From: "Joel Fernandes (Google)" <joel@joelfernandes.org>
To: linux-kernel@vger.kernel.org
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
Ingo Molnar <mingo@redhat.com>,
Richard Fontana <rfontana@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>
Subject: [RFC 3/3] Revert "tracepoint: Make rcuidle tracepoint callers use SRCU"
Date: Fri, 7 Feb 2020 15:56:56 -0500 [thread overview]
Message-ID: <20200207205656.61938-4-joel@joelfernandes.org> (raw)
In-Reply-To: <20200207205656.61938-1-joel@joelfernandes.org>
This reverts commit e6753f23d961d601dbae50a2fc2a3975c9715b14.
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
include/linux/tracepoint.h | 40 ++++++++------------------------------
kernel/tracepoint.c | 10 +---------
2 files changed, 9 insertions(+), 41 deletions(-)
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index ab1f13b7f7d2c..b2b13cf03e092 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -13,7 +13,6 @@
*/
#include <linux/smp.h>
-#include <linux/srcu.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/cpumask.h>
@@ -32,8 +31,6 @@ struct trace_eval_map {
#define TRACEPOINT_DEFAULT_PRIO 10
-extern struct srcu_struct tracepoint_srcu;
-
extern int
tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
extern int
@@ -76,16 +73,10 @@ int unregister_tracepoint_module_notifier(struct notifier_block *nb)
* probe unregistration and the end of module exit to make sure there is no
* caller executing a probe when it is freed.
*/
-#ifdef CONFIG_TRACEPOINTS
static inline void tracepoint_synchronize_unregister(void)
{
- synchronize_srcu(&tracepoint_srcu);
synchronize_rcu();
}
-#else
-static inline void tracepoint_synchronize_unregister(void)
-{ }
-#endif
#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
extern int syscall_regfunc(void);
@@ -159,31 +150,18 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
* as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just
* "void *data", where as the DECLARE_TRACE() will pass in "void *data, proto".
*/
-#define __DO_TRACE(tp, proto, args, cond, rcuidle) \
+#define __DO_TRACE(tp, proto, args, cond, rcucheck) \
do { \
struct tracepoint_func *it_func_ptr; \
void *it_func; \
void *__data; \
- int __maybe_unused idx = 0; \
\
if (!(cond)) \
return; \
- \
- /* srcu can't be used from NMI */ \
- WARN_ON_ONCE(rcuidle && in_nmi()); \
- \
- /* keep srcu and sched-rcu usage consistent */ \
- preempt_disable_notrace(); \
- \
- /* \
- * For rcuidle callers, use srcu since sched-rcu \
- * doesn't work from the idle path. \
- */ \
- if (rcuidle) \
- idx = srcu_read_lock_notrace(&tracepoint_srcu); \
- \
- it_func_ptr = rcu_dereference_raw((tp)->funcs); \
- \
+ if (rcucheck) \
+ rcu_irq_enter_irqson(); \
+ rcu_read_lock_sched_notrace(); \
+ it_func_ptr = rcu_dereference_sched((tp)->funcs); \
if (it_func_ptr) { \
do { \
it_func = (it_func_ptr)->func; \
@@ -191,11 +169,9 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
((void(*)(proto))(it_func))(args); \
} while ((++it_func_ptr)->func); \
} \
- \
- if (rcuidle) \
- srcu_read_unlock_notrace(&tracepoint_srcu, idx);\
- \
- preempt_enable_notrace(); \
+ rcu_read_unlock_sched_notrace(); \
+ if (rcucheck) \
+ rcu_irq_exit_irqson(); \
} while (0)
#ifndef MODULE
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 73956eaff8a9c..df956fc23ca57 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -18,9 +18,6 @@
extern tracepoint_ptr_t __start___tracepoints_ptrs[];
extern tracepoint_ptr_t __stop___tracepoints_ptrs[];
-DEFINE_SRCU(tracepoint_srcu);
-EXPORT_SYMBOL_GPL(tracepoint_srcu);
-
/* Set to 1 to enable tracepoint debug output */
static const int tracepoint_debug;
@@ -60,14 +57,9 @@ static inline void *allocate_probes(int count)
return p == NULL ? NULL : p->probes;
}
-static void srcu_free_old_probes(struct rcu_head *head)
-{
- kfree(container_of(head, struct tp_probes, rcu));
-}
-
static void rcu_free_old_probes(struct rcu_head *head)
{
- call_srcu(&tracepoint_srcu, head, srcu_free_old_probes);
+ kfree(container_of(head, struct tp_probes, rcu));
}
static __init int release_early_probes(void)
--
2.25.0.341.g760bfbb309-goog
next prev parent reply other threads:[~2020-02-07 20:57 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-07 20:56 [RFC 0/3] Revert SRCU from tracepoint infrastructure Joel Fernandes (Google)
2020-02-07 20:56 ` [RFC 1/3] Revert "tracepoint: Use __idx instead of idx in DO_TRACE macro to make it unique" Joel Fernandes (Google)
2020-02-07 21:07 ` Steven Rostedt
2020-02-07 20:56 ` [RFC 2/3] Revert "tracing: Add back in rcu_irq_enter/exit_irqson() for rcuidle tracepoints" Joel Fernandes (Google)
2020-02-07 20:56 ` Joel Fernandes (Google) [this message]
2020-02-07 21:24 ` [RFC 0/3] Revert SRCU from tracepoint infrastructure Paul E. McKenney
2020-02-07 21:43 ` Joel Fernandes
2020-02-08 16:39 ` Mathieu Desnoyers
2020-02-08 16:31 ` Mathieu Desnoyers
2020-02-10 9:46 ` Peter Zijlstra
2020-02-10 10:19 ` Peter Zijlstra
2020-02-10 13:36 ` Paul E. McKenney
2020-02-10 13:44 ` Peter Zijlstra
2020-02-10 13:57 ` Paul E. McKenney
2020-02-10 17:17 ` Joel Fernandes
2020-02-10 17:05 ` Steven Rostedt
2020-02-10 17:33 ` Mathieu Desnoyers
2020-02-10 18:30 ` Steven Rostedt
2020-02-10 19:05 ` Mathieu Desnoyers
2020-02-10 19:53 ` Joel Fernandes
2020-02-10 20:03 ` Steven Rostedt
2020-02-10 20:30 ` Joel Fernandes
2020-02-10 18:07 ` Paul E. McKenney
2020-02-10 16:59 ` Joel Fernandes
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