Document panic_on_unrecovered_nmi sysctl

This adds "panic_on_unrecovered_nmi" sysctl to
Documentation/filesystems/proc.txt. The text is mainly taken from
http://readlist.com/lists/vger.kernel.org/linux-kernel/43/217998.html.

Signed-off-by: Bernhard Walle <bwalle@suse.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 12 insertions, 0 deletions

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index f566ad9bcb7b..d2f77d959561 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -1322,6 +1322,18 @@ debugging information is displayed on console.
 NMI switch that most IA32 servers have fires unknown NMI up, for example.
 If a system hangs up, try pressing the NMI switch.
 
+panic_on_unrecovered_nmi
+------------------------
+
+The default Linux behaviour on an NMI of either memory or unknown is to continue
+operation. For many environments such as scientific computing it is preferable
+that the box is taken out and the error dealt with than an uncorrected
+parity/ECC error get propogated.
+
+A small number of systems do generate NMI's for bizarre random reasons such as
+power management so the default is off. That sysctl works like the existing
+panic controls already in that directory.
+
 nmi_watchdog
 ------------