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authorPaul E. McKenney <paulmck@kernel.org>2021-04-07 15:21:32 -0700
committerPaul E. McKenney <paulmck@kernel.org>2021-05-10 16:22:54 -0700
commit4d80b8e196fad9852050f3c8624eea09a6bbeada (patch)
tree0693cabb9fdcf73da9c4f4ca1c4a97089bade546 /kernel/rcu/Kconfig.debug
parentrcu: Make show_rcu_gp_kthreads() dump rcu_node structures blocking GP (diff)
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linux-dev-4d80b8e196fad9852050f3c8624eea09a6bbeada.zip
rcu: Restrict RCU_STRICT_GRACE_PERIOD to at most four CPUs
Kernels built with CONFIG_RCU_STRICT_GRACE_PERIOD=y can experience significant lock contention due to RCU's resulting focus on ending grace periods as soon as possible. This is OK, but only if there are not very many CPUs. This commit therefore puts this Kconfig option off-limits to systems with more than four CPUs. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu/Kconfig.debug')
-rw-r--r--kernel/rcu/Kconfig.debug2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
index 1942c1f1bb65..4fd64999300f 100644
--- a/kernel/rcu/Kconfig.debug
+++ b/kernel/rcu/Kconfig.debug
@@ -116,7 +116,7 @@ config RCU_EQS_DEBUG
config RCU_STRICT_GRACE_PERIOD
bool "Provide debug RCU implementation with short grace periods"
- depends on DEBUG_KERNEL && RCU_EXPERT
+ depends on DEBUG_KERNEL && RCU_EXPERT && NR_CPUS <= 4
default n
select PREEMPT_COUNT if PREEMPT=n
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