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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-02-23 15:57:07 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-02-26 12:11:03 -0800
commit675da67f24e2d6d8df0cedf12e59085ed8bbf4e7 (patch)
treed28ff66c2700afaebf2888a723f022766ce4a48c /kernel/rcu
parentc517d838eb7d07bbe9507871fab3931deccff539 (diff)
downloadlinux-675da67f24e2d6d8df0cedf12e59085ed8bbf4e7.tar.bz2
rcu: Fixes to NO_HZ_FULL sysidle accounting
On second and subsequent passes through quiescent-state forcing, the isidle variable was initialized to false, which would prevent full sysidle state from being reached if a grace period needed more than one round of quiescent-state forcing (which most should not). However, the check for offline CPUs in the quiescent-state forcing main loop had the wrong sense, which could prevent CPUs from ever entering full sysidle state. This commit fixes both of these bugs. Given that sysidle is not yet wired up, this has no effect in old kernels, but might have proven frustrating had anyone attempted to wire it up. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 48d640ca1a05..735bd7ee749a 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1798,7 +1798,7 @@ static int rcu_gp_fqs(struct rcu_state *rsp, int fqs_state_in)
fqs_state = RCU_FORCE_QS;
} else {
/* Handle dyntick-idle and offline CPUs. */
- isidle = false;
+ isidle = true;
force_qs_rnp(rsp, rcu_implicit_dynticks_qs, &isidle, &maxj);
}
/* Clear flag to prevent immediate re-entry. */
@@ -2596,8 +2596,8 @@ static void force_qs_rnp(struct rcu_state *rsp,
bit = 1;
for (; cpu <= rnp->grphi; cpu++, bit <<= 1) {
if ((rnp->qsmask & bit) != 0) {
- if ((rnp->qsmaskinit & bit) != 0)
- *isidle = false;
+ if ((rnp->qsmaskinit & bit) == 0)
+ *isidle = false; /* Pending hotplug. */
if (f(per_cpu_ptr(rsp->rda, cpu), isidle, maxj))
mask |= bit;
}