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>
63 lines
1.8 KiB
C
63 lines
1.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#ifndef _NET_HOTDATA_H
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#define _NET_HOTDATA_H
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#include <linux/llist.h>
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#include <linux/types.h>
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#include <linux/netdevice.h>
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#include <net/protocol.h>
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struct skb_defer_node {
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struct llist_head defer_list;
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atomic_long_t defer_count;
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} ____cacheline_aligned_in_smp;
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/* Read mostly data used in network fast paths. */
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struct net_hotdata {
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#if IS_ENABLED(CONFIG_INET)
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struct packet_offload ip_packet_offload;
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struct net_offload tcpv4_offload;
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struct net_protocol tcp_protocol;
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struct net_offload udpv4_offload;
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struct net_protocol udp_protocol;
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struct packet_offload ipv6_packet_offload;
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struct net_offload tcpv6_offload;
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#if IS_ENABLED(CONFIG_IPV6)
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struct inet6_protocol tcpv6_protocol;
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struct inet6_protocol udpv6_protocol;
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#endif
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struct net_offload udpv6_offload;
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#endif
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struct list_head offload_base;
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struct kmem_cache *skbuff_cache;
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struct kmem_cache *skbuff_fclone_cache;
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struct kmem_cache *skb_small_head_cache;
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#ifdef CONFIG_RPS
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struct rps_sock_flow_table __rcu *rps_sock_flow_table;
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u32 rps_cpu_mask;
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#endif
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struct skb_defer_node __percpu *skb_defer_nodes;
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int gro_normal_batch;
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int netdev_budget;
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int netdev_budget_usecs;
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int tstamp_prequeue;
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int max_backlog;
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int qdisc_max_burst;
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int dev_tx_weight;
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int dev_rx_weight;
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int sysctl_max_skb_frags;
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int sysctl_skb_defer_max;
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int sysctl_mem_pcpu_rsv;
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};
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#define inet_ehash_secret net_hotdata.tcp_protocol.secret
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#define udp_ehash_secret net_hotdata.udp_protocol.secret
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#define inet6_ehash_secret net_hotdata.tcpv6_protocol.secret
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#define tcp_ipv6_hash_secret net_hotdata.tcpv6_offload.secret
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#define udp6_ehash_secret net_hotdata.udpv6_protocol.secret
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#define udp_ipv6_hash_secret net_hotdata.udpv6_offload.secret
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extern struct net_hotdata net_hotdata;
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#endif /* _NET_HOTDATA_H */
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