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| author | David S. Miller <davem@davemloft.net> | 2009-03-18 23:53:57 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-03-18 23:53:57 -0700 |
| commit | 0702b30dd821ac8a4103ddbe545518713fdca9be (patch) | |
| tree | 8ce0c9f5e58c5ccb99870505eecd139986caa05e /include/linux/rcupreempt.h | |
| parent | 192d7a4667c6d11d1a174ec4cad9a3c5d5f9043c (diff) | |
| parent | a1e4ee22863d41a6fbb24310d7951836cb6dafe7 (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 3e05c09b54a..74304b4538d 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 */ |