Messages in this thread Patch in this message | | | Date | Mon, 21 Apr 2008 17:47:43 -0700 | From | "Paul E. McKenney" <> | Subject | [PATCH 3/5] Add rcu_barrier_sched() and rcu_barrier_bh() |
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Add rcu_barrier_sched() and rcu_barrier_bh(). With these in place, rcutorture no longer gives the occasional oops when repeatedly starting and stopping torturing rcu_bh. Also adds the API needed to flush out pre-existing call_rcu_sched() callbacks.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> ---
include/linux/rcupdate.h | 2 + kernel/rcupdate.c | 55 +++++++++++++++++++++++++++++++++++++++++------ 2 files changed, 51 insertions(+), 6 deletions(-)
diff -urpNa -X dontdiff linux-2.6.25-C2-rcuclassic-fixes/include/linux/rcupdate.h linux-2.6.25-C3-rcu_barrier_sched/include/linux/rcupdate.h --- linux-2.6.25-C2-rcuclassic-fixes/include/linux/rcupdate.h 2008-04-17 08:10:33.000000000 -0700 +++ linux-2.6.25-C3-rcu_barrier_sched/include/linux/rcupdate.h 2008-04-21 11:33:07.000000000 -0700 @@ -260,6 +260,8 @@ extern void call_rcu_bh(struct rcu_head /* Exported common interfaces */ extern void synchronize_rcu(void); extern void rcu_barrier(void); +extern void rcu_barrier_bh(void); +extern void rcu_barrier_sched(void); extern long rcu_batches_completed(void); extern long rcu_batches_completed_bh(void); diff -urpNa -X dontdiff linux-2.6.25-C2-rcuclassic-fixes/kernel/rcupdate.c linux-2.6.25-C3-rcu_barrier_sched/kernel/rcupdate.c --- linux-2.6.25-C2-rcuclassic-fixes/kernel/rcupdate.c 2008-04-17 08:10:33.000000000 -0700 +++ linux-2.6.25-C3-rcu_barrier_sched/kernel/rcupdate.c 2008-04-21 11:33:08.000000000 -0700 @@ -45,6 +45,12 @@ #include <linux/mutex.h> #include <linux/module.h> +enum rcu_barrier { + RCU_BARRIER_STD, + RCU_BARRIER_BH, + RCU_BARRIER_SCHED, +}; + static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL}; static atomic_t rcu_barrier_cpu_count; static DEFINE_MUTEX(rcu_barrier_mutex); @@ -83,19 +89,30 @@ static void rcu_barrier_callback(struct /* * Called with preemption disabled, and from cross-cpu IRQ context. */ -static void rcu_barrier_func(void *notused) +static void rcu_barrier_func(void *type) { int cpu = smp_processor_id(); struct rcu_head *head = &per_cpu(rcu_barrier_head, cpu); atomic_inc(&rcu_barrier_cpu_count); - call_rcu(head, rcu_barrier_callback); + switch ((enum rcu_barrier)type) { + case RCU_BARRIER_STD: + call_rcu(head, rcu_barrier_callback); + break; + case RCU_BARRIER_BH: + call_rcu_bh(head, rcu_barrier_callback); + break; + case RCU_BARRIER_SCHED: + call_rcu_sched(head, rcu_barrier_callback); + break; + } } -/** - * rcu_barrier - Wait until all the in-flight RCUs are complete. +/* + * Orchestrate the specified type of RCU barrier, waiting for all + * RCU callbacks of the specified type to complete. */ -void rcu_barrier(void) +static void _rcu_barrier(enum rcu_barrier type) { BUG_ON(in_interrupt()); /* Take cpucontrol mutex to protect against CPU hotplug */ @@ -111,13 +128,39 @@ void rcu_barrier(void) * until all the callbacks are queued. */ rcu_read_lock(); - on_each_cpu(rcu_barrier_func, NULL, 0, 1); + on_each_cpu(rcu_barrier_func, (void *)type, 0, 1); rcu_read_unlock(); wait_for_completion(&rcu_barrier_completion); mutex_unlock(&rcu_barrier_mutex); } + +/** + * rcu_barrier - Wait until all in-flight call_rcu() callbacks complete. + */ +void rcu_barrier(void) +{ + _rcu_barrier(RCU_BARRIER_STD); +} EXPORT_SYMBOL_GPL(rcu_barrier); +/** + * rcu_barrier_bh - Wait until all in-flight call_rcu_bh() callbacks complete. + */ +void rcu_barrier_bh(void) +{ + _rcu_barrier(RCU_BARRIER_BH); +} +EXPORT_SYMBOL_GPL(rcu_barrier_bh); + +/** + * rcu_barrier_sched - Wait for in-flight call_rcu_sched() callbacks. + */ +void rcu_barrier_sched(void) +{ + _rcu_barrier(RCU_BARRIER_SCHED); +} +EXPORT_SYMBOL_GPL(rcu_barrier_sched); + void __init rcu_init(void) { __rcu_init();
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