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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2009-10-06 21:48:17 -0700
committerIngo Molnar <mingo@elte.hu>2009-10-07 08:11:20 +0200
commite74f4c4564455c91a3b4075bb1721993c2a95dda (patch)
tree213f9df0974c6e1e729de207b2c6dd942a39ba8c /kernel/rcutree_trace.c
parentd0ec774cb2599c858be9d923bb873cf6697520d8 (diff)
rcu: Make hot-unplugged CPU relinquish its own RCU callbacks
The current interaction between RCU and CPU hotplug requires that RCU block in CPU notifiers waiting for callbacks to drain. This can be greatly simplified by having each CPU relinquish its own callbacks, and for both _rcu_barrier() and CPU_DEAD notifiers to adopt all callbacks that were previously relinquished. This change also eliminates the possibility of certain types of hangs due to the previous practice of waiting for callbacks to be invoked from within CPU notifiers. If you don't every wait, you cannot hang. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1254890898456-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/rcutree_trace.c')
-rw-r--r--kernel/rcutree_trace.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c
index f09af28b826..4b31c779e62 100644
--- a/kernel/rcutree_trace.c
+++ b/kernel/rcutree_trace.c
@@ -159,13 +159,13 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
struct rcu_node *rnp;
seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x "
- "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n",
+ "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld\n",
rsp->completed, rsp->gpnum, rsp->signaled,
(long)(rsp->jiffies_force_qs - jiffies),
(int)(jiffies & 0xffff),
rsp->n_force_qs, rsp->n_force_qs_ngp,
rsp->n_force_qs - rsp->n_force_qs_ngp,
- rsp->n_force_qs_lh);
+ rsp->n_force_qs_lh, rsp->orphan_qlen);
for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
if (rnp->level != level) {
seq_puts(m, "\n");