Re: [PATCH RFC v2 3/3] drivers: irqchip: pdc: log PDC info in FTRACE

From: Lina Iyer
Date: Mon Feb 05 2018 - 10:19:01 EST


On Fri, Feb 02 2018 at 23:02 +0000, Lina Iyer wrote:
On Fri, Feb 02 2018 at 15:57 +0000, Thomas Gleixner wrote:
On Fri, 2 Feb 2018, Lina Iyer wrote:
+++ b/include/trace/events/pdc.h
@@ -0,0 +1,55 @@
+/* Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.

Can you please use the proper SPDX identifiers instead of the boiler plate?
Same for the driver source file.

Sure.

+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM pdc
+
+#if !defined(_TRACE_PDC_) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PDC_H_
+
+#include <linux/tracepoint.h>
+
+#define PDC_ENTRY 1
+#define PDC_TYPE_CONFIG 2
+
+TRACE_EVENT(irq_pin_config,

This is really a too generic name for a PDC specific breakpoint.

Hmm.. right.

Aside of that the question is whether this really justifies a trace
point. Wouldn't it be sufficient to use the GENERIC_IRQ_DEBUGFS
infrastructure to make this accessible via debugfs?


Some product configurations disable debugfs. I will ask around if this
can be dropped.

Memory dumps after a crash have support for FTRACE and it helps greatly
on production issues. Hence the preference for FTRACE support.

-- Lina