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authorOleg Nesterov <oleg@tv-sign.ru>2006-10-04 13:17:17 +0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-04 18:55:31 +0400
commit20e9751bd9dd6b832fd84ada27840360f7e877f1 (patch)
treec598ff9cb9e540da7f8595f2c130f3674065e018 /include/linux
parent4b6c2cca6eef9cc4a15350bf1c61839e12e08b84 (diff)
downloadlinux-20e9751bd9dd6b832fd84ada27840360f7e877f1.tar.xz
[PATCH] rcu: simplify/improve batch tuning
Kill a hard-to-calculate 'rsinterval' boot parameter and per-cpu rcu_data.last_rs_qlen. Instead, it adds adds a flag rcu_ctrlblk.signaled, which records the fact that one of CPUs has sent a resched IPI since the last rcu_start_batch(). Roughly speaking, we need two rcu_start_batch()s in order to move callbacks from ->nxtlist to ->donelist. This means that when ->qlen exceeds qhimark and continues to grow, we should send a resched IPI, and then do it again after we gone through a quiescent state. On the other hand, if it was already sent, we don't need to do it again when another CPU detects overflow of the queue. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: 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 'include/linux')
-rw-r--r--include/linux/rcupdate.h5
1 files changed, 2 insertions, 3 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index b4ca73d65891..f6dd71bf8a4b 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -66,6 +66,8 @@ struct rcu_ctrlblk {
long completed; /* Number of the last completed batch */
int next_pending; /* Is the next batch already waiting? */
+ int signaled;
+
spinlock_t lock ____cacheline_internodealigned_in_smp;
cpumask_t cpumask; /* CPUs that need to switch in order */
/* for current batch to proceed. */
@@ -106,9 +108,6 @@ struct rcu_data {
long blimit; /* Upper limit on a processed batch */
int cpu;
struct rcu_head barrier;
-#ifdef CONFIG_SMP
- long last_rs_qlen; /* qlen during the last resched */
-#endif
};
DECLARE_PER_CPU(struct rcu_data, rcu_data);