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author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-03-03 14:32:04 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-03-03 14:32:04 -0800 |
commit | b24746c7be75384d182845375c96433d713981bb (patch) | |
tree | fdb0371d9e59c94e18c946a88c4aa3bcfa4af9b1 /include | |
parent | f41bf2ab998daaa2ac27348d5813e0ae21c57ded (diff) | |
parent | a682604838763981613e42015cd0e39f2989d6bb (diff) | |
download | linux-3.10-b24746c7be75384d182845375c96433d713981bb.tar.gz linux-3.10-b24746c7be75384d182845375c96433d713981bb.tar.bz2 linux-3.10-b24746c7be75384d182845375c96433d713981bb.zip |
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: Teach RCU that idle task is not quiscent state at boot
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/rcuclassic.h | 6 | ||||
-rw-r--r-- | include/linux/rcupdate.h | 4 | ||||
-rw-r--r-- | include/linux/rcupreempt.h | 15 | ||||
-rw-r--r-- | include/linux/rcutree.h | 6 |
4 files changed, 31 insertions, 0 deletions
diff --git a/include/linux/rcuclassic.h b/include/linux/rcuclassic.h index f3f697df1d7..80044a4f3ab 100644 --- a/include/linux/rcuclassic.h +++ b/include/linux/rcuclassic.h @@ -181,4 +181,10 @@ extern long rcu_batches_completed_bh(void); #define rcu_enter_nohz() do { } while (0) #define rcu_exit_nohz() do { } while (0) +/* A context switch is a grace period for rcuclassic. */ +static inline int rcu_blocking_is_gp(void) +{ + return num_online_cpus() == 1; +} + #endif /* __LINUX_RCUCLASSIC_H */ diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 921340a7b71..528343e6da5 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -52,6 +52,9 @@ struct rcu_head { void (*func)(struct rcu_head *head); }; +/* Internal to kernel, but needed by rcupreempt.h. */ +extern int rcu_scheduler_active; + #if defined(CONFIG_CLASSIC_RCU) #include <linux/rcuclassic.h> #elif defined(CONFIG_TREE_RCU) @@ -265,6 +268,7 @@ extern void rcu_barrier_sched(void); /* Internal to kernel */ extern void rcu_init(void); +extern void rcu_scheduler_starting(void); extern int rcu_needs_cpu(int cpu); #endif /* __LINUX_RCUPDATE_H */ 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 */ diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index d4368b7975c..a722fb67bb2 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -326,4 +326,10 @@ static inline void rcu_exit_nohz(void) } #endif /* CONFIG_NO_HZ */ +/* A context switch is a grace period for rcutree. */ +static inline int rcu_blocking_is_gp(void) +{ + return num_online_cpus() == 1; +} + #endif /* __LINUX_RCUTREE_H */ |