From: Nathan Zimmer <nzimmer@sgi.com>
Date: Wed, 20 Feb 2013 02:13:49 +0000 (+1100)
Subject: sched-proc-sched_stat-fails-on-very-very-large-machines-v2
X-Git-Tag: next-20130220~1^2~622
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=c3e55783c52e9ee4a1045d1d7c1ce01f258c5bff;p=karo-tx-linux.git

sched-proc-sched_stat-fails-on-very-very-large-machines-v2

v2: Took Andrew's suggestion to add comments, fix memleak

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>
---

diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
index 7eecdc7bb775..80226cc1798c 100644
--- a/kernel/sched/stats.c
+++ b/kernel/sched/stats.c
@@ -81,6 +81,13 @@ static int show_schedstat(struct seq_file *seq, void *v)
 	return 0;
 }
 
+/*
+ * 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 *schedstat_start(struct seq_file *file, loff_t *offset)
 {
 	unsigned long n = *offset;