diff options
| author | Paul E. McKenney <paulmck@us.ibm.com> | 2005-05-01 08:59:04 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-05-01 08:59:04 -0700 |
| commit | 9b06e818985d139fd9e82c28297f7744e1b484e1 (patch) | |
| tree | 3cd2ba33b22fc2812f714f86ea52c68704f8e2c3 /include/linux | |
| parent | 512345be2549308b8ae8e85a3ff7f6d56a38e5f6 (diff) | |
[PATCH] Deprecate synchronize_kernel, GPL replacement
The synchronize_kernel() primitive is used for quite a few different purposes:
waiting for RCU readers, waiting for NMIs, waiting for interrupts, and so on.
This makes RCU code harder to read, since synchronize_kernel() might or might
not have matching rcu_read_lock()s. This patch creates a new
synchronize_rcu() that is to be used for RCU readers and a new
synchronize_sched() that is used for the rest. These two new primitives
currently have the same implementation, but this is might well change with
additional real-time support. Both new primitives are GPL-only, the old
primitive is deprecated.
Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/rcupdate.h | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 4d747433916..fd276adf0fd 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -157,9 +157,9 @@ static inline int rcu_pending(int cpu) /** * rcu_read_lock - mark the beginning of an RCU read-side critical section. * - * When synchronize_kernel() is invoked on one CPU while other CPUs + * When synchronize_rcu() is invoked on one CPU while other CPUs * are within RCU read-side critical sections, then the - * synchronize_kernel() is guaranteed to block until after all the other + * synchronize_rcu() is guaranteed to block until after all the other * CPUs exit their critical sections. Similarly, if call_rcu() is invoked * on one CPU while other CPUs are within RCU read-side critical * sections, invocation of the corresponding RCU callback is deferred @@ -256,6 +256,21 @@ static inline int rcu_pending(int cpu) (p) = (v); \ }) +/** + * synchronize_sched - block until all CPUs have exited any non-preemptive + * kernel code sequences. + * + * This means that all preempt_disable code sequences, including NMI and + * hardware-interrupt handlers, in progress on entry will have completed + * before this primitive returns. However, this does not guarantee that + * softirq handlers will have completed, since in some kernels + * + * This primitive provides the guarantees made by the (deprecated) + * synchronize_kernel() API. In contrast, synchronize_rcu() only + * guarantees that rcu_read_lock() sections will have completed. + */ +#define synchronize_sched() synchronize_rcu() + extern void rcu_init(void); extern void rcu_check_callbacks(int cpu, int user); extern void rcu_restart_cpu(int cpu); @@ -265,7 +280,9 @@ extern void FASTCALL(call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *head))); extern void FASTCALL(call_rcu_bh(struct rcu_head *head, void (*func)(struct rcu_head *head))); -extern void synchronize_kernel(void); +extern __deprecated_for_modules void synchronize_kernel(void); +extern void synchronize_rcu(void); +void synchronize_idle(void); #endif /* __KERNEL__ */ #endif /* __LINUX_RCUPDATE_H */ |