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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2008-06-18 12:26:49 -0400
committerIngo Molnar <mingo@elte.hu>2008-06-19 05:22:15 -0400
commit31a72bce0bd6f3e0114009288bccbc96376eeeca (patch)
tree14a817fbe0b47511d3119360c47959d48f851140 /lib
parentd120f65f3aaf306c957bc4c82e510f5b0f1e9b27 (diff)
rcu: make rcutorture more vicious: reinstate boot-time testing
This patch re-institutes the ability to build rcutorture directly into the Linux kernel. The reason that this capability was removed was that this could result in your kernel being pretty much useless, as rcutorture would be running starting from early boot. This problem has been avoided by (1) making rcutorture run only three seconds of every six by default, (2) adding a CONFIG_RCU_TORTURE_TEST_RUNNABLE that permits rcutorture to be quiesced at boot time, and (3) adding a sysctl in /proc named /proc/sys/kernel/rcutorture_runnable that permits rcutorture to be quiesced and unquiesced when built into the kernel. Please note that this /proc file is -not- available when rcutorture is built as a module. Please also note that to get the earlier take-no-prisoners behavior, you must use the boot command line to set rcutorture's "stutter" parameter to zero. The rcutorture quiescing mechanism is currently quite crude: loops in each rcutorture process that poll a global variable once per tick. Suggestions for improvement are welcome. The default action will be to reduce the polling rate to a few times per second. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Suggested-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig.debug21
1 files changed, 19 insertions, 2 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index f51ba2fa2662..c35a86a516a0 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -537,11 +537,28 @@ config RCU_TORTURE_TEST
537 on the RCU infrastructure. The kernel module may be built 537 on the RCU infrastructure. The kernel module may be built
538 after the fact on the running kernel to be tested, if desired. 538 after the fact on the running kernel to be tested, if desired.
539 539
540 Say Y here if you want RCU torture tests to start automatically 540 Say Y here if you want RCU torture tests to be built into
541 at boot time (you probably don't). 541 the kernel.
542 Say M if you want the RCU torture tests to build as a module. 542 Say M if you want the RCU torture tests to build as a module.
543 Say N if you are unsure. 543 Say N if you are unsure.
544 544
545config RCU_TORTURE_TEST_RUNNABLE
546 bool "torture tests for RCU runnable by default"
547 depends on RCU_TORTURE_TEST = y
548 default n
549 help
550 This option provides a way to build the RCU torture tests
551 directly into the kernel without them starting up at boot
552 time. You can use /proc/sys/kernel/rcutorture_runnable
553 to manually override this setting. This /proc file is
554 available only when the RCU torture tests have been built
555 into the kernel.
556
557 Say Y here if you want the RCU torture tests to start during
558 boot (you probably don't).
559 Say N here if you want the RCU torture tests to start only
560 after being manually enabled via /proc.
561
545config KPROBES_SANITY_TEST 562config KPROBES_SANITY_TEST
546 bool "Kprobes sanity tests" 563 bool "Kprobes sanity tests"
547 depends on DEBUG_KERNEL 564 depends on DEBUG_KERNEL