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author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-11 13:20:18 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-11 13:20:18 -0700 |
commit | eee2775d9924b22643bd89b2e568cc5eed7e8a04 (patch) | |
tree | 095ad7851895c5d39596f3ff7ee1e078235a2501 /kernel/rcupdate.c | |
parent | 53e16fbd30005905168d9b75555fdc7e0a2eac58 (diff) | |
parent | 7db905e636f08ea5bc9825c1f73d77802e8ccad5 (diff) |
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (28 commits)
rcu: Move end of special early-boot RCU operation earlier
rcu: Changes from reviews: avoid casts, fix/add warnings, improve comments
rcu: Create rcutree plugins to handle hotplug CPU for multi-level trees
rcu: Remove lockdep annotations from RCU's _notrace() API members
rcu: Add #ifdef to suppress __rcu_offline_cpu() warning in !HOTPLUG_CPU builds
rcu: Add CPU-offline processing for single-node configurations
rcu: Add "notrace" to RCU function headers used by ftrace
rcu: Remove CONFIG_PREEMPT_RCU
rcu: Merge preemptable-RCU functionality into hierarchical RCU
rcu: Simplify rcu_pending()/rcu_check_callbacks() API
rcu: Use debugfs_remove_recursive() simplify code.
rcu: Merge per-RCU-flavor initialization into pre-existing macro
rcu: Fix online/offline indication for rcudata.csv trace file
rcu: Consolidate sparse and lockdep declarations in include/linux/rcupdate.h
rcu: Renamings to increase RCU clarity
rcu: Move private definitions from include/linux/rcutree.h to kernel/rcutree.h
rcu: Expunge lingering references to CONFIG_CLASSIC_RCU, optimize on !SMP
rcu: Delay rcu_barrier() wait until beginning of next CPU-hotunplug operation.
rcu: Fix typo in rcu_irq_exit() comment header
rcu: Make rcupreempt_trace.c look at offline CPUs
...
Diffstat (limited to 'kernel/rcupdate.c')
-rw-r--r-- | kernel/rcupdate.c | 44 |
1 files changed, 42 insertions, 2 deletions
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index a967c9feb90..bd5d5c8e514 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -98,6 +98,30 @@ void synchronize_rcu(void) } EXPORT_SYMBOL_GPL(synchronize_rcu); +/** + * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed. + * + * Control will return to the caller some time after a full rcu_bh grace + * period has elapsed, in other words after all currently executing rcu_bh + * read-side critical sections have completed. RCU read-side critical + * sections are delimited by rcu_read_lock_bh() and rcu_read_unlock_bh(), + * and may be nested. + */ +void synchronize_rcu_bh(void) +{ + struct rcu_synchronize rcu; + + if (rcu_blocking_is_gp()) + return; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu_bh(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(synchronize_rcu_bh); + static void rcu_barrier_callback(struct rcu_head *notused) { if (atomic_dec_and_test(&rcu_barrier_cpu_count)) @@ -129,6 +153,7 @@ static void rcu_barrier_func(void *type) static inline void wait_migrated_callbacks(void) { wait_event(rcu_migrate_wq, !atomic_read(&rcu_migrate_type_count)); + smp_mb(); /* In case we didn't sleep. */ } /* @@ -192,9 +217,13 @@ static void rcu_migrate_callback(struct rcu_head *notused) wake_up(&rcu_migrate_wq); } +extern int rcu_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu); + static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self, unsigned long action, void *hcpu) { + rcu_cpu_notify(self, action, hcpu); if (action == CPU_DYING) { /* * preempt_disable() in on_each_cpu() prevents stop_machine(), @@ -209,7 +238,8 @@ static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self, call_rcu_bh(rcu_migrate_head, rcu_migrate_callback); call_rcu_sched(rcu_migrate_head + 1, rcu_migrate_callback); call_rcu(rcu_migrate_head + 2, rcu_migrate_callback); - } else if (action == CPU_POST_DEAD) { + } else if (action == CPU_DOWN_PREPARE) { + /* Don't need to wait until next removal operation. */ /* rcu_migrate_head is protected by cpu_add_remove_lock */ wait_migrated_callbacks(); } @@ -219,8 +249,18 @@ static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self, void __init rcu_init(void) { + int i; + __rcu_init(); - hotcpu_notifier(rcu_barrier_cpu_hotplug, 0); + cpu_notifier(rcu_barrier_cpu_hotplug, 0); + + /* + * We don't need protection against CPU-hotplug here because + * this is called early in boot, before either interrupts + * or the scheduler are operational. + */ + for_each_online_cpu(i) + rcu_barrier_cpu_hotplug(NULL, CPU_UP_PREPARE, (void *)(long)i); } void rcu_scheduler_starting(void) |