From: Joel Fernandes <joel@joelfernandes.org>
To: linux-kernel@vger.kernel.org
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>,
Boqun Feng <boqun.feng@gmail.com>,
Byungchul Park <byungchul.park@lge.com>,
Ingo Molnar <mingo@redhat.com>, Julia Cartwright <julia@ni.com>,
linux-kselftest@vger.kernel.org,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Namhyung Kim <namhyung@kernel.org>,
Paul McKenney <paulmck@linux.vnet.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Glexiner <tglx@linutronix.de>,
Tom Zanussi <tom.zanussi@linux.intel.com>
Subject: [PATCH v9 2/7] srcu: Add notrace variant of srcu_dereference
Date: Thu, 28 Jun 2018 11:21:44 -0700 [thread overview]
Message-ID: <20180628182149.226164-3-joel@joelfernandes.org> (raw)
In-Reply-To: <20180628182149.226164-1-joel@joelfernandes.org>
From: "Joel Fernandes (Google)" <joel@joelfernandes.org>
In the last patch in this series, we are making lockdep register hooks
onto the irq_{disable,enable} tracepoints. These tracepoints use the
_rcuidle tracepoint variant. In this series we switch the _rcuidle
tracepoint callers to use SRCU instead of sched-RCU. Inorder to
dereference the pointer to the probe functions, we could call
srcu_dereference, however this API will call back into lockdep to check
if the lock is held *before* the lockdep probe hooks have a chance to
run and annotate the IRQ enabled/disabled state.
For this reason we need a notrace variant of srcu_dereference since
otherwise we get lockdep splats. This patch adds the needed
srcu_dereference_notrace variant.
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
include/linux/srcu.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 3e72a291c401..67135d4a8a30 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -169,6 +169,11 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp)
*/
#define srcu_dereference(p, sp) srcu_dereference_check((p), (sp), 0)
+/**
+ * srcu_dereference_notrace - no tracing and no lockdep calls from here
+ */
+#define srcu_dereference_notrace(p, sp) srcu_dereference_check((p), (sp), 1)
+
/**
* srcu_read_lock - register a new reader for an SRCU-protected structure.
* @sp: srcu_struct in which to register the new reader.
--
2.18.0.rc2.346.g013aa6912e-goog
next prev parent reply other threads:[~2018-06-28 18:23 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-28 18:21 [PATCH v9 0/7] Centralize and unify usage of preempt/irq tracepoints Joel Fernandes
2018-06-28 18:21 ` [PATCH v9 1/7] srcu: Add notrace variants of srcu_read_{lock,unlock} Joel Fernandes
2018-06-28 18:21 ` Joel Fernandes [this message]
2018-06-28 18:21 ` [PATCH v9 3/7] trace/irqsoff: Split reset into separate functions Joel Fernandes
2018-06-28 18:21 ` [PATCH v9 4/7] tracepoint: Make rcuidle tracepoint callers use SRCU Joel Fernandes
2018-07-11 12:49 ` Peter Zijlstra
2018-07-11 13:00 ` Steven Rostedt
2018-07-11 14:27 ` Paul E. McKenney
2018-07-11 14:46 ` Steven Rostedt
2018-07-11 15:15 ` Paul E. McKenney
2018-07-11 20:56 ` Joel Fernandes
2018-07-12 1:22 ` Steven Rostedt
2018-07-12 2:35 ` Joel Fernandes
2018-07-11 20:52 ` Joel Fernandes
2018-07-12 3:21 ` Steven Rostedt
2018-07-12 4:28 ` Joel Fernandes
2018-07-12 13:35 ` Steven Rostedt
2018-07-12 19:17 ` Joel Fernandes
2018-07-12 20:15 ` Steven Rostedt
2018-07-12 20:29 ` Joel Fernandes
2018-07-12 20:31 ` Steven Rostedt
2018-07-11 12:53 ` Peter Zijlstra
2018-07-12 2:32 ` Joel Fernandes
2018-07-11 12:56 ` Peter Zijlstra
2018-07-11 13:06 ` Steven Rostedt
2018-07-11 15:17 ` Peter Zijlstra
2018-07-11 15:26 ` Steven Rostedt
2018-07-11 16:46 ` Mathieu Desnoyers
2018-07-11 16:40 ` Mathieu Desnoyers
2018-07-12 0:31 ` Joel Fernandes
2018-07-12 1:26 ` Steven Rostedt
2018-06-28 18:21 ` [PATCH v9 5/7] tracing: Centralize preemptirq tracepoints and unify their usage Joel Fernandes
2018-07-06 22:06 ` Steven Rostedt
2018-07-07 4:20 ` Joel Fernandes
2018-07-10 14:20 ` Steven Rostedt
2018-07-10 17:33 ` Joel Fernandes
2018-07-11 13:12 ` Peter Zijlstra
2018-07-11 13:19 ` Steven Rostedt
2018-07-11 13:22 ` Steven Rostedt
2018-07-12 8:38 ` Joel Fernandes
2018-07-12 13:37 ` Steven Rostedt
2018-07-12 0:44 ` Joel Fernandes
2018-06-28 18:21 ` [PATCH v9 6/7] lib: Add module to simulate atomic sections for testing preemptoff tracers Joel Fernandes
2018-07-11 0:47 ` Steven Rostedt
2018-07-11 5:26 ` Joel Fernandes
2018-06-28 18:21 ` [PATCH v9 7/7] kselftests: Add tests for the preemptoff and irqsoff tracers Joel Fernandes
2018-07-11 0:49 ` Steven Rostedt
2018-07-11 5:27 ` Joel Fernandes
2018-07-03 14:15 ` [PATCH v9 0/7] Centralize and unify usage of preempt/irq tracepoints Joel Fernandes
2018-07-03 14:23 ` Steven Rostedt
-- strict thread matches above, loose matches on Subject: below --
2018-06-21 22:32 Joel Fernandes
2018-06-21 22:32 ` [PATCH v9 2/7] srcu: Add notrace variant of srcu_dereference Joel Fernandes
2018-06-07 20:38 [PATCH v9 0/7] Centralize and unify usage of preempt/irq Joel Fernandes
2018-06-07 20:38 ` [PATCH v9 2/7] srcu: Add notrace variant of srcu_dereference Joel Fernandes
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