aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/rcupdate.c
diff options
context:
space:
mode:
authorHeiko Carstens <heiko.carstens@de.ibm.com>2006-05-15 09:43:58 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-05-15 11:20:55 -0700
commit986733e01d258c26107f1da9d8d47c718349ad2f (patch)
tree5e0f04a707b8c341f79927ba6fffd0ad55d85c29 /kernel/rcupdate.c
parent3b7c8108273bed41a2fc04533cc9f2026ff38c8e (diff)
[PATCH] RCU: introduce rcu_needs_cpu() interface
With "Paul E. McKenney" <paulmck@us.ibm.com> Introduce rcu_needs_cpu() interface. This can be used to tell if there will be a new rcu batch on a cpu soon by looking at the curlist pointer. This can be used to avoid to enter a tickless idle state where the cpu would miss that a new batch is ready when rcu_start_batch would be called on a different cpu. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/rcupdate.c')
-rw-r--r--kernel/rcupdate.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index 6d32ff26f948..2058f88c7bbb 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -479,12 +479,31 @@ static int __rcu_pending(struct rcu_ctrlblk *rcp, struct rcu_data *rdp)
return 0;
}
+/*
+ * Check to see if there is any immediate RCU-related work to be done
+ * by the current CPU, returning 1 if so. This function is part of the
+ * RCU implementation; it is -not- an exported member of the RCU API.
+ */
int rcu_pending(int cpu)
{
return __rcu_pending(&rcu_ctrlblk, &per_cpu(rcu_data, cpu)) ||
__rcu_pending(&rcu_bh_ctrlblk, &per_cpu(rcu_bh_data, cpu));
}
+/*
+ * Check to see if any future RCU-related work will need to be done
+ * by the current CPU, even if none need be done immediately, returning
+ * 1 if so. This function is part of the RCU implementation; it is -not-
+ * an exported member of the RCU API.
+ */
+int rcu_needs_cpu(int cpu)
+{
+ struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
+ struct rcu_data *rdp_bh = &per_cpu(rcu_bh_data, cpu);
+
+ return (!!rdp->curlist || !!rdp_bh->curlist || rcu_pending(cpu));
+}
+
void rcu_check_callbacks(int cpu, int user)
{
if (user ||

Privacy Policy