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authorLinus Torvalds <torvalds@linux-foundation.org>2009-03-03 17:32:04 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2009-03-03 17:32:04 -0500
commitb24746c7be75384d182845375c96433d713981bb (patch)
treefdb0371d9e59c94e18c946a88c4aa3bcfa4af9b1 /include/linux
parentf41bf2ab998daaa2ac27348d5813e0ae21c57ded (diff)
parenta682604838763981613e42015cd0e39f2989d6bb (diff)
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/linux')
-rw-r--r--include/linux/rcuclassic.h6
-rw-r--r--include/linux/rcupdate.h4
-rw-r--r--include/linux/rcupreempt.h15
-rw-r--r--include/linux/rcutree.h6
4 files changed, 31 insertions, 0 deletions
diff --git a/include/linux/rcuclassic.h b/include/linux/rcuclassic.h
index f3f697df1d71..80044a4f3ab9 100644
--- a/include/linux/rcuclassic.h
+++ b/include/linux/rcuclassic.h
@@ -181,4 +181,10 @@ extern long rcu_batches_completed_bh(void);
181#define rcu_enter_nohz() do { } while (0) 181#define rcu_enter_nohz() do { } while (0)
182#define rcu_exit_nohz() do { } while (0) 182#define rcu_exit_nohz() do { } while (0)
183 183
184/* A context switch is a grace period for rcuclassic. */
185static inline int rcu_blocking_is_gp(void)
186{
187 return num_online_cpus() == 1;
188}
189
184#endif /* __LINUX_RCUCLASSIC_H */ 190#endif /* __LINUX_RCUCLASSIC_H */
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 921340a7b71c..528343e6da51 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -52,6 +52,9 @@ struct rcu_head {
52 void (*func)(struct rcu_head *head); 52 void (*func)(struct rcu_head *head);
53}; 53};
54 54
55/* Internal to kernel, but needed by rcupreempt.h. */
56extern int rcu_scheduler_active;
57
55#if defined(CONFIG_CLASSIC_RCU) 58#if defined(CONFIG_CLASSIC_RCU)
56#include <linux/rcuclassic.h> 59#include <linux/rcuclassic.h>
57#elif defined(CONFIG_TREE_RCU) 60#elif defined(CONFIG_TREE_RCU)
@@ -265,6 +268,7 @@ extern void rcu_barrier_sched(void);
265 268
266/* Internal to kernel */ 269/* Internal to kernel */
267extern void rcu_init(void); 270extern void rcu_init(void);
271extern void rcu_scheduler_starting(void);
268extern int rcu_needs_cpu(int cpu); 272extern int rcu_needs_cpu(int cpu);
269 273
270#endif /* __LINUX_RCUPDATE_H */ 274#endif /* __LINUX_RCUPDATE_H */
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)
142#define rcu_exit_nohz() do { } while (0) 142#define rcu_exit_nohz() do { } while (0)
143#endif /* CONFIG_NO_HZ */ 143#endif /* CONFIG_NO_HZ */
144 144
145/*
146 * A context switch is a grace period for rcupreempt synchronize_rcu()
147 * only during early boot, before the scheduler has been initialized.
148 * So, how the heck do we get a context switch? Well, if the caller
149 * invokes synchronize_rcu(), they are willing to accept a context
150 * switch, so we simply pretend that one happened.
151 *
152 * After boot, there might be a blocked or preempted task in an RCU
153 * read-side critical section, so we cannot then take the fastpath.
154 */
155static inline int rcu_blocking_is_gp(void)
156{
157 return num_online_cpus() == 1 && !rcu_scheduler_active;
158}
159
145#endif /* __LINUX_RCUPREEMPT_H */ 160#endif /* __LINUX_RCUPREEMPT_H */
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index d4368b7975c3..a722fb67bb2d 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -326,4 +326,10 @@ static inline void rcu_exit_nohz(void)
326} 326}
327#endif /* CONFIG_NO_HZ */ 327#endif /* CONFIG_NO_HZ */
328 328
329/* A context switch is a grace period for rcutree. */
330static inline int rcu_blocking_is_gp(void)
331{
332 return num_online_cpus() == 1;
333}
334
329#endif /* __LINUX_RCUTREE_H */ 335#endif /* __LINUX_RCUTREE_H */