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rcu: Remove *_SLOW_* Kconfig options

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The RCU_TORTURE_TEST_SLOW_PREINIT, RCU_TORTURE_TEST_SLOW_PREINIT_DELAY,
RCU_TORTURE_TEST_SLOW_PREINIT_DELAY, RCU_TORTURE_TEST_SLOW_INIT,
RCU_TORTURE_TEST_SLOW_INIT_DELAY, RCU_TORTURE_TEST_SLOW_CLEANUP,
and RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY Kconfig options are only
useful for torture testing, and there are the rcutree.gp_cleanup_delay,
rcutree.gp_init_delay, and rcutree.gp_preinit_delay kernel boot parameters
that rcutorture can use instead.  The effect of these parameters is to
artificially slow down grace period initialization and cleanup in order
to make some types of race conditions happen more often.

This commit therefore simplifies Tree RCU a bit by removing the Kconfig
options and adding the corresponding kernel parameters to rcutorture's
.boot files instead.  However, this commit also leaves out the kernel
parameters for TREE02, TREE04, and TREE07 in order to have about the
same number of tests slowed as not slowed.  TREE01, TREE03, TREE05,
and TREE06 are slowed, and the rest are not slowed.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2017-05-10 14:36:55 -07:00
parent a3883df393
commit 90040c9e30
16 changed files with 24 additions and 135 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
Documentation/admin-guide/kernel-parameters.txt
View File

@ -3229,21 +3229,17 @@
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.
RCU grace-period cleanup.
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.
RCU grace-period initialization.
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.
the rcu_node combining tree.
rcutree.rcu_fanout_exact= [KNL]
Disable autobalancing of the rcu_node combining

26
kernel/rcu/tree.c
View File

@ -177,26 +177,12 @@ module_param(kthread_prio, int, 0644);
/* Delay in jiffies for grace-period initialization delays, debug only. */
#ifdef CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT
static int gp_preinit_delay = CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT_DELAY;
module_param(gp_preinit_delay, int, 0644);
#else /* #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT */
static const int gp_preinit_delay;
#endif /* #else #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT */
#ifdef CONFIG_RCU_TORTURE_TEST_SLOW_INIT
static int gp_init_delay = CONFIG_RCU_TORTURE_TEST_SLOW_INIT_DELAY;
module_param(gp_init_delay, int, 0644);
#else /* #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_INIT */
static const int gp_init_delay;
#endif /* #else #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_INIT */
#ifdef CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP
static int gp_cleanup_delay = CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY;
module_param(gp_cleanup_delay, int, 0644);
#else /* #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP */
static const int gp_cleanup_delay;
#endif /* #else #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP */
static int gp_preinit_delay;
module_param(gp_preinit_delay, int, 0444);
static int gp_init_delay;
module_param(gp_init_delay, int, 0444);
static int gp_cleanup_delay;
module_param(gp_cleanup_delay, int, 0444);
/*
* Number of grace periods between delays, normalized by the duration of

6
kernel/rcu/tree_plugin.h
View File

@ -109,11 +109,11 @@ static void __init rcu_bootup_announce_oddness(void)
pr_info("\tKick kthreads if too-long grace period.\n");
if (IS_ENABLED(CONFIG_DEBUG_OBJECTS_RCU_HEAD))
pr_info("\tRCU callback double-/use-after-free debug enabled.\n");
if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT))
if (gp_preinit_delay)
pr_info("\tRCU debug GP pre-init slowdown %d jiffies.\n", gp_preinit_delay);
if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_SLOW_INIT))
if (gp_init_delay)
pr_info("\tRCU debug GP init slowdown %d jiffies.\n", gp_init_delay);
if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP))
if (gp_cleanup_delay)
pr_info("\tRCU debug GP init slowdown %d jiffies.\n", gp_cleanup_delay);
if (IS_ENABLED(CONFIG_RCU_EQS_DEBUG))
pr_info("\tRCU debug extended QS entry/exit.\n");

75
lib/Kconfig.debug
View File

@ -1373,81 +1373,6 @@ config RCU_TORTURE_TEST
Say M if you want the RCU torture tests to build as a module.
Say N if you are unsure.
config RCU_TORTURE_TEST_SLOW_PREINIT
bool "Slow down RCU grace-period pre-initialization to expose races"
depends on RCU_TORTURE_TEST
help
This option delays grace-period pre-initialization (the
propagation of CPU-hotplug changes up the rcu_node combining
tree) for a few jiffies between initializing each pair of
consecutive rcu_node structures. This helps to expose races
involving grace-period pre-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_PREINIT_DELAY
int "How much to slow down RCU grace-period pre-initialization"
range 0 5
default 3
depends on RCU_TORTURE_TEST_SLOW_PREINIT
help
This option specifies the number of jiffies to wait between
each rcu_node structure pre-initialization step.
config RCU_TORTURE_TEST_SLOW_INIT
bool "Slow down RCU grace-period initialization to expose races"
depends on RCU_TORTURE_TEST
help
This option delays grace-period initialization 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 3
depends on RCU_TORTURE_TEST_SLOW_INIT
help
This option specifies the number of jiffies to wait between
each rcu_node structure initialization.
config RCU_TORTURE_TEST_SLOW_CLEANUP
bool "Slow down RCU grace-period cleanup to expose races"
depends on RCU_TORTURE_TEST
help
This option delays grace-period cleanup for a few jiffies
between cleaning up each pair of consecutive rcu_node
structures. This helps to expose races involving grace-period
cleanup, 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_CLEANUP_DELAY
int "How much to slow down RCU grace-period cleanup"
range 0 5
default 3
depends on RCU_TORTURE_TEST_SLOW_CLEANUP
help
This option specifies the number of jiffies to wait between
each rcu_node structure cleanup operation.
config RCU_CPU_STALL_TIMEOUT
int "RCU CPU stall timeout in seconds"
depends on RCU_STALL_COMMON

3
tools/testing/selftests/rcutorture/configs/rcu/TREE01
View File

@ -17,6 +17,3 @@ CONFIG_DEBUG_LOCK_ALLOC=n
CONFIG_RCU_BOOST=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y

3
tools/testing/selftests/rcutorture/configs/rcu/TREE01.boot
View File

@ -1 +1,4 @@
rcutorture.torture_type=rcu_bh maxcpus=8
rcutree.gp_preinit_delay=3
rcutree.gp_init_delay=3
rcutree.gp_cleanup_delay=3

3
tools/testing/selftests/rcutorture/configs/rcu/TREE02
View File

@ -19,8 +19,5 @@ CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_PROVE_LOCKING=n
CONFIG_RCU_BOOST=n
CONFIG_RCU_EXPERT=y
CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y
CONFIG_DEBUG_OBJECTS=y
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y

3
tools/testing/selftests/rcutorture/configs/rcu/TREE03
View File

@ -17,6 +17,3 @@ CONFIG_RCU_BOOST=y
CONFIG_RCU_KTHREAD_PRIO=2
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y

3
tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot
View File

@ -1 +1,4 @@
rcutorture.onoff_interval=1 rcutorture.onoff_holdoff=30
rcutree.gp_preinit_delay=3
rcutree.gp_init_delay=3
rcutree.gp_cleanup_delay=3

3
tools/testing/selftests/rcutorture/configs/rcu/TREE04
View File

@ -18,7 +18,4 @@ CONFIG_RCU_FANOUT_LEAF=3
CONFIG_DEBUG_LOCK_ALLOC=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y
CONFIG_RCU_EQS_DEBUG=y

3
tools/testing/selftests/rcutorture/configs/rcu/TREE05
View File

@ -19,6 +19,3 @@ CONFIG_PROVE_LOCKING=y
#CHECK#CONFIG_PROVE_RCU=y
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y

3
tools/testing/selftests/rcutorture/configs/rcu/TREE05.boot
View File

@ -1,2 +1,5 @@
rcutorture.torture_type=sched
rcupdate.rcu_self_test_sched=1
rcutree.gp_preinit_delay=3
rcutree.gp_init_delay=3
rcutree.gp_cleanup_delay=3

3
tools/testing/selftests/rcutorture/configs/rcu/TREE06
View File

@ -21,6 +21,3 @@ CONFIG_PROVE_LOCKING=y
CONFIG_DEBUG_OBJECTS=y
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
CONFIG_RCU_EXPERT=y
CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y

3
tools/testing/selftests/rcutorture/configs/rcu/TREE06.boot
View File

@ -2,3 +2,6 @@ rcupdate.rcu_self_test=1
rcupdate.rcu_self_test_bh=1
rcupdate.rcu_self_test_sched=1
rcutree.rcu_fanout_exact=1
rcutree.gp_preinit_delay=3
rcutree.gp_init_delay=3
rcutree.gp_cleanup_delay=3

3
tools/testing/selftests/rcutorture/configs/rcu/TREE07
View File

@ -17,6 +17,3 @@ CONFIG_RCU_FANOUT_LEAF=2
CONFIG_DEBUG_LOCK_ALLOC=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y

9
tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
View File

@ -28,9 +28,6 @@ CONFIG_RCU_TRACE -- Do half.
CONFIG_SMP -- Need one !SMP for PREEMPT_RCU.
CONFIG_RCU_EXPERT=n -- Do a few, but these have to be vanilla configurations.
CONFIG_RCU_EQS_DEBUG -- Do at least one for CONFIG_NO_HZ_FULL and not.
CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP -- Do for all but a couple TREE scenarios.
CONFIG_RCU_TORTURE_TEST_SLOW_INIT -- Do for all but a couple TREE scenarios.
CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT -- Do for all but a couple TREE scenarios.
RCU-bh: Do one with PREEMPT and one with !PREEMPT.
RCU-sched: Do one with PREEMPT but not BOOST.
@ -78,12 +75,6 @@ CONFIG_RCU_TORTURE_TEST_RUNNABLE
Always used in KVM testing.
CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT_DELAY
CONFIG_RCU_TORTURE_TEST_SLOW_INIT_DELAY
CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY
Inspection suffices, ignore.
CONFIG_PREEMPT_RCU
CONFIG_TREE_RCU
CONFIG_TINY_RCU