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| author |   Paul E. McKenney <paulmck@linux.ibm.com> | 2019-07-08 08:01:50 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-08-01 14:07:41 -0700 |
| commit | 0500873de968df6fdef5752d7bbdca317ddc220b (patch) | |
| tree | e0d627a5c71019afb30a58959f8d64903f0e5b6f /Documentation/RCU | |
| parent | rcu: Change return type of rcu_spawn_one_boost_kthread() (diff) | |
| download | linux-dev-0500873de968df6fdef5752d7bbdca317ddc220b.tar.xz linux-dev-0500873de968df6fdef5752d7bbdca317ddc220b.zip | |
doc: Add rcutree.kthread_prio pointer to stallwarn.txt
This commit adds mention of the rcutree.kthread_prio kernel boot parameter
to the discussion of how high-priority real-time tasks can result in
RCU CPU stall warnings. (However, this does not necessarily help when
the high-priority real-time tasks are using dubious deadlines.)
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'Documentation/RCU')
| -rw-r--r-- | Documentation/RCU/stallwarn.txt | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt index 13e88fc00f01..f48f4621ccbc 100644 --- a/Documentation/RCU/stallwarn.txt +++ b/Documentation/RCU/stallwarn.txt @@ -57,6 +57,12 @@ o A CPU-bound real-time task in a CONFIG_PREEMPT_RT kernel that CONFIG_PREEMPT_RCU case, you might see stall-warning messages. + You can use the rcutree.kthread_prio kernel boot parameter to + increase the scheduling priority of RCU's kthreads, which can + help avoid this problem. However, please note that doing this + can increase your system's context-switch rate and thus degrade + performance. + o A periodic interrupt whose handler takes longer than the time interval between successive pairs of interrupts. This can prevent RCU's kthreads and softirq handlers from running. |