520ac30f45
Qdisc performance suffers when packets are dropped at enqueue() time because drops (kfree_skb()) are done while qdisc lock is held, delaying a dequeue() draining the queue. Nominal throughput can be reduced by 50 % when this happens, at a time we would like the dequeue() to proceed as fast as possible. Even FQ is vulnerable to this problem, while one of FQ goals was to provide some flow isolation. This patch adds a 'struct sk_buff **to_free' parameter to all qdisc->enqueue(), and in qdisc_drop() helper. I measured a performance increase of up to 12 %, but this patch is a prereq so that future batches in enqueue() can fly. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
45 lines
1.1 KiB
C
45 lines
1.1 KiB
C
/*
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* net/sched/sch_blackhole.c Black hole queue
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Authors: Thomas Graf <tgraf@suug.ch>
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*
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* Note: Quantum tunneling is not supported.
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*/
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <net/pkt_sched.h>
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static int blackhole_enqueue(struct sk_buff *skb, struct Qdisc *sch,
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struct sk_buff **to_free)
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{
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qdisc_drop(skb, sch, to_free);
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return NET_XMIT_SUCCESS;
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}
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static struct sk_buff *blackhole_dequeue(struct Qdisc *sch)
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{
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return NULL;
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}
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static struct Qdisc_ops blackhole_qdisc_ops __read_mostly = {
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.id = "blackhole",
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.priv_size = 0,
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.enqueue = blackhole_enqueue,
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.dequeue = blackhole_dequeue,
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.peek = blackhole_dequeue,
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.owner = THIS_MODULE,
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};
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static int __init blackhole_init(void)
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{
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return register_qdisc(&blackhole_qdisc_ops);
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}
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device_initcall(blackhole_init)
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