Re: [RFC PATCH 07/13] net: sched: support qdisc_reset on NOLOCK qdisc

On 16-08-17 03:53 PM, Eric Dumazet wrote:

On Wed, 2016-08-17 at 12:36 -0700, John Fastabend wrote:

quoted

The qdisc_reset operation depends on the qdisc lock at the moment
to halt any additions to gso_skb and statistics while the list is
free'd and the stats zeroed.

...

quoted

Signed-off-by: John Fastabend <redacted>
---
 net/sched/sch_generic.c |   45 +++++++++++++++++++++++++++++++++++----------
 1 file changed, 35 insertions(+), 10 deletions(-)

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 3b9a21f..29238c4 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c

@@ -737,6 +737,20 @@ void qdisc_reset(struct Qdisc *qdisc)
 	kfree_skb(qdisc->skb_bad_txq);
 	qdisc->skb_bad_txq = NULL;
 
+	if (qdisc->gso_cpu_skb) {
+		int i;
+
+		for_each_possible_cpu(i) {
+			struct gso_cell *cell;
+
+			cell = per_cpu_ptr(qdisc->gso_cpu_skb, i);
+			if (cell) {
+				kfree_skb_list(cell->skb);
+				cell = NULL;

	You probably wanted :
			cell->skb = NULL;

Yep thanks!

quoted

+			}
+		}
+	}
+
 	if (qdisc->gso_skb) {
 		kfree_skb_list(qdisc->gso_skb);
 		qdisc->gso_skb = NULL;

@@ -812,10 +826,6 @@ struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
 	root_lock = qdisc_lock(oqdisc);
 	spin_lock_bh(root_lock);
 
-	/* Prune old scheduler */
-	if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1)
-		qdisc_reset(oqdisc);
-
 

This probably belongs to a separate patch, before any per cpu / lockless
qdisc changes ?

Agreed will do for next rev thanks for reviewing.