From 8b09dee67f484e9b42114b1a1f068e080fd7aa56 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 12 May 2008 21:21:05 +0200 Subject: rcupreempt: remove duplicate prototypes rcu_batches_completed and rcu_patches_completed_bh are both declared in rcuclassic.h and rcupreempt.h. This patch removes the extra prototypes for them from rcupdate.h. rcu_batches_completed_bh is defined as a static inline in the rcupreempt.h header file. Trying to export this as EXPORT_SYMBOL_GPL causes linking problems with the powerpc linker. There's no need to export a static inlined function. Modules must be compiled with the same type of RCU implementation as the kernel they are for. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- include/linux/rcupdate.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux/rcupdate.h') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index d42dbec06083..ec2fc5b32646 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -224,8 +224,6 @@ extern void call_rcu_bh(struct rcu_head *head, /* Exported common interfaces */ extern void synchronize_rcu(void); extern void rcu_barrier(void); -extern long rcu_batches_completed(void); -extern long rcu_batches_completed_bh(void); /* Internal to kernel */ extern void rcu_init(void); -- cgit v1.2.1 From 4446a36ff8c74ac3b32feb009b651048e129c6af Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 12 May 2008 21:21:05 +0200 Subject: rcu: add call_rcu_sched() Fourth cut of patch to provide the call_rcu_sched(). This is again to synchronize_sched() as call_rcu() is to synchronize_rcu(). Should be fine for experimental and -rt use, but not ready for inclusion. With some luck, I will be able to tell Andrew to come out of hiding on the next round. Passes multi-day rcutorture sessions with concurrent CPU hotplugging. Fixes since the first version include a bug that could result in indefinite blocking (spotted by Gautham Shenoy), better resiliency against CPU-hotplug operations, and other minor fixes. Fixes since the second version include reworking grace-period detection to avoid deadlocks that could happen when running concurrently with CPU hotplug, adding Mathieu's fix to avoid the softlockup messages, as well as Mathieu's fix to allow use earlier in boot. Fixes since the third version include a wrong-CPU bug spotted by Andrew, getting rid of the obsolete synchronize_kernel API that somehow snuck back in, merging spin_unlock() and local_irq_restore() in a few places, commenting the code that checks for quiescent states based on interrupting from user-mode execution or the idle loop, removing some inline attributes, and some code-style changes. Known/suspected shortcomings: o I still do not entirely trust the sleep/wakeup logic. Next step will be to use a private snapshot of the CPU online mask in rcu_sched_grace_period() -- if the CPU wasn't there at the start of the grace period, we don't need to hear from it. And the bit about accounting for changes in online CPUs inside of rcu_sched_grace_period() is ugly anyway. o It might be good for rcu_sched_grace_period() to invoke resched_cpu() when a given CPU wasn't responding quickly, but resched_cpu() is declared static... This patch also fixes a long-standing bug in the earlier preemptable-RCU implementation of synchronize_rcu() that could result in loss of concurrent external changes to a task's CPU affinity mask. I still cannot remember who reported this... Signed-off-by: Paul E. McKenney Signed-off-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- include/linux/rcupdate.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'include/linux/rcupdate.h') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index ec2fc5b32646..411969cb5243 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -40,6 +40,7 @@ #include #include #include +#include /** * struct rcu_head - callback structure for use with RCU @@ -168,6 +169,27 @@ struct rcu_head { (p) = (v); \ }) +/* Infrastructure to implement the synchronize_() primitives. */ + +struct rcu_synchronize { + struct rcu_head head; + struct completion completion; +}; + +extern void wakeme_after_rcu(struct rcu_head *head); + +#define synchronize_rcu_xxx(name, func) \ +void name(void) \ +{ \ + struct rcu_synchronize rcu; \ + \ + init_completion(&rcu.completion); \ + /* Will wake me after RCU finished. */ \ + func(&rcu.head, wakeme_after_rcu); \ + /* Wait for it. */ \ + wait_for_completion(&rcu.completion); \ +} + /** * synchronize_sched - block until all CPUs have exited any non-preemptive * kernel code sequences. -- cgit v1.2.1 From 70f12f848d3e981479b4f6f751e73c14f7c13e5b Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 12 May 2008 21:21:05 +0200 Subject: rcu: add rcu_barrier_sched() and rcu_barrier_bh() 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 Signed-off-by: Mathieu Desnoyers Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- include/linux/rcupdate.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/rcupdate.h') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 411969cb5243..e8b4039cfb2f 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -246,6 +246,8 @@ extern void call_rcu_bh(struct rcu_head *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); /* Internal to kernel */ extern void rcu_init(void); -- cgit v1.2.1