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| author | Ingo Molnar <mingo@elte.hu> | 2009-03-05 12:47:28 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-03-05 12:47:28 +0100 |
| commit | 7df4edb07cf54a4868b9a750424c0d2aa68f8d66 (patch) | |
| tree | 0ad0ad3f3dcb6f9edf26dde42ba625053dddf54f /include/linux/rcupreempt.h | |
| parent | 0d688da5505d77bcef2441e0a22d8cc26459702d (diff) | |
| parent | 559595a985e106d2fa9f0c79b7f5805453fed593 (diff) | |
| download | lwn-7df4edb07cf54a4868b9a750424c0d2aa68f8d66.tar.gz lwn-7df4edb07cf54a4868b9a750424c0d2aa68f8d66.zip | |
Merge branch 'linus' into core/iommu
Diffstat (limited to 'include/linux/rcupreempt.h')
| -rw-r--r-- | include/linux/rcupreempt.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/rcupreempt.h b/include/linux/rcupreempt.h index 3e05c09b54a2..74304b4538d8 100644 --- a/include/linux/rcupreempt.h +++ b/include/linux/rcupreempt.h @@ -142,4 +142,19 @@ static inline void rcu_exit_nohz(void) #define rcu_exit_nohz() do { } while (0) #endif /* CONFIG_NO_HZ */ +/* + * A context switch is a grace period for rcupreempt synchronize_rcu() + * only during early boot, before the scheduler has been initialized. + * So, how the heck do we get a context switch? Well, if the caller + * invokes synchronize_rcu(), they are willing to accept a context + * switch, so we simply pretend that one happened. + * + * After boot, there might be a blocked or preempted task in an RCU + * read-side critical section, so we cannot then take the fastpath. + */ +static inline int rcu_blocking_is_gp(void) +{ + return num_online_cpus() == 1 && !rcu_scheduler_active; +} + #endif /* __LINUX_RCUPREEMPT_H */ |