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Groups > linux.kernel > #1303846
| From | Konstantin Khlebnikov <koct9i@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation |
| Date | 2016-01-07 20:40 +0100 |
| Message-ID | <qOozE-4bb-19@gated-at.bofh.it> (permalink) |
| References | (6 earlier) <qOgC5-7hc-3@gated-at.bofh.it> <qOh57-7sH-7@gated-at.bofh.it> <qOhou-7Bh-3@gated-at.bofh.it> <qOhya-7Vb-35@gated-at.bofh.it> <qOikz-8ew-23@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Jan 7, 2016 at 3:54 PM, Eric Dumazet <edumazet@google.com> wrote: > On Thu, Jan 7, 2016 at 7:04 AM, Konstantin Khlebnikov <koct9i@gmail.com> wrote: >> On Thu, Jan 7, 2016 at 2:59 PM, Eric Dumazet <edumazet@google.com> wrote: >>> On Thu, Jan 7, 2016 at 6:38 AM, Konstantin Khlebnikov <koct9i@gmail.com> wrote: >>>> >>>> Also I've found strange thing: reason of expanding skb->cb from 40 to >>>> 48 bypes in 2006 >>>> 3e3850e989c5d2eb1aab6f0fd9257759f0f4cbc6 was that struct inet6_skb_parm does >>>> not fit. But it's is only 24 bytes. Does some arches add pad after >>>> each _u16 field? >>> >>> "struct inet6_skb_parm" is part of struct tcp_skb_cb >>> >>> This is why Patrick had to increase skb->cb[] >> >> Whoa. Funny. TCP moves that chunk back and forward instead of just >> putting it at the first place in struct. > > You probably want to look at git history to find out why it is done this way. > > TCP performance is critical for some of us, and doing such trick avoid > one cache miss per skb in some critical list traversals. Right. This way tcp stuff perfectly fits into leftovers of first cache line. Then probably it's better to put ipv4/ipv6 cb into second line from the beginning.
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[BUG] skb corruption and kernel panic at forwarding with fragmentation Konstantin Khlebnikov <koct9i@gmail.com> - 2016-01-06 20:20 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Cong Wang <xiyou.wangcong@gmail.com> - 2016-01-06 21:00 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Konstantin Khlebnikov <koct9i@gmail.com> - 2016-01-06 21:20 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Thadeu Lima de Souza Cascardo <cascardo@redhat.com> - 2016-01-06 22:10 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Florian Westphal <fw@strlen.de> - 2016-01-06 23:10 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Florian Westphal <fw@strlen.de> - 2016-01-07 01:00 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Konstantin Khlebnikov <koct9i@gmail.com> - 2016-01-07 12:10 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Konstantin Khlebnikov <koct9i@gmail.com> - 2016-01-07 12:40 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Eric Dumazet <edumazet@google.com> - 2016-01-07 13:00 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Konstantin Khlebnikov <koct9i@gmail.com> - 2016-01-07 13:10 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Eric Dumazet <edumazet@google.com> - 2016-01-07 14:00 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Konstantin Khlebnikov <koct9i@gmail.com> - 2016-01-07 20:40 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Eric Dumazet <edumazet@google.com> - 2016-01-07 20:50 +0100
Re: [BUG] skb corruption and kernel panic at forwarding with fragmentation Florian Westphal <fw@strlen.de> - 2016-01-07 13:10 +0100
[PATCH] net: prevent corruption of skb when using skb_gso_segment Thadeu Lima de Souza Cascardo <cascardo@redhat.com> - 2016-01-07 19:50 +0100
Re: [PATCH] net: prevent corruption of skb when using skb_gso_segment Florian Westphal <fw@strlen.de> - 2016-01-07 20:40 +0100
[PATCH v2] net: prevent corruption of skb when using skb_gso_segment Thadeu Lima de Souza Cascardo <cascardo@redhat.com> - 2016-01-07 22:20 +0100
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