swh:1:snp:77163734605b0ec556b01d897b7bb4a7e30d46b6
Revision 3dd1c9a1270736029ffca670e9bd0265f4120600 authored by Paolo Abeni on 23 July 2018, 14:50:48 UTC, committed by David S. Miller on 23 July 2018, 18:39:30 UTC
The skb hash for locally generated ip[v6] fragments belonging to the same datagram can vary in several circumstances: * for connected UDP[v6] sockets, the first fragment get its hash via set_owner_w()/skb_set_hash_from_sk() * for unconnected IPv6 UDPv6 sockets, the first fragment can get its hash via ip6_make_flowlabel()/skb_get_hash_flowi6(), if auto_flowlabel is enabled For the following frags the hash is usually computed via skb_get_hash(). The above can cause OoO for unconnected IPv6 UDPv6 socket: in that scenario the egress tx queue can be selected on a per packet basis via the skb hash. It may also fool flow-oriented schedulers to place fragments belonging to the same datagram in different flows. Fix the issue by copying the skb hash from the head frag into the others at fragmentation time. Before this commit: perf probe -a "dev_queue_xmit skb skb->hash skb->l4_hash:b1@0/8 skb->sw_hash:b1@1/8" netperf -H $IPV4 -t UDP_STREAM -l 5 -- -m 2000 -n & perf record -e probe:dev_queue_xmit -e probe:skb_set_owner_w -a sleep 0.1 perf script probe:dev_queue_xmit: (ffffffff8c6b1b20) hash=3713014309 l4_hash=1 sw_hash=0 probe:dev_queue_xmit: (ffffffff8c6b1b20) hash=0 l4_hash=0 sw_hash=0 After this commit: probe:dev_queue_xmit: (ffffffff8c6b1b20) hash=2171763177 l4_hash=1 sw_hash=0 probe:dev_queue_xmit: (ffffffff8c6b1b20) hash=2171763177 l4_hash=1 sw_hash=0 Fixes: b73c3d0e4f0e ("net: Save TX flow hash in sock and set in skbuf on xmit") Fixes: 67800f9b1f4e ("ipv6: Call skb_get_hash_flowi6 to get skb->hash in ip6_make_flowlabel") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent e873e4b
Tip revision: a4412fdd49dc011bcc2c0d81ac4cab7457092650 authored by Steven Rostedt (Google) on 21 November 2022, 15:44:03 UTC
error-injection: Add prompt for function error injection
error-injection: Add prompt for function error injection
Tip revision: a4412fd
File | Mode | Size |
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LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | -rw-r--r-- | 12.8 KB |
.cocciconfig | -rw-r--r-- | 59 bytes |
.get_maintainer.ignore | -rw-r--r-- | 31 bytes |
.gitattributes | -rw-r--r-- | 30 bytes |
.gitignore | -rw-r--r-- | 1.5 KB |
.mailmap | -rw-r--r-- | 9.3 KB |
COPYING | -rw-r--r-- | 423 bytes |
CREDITS | -rw-r--r-- | 96.3 KB |
Kbuild | -rw-r--r-- | 2.2 KB |
Kconfig | -rw-r--r-- | 321 bytes |
MAINTAINERS | -rw-r--r-- | 449.4 KB |
Makefile | -rw-r--r-- | 58.2 KB |
README | -rw-r--r-- | 800 bytes |
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