rcu/tree.c:892 rcu_irq_exit+0x4d/0x19a
[ 0.001000] Modules linked in:
[ 0.001000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc7-00430-g8e130b0 #35
[ 0.001000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[ 0.001000] RIP: 0010:rcu_irq_exit+0x4d/0x19a
[ 0.001000] RSP: 0000:ffffffff92803e18 EFLAGS: 00010082
[ 0.001000] RAX: 000000000000001d RBX: 0000000000000082 RCX: 70a3d70a3d70a3e0
[ 0.001000] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000046
[ 0.001000] RBP: ffffffff910fa412 R08: 00000000c5610c9a R09: 0000000000000004
[ 0.001000] R10: 0000000000000001 R11: ffffffff93dc0469 R12: 0000000000000000
[ 0.001000] R13: ffffffff93dc0880 R14: 0000000000000002 R15: 0000000000000048
[ 0.001000] FS: 0000000000000000(0000) GS:ffff8bfa5f600000(0000) knlGS:0000000000000000
[ 0.001000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.001000] CR2: 00000000ffffffff CR3: 0000000009824000 CR4: 00000000000006b0
[ 0.001000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 0.001000] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 0.001000] Call Trace:
[ 0.001000] ? vprintk_emit+0x26c/0x29c
[ 0.001000] rcu_irq_exit_irqson+0x21/0x48
[ 0.001000] trace_hardirqs_on+0xc2/0xd0
[ 0.001000] vprintk_emit+0x26c/0x29c
[ 0.001000] printk+0x43/0x4b
[ 0.001000] lockdep_init+0x36/0xcf
[ 0.001000] start_kernel+0x2fd/0x416
[ 0.001000] secondary_startup_64+0xa5/0xb0
[ 0.001000] Code: 08 00 00 00 75 27 83 b8 88 08 00 00 00 74 1e 80 3d ef 68 8c 01 00 75 15 48 c7 c7 a9 e3 5e 92 c6 05 df 68 8c 01 01 e8 31 9d f8 ff <0f> ff 48 c7 c5 a0 9d 1d 00 65 48 03 2d 70 cf ef 6e 83 7d 08 00
[ 0.001000] ---[ end trace 2507864299958132 ]---
To reproduce:
git clone https://github.com/intel/lkp-tests.git
cd lkp-tests
bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email
Thanks,
lkp