From a00e0d714fbded07a7a2254391ce9ed5a5cb9d82 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 8 Feb 2011 17:14:39 -0800 Subject: rcu: Remove conditional compilation for RCU CPU stall warnings The RCU CPU stall warnings can now be controlled using the rcu_cpu_stall_suppress boot-time parameter or via the same parameter from sysfs. There is therefore no longer any reason to have kernel config parameters for this feature. This commit therefore removes the RCU_CPU_STALL_DETECTOR and RCU_CPU_STALL_DETECTOR_RUNNABLE kernel config parameters. The RCU_CPU_STALL_TIMEOUT parameter remains to allow the timeout to be tuned and the RCU_CPU_STALL_VERBOSE parameter remains to allow task-stall information to be suppressed if desired. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- lib/Kconfig.debug | 30 ++---------------------------- 1 file changed, 2 insertions(+), 28 deletions(-) (limited to 'lib') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c768bcdda1b7..93ce6de3300d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -875,22 +875,9 @@ 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_CPU_STALL_DETECTOR - bool "Check for stalled CPUs delaying RCU grace periods" - depends on TREE_RCU || TREE_PREEMPT_RCU - default y - help - This option causes RCU to printk information on which - CPUs are delaying the current grace period, but only when - the grace period extends for excessive time periods. - - Say N if you want to disable such checks. - - Say Y if you are unsure. - config RCU_CPU_STALL_TIMEOUT int "RCU CPU stall timeout in seconds" - depends on RCU_CPU_STALL_DETECTOR + depends on TREE_RCU || TREE_PREEMPT_RCU range 3 300 default 60 help @@ -899,22 +886,9 @@ config RCU_CPU_STALL_TIMEOUT RCU grace period persists, additional CPU stall warnings are printed at more widely spaced intervals. -config RCU_CPU_STALL_DETECTOR_RUNNABLE - bool "RCU CPU stall checking starts automatically at boot" - depends on RCU_CPU_STALL_DETECTOR - default y - help - If set, start checking for RCU CPU stalls immediately on - boot. Otherwise, RCU CPU stall checking must be manually - enabled. - - Say Y if you are unsure. - - Say N if you wish to suppress RCU CPU stall checking during boot. - config RCU_CPU_STALL_VERBOSE bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR" - depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU + depends on TREE_PREEMPT_RCU default y help This option causes RCU to printk detailed per-task information -- cgit v1.2.3-58-ga151 From fc2ecf7ec76c5ee150b83dcefc863fa03fd365fb Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Wed, 23 Feb 2011 09:42:14 -0800 Subject: rcu: Enable DEBUG_OBJECTS_RCU_HEAD from !PREEMPT The prohibition of DEBUG_OBJECTS_RCU_HEAD from !PREEMPT was due to the fixup actions. So just produce a warning from !PREEMPT. Signed-off-by: Mathieu Desnoyers Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- kernel/rcupdate.c | 26 +++++++++++++++++++++----- lib/Kconfig.debug | 2 +- 2 files changed, 22 insertions(+), 6 deletions(-) (limited to 'lib') diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index f3240e987928..b54d6d18258c 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -142,7 +142,14 @@ static int rcuhead_fixup_init(void *addr, enum debug_obj_state state) * Ensure that queued callbacks are all executed. * If we detect that we are nested in a RCU read-side critical * section, we should simply fail, otherwise we would deadlock. + * In !PREEMPT configurations, there is no way to tell if we are + * in a RCU read-side critical section or not, so we never + * attempt any fixup and just print a warning. */ +#ifndef CONFIG_PREEMPT + WARN_ON(1); + return 0; +#endif if (rcu_preempt_depth() != 0 || preempt_count() != 0 || irqs_disabled()) { WARN_ON(1); @@ -184,7 +191,14 @@ static int rcuhead_fixup_activate(void *addr, enum debug_obj_state state) * Ensure that queued callbacks are all executed. * If we detect that we are nested in a RCU read-side critical * section, we should simply fail, otherwise we would deadlock. + * In !PREEMPT configurations, there is no way to tell if we are + * in a RCU read-side critical section or not, so we never + * attempt any fixup and just print a warning. */ +#ifndef CONFIG_PREEMPT + WARN_ON(1); + return 0; +#endif if (rcu_preempt_depth() != 0 || preempt_count() != 0 || irqs_disabled()) { WARN_ON(1); @@ -214,12 +228,14 @@ static int rcuhead_fixup_free(void *addr, enum debug_obj_state state) * Ensure that queued callbacks are all executed. * If we detect that we are nested in a RCU read-side critical * section, we should simply fail, otherwise we would deadlock. - * Note that the machinery to reliably determine whether - * or not we are in an RCU read-side critical section - * exists only in the preemptible RCU implementations - * (TINY_PREEMPT_RCU and TREE_PREEMPT_RCU), which is why - * DEBUG_OBJECTS_RCU_HEAD is disallowed if !PREEMPT. + * In !PREEMPT configurations, there is no way to tell if we are + * in a RCU read-side critical section or not, so we never + * attempt any fixup and just print a warning. */ +#ifndef CONFIG_PREEMPT + WARN_ON(1); + return 0; +#endif if (rcu_preempt_depth() != 0 || preempt_count() != 0 || irqs_disabled()) { WARN_ON(1); diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 93ce6de3300d..3aa278046d78 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -337,7 +337,7 @@ config DEBUG_OBJECTS_WORK config DEBUG_OBJECTS_RCU_HEAD bool "Debug RCU callbacks objects" - depends on DEBUG_OBJECTS && PREEMPT + depends on DEBUG_OBJECTS help Enable this to turn on debugging of RCU list heads (call_rcu() usage). -- cgit v1.2.3-58-ga151