<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/net/core, branch v6.9-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>net: mark racy access on sk-&gt;sk_rcvbuf</title>
<updated>2024-03-25T14:46:59+00:00</updated>
<author>
<name>linke li</name>
<email>lilinke99@qq.com</email>
</author>
<published>2024-03-21T08:44:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c2deb2e971f5d9aca941ef13ee05566979e337a4'/>
<id>c2deb2e971f5d9aca941ef13ee05566979e337a4</id>
<content type='text'>
sk-&gt;sk_rcvbuf in __sock_queue_rcv_skb() and __sk_receive_skb() can be
changed by other threads. Mark this as benign using READ_ONCE().

This patch is aimed at reducing the number of benign races reported by
KCSAN in order to focus future debugging effort on harmful races.

Signed-off-by: linke li &lt;lilinke99@qq.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
sk-&gt;sk_rcvbuf in __sock_queue_rcv_skb() and __sk_receive_skb() can be
changed by other threads. Mark this as benign using READ_ONCE().

This patch is aimed at reducing the number of benign races reported by
KCSAN in order to focus future debugging effort on harmful races.

Signed-off-by: linke li &lt;lilinke99@qq.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: report RCU QS on threaded NAPI repolling</title>
<updated>2024-03-21T04:05:42+00:00</updated>
<author>
<name>Yan Zhai</name>
<email>yan@cloudflare.com</email>
</author>
<published>2024-03-19T20:44:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d6dbbb11247c71203785a2c9da474c36f4b19eae'/>
<id>d6dbbb11247c71203785a2c9da474c36f4b19eae</id>
<content type='text'>
NAPI threads can keep polling packets under load. Currently it is only
calling cond_resched() before repolling, but it is not sufficient to
clear out the holdout of RCU tasks, which prevent BPF tracing programs
from detaching for long period. This can be reproduced easily with
following set up:

ip netns add test1
ip netns add test2

ip -n test1 link add veth1 type veth peer name veth2 netns test2

ip -n test1 link set veth1 up
ip -n test1 link set lo up
ip -n test2 link set veth2 up
ip -n test2 link set lo up

ip -n test1 addr add 192.168.1.2/31 dev veth1
ip -n test1 addr add 1.1.1.1/32 dev lo
ip -n test2 addr add 192.168.1.3/31 dev veth2
ip -n test2 addr add 2.2.2.2/31 dev lo

ip -n test1 route add default via 192.168.1.3
ip -n test2 route add default via 192.168.1.2

for i in `seq 10 210`; do
 for j in `seq 10 210`; do
    ip netns exec test2 iptables -I INPUT -s 3.3.$i.$j -p udp --dport 5201
 done
done

ip netns exec test2 ethtool -K veth2 gro on
ip netns exec test2 bash -c 'echo 1 &gt; /sys/class/net/veth2/threaded'
ip netns exec test1 ethtool -K veth1 tso off

Then run an iperf3 client/server and a bpftrace script can trigger it:

ip netns exec test2 iperf3 -s -B 2.2.2.2 &gt;/dev/null&amp;
ip netns exec test1 iperf3 -c 2.2.2.2 -B 1.1.1.1 -u -l 1500 -b 3g -t 100 &gt;/dev/null&amp;
bpftrace -e 'kfunc:__napi_poll{@=count();} interval:s:1{exit();}'

Report RCU quiescent states periodically will resolve the issue.

Fixes: 29863d41bb6e ("net: implement threaded-able napi poll loop support")
Reviewed-by: Jesper Dangaard Brouer &lt;hawk@kernel.org&gt;
Signed-off-by: Yan Zhai &lt;yan@cloudflare.com&gt;
Acked-by: Paul E. McKenney &lt;paulmck@kernel.org&gt;
Acked-by: Jesper Dangaard Brouer &lt;hawk@kernel.org&gt;
Link: https://lore.kernel.org/r/4c3b0d3f32d3b18949d75b18e5e1d9f13a24f025.1710877680.git.yan@cloudflare.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
NAPI threads can keep polling packets under load. Currently it is only
calling cond_resched() before repolling, but it is not sufficient to
clear out the holdout of RCU tasks, which prevent BPF tracing programs
from detaching for long period. This can be reproduced easily with
following set up:

ip netns add test1
ip netns add test2

ip -n test1 link add veth1 type veth peer name veth2 netns test2

ip -n test1 link set veth1 up
ip -n test1 link set lo up
ip -n test2 link set veth2 up
ip -n test2 link set lo up

ip -n test1 addr add 192.168.1.2/31 dev veth1
ip -n test1 addr add 1.1.1.1/32 dev lo
ip -n test2 addr add 192.168.1.3/31 dev veth2
ip -n test2 addr add 2.2.2.2/31 dev lo

ip -n test1 route add default via 192.168.1.3
ip -n test2 route add default via 192.168.1.2

for i in `seq 10 210`; do
 for j in `seq 10 210`; do
    ip netns exec test2 iptables -I INPUT -s 3.3.$i.$j -p udp --dport 5201
 done
done

ip netns exec test2 ethtool -K veth2 gro on
ip netns exec test2 bash -c 'echo 1 &gt; /sys/class/net/veth2/threaded'
ip netns exec test1 ethtool -K veth1 tso off

Then run an iperf3 client/server and a bpftrace script can trigger it:

ip netns exec test2 iperf3 -s -B 2.2.2.2 &gt;/dev/null&amp;
ip netns exec test1 iperf3 -c 2.2.2.2 -B 1.1.1.1 -u -l 1500 -b 3g -t 100 &gt;/dev/null&amp;
bpftrace -e 'kfunc:__napi_poll{@=count();} interval:s:1{exit();}'

Report RCU quiescent states periodically will resolve the issue.

Fixes: 29863d41bb6e ("net: implement threaded-able napi poll loop support")
Reviewed-by: Jesper Dangaard Brouer &lt;hawk@kernel.org&gt;
Signed-off-by: Yan Zhai &lt;yan@cloudflare.com&gt;
Acked-by: Paul E. McKenney &lt;paulmck@kernel.org&gt;
Acked-by: Jesper Dangaard Brouer &lt;hawk@kernel.org&gt;
Link: https://lore.kernel.org/r/4c3b0d3f32d3b18949d75b18e5e1d9f13a24f025.1710877680.git.yan@cloudflare.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: move dev-&gt;state into net_device_read_txrx group</title>
<updated>2024-03-19T09:47:47+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2024-03-14T20:08:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f6e0a4984c2e7244689ea87b62b433bed9d07e94'/>
<id>f6e0a4984c2e7244689ea87b62b433bed9d07e94</id>
<content type='text'>
dev-&gt;state can be read in rx and tx fast paths.

netif_running() which needs dev-&gt;state is called from
- enqueue_to_backlog() [RX path]
- __dev_direct_xmit()  [TX path]

Fixes: 43a71cd66b9c ("net-device: reorganize net_device fast path variables")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Coco Li &lt;lixiaoyan@google.com&gt;
Reviewed-by: Jiri Pirko &lt;jiri@nvidia.com&gt;
Link: https://lore.kernel.org/r/20240314200845.3050179-1-edumazet@google.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
dev-&gt;state can be read in rx and tx fast paths.

netif_running() which needs dev-&gt;state is called from
- enqueue_to_backlog() [RX path]
- __dev_direct_xmit()  [TX path]

Fixes: 43a71cd66b9c ("net-device: reorganize net_device fast path variables")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Coco Li &lt;lixiaoyan@google.com&gt;
Reviewed-by: Jiri Pirko &lt;jiri@nvidia.com&gt;
Link: https://lore.kernel.org/r/20240314200845.3050179-1-edumazet@google.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>packet: annotate data-races around ignore_outgoing</title>
<updated>2024-03-18T09:34:54+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2024-03-14T14:18:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6ebfad33161afacb3e1e59ed1c2feefef70f9f97'/>
<id>6ebfad33161afacb3e1e59ed1c2feefef70f9f97</id>
<content type='text'>
ignore_outgoing is read locklessly from dev_queue_xmit_nit()
and packet_getsockopt()

Add appropriate READ_ONCE()/WRITE_ONCE() annotations.

syzbot reported:

BUG: KCSAN: data-race in dev_queue_xmit_nit / packet_setsockopt

write to 0xffff888107804542 of 1 bytes by task 22618 on cpu 0:
 packet_setsockopt+0xd83/0xfd0 net/packet/af_packet.c:4003
 do_sock_setsockopt net/socket.c:2311 [inline]
 __sys_setsockopt+0x1d8/0x250 net/socket.c:2334
 __do_sys_setsockopt net/socket.c:2343 [inline]
 __se_sys_setsockopt net/socket.c:2340 [inline]
 __x64_sys_setsockopt+0x66/0x80 net/socket.c:2340
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

read to 0xffff888107804542 of 1 bytes by task 27 on cpu 1:
 dev_queue_xmit_nit+0x82/0x620 net/core/dev.c:2248
 xmit_one net/core/dev.c:3527 [inline]
 dev_hard_start_xmit+0xcc/0x3f0 net/core/dev.c:3547
 __dev_queue_xmit+0xf24/0x1dd0 net/core/dev.c:4335
 dev_queue_xmit include/linux/netdevice.h:3091 [inline]
 batadv_send_skb_packet+0x264/0x300 net/batman-adv/send.c:108
 batadv_send_broadcast_skb+0x24/0x30 net/batman-adv/send.c:127
 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:392 [inline]
 batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:420 [inline]
 batadv_iv_send_outstanding_bat_ogm_packet+0x3f0/0x4b0 net/batman-adv/bat_iv_ogm.c:1700
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
 worker_thread+0x526/0x730 kernel/workqueue.c:3416
 kthread+0x1d1/0x210 kernel/kthread.c:388
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

value changed: 0x00 -&gt; 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 27 Comm: kworker/u8:1 Tainted: G        W          6.8.0-syzkaller-08073-g480e035fc4c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet

Fixes: fa788d986a3a ("packet: add sockopt to ignore outgoing packets")
Reported-by: syzbot+c669c1136495a2e7c31f@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/CANn89i+Z7MfbkBLOv=p7KZ7=K1rKHO4P1OL5LYDCtBiyqsa9oQ@mail.gmail.com/T/#t
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Willem de Bruijn &lt;willemdebruijn.kernel@gmail.com&gt;
Reviewed-by: Willem de Bruijn &lt;willemb@google.com&gt;
Reviewed-by: Jason Xing &lt;kerneljasonxing@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
ignore_outgoing is read locklessly from dev_queue_xmit_nit()
and packet_getsockopt()

Add appropriate READ_ONCE()/WRITE_ONCE() annotations.

syzbot reported:

BUG: KCSAN: data-race in dev_queue_xmit_nit / packet_setsockopt

write to 0xffff888107804542 of 1 bytes by task 22618 on cpu 0:
 packet_setsockopt+0xd83/0xfd0 net/packet/af_packet.c:4003
 do_sock_setsockopt net/socket.c:2311 [inline]
 __sys_setsockopt+0x1d8/0x250 net/socket.c:2334
 __do_sys_setsockopt net/socket.c:2343 [inline]
 __se_sys_setsockopt net/socket.c:2340 [inline]
 __x64_sys_setsockopt+0x66/0x80 net/socket.c:2340
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

read to 0xffff888107804542 of 1 bytes by task 27 on cpu 1:
 dev_queue_xmit_nit+0x82/0x620 net/core/dev.c:2248
 xmit_one net/core/dev.c:3527 [inline]
 dev_hard_start_xmit+0xcc/0x3f0 net/core/dev.c:3547
 __dev_queue_xmit+0xf24/0x1dd0 net/core/dev.c:4335
 dev_queue_xmit include/linux/netdevice.h:3091 [inline]
 batadv_send_skb_packet+0x264/0x300 net/batman-adv/send.c:108
 batadv_send_broadcast_skb+0x24/0x30 net/batman-adv/send.c:127
 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:392 [inline]
 batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:420 [inline]
 batadv_iv_send_outstanding_bat_ogm_packet+0x3f0/0x4b0 net/batman-adv/bat_iv_ogm.c:1700
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
 worker_thread+0x526/0x730 kernel/workqueue.c:3416
 kthread+0x1d1/0x210 kernel/kthread.c:388
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

value changed: 0x00 -&gt; 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 27 Comm: kworker/u8:1 Tainted: G        W          6.8.0-syzkaller-08073-g480e035fc4c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet

Fixes: fa788d986a3a ("packet: add sockopt to ignore outgoing packets")
Reported-by: syzbot+c669c1136495a2e7c31f@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/CANn89i+Z7MfbkBLOv=p7KZ7=K1rKHO4P1OL5LYDCtBiyqsa9oQ@mail.gmail.com/T/#t
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Willem de Bruijn &lt;willemdebruijn.kernel@gmail.com&gt;
Reviewed-by: Willem de Bruijn &lt;willemb@google.com&gt;
Reviewed-by: Jason Xing &lt;kerneljasonxing@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'net-next-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next</title>
<updated>2024-03-13T00:44:08+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-03-13T00:44:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=9187210eee7d87eea37b45ea93454a88681894a4'/>
<id>9187210eee7d87eea37b45ea93454a88681894a4</id>
<content type='text'>
Pull networking updates from Jakub Kicinski:
 "Core &amp; protocols:

   - Large effort by Eric to lower rtnl_lock pressure and remove locks:

      - Make commonly used parts of rtnetlink (address, route dumps
        etc) lockless, protected by RCU instead of rtnl_lock.

      - Add a netns exit callback which already holds rtnl_lock,
        allowing netns exit to take rtnl_lock once in the core instead
        of once for each driver / callback.

      - Remove locks / serialization in the socket diag interface.

      - Remove 6 calls to synchronize_rcu() while holding rtnl_lock.

      - Remove the dev_base_lock, depend on RCU where necessary.

   - Support busy polling on a per-epoll context basis. Poll length and
     budget parameters can be set independently of system defaults.

   - Introduce struct net_hotdata, to make sure read-mostly global
     config variables fit in as few cache lines as possible.

   - Add optional per-nexthop statistics to ease monitoring / debug of
     ECMP imbalance problems.

   - Support TCP_NOTSENT_LOWAT in MPTCP.

   - Ensure that IPv6 temporary addresses' preferred lifetimes are long
     enough, compared to other configured lifetimes, and at least 2 sec.

   - Support forwarding of ICMP Error messages in IPSec, per RFC 4301.

   - Add support for the independent control state machine for bonding
     per IEEE 802.1AX-2008 5.4.15 in addition to the existing coupled
     control state machine.

   - Add "network ID" to MCTP socket APIs to support hosts with multiple
     disjoint MCTP networks.

   - Re-use the mono_delivery_time skbuff bit for packets which user
     space wants to be sent at a specified time. Maintain the timing
     information while traversing veth links, bridge etc.

   - Take advantage of MSG_SPLICE_PAGES for RxRPC DATA and ACK packets.

   - Simplify many places iterating over netdevs by using an xarray
     instead of a hash table walk (hash table remains in place, for use
     on fastpaths).

   - Speed up scanning for expired routes by keeping a dedicated list.

   - Speed up "generic" XDP by trying harder to avoid large allocations.

   - Support attaching arbitrary metadata to netconsole messages.

  Things we sprinkled into general kernel code:

   - Enforce VM_IOREMAP flag and range in ioremap_page_range and
     introduce VM_SPARSE kind and vm_area_[un]map_pages (used by
     bpf_arena).

   - Rework selftest harness to enable the use of the full range of ksft
     exit code (pass, fail, skip, xfail, xpass).

  Netfilter:

   - Allow userspace to define a table that is exclusively owned by a
     daemon (via netlink socket aliveness) without auto-removing this
     table when the userspace program exits. Such table gets marked as
     orphaned and a restarting management daemon can re-attach/regain
     ownership.

   - Speed up element insertions to nftables' concatenated-ranges set
     type. Compact a few related data structures.

  BPF:

   - Add BPF token support for delegating a subset of BPF subsystem
     functionality from privileged system-wide daemons such as systemd
     through special mount options for userns-bound BPF fs to a trusted
     &amp; unprivileged application.

   - Introduce bpf_arena which is sparse shared memory region between
     BPF program and user space where structures inside the arena can
     have pointers to other areas of the arena, and pointers work
     seamlessly for both user-space programs and BPF programs.

   - Introduce may_goto instruction that is a contract between the
     verifier and the program. The verifier allows the program to loop
     assuming it's behaving well, but reserves the right to terminate
     it.

   - Extend the BPF verifier to enable static subprog calls in spin lock
     critical sections.

   - Support registration of struct_ops types from modules which helps
     projects like fuse-bpf that seeks to implement a new struct_ops
     type.

   - Add support for retrieval of cookies for perf/kprobe multi links.

   - Support arbitrary TCP SYN cookie generation / validation in the TC
     layer with BPF to allow creating SYN flood handling in BPF
     firewalls.

   - Add code generation to inline the bpf_kptr_xchg() helper which
     improves performance when stashing/popping the allocated BPF
     objects.

  Wireless:

   - Add SPP (signaling and payload protected) AMSDU support.

   - Support wider bandwidth OFDMA, as required for EHT operation.

  Driver API:

   - Major overhaul of the Energy Efficient Ethernet internals to
     support new link modes (2.5GE, 5GE), share more code between
     drivers (especially those using phylib), and encourage more
     uniform behavior. Convert and clean up drivers.

   - Define an API for querying per netdev queue statistics from
     drivers.

   - IPSec: account in global stats for fully offloaded sessions.

   - Create a concept of Ethernet PHY Packages at the Device Tree level,
     to allow parameterizing the existing PHY package code.

   - Enable Rx hashing (RSS) on GTP protocol fields.

  Misc:

   - Improvements and refactoring all over networking selftests.

   - Create uniform module aliases for TC classifiers, actions, and
     packet schedulers to simplify creating modprobe policies.

   - Address all missing MODULE_DESCRIPTION() warnings in networking.

   - Extend the Netlink descriptions in YAML to cover message
     encapsulation or "Netlink polymorphism", where interpretation of
     nested attributes depends on link type, classifier type or some
     other "class type".

  Drivers:

   - Ethernet high-speed NICs:
      - Add a new driver for Marvell's Octeon PCI Endpoint NIC VF.
      - Intel (100G, ice, idpf):
         - support E825-C devices
      - nVidia/Mellanox:
         - support devices with one port and multiple PCIe links
      - Broadcom (bnxt):
         - support n-tuple filters
         - support configuring the RSS key
      - Wangxun (ngbe/txgbe):
         - implement irq_domain for TXGBE's sub-interrupts
      - Pensando/AMD:
         - support XDP
         - optimize queue submission and wakeup handling (+17% bps)
         - optimize struct layout, saving 28% of memory on queues

   - Ethernet NICs embedded and virtual:
      - Google cloud vNIC:
         - refactor driver to perform memory allocations for new queue
           config before stopping and freeing the old queue memory
      - Synopsys (stmmac):
         - obey queueMaxSDU and implement counters required by 802.1Qbv
      - Renesas (ravb):
         - support packet checksum offload
         - suspend to RAM and runtime PM support

   - Ethernet switches:
      - nVidia/Mellanox:
         - support for nexthop group statistics
      - Microchip:
         - ksz8: implement PHY loopback
         - add support for KSZ8567, a 7-port 10/100Mbps switch

   - PTP:
      - New driver for RENESAS FemtoClock3 Wireless clock generator.
      - Support OCP PTP cards designed and built by Adva.

   - CAN:
      - Support recvmsg() flags for own, local and remote traffic on CAN
        BCM sockets.
      - Support for esd GmbH PCIe/402 CAN device family.
      - m_can:
         - Rx/Tx submission coalescing
         - wake on frame Rx

   - WiFi:
      - Intel (iwlwifi):
         - enable signaling and payload protected A-MSDUs
         - support wider-bandwidth OFDMA
         - support for new devices
         - bump FW API to 89 for AX devices; 90 for BZ/SC devices
      - MediaTek (mt76):
         - mt7915: newer ADIE version support
         - mt7925: radio temperature sensor support
      - Qualcomm (ath11k):
         - support 6 GHz station power modes: Low Power Indoor (LPI),
           Standard Power) SP and Very Low Power (VLP)
         - QCA6390 &amp; WCN6855: support 2 concurrent station interfaces
         - QCA2066 support
      - Qualcomm (ath12k):
         - refactoring in preparation for Multi-Link Operation (MLO)
           support
         - 1024 Block Ack window size support
         - firmware-2.bin support
         - support having multiple identical PCI devices (firmware needs
           to have ATH12K_FW_FEATURE_MULTI_QRTR_ID)
         - QCN9274: support split-PHY devices
         - WCN7850: enable Power Save Mode in station mode
         - WCN7850: P2P support
      - RealTek:
         - rtw88: support for more rtw8811cu and rtw8821cu devices
         - rtw89: support SCAN_RANDOM_SN and SET_SCAN_DWELL
         - rtlwifi: speed up USB firmware initialization
         - rtwl8xxxu:
             - RTL8188F: concurrent interface support
             - Channel Switch Announcement (CSA) support in AP mode
      - Broadcom (brcmfmac):
         - per-vendor feature support
         - per-vendor SAE password setup
         - DMI nvram filename quirk for ACEPC W5 Pro"

* tag 'net-next-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2255 commits)
  nexthop: Fix splat with CONFIG_DEBUG_PREEMPT=y
  nexthop: Fix out-of-bounds access during attribute validation
  nexthop: Only parse NHA_OP_FLAGS for dump messages that require it
  nexthop: Only parse NHA_OP_FLAGS for get messages that require it
  bpf: move sleepable flag from bpf_prog_aux to bpf_prog
  bpf: hardcode BPF_PROG_PACK_SIZE to 2MB * num_possible_nodes()
  selftests/bpf: Add kprobe multi triggering benchmarks
  ptp: Move from simple ida to xarray
  vxlan: Remove generic .ndo_get_stats64
  vxlan: Do not alloc tstats manually
  devlink: Add comments to use netlink gen tool
  nfp: flower: handle acti_netdevs allocation failure
  net/packet: Add getsockopt support for PACKET_COPY_THRESH
  net/netlink: Add getsockopt support for NETLINK_LISTEN_ALL_NSID
  selftests/bpf: Add bpf_arena_htab test.
  selftests/bpf: Add bpf_arena_list test.
  selftests/bpf: Add unit tests for bpf_arena_alloc/free_pages
  bpf: Add helper macro bpf_addr_space_cast()
  libbpf: Recognize __arena global variables.
  bpftool: Recognize arena map type
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull networking updates from Jakub Kicinski:
 "Core &amp; protocols:

   - Large effort by Eric to lower rtnl_lock pressure and remove locks:

      - Make commonly used parts of rtnetlink (address, route dumps
        etc) lockless, protected by RCU instead of rtnl_lock.

      - Add a netns exit callback which already holds rtnl_lock,
        allowing netns exit to take rtnl_lock once in the core instead
        of once for each driver / callback.

      - Remove locks / serialization in the socket diag interface.

      - Remove 6 calls to synchronize_rcu() while holding rtnl_lock.

      - Remove the dev_base_lock, depend on RCU where necessary.

   - Support busy polling on a per-epoll context basis. Poll length and
     budget parameters can be set independently of system defaults.

   - Introduce struct net_hotdata, to make sure read-mostly global
     config variables fit in as few cache lines as possible.

   - Add optional per-nexthop statistics to ease monitoring / debug of
     ECMP imbalance problems.

   - Support TCP_NOTSENT_LOWAT in MPTCP.

   - Ensure that IPv6 temporary addresses' preferred lifetimes are long
     enough, compared to other configured lifetimes, and at least 2 sec.

   - Support forwarding of ICMP Error messages in IPSec, per RFC 4301.

   - Add support for the independent control state machine for bonding
     per IEEE 802.1AX-2008 5.4.15 in addition to the existing coupled
     control state machine.

   - Add "network ID" to MCTP socket APIs to support hosts with multiple
     disjoint MCTP networks.

   - Re-use the mono_delivery_time skbuff bit for packets which user
     space wants to be sent at a specified time. Maintain the timing
     information while traversing veth links, bridge etc.

   - Take advantage of MSG_SPLICE_PAGES for RxRPC DATA and ACK packets.

   - Simplify many places iterating over netdevs by using an xarray
     instead of a hash table walk (hash table remains in place, for use
     on fastpaths).

   - Speed up scanning for expired routes by keeping a dedicated list.

   - Speed up "generic" XDP by trying harder to avoid large allocations.

   - Support attaching arbitrary metadata to netconsole messages.

  Things we sprinkled into general kernel code:

   - Enforce VM_IOREMAP flag and range in ioremap_page_range and
     introduce VM_SPARSE kind and vm_area_[un]map_pages (used by
     bpf_arena).

   - Rework selftest harness to enable the use of the full range of ksft
     exit code (pass, fail, skip, xfail, xpass).

  Netfilter:

   - Allow userspace to define a table that is exclusively owned by a
     daemon (via netlink socket aliveness) without auto-removing this
     table when the userspace program exits. Such table gets marked as
     orphaned and a restarting management daemon can re-attach/regain
     ownership.

   - Speed up element insertions to nftables' concatenated-ranges set
     type. Compact a few related data structures.

  BPF:

   - Add BPF token support for delegating a subset of BPF subsystem
     functionality from privileged system-wide daemons such as systemd
     through special mount options for userns-bound BPF fs to a trusted
     &amp; unprivileged application.

   - Introduce bpf_arena which is sparse shared memory region between
     BPF program and user space where structures inside the arena can
     have pointers to other areas of the arena, and pointers work
     seamlessly for both user-space programs and BPF programs.

   - Introduce may_goto instruction that is a contract between the
     verifier and the program. The verifier allows the program to loop
     assuming it's behaving well, but reserves the right to terminate
     it.

   - Extend the BPF verifier to enable static subprog calls in spin lock
     critical sections.

   - Support registration of struct_ops types from modules which helps
     projects like fuse-bpf that seeks to implement a new struct_ops
     type.

   - Add support for retrieval of cookies for perf/kprobe multi links.

   - Support arbitrary TCP SYN cookie generation / validation in the TC
     layer with BPF to allow creating SYN flood handling in BPF
     firewalls.

   - Add code generation to inline the bpf_kptr_xchg() helper which
     improves performance when stashing/popping the allocated BPF
     objects.

  Wireless:

   - Add SPP (signaling and payload protected) AMSDU support.

   - Support wider bandwidth OFDMA, as required for EHT operation.

  Driver API:

   - Major overhaul of the Energy Efficient Ethernet internals to
     support new link modes (2.5GE, 5GE), share more code between
     drivers (especially those using phylib), and encourage more
     uniform behavior. Convert and clean up drivers.

   - Define an API for querying per netdev queue statistics from
     drivers.

   - IPSec: account in global stats for fully offloaded sessions.

   - Create a concept of Ethernet PHY Packages at the Device Tree level,
     to allow parameterizing the existing PHY package code.

   - Enable Rx hashing (RSS) on GTP protocol fields.

  Misc:

   - Improvements and refactoring all over networking selftests.

   - Create uniform module aliases for TC classifiers, actions, and
     packet schedulers to simplify creating modprobe policies.

   - Address all missing MODULE_DESCRIPTION() warnings in networking.

   - Extend the Netlink descriptions in YAML to cover message
     encapsulation or "Netlink polymorphism", where interpretation of
     nested attributes depends on link type, classifier type or some
     other "class type".

  Drivers:

   - Ethernet high-speed NICs:
      - Add a new driver for Marvell's Octeon PCI Endpoint NIC VF.
      - Intel (100G, ice, idpf):
         - support E825-C devices
      - nVidia/Mellanox:
         - support devices with one port and multiple PCIe links
      - Broadcom (bnxt):
         - support n-tuple filters
         - support configuring the RSS key
      - Wangxun (ngbe/txgbe):
         - implement irq_domain for TXGBE's sub-interrupts
      - Pensando/AMD:
         - support XDP
         - optimize queue submission and wakeup handling (+17% bps)
         - optimize struct layout, saving 28% of memory on queues

   - Ethernet NICs embedded and virtual:
      - Google cloud vNIC:
         - refactor driver to perform memory allocations for new queue
           config before stopping and freeing the old queue memory
      - Synopsys (stmmac):
         - obey queueMaxSDU and implement counters required by 802.1Qbv
      - Renesas (ravb):
         - support packet checksum offload
         - suspend to RAM and runtime PM support

   - Ethernet switches:
      - nVidia/Mellanox:
         - support for nexthop group statistics
      - Microchip:
         - ksz8: implement PHY loopback
         - add support for KSZ8567, a 7-port 10/100Mbps switch

   - PTP:
      - New driver for RENESAS FemtoClock3 Wireless clock generator.
      - Support OCP PTP cards designed and built by Adva.

   - CAN:
      - Support recvmsg() flags for own, local and remote traffic on CAN
        BCM sockets.
      - Support for esd GmbH PCIe/402 CAN device family.
      - m_can:
         - Rx/Tx submission coalescing
         - wake on frame Rx

   - WiFi:
      - Intel (iwlwifi):
         - enable signaling and payload protected A-MSDUs
         - support wider-bandwidth OFDMA
         - support for new devices
         - bump FW API to 89 for AX devices; 90 for BZ/SC devices
      - MediaTek (mt76):
         - mt7915: newer ADIE version support
         - mt7925: radio temperature sensor support
      - Qualcomm (ath11k):
         - support 6 GHz station power modes: Low Power Indoor (LPI),
           Standard Power) SP and Very Low Power (VLP)
         - QCA6390 &amp; WCN6855: support 2 concurrent station interfaces
         - QCA2066 support
      - Qualcomm (ath12k):
         - refactoring in preparation for Multi-Link Operation (MLO)
           support
         - 1024 Block Ack window size support
         - firmware-2.bin support
         - support having multiple identical PCI devices (firmware needs
           to have ATH12K_FW_FEATURE_MULTI_QRTR_ID)
         - QCN9274: support split-PHY devices
         - WCN7850: enable Power Save Mode in station mode
         - WCN7850: P2P support
      - RealTek:
         - rtw88: support for more rtw8811cu and rtw8821cu devices
         - rtw89: support SCAN_RANDOM_SN and SET_SCAN_DWELL
         - rtlwifi: speed up USB firmware initialization
         - rtwl8xxxu:
             - RTL8188F: concurrent interface support
             - Channel Switch Announcement (CSA) support in AP mode
      - Broadcom (brcmfmac):
         - per-vendor feature support
         - per-vendor SAE password setup
         - DMI nvram filename quirk for ACEPC W5 Pro"

* tag 'net-next-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2255 commits)
  nexthop: Fix splat with CONFIG_DEBUG_PREEMPT=y
  nexthop: Fix out-of-bounds access during attribute validation
  nexthop: Only parse NHA_OP_FLAGS for dump messages that require it
  nexthop: Only parse NHA_OP_FLAGS for get messages that require it
  bpf: move sleepable flag from bpf_prog_aux to bpf_prog
  bpf: hardcode BPF_PROG_PACK_SIZE to 2MB * num_possible_nodes()
  selftests/bpf: Add kprobe multi triggering benchmarks
  ptp: Move from simple ida to xarray
  vxlan: Remove generic .ndo_get_stats64
  vxlan: Do not alloc tstats manually
  devlink: Add comments to use netlink gen tool
  nfp: flower: handle acti_netdevs allocation failure
  net/packet: Add getsockopt support for PACKET_COPY_THRESH
  net/netlink: Add getsockopt support for NETLINK_LISTEN_ALL_NSID
  selftests/bpf: Add bpf_arena_htab test.
  selftests/bpf: Add bpf_arena_list test.
  selftests/bpf: Add unit tests for bpf_arena_alloc/free_pages
  bpf: Add helper macro bpf_addr_space_cast()
  libbpf: Recognize __arena global variables.
  bpftool: Recognize arena map type
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>net: page_pool: factor out page_pool recycle check</title>
<updated>2024-03-11T20:01:15+00:00</updated>
<author>
<name>Mina Almasry</name>
<email>almasrymina@google.com</email>
</author>
<published>2024-03-08T20:44:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=46f40172b68154106cae660c90c7801b61080892'/>
<id>46f40172b68154106cae660c90c7801b61080892</id>
<content type='text'>
The check is duplicated in 2 places, factor it out into a common helper.

Signed-off-by: Mina Almasry &lt;almasrymina@google.com&gt;
Reviewed-by: Yunsheng Lin &lt;linyunsheng@huawei.com&gt;
Reviewed-by: Ilias Apalodimas &lt;ilias.apalodimas@linaro.org&gt;
Link: https://lore.kernel.org/r/20240308204500.1112858-1-almasrymina@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The check is duplicated in 2 places, factor it out into a common helper.

Signed-off-by: Mina Almasry &lt;almasrymina@google.com&gt;
Reviewed-by: Yunsheng Lin &lt;linyunsheng@huawei.com&gt;
Reviewed-by: Ilias Apalodimas &lt;ilias.apalodimas@linaro.org&gt;
Link: https://lore.kernel.org/r/20240308204500.1112858-1-almasrymina@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-6.9/io_uring-20240310' of git://git.kernel.dk/linux</title>
<updated>2024-03-11T18:35:31+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-03-11T18:35:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d2c84bdce25a678c1e1f116d65b58790bd241af0'/>
<id>d2c84bdce25a678c1e1f116d65b58790bd241af0</id>
<content type='text'>
Pull io_uring updates from Jens Axboe:

 - Make running of task_work internal loops more fair, and unify how the
   different methods deal with them (me)

 - Support for per-ring NAPI. The two minor networking patches are in a
   shared branch with netdev (Stefan)

 - Add support for truncate (Tony)

 - Export SQPOLL utilization stats (Xiaobing)

 - Multishot fixes (Pavel)

 - Fix for a race in manipulating the request flags via poll (Pavel)

 - Cleanup the multishot checking by making it generic, moving it out of
   opcode handlers (Pavel)

 - Various tweaks and cleanups (me, Kunwu, Alexander)

* tag 'for-6.9/io_uring-20240310' of git://git.kernel.dk/linux: (53 commits)
  io_uring: Fix sqpoll utilization check racing with dying sqpoll
  io_uring/net: dedup io_recv_finish req completion
  io_uring: refactor DEFER_TASKRUN multishot checks
  io_uring: fix mshot io-wq checks
  io_uring/net: add io_req_msg_cleanup() helper
  io_uring/net: simplify msghd-&gt;msg_inq checking
  io_uring/kbuf: rename REQ_F_PARTIAL_IO to REQ_F_BL_NO_RECYCLE
  io_uring/net: remove dependency on REQ_F_PARTIAL_IO for sr-&gt;done_io
  io_uring/net: correctly handle multishot recvmsg retry setup
  io_uring/net: clear REQ_F_BL_EMPTY in the multishot retry handler
  io_uring: fix io_queue_proc modifying req-&gt;flags
  io_uring: fix mshot read defer taskrun cqe posting
  io_uring/net: fix overflow check in io_recvmsg_mshot_prep()
  io_uring/net: correct the type of variable
  io_uring/sqpoll: statistics of the true utilization of sq threads
  io_uring/net: move recv/recvmsg flags out of retry loop
  io_uring/kbuf: flag request if buffer pool is empty after buffer pick
  io_uring/net: improve the usercopy for sendmsg/recvmsg
  io_uring/net: move receive multishot out of the generic msghdr path
  io_uring/net: unify how recvmsg and sendmsg copy in the msghdr
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull io_uring updates from Jens Axboe:

 - Make running of task_work internal loops more fair, and unify how the
   different methods deal with them (me)

 - Support for per-ring NAPI. The two minor networking patches are in a
   shared branch with netdev (Stefan)

 - Add support for truncate (Tony)

 - Export SQPOLL utilization stats (Xiaobing)

 - Multishot fixes (Pavel)

 - Fix for a race in manipulating the request flags via poll (Pavel)

 - Cleanup the multishot checking by making it generic, moving it out of
   opcode handlers (Pavel)

 - Various tweaks and cleanups (me, Kunwu, Alexander)

* tag 'for-6.9/io_uring-20240310' of git://git.kernel.dk/linux: (53 commits)
  io_uring: Fix sqpoll utilization check racing with dying sqpoll
  io_uring/net: dedup io_recv_finish req completion
  io_uring: refactor DEFER_TASKRUN multishot checks
  io_uring: fix mshot io-wq checks
  io_uring/net: add io_req_msg_cleanup() helper
  io_uring/net: simplify msghd-&gt;msg_inq checking
  io_uring/kbuf: rename REQ_F_PARTIAL_IO to REQ_F_BL_NO_RECYCLE
  io_uring/net: remove dependency on REQ_F_PARTIAL_IO for sr-&gt;done_io
  io_uring/net: correctly handle multishot recvmsg retry setup
  io_uring/net: clear REQ_F_BL_EMPTY in the multishot retry handler
  io_uring: fix io_queue_proc modifying req-&gt;flags
  io_uring: fix mshot read defer taskrun cqe posting
  io_uring/net: fix overflow check in io_recvmsg_mshot_prep()
  io_uring/net: correct the type of variable
  io_uring/sqpoll: statistics of the true utilization of sq threads
  io_uring/net: move recv/recvmsg flags out of retry loop
  io_uring/kbuf: flag request if buffer pool is empty after buffer pick
  io_uring/net: improve the usercopy for sendmsg/recvmsg
  io_uring/net: move receive multishot out of the generic msghdr path
  io_uring/net: unify how recvmsg and sendmsg copy in the msghdr
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'linux_kselftest-kunit-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest</title>
<updated>2024-03-11T16:32:28+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-03-11T16:32:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=97ec9715a84e6f0979242e1ea98b9af1a39acf3b'/>
<id>97ec9715a84e6f0979242e1ea98b9af1a39acf3b</id>
<content type='text'>
Pull KUnit updates from Shuah Khan:

 - fix to make kunit_bus_type const

 - kunit tool change to Print UML command

 - DRM device creation helpers are now using the new kunit device
   creation helpers. This change resulted in DRM helpers switching from
   using a platform_device, to a dedicated bus and device type used by
   kunit. kunit devices don't set DMA mask and this caused regression on
   some drm tests as they can't allocate DMA buffers. Fix this problem
   by setting DMA masks on the kunit device during initialization.

 - KUnit has several macros which accept a log message, which can
   contain printf format specifiers. Some of these (the explicit log
   macros) already use the __printf() gcc attribute to ensure the format
   specifiers are valid, but those which could fail the test, and hence
   used __kunit_do_failed_assertion() behind the scenes, did not.

   These include: KUNIT_EXPECT_*_MSG(), KUNIT_ASSERT_*_MSG(), and
   KUNIT_FAIL()

   A nine-patch series adds the __printf() attribute, and fixes all of
   the issues uncovered.

* tag 'linux_kselftest-kunit-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  kunit: Annotate _MSG assertion variants with gnu printf specifiers
  drm: tests: Fix invalid printf format specifiers in KUnit tests
  drm/xe/tests: Fix printf format specifiers in xe_migrate test
  net: test: Fix printf format specifier in skb_segment kunit test
  rtc: test: Fix invalid format specifier.
  time: test: Fix incorrect format specifier
  lib: memcpy_kunit: Fix an invalid format specifier in an assertion msg
  lib/cmdline: Fix an invalid format specifier in an assertion msg
  kunit: test: Log the correct filter string in executor_test
  kunit: Setup DMA masks on the kunit device
  kunit: make kunit_bus_type const
  kunit: Mark filter* params as rw
  kunit: tool: Print UML command
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull KUnit updates from Shuah Khan:

 - fix to make kunit_bus_type const

 - kunit tool change to Print UML command

 - DRM device creation helpers are now using the new kunit device
   creation helpers. This change resulted in DRM helpers switching from
   using a platform_device, to a dedicated bus and device type used by
   kunit. kunit devices don't set DMA mask and this caused regression on
   some drm tests as they can't allocate DMA buffers. Fix this problem
   by setting DMA masks on the kunit device during initialization.

 - KUnit has several macros which accept a log message, which can
   contain printf format specifiers. Some of these (the explicit log
   macros) already use the __printf() gcc attribute to ensure the format
   specifiers are valid, but those which could fail the test, and hence
   used __kunit_do_failed_assertion() behind the scenes, did not.

   These include: KUNIT_EXPECT_*_MSG(), KUNIT_ASSERT_*_MSG(), and
   KUNIT_FAIL()

   A nine-patch series adds the __printf() attribute, and fixes all of
   the issues uncovered.

* tag 'linux_kselftest-kunit-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  kunit: Annotate _MSG assertion variants with gnu printf specifiers
  drm: tests: Fix invalid printf format specifiers in KUnit tests
  drm/xe/tests: Fix printf format specifiers in xe_migrate test
  net: test: Fix printf format specifier in skb_segment kunit test
  rtc: test: Fix invalid format specifier.
  time: test: Fix incorrect format specifier
  lib: memcpy_kunit: Fix an invalid format specifier in an assertion msg
  lib/cmdline: Fix an invalid format specifier in an assertion msg
  kunit: test: Log the correct filter string in executor_test
  kunit: Setup DMA masks on the kunit device
  kunit: make kunit_bus_type const
  kunit: Mark filter* params as rw
  kunit: tool: Print UML command
</pre>
</div>
</content>
</entry>
<entry>
<title>net: add skb_data_unref() helper</title>
<updated>2024-03-08T19:38:45+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2024-03-07T12:34:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1cface552a5b5f6e53a855de1a503ff958e2e253'/>
<id>1cface552a5b5f6e53a855de1a503ff958e2e253</id>
<content type='text'>
Similar to skb_unref(), add skb_data_unref() to save an expensive
atomic operation (and cache line dirtying) when last reference
on shinfo-&gt;dataref is released.

I saw this opportunity on hosts with RAW sockets accidentally
bound to UDP protocol, forcing an skb_clone() on all received packets.

These RAW sockets had their receive queue full, so all clone
packets were immediately dropped.

When UDP recvmsg() consumes later the original skb, skb_release_data()
is hitting atomic_sub_return() quite badly, because skb-&gt;clone
has been set permanently.

Note that this patch helps TCP TX performance, because
TCP stack also use (fast) clones.

This means that at least one of the two packets (the main skb or
its clone) will no longer have to perform this atomic operation
in skb_release_data().

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/20240307123446.2302230-1-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Similar to skb_unref(), add skb_data_unref() to save an expensive
atomic operation (and cache line dirtying) when last reference
on shinfo-&gt;dataref is released.

I saw this opportunity on hosts with RAW sockets accidentally
bound to UDP protocol, forcing an skb_clone() on all received packets.

These RAW sockets had their receive queue full, so all clone
packets were immediately dropped.

When UDP recvmsg() consumes later the original skb, skb_release_data()
is hitting atomic_sub_return() quite badly, because skb-&gt;clone
has been set permanently.

Note that this patch helps TCP TX performance, because
TCP stack also use (fast) clones.

This means that at least one of the two packets (the main skb or
its clone) will no longer have to perform this atomic operation
in skb_release_data().

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/20240307123446.2302230-1-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dqs: add NIC stall detector based on BQL</title>
<updated>2024-03-08T10:23:26+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2024-03-04T14:08:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6025b9135f7a8b46826a5fcf947259da43bac281'/>
<id>6025b9135f7a8b46826a5fcf947259da43bac281</id>
<content type='text'>
softnet_data-&gt;time_squeeze is sometimes used as a proxy for
host overload or indication of scheduling problems. In practice
this statistic is very noisy and has hard to grasp units -
e.g. is 10 squeezes a second to be expected, or high?

Delaying network (NAPI) processing leads to drops on NIC queues
but also RTT bloat, impacting pacing and CA decisions.
Stalls are a little hard to detect on the Rx side, because
there may simply have not been any packets received in given
period of time. Packet timestamps help a little bit, but
again we don't know if packets are stale because we're
not keeping up or because someone (*cough* cgroups)
disabled IRQs for a long time.

We can, however, use Tx as a proxy for Rx stalls. Most drivers
use combined Rx+Tx NAPIs so if Tx gets starved so will Rx.
On the Tx side we know exactly when packets get queued,
and completed, so there is no uncertainty.

This patch adds stall checks to BQL. Why BQL? Because
it's a convenient place to add such checks, already
called by most drivers, and it has copious free space
in its structures (this patch adds no extra cache
references or dirtying to the fast path).

The algorithm takes one parameter - max delay AKA stall
threshold and increments a counter whenever NAPI got delayed
for at least that amount of time. It also records the length
of the longest stall.

To be precise every time NAPI has not polled for at least
stall thrs we check if there were any Tx packets queued
between last NAPI run and now - stall_thrs/2.

Unlike the classic Tx watchdog this mechanism does not
ignore stalls caused by Tx being disabled, or loss of link.
I don't think the check is worth the complexity, and
stall is a stall, whether due to host overload, flow
control, link down... doesn't matter much to the application.

We have been running this detector in production at Meta
for 2 years, with the threshold of 8ms. It's the lowest
value where false positives become rare. There's still
a constant stream of reported stalls (especially without
the ksoftirqd deferral patches reverted), those who like
their stall metrics to be 0 may prefer higher value.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Breno Leitao &lt;leitao@debian.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
softnet_data-&gt;time_squeeze is sometimes used as a proxy for
host overload or indication of scheduling problems. In practice
this statistic is very noisy and has hard to grasp units -
e.g. is 10 squeezes a second to be expected, or high?

Delaying network (NAPI) processing leads to drops on NIC queues
but also RTT bloat, impacting pacing and CA decisions.
Stalls are a little hard to detect on the Rx side, because
there may simply have not been any packets received in given
period of time. Packet timestamps help a little bit, but
again we don't know if packets are stale because we're
not keeping up or because someone (*cough* cgroups)
disabled IRQs for a long time.

We can, however, use Tx as a proxy for Rx stalls. Most drivers
use combined Rx+Tx NAPIs so if Tx gets starved so will Rx.
On the Tx side we know exactly when packets get queued,
and completed, so there is no uncertainty.

This patch adds stall checks to BQL. Why BQL? Because
it's a convenient place to add such checks, already
called by most drivers, and it has copious free space
in its structures (this patch adds no extra cache
references or dirtying to the fast path).

The algorithm takes one parameter - max delay AKA stall
threshold and increments a counter whenever NAPI got delayed
for at least that amount of time. It also records the length
of the longest stall.

To be precise every time NAPI has not polled for at least
stall thrs we check if there were any Tx packets queued
between last NAPI run and now - stall_thrs/2.

Unlike the classic Tx watchdog this mechanism does not
ignore stalls caused by Tx being disabled, or loss of link.
I don't think the check is worth the complexity, and
stall is a stall, whether due to host overload, flow
control, link down... doesn't matter much to the application.

We have been running this detector in production at Meta
for 2 years, with the threshold of 8ms. It's the lowest
value where false positives become rare. There's still
a constant stream of reported stalls (especially without
the ksoftirqd deferral patches reverted), those who like
their stall metrics to be 0 may prefer higher value.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Breno Leitao &lt;leitao@debian.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
</feed>
