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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-01-06 14:11:30 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-02-21 09:03:25 -0800
commit486e259340fc4c60474f2c14703e3b3634bb58ca (patch)
tree70a58702194588fa0773463523f72c682785d040 /include/linux/rcutiny.h
parent0bb7b59d6e2b8440cd7097097dd4bbfc4d76ed07 (diff)
rcu: Avoid waking up CPUs having only kfree_rcu() callbacks
When CONFIG_RCU_FAST_NO_HZ is enabled, RCU will allow a given CPU to enter dyntick-idle mode even if it still has RCU callbacks queued. RCU avoids system hangs in this case by scheduling a timer for several jiffies in the future. However, if all of the callbacks on that CPU are from kfree_rcu(), there is no reason to wake the CPU up, as it is not a problem to defer freeing of memory. This commit therefore tracks the number of callbacks on a given CPU that are from kfree_rcu(), and avoids scheduling the timer if all of a given CPU's callbacks are from kfree_rcu(). Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'include/linux/rcutiny.h')
-rw-r--r--include/linux/rcutiny.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 00b7a5e493d2..51bf29c81485 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -83,6 +83,12 @@ static inline void synchronize_sched_expedited(void)
synchronize_sched();
}
+static inline void kfree_call_rcu(struct rcu_head *head,
+ void (*func)(struct rcu_head *rcu))
+{
+ call_rcu(head, func);
+}
+
#ifdef CONFIG_TINY_RCU
static inline void rcu_preempt_note_context_switch(void)