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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-05-13 06:53:37 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-05-14 10:53:41 -0700
commit6faf72834d9d0c0dc6632604eaeffb621e87fcf9 (patch)
treef72dcd0bfd3b3a43852fd745d580faff6d520141 /kernel
parentf722406faae2d073cc1d01063d1123c35425939e (diff)
downloadlinux-6faf72834d9d0c0dc6632604eaeffb621e87fcf9.tar.gz
rcu: Fix comparison sense in rcu_needs_cpu()
Commit c0f4dfd4f (rcu: Make RCU_FAST_NO_HZ take advantage of numbered callbacks) introduced a bug that can result in excessively long grace periods. This bug reverse the senes of the "if" statement checking for lazy callbacks, so that RCU takes a lazy approach when there are in fact non-lazy callbacks. This can result in excessive boot, suspend, and resume times. This commit therefore fixes the sense of this "if" statement. Reported-by: Borislav Petkov <bp@alien8.de> Reported-by: Bjørn Mork <bjorn@mork.no> Reported-by: Joerg Roedel <joro@8bytes.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Bjørn Mork <bjorn@mork.no> Tested-by: Joerg Roedel <joro@8bytes.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/rcutree_plugin.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 170814dc418..6d939a645da 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -1667,7 +1667,7 @@ int rcu_needs_cpu(int cpu, unsigned long *dj)
rdtp->last_accelerate = jiffies;
/* Request timer delay depending on laziness, and round. */
- if (rdtp->all_lazy) {
+ if (!rdtp->all_lazy) {
*dj = round_up(rcu_idle_gp_delay + jiffies,
rcu_idle_gp_delay) - jiffies;
} else {