From 103dcbdd881086d40d095926094f31808a19befb Mon Sep 17 00:00:00 2001
From: Nathan Zimmer <nzimmer@sgi.com>
Date: Wed, 20 Feb 2013 13:13:51 +1100
Subject: [PATCH] sched-proc-sched_debug-fails-on-very-very-large-machines-v2

v2: Took suggetion for adding comments

Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 kernel/sched/debug.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 25be2dd939a5..1ed4c2dca389 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -406,6 +406,13 @@ void sysrq_sched_debug_show(void)
 
 }
 
+/*
+ * This itererator needs some explination.
+ * It returns 1 for the header position.
+ * This means 2 is cpu 0.
+ * In a hotplugged system some cpus, including cpu 0, may be missing so we have
+ * to use cpumask_* to iterate over the cpus.
+ */
 static void *sched_debug_start(struct seq_file *file, loff_t *offset)
 {
 	unsigned long n = *offset;
-- 
2.39.5