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authorAristeu Rozanski <aris@redhat.com>2008-10-30 13:08:50 -0400
committerIngo Molnar <mingo@elte.hu>2008-10-30 19:07:04 +0100
commit8a1c8eb75be492e20003966652c9cd5ff57a559d (patch)
tree9cd97cc9f80fa538017a2ed741de7393876aba08
parentb062f841b569791d3054e975cd85f48562161565 (diff)
x86, nmi-watchdog: update procfs nmi_watchdog file documentation v2
Impact: improve documentation This patch updates the /proc/sys/kernel/nmi_watchdog documentation. Updated: included Randy Dunlap's corrections. Signed-off-by: Aristeu Rozanski <aris@redhat.com> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--Documentation/filesystems/proc.txt9
-rw-r--r--Documentation/nmi_watchdog.txt5
2 files changed, 11 insertions, 3 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index bcceb99b81d..86be879ed70 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -1338,10 +1338,13 @@ nmi_watchdog
Enables/Disables the NMI watchdog on x86 systems. When the value is non-zero
the NMI watchdog is enabled and will continuously test all online cpus to
-determine whether or not they are still functioning properly.
+determine whether or not they are still functioning properly. Currently,
+passing "nmi_watchdog=" parameter at boot time is required for this function
+to work.
-Because the NMI watchdog shares registers with oprofile, by disabling the NMI
-watchdog, oprofile may have more registers to utilize.
+If LAPIC NMI watchdog method is in use (nmi_watchdog=2 kernel parameter), the
+NMI watchdog shares registers with oprofile. By disabling the NMI watchdog,
+oprofile may have more registers to utilize.
msgmni
------
diff --git a/Documentation/nmi_watchdog.txt b/Documentation/nmi_watchdog.txt
index 90aa4531cb6..bf9f80a9828 100644
--- a/Documentation/nmi_watchdog.txt
+++ b/Documentation/nmi_watchdog.txt
@@ -69,6 +69,11 @@ to the overall system performance.
On x86 nmi_watchdog is disabled by default so you have to enable it with
a boot time parameter.
+It's possible to disable the NMI watchdog in run-time by writing "0" to
+/proc/sys/kernel/nmi_watchdog. Writing "1" to the same file will re-enable
+the NMI watchdog. Notice that you still need to use "nmi_watchdog=" parameter
+at boot time.
+
NOTE: In kernels prior to 2.4.2-ac18 the NMI-oopser is enabled unconditionally
on x86 SMP boxes.