ffe4ccd359
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: 100dfa74ca ("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>
31 lines
840 B
C
31 lines
840 B
C
// SPDX-License-Identifier: GPL-2.0-or-later
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#include <linux/cache.h>
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#include <linux/jiffies.h>
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#include <linux/list.h>
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#include <net/aligned_data.h>
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#include <net/hotdata.h>
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#include <net/ip.h>
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#include <net/proto_memory.h>
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struct net_hotdata net_hotdata __cacheline_aligned = {
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.offload_base = LIST_HEAD_INIT(net_hotdata.offload_base),
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.gro_normal_batch = 8,
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.netdev_budget = 300,
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/* Must be at least 2 jiffes to guarantee 1 jiffy timeout */
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.netdev_budget_usecs = 2 * USEC_PER_SEC / HZ,
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.tstamp_prequeue = 1,
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.max_backlog = 1000,
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.qdisc_max_burst = 1000,
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.dev_tx_weight = 64,
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.dev_rx_weight = 64,
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.sysctl_max_skb_frags = MAX_SKB_FRAGS,
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.sysctl_skb_defer_max = 128,
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.sysctl_mem_pcpu_rsv = SK_MEMORY_PCPU_RESERVE
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};
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EXPORT_SYMBOL(net_hotdata);
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struct net_aligned_data net_aligned_data;
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EXPORT_IPV6_MOD(net_aligned_data);
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