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author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-03-11 01:33:20 (GMT) |
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committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-05-27 19:59:02 (GMT) |
commit | 0f41c0ddadfb3d5baffe62351c380e2881aacd58 (patch) | |
tree | d0e4b7585f3016f68b6f9afd23342c4dba7e8f93 /Documentation/kernel-parameters.txt | |
parent | 3eaaaf6cd6d7fbaf552cc543ccb93d7da81f43ec (diff) | |
download | linux-0f41c0ddadfb3d5baffe62351c380e2881aacd58.tar.xz |
rcu: Provide diagnostic option to slow down grace-period scans
Grace-period scans of the rcu_node combining tree normally
proceed quite quickly, so that it is very difficult to reproduce
races against them. This commit therefore allows grace-period
pre-initialization and cleanup to be artificially slowed down,
increasing race-reproduction probability. A pair of pairs of new
Kconfig parameters are provided, RCU_TORTURE_TEST_SLOW_PREINIT to
enable the slowing down of propagating CPU-hotplug changes up the
combining tree along with RCU_TORTURE_TEST_SLOW_PREINIT_DELAY to
specify the delay in jiffies, and RCU_TORTURE_TEST_SLOW_CLEANUP
to enable the slowing down of the end-of-grace-period cleanup scan
along with RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY to specify the delay
in jiffies. Boot-time parameters named rcutree.gp_preinit_delay and
rcutree.gp_cleanup_delay allow these delays to be specified at boot time.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
-rw-r--r-- | Documentation/kernel-parameters.txt | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 61ab162..10a4fb8 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2992,11 +2992,23 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Set maximum number of finished RCU callbacks to process in one batch. + 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_leaf= [KNL] Increase the number of CPUs assigned to each |