# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1274274397 -3600
# Node ID bc2364ad816d1979b21a869316abdaa6e6dfc033
# Parent a3cf0d9a1b188d65c84186536a7c004790235af6
rcu: Migrate RCU work when taking a CPU offline.
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
xen/common/rcupdate.c | 39 ++++++++++++++++++++++++++++++++++++---
1 files changed, 36 insertions(+), 3 deletions(-)
diff -r a3cf0d9a1b18 -r bc2364ad816d xen/common/rcupdate.c
--- a/xen/common/rcupdate.c Wed May 19 12:53:44 2010 +0100
+++ b/xen/common/rcupdate.c Wed May 19 14:06:37 2010 +0100
@@ -322,6 +322,36 @@ void rcu_check_callbacks(int cpu)
raise_softirq(RCU_SOFTIRQ);
}
+static void rcu_move_batch(struct rcu_data *this_rdp, struct rcu_head *list,
+ struct rcu_head **tail)
+{
+ local_irq_disable();
+ *this_rdp->nxttail = list;
+ if (list)
+ this_rdp->nxttail = tail;
+ local_irq_enable();
+}
+
+static void rcu_offline_cpu(struct rcu_data *this_rdp,
+ struct rcu_ctrlblk *rcp, struct rcu_data *rdp)
+{
+ /* If the cpu going offline owns the grace period we can block
+ * indefinitely waiting for it, so flush it here.
+ */
+ spin_lock(&rcp->lock);
+ if (rcp->cur != rcp->completed)
+ cpu_quiet(rdp->cpu, rcp);
+ spin_unlock(&rcp->lock);
+
+ rcu_move_batch(this_rdp, rdp->donelist, rdp->donetail);
+ rcu_move_batch(this_rdp, rdp->curlist, rdp->curtail);
+ rcu_move_batch(this_rdp, rdp->nxtlist, rdp->nxttail);
+
+ local_irq_disable();
+ this_rdp->qlen += rdp->qlen;
+ local_irq_enable();
+}
+
static void rcu_init_percpu_data(int cpu, struct rcu_ctrlblk *rcp,
struct rcu_data *rdp)
{
@@ -339,14 +369,17 @@ static int cpu_callback(
struct notifier_block *nfb, unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
+ struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
switch ( action )
{
- case CPU_UP_PREPARE: {
- struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
+ case CPU_UP_PREPARE:
rcu_init_percpu_data(cpu, &rcu_ctrlblk, rdp);
break;
- }
+ case CPU_UP_CANCELED:
+ case CPU_DEAD:
+ rcu_offline_cpu(&this_cpu(rcu_data), &rcu_ctrlblk, rdp);
+ break;
default:
break;
}
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