diff options
| author | Eric Dumazet <edumazet@google.com> | 2026-01-07 10:41:59 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2026-01-13 10:12:11 +0100 |
| commit | ffe4ccd359d006eba559cb1a3c6113144b7fb38c (patch) | |
| tree | 00547b3df467260871b935d0fb3347f3c556c026 /net/core/hotdata.c | |
| parent | dfdf774656205515b2d6ad94fce63c7ccbe92d91 (diff) | |
net: add net.core.qdisc_max_burst
In blamed commit, I added a check against the temporary queue
built in __dev_xmit_skb(). Idea was to drop packets early,
before any spinlock was acquired.
if (unlikely(defer_count > READ_ONCE(q->limit))) {
kfree_skb_reason(skb, SKB_DROP_REASON_QDISC_DROP);
return NET_XMIT_DROP;
}
It turned out that HTB Qdisc has a zero q->limit.
HTB limits packets on a per-class basis.
Some of our tests became flaky.
Add a new sysctl : net.core.qdisc_max_burst to control
how many packets can be stored in the temporary lockless queue.
Also add a new QDISC_BURST_DROP drop reason to better diagnose
future issues.
Thanks Neal !
Fixes: 100dfa74cad9 ("net: dev_queue_xmit() llist adoption")
Reported-and-bisected-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20260107104159.3669285-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net/core/hotdata.c')
| -rw-r--r-- | net/core/hotdata.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/net/core/hotdata.c b/net/core/hotdata.c index dddd5c287cf0..a6db36580817 100644 --- a/net/core/hotdata.c +++ b/net/core/hotdata.c @@ -17,6 +17,7 @@ struct net_hotdata net_hotdata __cacheline_aligned = { .tstamp_prequeue = 1, .max_backlog = 1000, + .qdisc_max_burst = 1000, .dev_tx_weight = 64, .dev_rx_weight = 64, .sysctl_max_skb_frags = MAX_SKB_FRAGS, |