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| author |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-01-22 18:24:08 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-03-11 13:22:38 -0700 |
| commit | 37745d281069682d901f00c0121949a7d224195f (patch) | |
| tree | 0c15fd487faa046a257336b4205572b066873ca7 /lib | |
| parent | rcu: Detect stalls caused by failure to propagate up rcu_node tree (diff) | |
| download | linux-dev-37745d281069682d901f00c0121949a7d224195f.tar.xz linux-dev-37745d281069682d901f00c0121949a7d224195f.zip | |
rcu: Provide diagnostic option to slow down grace-period initialization
Grace-period initialization normally proceeds quite quickly, so
that it is very difficult to reproduce races against grace-period
initialization. This commit therefore allows grace-period
initialization to be artificially slowed down, increasing
race-reproduction probability. A pair of new Kconfig parameters are
provided, CONFIG_RCU_TORTURE_TEST_SLOW_INIT to enable the slowdowns, and
CONFIG_RCU_TORTURE_TEST_SLOW_INIT_DELAY to specify the number of jiffies
of slowdown to apply. A boot-time parameter named rcutree.gp_init_delay
allows boot-time delay to be specified. By default, no delay will be
applied even if CONFIG_RCU_TORTURE_TEST_SLOW_INIT is set.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c5cefb3c009c..feee8dab441e 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1257,6 +1257,30 @@ config RCU_TORTURE_TEST_RUNNABLE Say N here if you want the RCU torture tests to start only after being manually enabled via /proc. +config RCU_TORTURE_TEST_SLOW_INIT + bool "Slow down RCU grace-period initialization to expose races" + depends on RCU_TORTURE_TEST + help + This option makes grace-period initialization block for a + few jiffies between initializing each pair of consecutive + rcu_node structures. This helps to expose races involving + grace-period initialization, in other words, it makes your + kernel less stable. It can also greatly increase grace-period + latency, especially on systems with large numbers of CPUs. + This is useful when torture-testing RCU, but in almost no + other circumstance. + + Say Y here if you want your system to crash and hang more often. + Say N if you want a sane system. + +config RCU_TORTURE_TEST_SLOW_INIT_DELAY + int "How much to slow down RCU grace-period initialization" + range 0 5 + default 0 + help + This option specifies the number of jiffies to wait between + each rcu_node structure initialization. + config RCU_CPU_STALL_TIMEOUT int "RCU CPU stall timeout in seconds" depends on RCU_STALL_COMMON |