From: Joel Fernandes <joelaf@google.com> To: linux-kernel@vger.kernel.org Cc: kernel-team@android.com, "Joel Fernandes (Google)" <joel@joelfernandes.org>, Boqun Feng <boqun.feng@gmail.com>, Byungchul Park <byungchul.park@lge.com>, Erick Reyes <erickreyes@google.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>, Shuah Khan <shuah@kernel.org>, Steven Rostedt <rostedt@goodmis.org>, Thomas Glexiner <tglx@linutronix.de>, Todd Kjos <tkjos@google.com>, Tom Zanussi <tom.zanussi@linux.intel.com> Subject: [PATCH v7 3/8] srcu: Add notrace variant of srcu_dereference Date: Wed, 23 May 2018 18:21:52 -0700 [thread overview] Message-ID: <20180524012157.181277-4-joel@joelfernandes.org> (raw) In-Reply-To: <20180524012157.181277-1-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 2ec618979b20..a1c4947be877 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -135,6 +135,11 @@ 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. -- 2.17.0.441.gb46fe60e1d-goog
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From: joelaf at google.com (Joel Fernandes) Subject: [PATCH v7 3/8] srcu: Add notrace variant of srcu_dereference Date: Wed, 23 May 2018 18:21:52 -0700 [thread overview] Message-ID: <20180524012157.181277-4-joel@joelfernandes.org> (raw) In-Reply-To: <20180524012157.181277-1-joel@joelfernandes.org> From: "Joel Fernandes (Google)" <joel at 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 at linux.vnet.ibm.com> Signed-off-by: Joel Fernandes (Google) <joel at 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 2ec618979b20..a1c4947be877 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -135,6 +135,11 @@ 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. -- 2.17.0.441.gb46fe60e1d-goog -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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From: joelaf@google.com (Joel Fernandes) Subject: [PATCH v7 3/8] srcu: Add notrace variant of srcu_dereference Date: Wed, 23 May 2018 18:21:52 -0700 [thread overview] Message-ID: <20180524012157.181277-4-joel@joelfernandes.org> (raw) Message-ID: <20180524012152.bCKGcQosnu_D3j6Az4PplgUZPN2JTJGiClOr9oxoaAY@z> (raw) In-Reply-To: <20180524012157.181277-1-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 at linux.vnet.ibm.com> Signed-off-by: Joel Fernandes (Google) <joel at 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 2ec618979b20..a1c4947be877 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -135,6 +135,11 @@ 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. -- 2.17.0.441.gb46fe60e1d-goog -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2018-05-24 1:22 UTC|newest] Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-05-24 1:21 [PATCH v7 0/8] Centralize and unify usage of preempt/irq tracepoints Joel Fernandes 2018-05-24 1:21 ` Joel Fernandes 2018-05-24 1:21 ` joelaf 2018-05-24 1:21 ` [PATCH v7 1/8] softirq: reorder trace_softirqs_on to prevent lockdep splat Joel Fernandes 2018-05-24 1:21 ` Joel Fernandes 2018-05-24 1:21 ` joelaf 2018-05-24 1:21 ` [PATCH v7 2/8] srcu: Add notrace variants of srcu_read_{lock,unlock} Joel Fernandes 2018-05-24 1:21 ` Joel Fernandes 2018-05-24 1:21 ` joelaf 2018-05-24 1:21 ` Joel Fernandes [this message] 2018-05-24 1:21 ` [PATCH v7 3/8] srcu: Add notrace variant of srcu_dereference Joel Fernandes 2018-05-24 1:21 ` joelaf 2018-05-24 1:21 ` [PATCH v7 4/8] trace/irqsoff: Split reset into separate functions Joel Fernandes 2018-05-24 1:21 ` Joel Fernandes 2018-05-24 1:21 ` joelaf 2018-05-24 1:21 ` [PATCH v7 5/8] tracepoint: Make rcuidle tracepoint callers use SRCU Joel Fernandes 2018-05-24 1:21 ` Joel Fernandes 2018-05-24 1:21 ` joelaf 2018-05-24 1:21 ` [PATCH v7 6/8] tracing: Centralize preemptirq tracepoints and unify their usage Joel Fernandes 2018-05-24 1:21 ` Joel Fernandes 2018-05-24 1:21 ` joelaf 2018-05-25 11:43 ` Namhyung Kim 2018-05-25 11:43 ` Namhyung Kim 2018-05-25 11:43 ` namhyung 2018-05-25 23:20 ` Joel Fernandes 2018-05-25 23:20 ` Joel Fernandes 2018-05-25 23:20 ` joel 2018-05-24 1:21 ` [PATCH v7 7/8] lib: Add module to simulate atomic sections for testing preemptoff tracers Joel Fernandes 2018-05-24 1:21 ` Joel Fernandes 2018-05-24 1:21 ` joelaf 2018-05-24 1:21 ` [PATCH v7 8/8] kselftests: Add tests for the preemptoff and irqsoff tracers Joel Fernandes 2018-05-24 1:21 ` Joel Fernandes 2018-05-24 1:21 ` joelaf
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