summaryrefslogtreecommitdiff
path: root/include/linux/rcupdate_wait.h
diff options
context:
space:
mode:
authorIngo Molnar <mingo@kernel.org>2017-02-06 09:50:49 +0100
committerIngo Molnar <mingo@kernel.org>2017-03-02 08:42:24 +0100
commitf9411ebe3d85cbbea06298241e6053d031d281fc (patch)
tree291b7e3950f83a9a6c072bb9432e3cb83dc1c65a /include/linux/rcupdate_wait.h
parent4b53a3412d6663214ce9c754eff9373a9cff9dee (diff)
rcu: Separate the RCU synchronization types and APIs into <linux/rcupdate_wait.h>
So rcupdate.h is a pretty complex header, in particular it includes <linux/completion.h> which includes <linux/wait.h> - creating a dependency that includes <linux/wait.h> in <linux/sched.h>, which prevents the isolation of <linux/sched.h> from the derived <linux/wait.h> header. Solve part of the problem by decoupling rcupdate.h from completions: this can be done by separating out the rcu_synchronize types and APIs, and updating their usage sites. Since this is a mostly RCU-internal types this will not just simplify <linux/sched.h>'s dependencies, but will make all the hundreds of .c files that include rcupdate.h but not completions or wait.h build faster. ( For rcutiny this means that two dependent APIs have to be uninlined, but that shouldn't be much of a problem as they are rare variants. ) Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/rcupdate_wait.h')
-rw-r--r--include/linux/rcupdate_wait.h50
1 files changed, 50 insertions, 0 deletions
diff --git a/include/linux/rcupdate_wait.h b/include/linux/rcupdate_wait.h
new file mode 100644
index 000000000000..e774b4f5f220
--- /dev/null
+++ b/include/linux/rcupdate_wait.h
@@ -0,0 +1,50 @@
+#ifndef _LINUX_SCHED_RCUPDATE_WAIT_H
+#define _LINUX_SCHED_RCUPDATE_WAIT_H
+
+/*
+ * RCU synchronization types and methods:
+ */
+
+#include <linux/rcupdate.h>
+#include <linux/completion.h>
+
+/*
+ * Structure allowing asynchronous waiting on RCU.
+ */
+struct rcu_synchronize {
+ struct rcu_head head;
+ struct completion completion;
+};
+void wakeme_after_rcu(struct rcu_head *head);
+
+void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
+ struct rcu_synchronize *rs_array);
+
+#define _wait_rcu_gp(checktiny, ...) \
+do { \
+ call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
+ struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)]; \
+ __wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array), \
+ __crcu_array, __rs_array); \
+} while (0)
+
+#define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)
+
+/**
+ * synchronize_rcu_mult - Wait concurrently for multiple grace periods
+ * @...: List of call_rcu() functions for the flavors to wait on.
+ *
+ * This macro waits concurrently for multiple flavors of RCU grace periods.
+ * For example, synchronize_rcu_mult(call_rcu, call_rcu_bh) would wait
+ * on concurrent RCU and RCU-bh grace periods. Waiting on a give SRCU
+ * domain requires you to write a wrapper function for that SRCU domain's
+ * call_srcu() function, supplying the corresponding srcu_struct.
+ *
+ * If Tiny RCU, tell _wait_rcu_gp() not to bother waiting for RCU
+ * or RCU-bh, given that anywhere synchronize_rcu_mult() can be called
+ * is automatically a grace period.
+ */
+#define synchronize_rcu_mult(...) \
+ _wait_rcu_gp(IS_ENABLED(CONFIG_TINY_RCU), __VA_ARGS__)
+
+#endif /* _LINUX_SCHED_RCUPDATE_WAIT_H */