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| author | Jason Xing <kernelxing@tencent.com> | 2024-04-12 06:07:18 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2024-04-15 12:34:59 +0300 |
| commit | 4d0470b9ad73e965f5a1e52f1deb0edbb6d03c89 (patch) | |
| tree | 568b10f31df6dc8bba09d9ad235b4e43136bc825 /net/core | |
| parent | 71329c491888c9309af41fafb5129a48843ffa09 (diff) | |
| download | linux-4d0470b9ad73e965f5a1e52f1deb0edbb6d03c89.tar.xz | |
net: save some cycles when doing skb_attempt_defer_free()
Normally, we don't face these two exceptions very often meanwhile
we have some chance to meet the condition where the current cpu id
is the same as skb->alloc_cpu.
One simple test that can help us see the frequency of this statement
'cpu == raw_smp_processor_id()':
1. running iperf -s and iperf -c [ip] -P [MAX CPU]
2. using BPF to capture skb_attempt_defer_free()
I can see around 4% chance that happens to satisfy the statement.
So moving this statement at the beginning can save some cycles in
most cases.
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/skbuff.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index ea052fa710d8..37c858dc11a6 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -6965,9 +6965,9 @@ void skb_attempt_defer_free(struct sk_buff *skb) unsigned int defer_max; bool kick; - if (WARN_ON_ONCE(cpu >= nr_cpu_ids) || - !cpu_online(cpu) || - cpu == raw_smp_processor_id()) { + if (cpu == raw_smp_processor_id() || + WARN_ON_ONCE(cpu >= nr_cpu_ids) || + !cpu_online(cpu)) { nodefer: kfree_skb_napi_cache(skb); return; } |