linux-kernel - [PATCH v6 2/6] locking/lockdep: Display irq_context names in /proc/lockdep

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Date:   Thu,  6 Feb 2020 10:24:04 -0500
From:   Waiman Long <longman@...hat.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Will Deacon <will.deacon@....com>
Cc:     linux-kernel@...r.kernel.org, Bart Van Assche <bvanassche@....org>,
        Waiman Long <longman@...hat.com>
Subject: [PATCH v6 2/6] locking/lockdep: Display irq_context names in /proc/lockdep_chains

Currently, the irq_context field of a lock chains displayed in
/proc/lockdep_chains is just a number. It is likely that many people
may not know what a non-zero number means. To make the information more
useful, print the actual irq names ("softirq" and "hardirq") instead.

Signed-off-by: Waiman Long <longman@...hat.com>
---
 kernel/locking/lockdep_proc.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index 9bb6d2497b04..0f6842bcfba8 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -128,6 +128,13 @@ static int lc_show(struct seq_file *m, void *v)
 	struct lock_chain *chain = v;
 	struct lock_class *class;
 	int i;
+	static const char * const irq_strs[] = {
+		[0]			     = "0",
+		[LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq",
+		[LOCK_CHAIN_SOFTIRQ_CONTEXT] = "softirq",
+		[LOCK_CHAIN_SOFTIRQ_CONTEXT|
+		 LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq|softirq",
+	};
 
 	if (v == SEQ_START_TOKEN) {
 		if (nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)
@@ -136,7 +143,7 @@ static int lc_show(struct seq_file *m, void *v)
 		return 0;
 	}
 
-	seq_printf(m, "irq_context: %d\n", chain->irq_context);
+	seq_printf(m, "irq_context: %s\n", irq_strs[chain->irq_context]);
 
 	for (i = 0; i < chain->depth; i++) {
 		class = lock_chain_get_class(chain, i);
-- 
2.18.1