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| author | David S. Miller <davem@davemloft.net> | 2009-03-04 23:59:54 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-03-04 23:59:54 -0800 |
| commit | 77827a7cf3aa415f8afec6d9d0537dda8de90ef1 (patch) | |
| tree | 503ab81e2b997e3625360b380f1cd18f923a6454 /include/linux/rcupreempt.h | |
| parent | 9d40bbda599def1e1d155d7f7dca14fe8744bd2b (diff) | |
| parent | 559595a985e106d2fa9f0c79b7f5805453fed593 (diff) | |
Merge branch 'master' of /home/davem/src/GIT/linux-2.6/
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 */ |