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| author | Paul E. McKenney <paulmck@kernel.org> | 2021-09-27 19:54:22 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-12-01 02:23:06 +0100 |
| commit | db4cb76861282604cf14fb362f507bb587d676ba (patch) | |
| tree | 279a84f3c698df8ad01e3dbeef50362f6aed2d99 /Documentation/admin-guide/kernel-per-CPU-kthreads.rst | |
| parent | rcutorture: Add CONFIG_PREEMPT_DYNAMIC=n to tiny scenarios (diff) | |
| download | linux-db4cb76861282604cf14fb362f507bb587d676ba.tar.xz linux-db4cb76861282604cf14fb362f507bb587d676ba.zip | |
doc: Remove obsolete kernel-per-CPU-kthreads RCU_FAST_NO_HZ advice
This document advises building with both CONFIG_NO_HZ=y and
CONFIG_RCU_FAST_NO_HZ=y. However, CONFIG_NO_HZ=y offloads callbacks from
all nohz_full CPUs, and CPUs with offloaded callbacks do not benefit from
CONFIG_RCU_FAST_NO_HZ=y. Quite the opposite: CONFIG_RCU_FAST_NO_HZ=y
simply adds a bit of idle entry/exit overhead.
This commit therefore changes that advice to only CONFIG_NO_HZ=y.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'Documentation/admin-guide/kernel-per-CPU-kthreads.rst')
| -rw-r--r-- | Documentation/admin-guide/kernel-per-CPU-kthreads.rst | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/Documentation/admin-guide/kernel-per-CPU-kthreads.rst b/Documentation/admin-guide/kernel-per-CPU-kthreads.rst index 5e51ee5b0358..e4a5fc26f1a9 100644 --- a/Documentation/admin-guide/kernel-per-CPU-kthreads.rst +++ b/Documentation/admin-guide/kernel-per-CPU-kthreads.rst @@ -208,7 +208,7 @@ Do at least one of the following: 2. Enable RCU to do its processing remotely via dyntick-idle by doing all of the following: - a. Build with CONFIG_NO_HZ=y and CONFIG_RCU_FAST_NO_HZ=y. + a. Build with CONFIG_NO_HZ=y. b. Ensure that the CPU goes idle frequently, allowing other CPUs to detect that it has passed through an RCU quiescent state. If the kernel is built with CONFIG_NO_HZ_FULL=y, |