doc: admin-guide: remove explanation of "watchdog/%u"

"watchdog/%u" threads has be replaced by cpu_stop_work,
which will mislead the reader.

Signed-off-by: Wang Qing <wangqing@vivo.com>
Link: https://lore.kernel.org/r/1615801744-31548-1-git-send-email-wangqing@vivo.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

diff --git a/Documentation/admin-guide/kernel-per-CPU-kthreads.rst b/Documentation/admin-guide/kernel-per-CPU-kthreads.rst
index 531f689311f24745531a6d835a4bee920014bbfe..5e51ee5b03589fc9b538daaeb2289fd85f5ce609 100644 (file)
--- a/Documentation/admin-guide/kernel-per-CPU-kthreads.rst
+++ b/Documentation/admin-guide/kernel-per-CPU-kthreads.rst
@@ -332,23 +332,3 @@ To reduce its OS jitter, do at least one of the following:
        kthreads from being created in the first place.  However, please
        note that this will not eliminate OS jitter, but will instead
        shift it to RCU_SOFTIRQ.
-
-Name:
-  watchdog/%u
-
-Purpose:
-  Detect software lockups on each CPU.
-
-To reduce its OS jitter, do at least one of the following:
-
-1.     Build with CONFIG_LOCKUP_DETECTOR=n, which will prevent these
-       kthreads from being created in the first place.
-2.     Boot with "nosoftlockup=0", which will also prevent these kthreads
-       from being created.  Other related watchdog and softlockup boot
-       parameters may be found in Documentation/admin-guide/kernel-parameters.rst
-       and Documentation/watchdog/watchdog-parameters.rst.
-3.     Echo a zero to /proc/sys/kernel/watchdog to disable the
-       watchdog timer.
-4.     Echo a large number of /proc/sys/kernel/watchdog_thresh in
-       order to reduce the frequency of OS jitter due to the watchdog
-       timer down to a level that is acceptable for your workload.