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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-04-20 10:27:15 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-05-27 12:59:04 -0700
commit7fa270010e0ddd3693381431f373b3e3135b0695 (patch)
tree896b3eaa0bbc48b80ca45b4e01711699e7e1199f /Documentation
parent7db21edfecb079b2257ced7a2cf2e32ae5e5d966 (diff)
downloadlwn-7fa270010e0ddd3693381431f373b3e3135b0695.tar.gz
lwn-7fa270010e0ddd3693381431f373b3e3135b0695.zip
rcu: Convert CONFIG_RCU_FANOUT_EXACT to boot parameter
The CONFIG_RCU_FANOUT_EXACT Kconfig parameter is used primarily (and perhaps only) by rcutorture to verify that RCU works correctly in specific rcu_node combining-tree configurations. It therefore does not make much sense have this as a question to people attempting to configure their kernels. So this commit creates an rcutree.rcu_fanout_exact= boot parameter that rcutorture can use, and eliminates the original CONFIG_RCU_FANOUT_EXACT Kconfig parameter. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kernel-parameters.txt6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 10a4fb80c033..f5582dcdf80d 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3010,6 +3010,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
the rcu_node combining tree. This only has effect
when CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT is set.
+ rcutree.rcu_fanout_exact= [KNL]
+ Disable autobalancing of the rcu_node combining
+ tree. This is used by rcutorture, and might
+ possibly be useful for architectures having high
+ cache-to-cache transfer latencies.
+
rcutree.rcu_fanout_leaf= [KNL]
Increase the number of CPUs assigned to each
leaf rcu_node structure. Useful for very large