From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: [PATCH v3 11/22] perf,tracing: Prepare the perf-trace interface for RCU changes Date: Wed, 19 Feb 2020 15:47:35 +0100 Message-ID: <20200219150745.003368327@infradead.org> References: <20200219144724.800607165@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from merlin.infradead.org ([205.233.59.134]:52030 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727806AbgBSPOh (ORCPT ); Wed, 19 Feb 2020 10:14:37 -0500 Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rostedt@goodmis.org Cc: peterz@infradead.org, mingo@kernel.org, joel@joelfernandes.org, gregkh@linuxfoundation.org, gustavo@embeddedor.com, tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, luto@kernel.org, tony.luck@intel.com, frederic@kernel.org, dan.carpenter@oracle.com, mhiramat@kernel.org, "Steven Rostedt (VMware)" The tracepoint interface will stop providing regular RCU context; make sure we do it ourselves, since perf makes use of regular RCU protected data. Suggested-by: Steven Rostedt (VMware) Suggested-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) --- kernel/events/core.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8950,6 +8950,7 @@ void perf_tp_event(u16 event_type, u64 c { struct perf_sample_data data; struct perf_event *event; + unsigned long rcu_flags; struct perf_raw_record raw = { .frag = { @@ -8961,6 +8962,8 @@ void perf_tp_event(u16 event_type, u64 c perf_sample_data_init(&data, 0, 0); data.raw = &raw; + rcu_flags = trace_rcu_enter(); + perf_trace_buf_update(record, event_type); hlist_for_each_entry_rcu(event, head, hlist_entry) { @@ -8996,6 +8999,8 @@ void perf_tp_event(u16 event_type, u64 c } perf_swevent_put_recursion_context(rctx); + + trace_rcu_exit(rcu_flags); } EXPORT_SYMBOL_GPL(perf_tp_event);