Merge branches 'array.2015.05.27a', 'doc.2015.05.27a', 'fixes.2015.05.27a', 'hotplug...

[mirror_ubuntu-bionic-kernel.git] / Documentation / kernel-parameters.txt

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 61ab1628a057cc2c4d8b11d892d834f7e5f7773a..0b7f3e7a029cca56702f169f611e13c2cd889366 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2992,11 +2992,34 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        Set maximum number of finished RCU callbacks to
                        process in one batch.
 
+       rcutree.dump_tree=      [KNL]
+                       Dump the structure of the rcu_node combining tree
+                       out at early boot.  This is used for diagnostic
+                       purposes, to verify correct tree setup.
+
+       rcutree.gp_cleanup_delay=       [KNL]
+                       Set the number of jiffies to delay each step of
+                       RCU grace-period cleanup.  This only has effect
+                       when CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP is set.
+
        rcutree.gp_init_delay=  [KNL]
                        Set the number of jiffies to delay each step of
                        RCU grace-period initialization.  This only has
-                       effect when CONFIG_RCU_TORTURE_TEST_SLOW_INIT is
-                       set.
+                       effect when CONFIG_RCU_TORTURE_TEST_SLOW_INIT
+                       is set.
+
+       rcutree.gp_preinit_delay=       [KNL]
+                       Set the number of jiffies to delay each step of
+                       RCU grace-period pre-initialization, that is,
+                       the propagation of recent CPU-hotplug changes up
+                       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
@@ -3101,7 +3124,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        test, hence the "fake".
 
        rcutorture.nreaders= [KNL]
-                       Set number of RCU readers.
+                       Set number of RCU readers.  The value -1 selects
+                       N-1, where N is the number of CPUs.  A value
+                       "n" less than -1 selects N-n-2, where N is again
+                       the number of CPUs.  For example, -2 selects N
+                       (the number of CPUs), -3 selects N+1, and so on.
 
        rcutorture.object_debug= [KNL]
                        Enable debug-object double-call_rcu() testing.