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2022-10-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-1/+4
Merge in the left-over fixes before the net-next pull-request. Conflicts: drivers/net/ethernet/mediatek/mtk_ppe.c ae3ed15da588 ("net: ethernet: mtk_eth_soc: fix state in __mtk_foe_entry_clear") 9d8cb4c096ab ("net: ethernet: mtk_eth_soc: add foe_entry_size to mtk_eth_soc") https://lore.kernel.org/all/6cb6893b-4921-a068-4c30-1109795110bb@tessares.net/ kernel/bpf/helpers.c 8addbfc7b308 ("bpf: Gate dynptr API behind CAP_BPF") 5679ff2f138f ("bpf: Move bpf_loop and bpf_for_each_map_elem under CAP_BPF") 8a67f2de9b1d ("bpf: expose bpf_strtol and bpf_strtoul to all program types") https://lore.kernel.org/all/20221003201957.13149-1-daniel@iogearbox.net/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-30tcp: fix tcp_cwnd_validate() to not forget is_cwnd_limitedNeal Cardwell1-1/+4
This commit fixes a bug in the tracking of max_packets_out and is_cwnd_limited. This bug can cause the connection to fail to remember that is_cwnd_limited is true, causing the connection to fail to grow cwnd when it should, causing throughput to be lower than it should be. The following event sequence is an example that triggers the bug: (a) The connection is cwnd_limited, but packets_out is not at its peak due to TSO deferral deciding not to send another skb yet. In such cases the connection can advance max_packets_seq and set tp->is_cwnd_limited to true and max_packets_out to a small number. (b) Then later in the round trip the connection is pacing-limited (not cwnd-limited), and packets_out is larger. In such cases the connection would raise max_packets_out to a bigger number but (unexpectedly) flip tp->is_cwnd_limited from true to false. This commit fixes that bug. One straightforward fix would be to separately track (a) the next window after max_packets_out reaches a maximum, and (b) the next window after tp->is_cwnd_limited is set to true. But this would require consuming an extra u32 sequence number. Instead, to save space we track only the most important information. Specifically, we track the strongest available signal of the degree to which the cwnd is fully utilized: (1) If the connection is cwnd-limited then we remember that fact for the current window. (2) If the connection not cwnd-limited then we track the maximum number of outstanding packets in the current window. In particular, note that the new logic cannot trigger the buggy (a)/(b) sequence above because with the new logic a condition where tp->packets_out > tp->max_packets_out can only trigger an update of tp->is_cwnd_limited if tp->is_cwnd_limited is false. This first showed up in a testing of a BBRv2 dev branch, but this buggy behavior highlighted a general issue with the tcp_cwnd_validate() logic that can cause cwnd to fail to increase at the proper rate for any TCP congestion control, including Reno or CUBIC. Fixes: ca8a22634381 ("tcp: make cwnd-limited checks measurement-based, and gentler") Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Kevin(Yudong) Yang <yyd@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-09-28tcp: export tcp_sendmsg_fastopenBenjamin Hesmans1-0/+2
It will be used to support TCP FastOpen with MPTCP in the following commit. Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Co-developed-by: Dmytro Shytyi <dmytro@shytyi.net> Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net> Signed-off-by: Benjamin Hesmans <benjamin.hesmans@tessares.net> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-20tcp: Save unnecessary inet_twsk_purge() calls.Kuniyuki Iwashima1-0/+1
While destroying netns, we call inet_twsk_purge() in tcp_sk_exit_batch() and tcpv6_net_exit_batch() for AF_INET and AF_INET6. These commands trigger the kernel to walk through the potentially big ehash twice even though the netns has no TIME_WAIT sockets. # ip netns add test # ip netns del test or # unshare -n /bin/true >/dev/null When tw_refcount is 1, we need not call inet_twsk_purge() at least for the net. We can save such unneeded iterations if all netns in net_exit_list have no TIME_WAIT sockets. This change eliminates the tax by the additional unshare() described in the next patch to guarantee the per-netns ehash size. Tested: # mount -t debugfs none /sys/kernel/debug/ # echo cleanup_net > /sys/kernel/debug/tracing/set_ftrace_filter # echo inet_twsk_purge >> /sys/kernel/debug/tracing/set_ftrace_filter # echo function > /sys/kernel/debug/tracing/current_tracer # cat ./add_del_unshare.sh for i in `seq 1 40` do (for j in `seq 1 100` ; do unshare -n /bin/true >/dev/null ; done) & done wait; # ./add_del_unshare.sh Before the patch: # cat /sys/kernel/debug/tracing/trace_pipe kworker/u128:0-8 [031] ...1. 174.162765: cleanup_net <-process_one_work kworker/u128:0-8 [031] ...1. 174.240796: inet_twsk_purge <-cleanup_net kworker/u128:0-8 [032] ...1. 174.244759: inet_twsk_purge <-tcp_sk_exit_batch kworker/u128:0-8 [034] ...1. 174.290861: cleanup_net <-process_one_work kworker/u128:0-8 [039] ...1. 175.245027: inet_twsk_purge <-cleanup_net kworker/u128:0-8 [046] ...1. 175.290541: inet_twsk_purge <-tcp_sk_exit_batch kworker/u128:0-8 [037] ...1. 175.321046: cleanup_net <-process_one_work kworker/u128:0-8 [024] ...1. 175.941633: inet_twsk_purge <-cleanup_net kworker/u128:0-8 [025] ...1. 176.242539: inet_twsk_purge <-tcp_sk_exit_batch After: # cat /sys/kernel/debug/tracing/trace_pipe kworker/u128:0-8 [038] ...1. 428.116174: cleanup_net <-process_one_work kworker/u128:0-8 [038] ...1. 428.262532: cleanup_net <-process_one_work kworker/u128:0-8 [030] ...1. 429.292645: cleanup_net <-process_one_work Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-02bpf: Change bpf_getsockopt(SOL_TCP) to reuse do_tcp_getsockopt()Martin KaFai Lau1-0/+2
This patch changes bpf_getsockopt(SOL_TCP) to reuse do_tcp_getsockopt(). It removes the duplicated code from bpf_getsockopt(SOL_TCP). Before this patch, there were some optnames available to bpf_setsockopt(SOL_TCP) but missing in bpf_getsockopt(SOL_TCP). For example, TCP_NODELAY, TCP_MAXSEG, TCP_KEEPIDLE, TCP_KEEPINTVL, and a few more. It surprises users from time to time. This patch automatically closes this gap without duplicating more code. bpf_getsockopt(TCP_SAVED_SYN) does not free the saved_syn, so it stays in sol_tcp_sockopt(). For string name value like TCP_CONGESTION, bpf expects it is always null terminated, so sol_tcp_sockopt() decrements optlen by one before calling do_tcp_getsockopt() and the 'if (optlen < saved_optlen) memset(..,0,..);' in __bpf_getsockopt() will always do a null termination. Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20220902002918.2894511-1-kafai@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-08-18bpf: Change bpf_setsockopt(SOL_TCP) to reuse do_tcp_setsockopt()Martin KaFai Lau1-0/+2
After the prep work in the previous patches, this patch removes all the dup code from bpf_setsockopt(SOL_TCP) and reuses the do_tcp_setsockopt(). The existing optname white-list is refactored into a new function sol_tcp_setsockopt(). The sol_tcp_setsockopt() also calls the bpf_sol_tcp_setsockopt() to handle the TCP_BPF_XXX specific optnames. bpf_setsockopt(TCP_SAVE_SYN) now also allows a value 2 to save the eth header also and it comes for free from do_tcp_setsockopt(). Reviewed-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/r/20220817061819.4180146-1-kafai@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-28Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-1/+1
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-07-26tcp: allow tls to decrypt directly from the tcp rcv queueJakub Kicinski1-0/+2
Expose TCP rx queue accessor and cleanup, so that TLS can decrypt directly from the TCP queue. The expectation is that the caller can access the skb returned from tcp_recv_skb() and up to inq bytes worth of data (some of which may be in ->next skbs) and then call tcp_read_done() when data has been consumed. The socket lock must be held continuously across those two operations. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-07-22tcp: Fix a data-race around sysctl_tcp_adv_win_scale.Kuniyuki Iwashima1-1/+1
While reading sysctl_tcp_adv_win_scale, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-21Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-8/+12
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-07-20tcp: Fix data-races around sysctl_tcp_slow_start_after_idle.Kuniyuki Iwashima1-2/+2
While reading sysctl_tcp_slow_start_after_idle, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 35089bb203f4 ("[TCP]: Add tcp_slow_start_after_idle sysctl.") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-18tcp: Fix a data-race around sysctl_tcp_notsent_lowat.Kuniyuki Iwashima1-1/+1
While reading sysctl_tcp_notsent_lowat, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: c9bee3b7fdec ("tcp: TCP_NOTSENT_LOWAT socket option") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-18tcp: Fix data-races around some timeout sysctl knobs.Kuniyuki Iwashima1-1/+2
While reading these sysctl knobs, they can be changed concurrently. Thus, we need to add READ_ONCE() to their readers. - tcp_retries1 - tcp_retries2 - tcp_orphan_retries - tcp_fin_timeout Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-18tcp: Fix data-races around keepalive sysctl knobs.Kuniyuki Iwashima1-3/+6
While reading sysctl_tcp_keepalive_(time|probes|intvl), they can be changed concurrently. Thus, we need to add READ_ONCE() to their readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-15tcp/udp: Make early_demux back namespacified.Kuniyuki Iwashima1-1/+1
Commit e21145a9871a ("ipv4: namespacify ip_early_demux sysctl knob") made it possible to enable/disable early_demux on a per-netns basis. Then, we introduced two knobs, tcp_early_demux and udp_early_demux, to switch it for TCP/UDP in commit dddb64bcb346 ("net: Add sysctl to toggle early demux for tcp and udp"). However, the .proc_handler() was wrong and actually disabled us from changing the behaviour in each netns. We can execute early_demux if net.ipv4.ip_early_demux is on and each proto .early_demux() handler is not NULL. When we toggle (tcp|udp)_early_demux, the change itself is saved in each netns variable, but the .early_demux() handler is a global variable, so the handler is switched based on the init_net's sysctl variable. Thus, netns (tcp|udp)_early_demux knobs have nothing to do with the logic. Whether we CAN execute proto .early_demux() is always decided by init_net's sysctl knob, and whether we DO it or not is by each netns ip_early_demux knob. This patch namespacifies (tcp|udp)_early_demux again. For now, the users of the .early_demux() handler are TCP and UDP only, and they are called directly to avoid retpoline. So, we can remove the .early_demux() handler from inet6?_protos and need not dereference them in ip6?_rcv_finish_core(). If another proto needs .early_demux(), we can restore it at that time. Fixes: dddb64bcb346 ("net: Add sysctl to toggle early demux for tcp and udp") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://lore.kernel.org/r/20220713175207.7727-1-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-20net: Introduce a new proto_ops ->read_skb()Cong Wang1-2/+1
Currently both splice() and sockmap use ->read_sock() to read skb from receive queue, but for sockmap we only read one entire skb at a time, so ->read_sock() is too conservative to use. Introduce a new proto_ops ->read_skb() which supports this sematic, with this we can finally pass the ownership of skb to recv actors. For non-TCP protocols, all ->read_sock() can be simply converted to ->read_skb(). Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20220615162014.89193-3-xiyou.wangcong@gmail.com
2022-06-20tcp: Introduce tcp_read_skb()Cong Wang1-0/+2
This patch inroduces tcp_read_skb() based on tcp_read_sock(), a preparation for the next patch which actually introduces a new sock ops. TCP is special here, because it has tcp_read_sock() which is mainly used by splice(). tcp_read_sock() supports partial read and arbitrary offset, neither of them is needed for sockmap. Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20220615162014.89193-2-xiyou.wangcong@gmail.com
2022-06-17Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski1-0/+1
Daniel Borkmann says: ==================== pull-request: bpf-next 2022-06-17 We've added 72 non-merge commits during the last 15 day(s) which contain a total of 92 files changed, 4582 insertions(+), 834 deletions(-). The main changes are: 1) Add 64 bit enum value support to BTF, from Yonghong Song. 2) Implement support for sleepable BPF uprobe programs, from Delyan Kratunov. 3) Add new BPF helpers to issue and check TCP SYN cookies without binding to a socket especially useful in synproxy scenarios, from Maxim Mikityanskiy. 4) Fix libbpf's internal USDT address translation logic for shared libraries as well as uprobe's symbol file offset calculation, from Andrii Nakryiko. 5) Extend libbpf to provide an API for textual representation of the various map/prog/attach/link types and use it in bpftool, from Daniel Müller. 6) Provide BTF line info for RV64 and RV32 JITs, and fix a put_user bug in the core seen in 32 bit when storing BPF function addresses, from Pu Lehui. 7) Fix libbpf's BTF pointer size guessing by adding a list of various aliases for 'long' types, from Douglas Raillard. 8) Fix bpftool to readd setting rlimit since probing for memcg-based accounting has been unreliable and caused a regression on COS, from Quentin Monnet. 9) Fix UAF in BPF cgroup's effective program computation triggered upon BPF link detachment, from Tadeusz Struk. 10) Fix bpftool build bootstrapping during cross compilation which was pointing to the wrong AR process, from Shahab Vahedi. 11) Fix logic bug in libbpf's is_pow_of_2 implementation, from Yuze Chi. 12) BPF hash map optimization to avoid grabbing spinlocks of all CPUs when there is no free element. Also add a benchmark as reproducer, from Feng Zhou. 13) Fix bpftool's codegen to bail out when there's no BTF, from Michael Mullin. 14) Various minor cleanup and improvements all over the place. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (72 commits) bpf: Fix bpf_skc_lookup comment wrt. return type bpf: Fix non-static bpf_func_proto struct definitions selftests/bpf: Don't force lld on non-x86 architectures selftests/bpf: Add selftests for raw syncookie helpers in TC mode bpf: Allow the new syncookie helpers to work with SKBs selftests/bpf: Add selftests for raw syncookie helpers bpf: Add helpers to issue and check SYN cookies in XDP bpf: Allow helpers to accept pointers with a fixed size bpf: Fix documentation of th_len in bpf_tcp_{gen,check}_syncookie selftests/bpf: add tests for sleepable (uk)probes libbpf: add support for sleepable uprobe programs bpf: allow sleepable uprobe programs to attach bpf: implement sleepable uprobes by chaining gps bpf: move bpf_prog to bpf.h libbpf: Fix internal USDT address translation logic for shared libraries samples/bpf: Check detach prog exist or not in xdp_fwd selftests/bpf: Avoid skipping certain subtests selftests/bpf: Fix test_varlen verification failure with latest llvm bpftool: Do not check return value from libbpf_set_strict_mode() Revert "bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK" ... ==================== Link: https://lore.kernel.org/r/20220617220836.7373-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-16bpf: Add helpers to issue and check SYN cookies in XDPMaxim Mikityanskiy1-0/+1
The new helpers bpf_tcp_raw_{gen,check}_syncookie_ipv{4,6} allow an XDP program to generate SYN cookies in response to TCP SYN packets and to check those cookies upon receiving the first ACK packet (the final packet of the TCP handshake). Unlike bpf_tcp_{gen,check}_syncookie these new helpers don't need a listening socket on the local machine, which allows to use them together with synproxy to accelerate SYN cookie generation. Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Link: https://lore.kernel.org/r/20220615134847.3753567-4-maximmi@nvidia.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-10net: add per_cpu_fw_alloc field to struct protoEric Dumazet1-0/+2
Each protocol having a ->memory_allocated pointer gets a corresponding per-cpu reserve, that following patches will use. Instead of having reserved bytes per socket, we want to have per-cpu reserves. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-28Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-0/+8
include/linux/netdevice.h net/core/dev.c 6510ea973d8d ("net: Use this_cpu_inc() to increment net->core_stats") 794c24e9921f ("net-core: rx_otherhost_dropped to core_stats") https://lore.kernel.org/all/20220428111903.5f4304e0@canb.auug.org.au/ drivers/net/wan/cosa.c d48fea8401cf ("net: cosa: fix error check return value of register_chrdev()") 89fbca3307d4 ("net: wan: remove support for COSA and SRP synchronous serial boards") https://lore.kernel.org/all/20220428112130.1f689e5e@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-26net: generalize skb freeing deferral to per-cpu listsEric Dumazet1-12/+0
Logic added in commit f35f821935d8 ("tcp: defer skb freeing after socket lock is released") helped bulk TCP flows to move the cost of skbs frees outside of critical section where socket lock was held. But for RPC traffic, or hosts with RFS enabled, the solution is far from being ideal. For RPC traffic, recvmsg() has to return to user space right after skb payload has been consumed, meaning that BH handler has no chance to pick the skb before recvmsg() thread. This issue is more visible with BIG TCP, as more RPC fit one skb. For RFS, even if BH handler picks the skbs, they are still picked from the cpu on which user thread is running. Ideally, it is better to free the skbs (and associated page frags) on the cpu that originally allocated them. This patch removes the per socket anchor (sk->defer_list) and instead uses a per-cpu list, which will hold more skbs per round. This new per-cpu list is drained at the end of net_action_rx(), after incoming packets have been processed, to lower latencies. In normal conditions, skbs are added to the per-cpu list with no further action. In the (unlikely) cases where the cpu does not run net_action_rx() handler fast enough, we use an IPI to raise NET_RX_SOFTIRQ on the remote cpu. Also, we do not bother draining the per-cpu list from dev_cpu_dead() This is because skbs in this list have no requirement on how fast they should be freed. Note that we can add in the future a small per-cpu cache if we see any contention on sd->defer_lock. Tested on a pair of hosts with 100Gbit NIC, RFS enabled, and /proc/sys/net/ipv4/tcp_rmem[2] tuned to 16MB to work around page recycling strategy used by NIC driver (its page pool capacity being too small compared to number of skbs/pages held in sockets receive queues) Note that this tuning was only done to demonstrate worse conditions for skb freeing for this particular test. These conditions can happen in more general production workload. 10 runs of one TCP_STREAM flow Before: Average throughput: 49685 Mbit. Kernel profiles on cpu running user thread recvmsg() show high cost for skb freeing related functions (*) 57.81% [kernel] [k] copy_user_enhanced_fast_string (*) 12.87% [kernel] [k] skb_release_data (*) 4.25% [kernel] [k] __free_one_page (*) 3.57% [kernel] [k] __list_del_entry_valid 1.85% [kernel] [k] __netif_receive_skb_core 1.60% [kernel] [k] __skb_datagram_iter (*) 1.59% [kernel] [k] free_unref_page_commit (*) 1.16% [kernel] [k] __slab_free 1.16% [kernel] [k] _copy_to_iter (*) 1.01% [kernel] [k] kfree (*) 0.88% [kernel] [k] free_unref_page 0.57% [kernel] [k] ip6_rcv_core 0.55% [kernel] [k] ip6t_do_table 0.54% [kernel] [k] flush_smp_call_function_queue (*) 0.54% [kernel] [k] free_pcppages_bulk 0.51% [kernel] [k] llist_reverse_order 0.38% [kernel] [k] process_backlog (*) 0.38% [kernel] [k] free_pcp_prepare 0.37% [kernel] [k] tcp_recvmsg_locked (*) 0.37% [kernel] [k] __list_add_valid 0.34% [kernel] [k] sock_rfree 0.34% [kernel] [k] _raw_spin_lock_irq (*) 0.33% [kernel] [k] __page_cache_release 0.33% [kernel] [k] tcp_v6_rcv (*) 0.33% [kernel] [k] __put_page (*) 0.29% [kernel] [k] __mod_zone_page_state 0.27% [kernel] [k] _raw_spin_lock After patch: Average throughput: 73076 Mbit. Kernel profiles on cpu running user thread recvmsg() looks better: 81.35% [kernel] [k] copy_user_enhanced_fast_string 1.95% [kernel] [k] _copy_to_iter 1.95% [kernel] [k] __skb_datagram_iter 1.27% [kernel] [k] __netif_receive_skb_core 1.03% [kernel] [k] ip6t_do_table 0.60% [kernel] [k] sock_rfree 0.50% [kernel] [k] tcp_v6_rcv 0.47% [kernel] [k] ip6_rcv_core 0.45% [kernel] [k] read_tsc 0.44% [kernel] [k] _raw_spin_lock_irqsave 0.37% [kernel] [k] _raw_spin_lock 0.37% [kernel] [k] native_irq_return_iret 0.33% [kernel] [k] __inet6_lookup_established 0.31% [kernel] [k] ip6_protocol_deliver_rcu 0.29% [kernel] [k] tcp_rcv_established 0.29% [kernel] [k] llist_reverse_order v2: kdoc issue (kernel bots) do not defer if (alloc_cpu == smp_processor_id()) (Paolo) replace the sk_buff_head with a single-linked list (Jakub) add a READ_ONCE()/WRITE_ONCE() for the lockless read of sd->defer_list Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://lore.kernel.org/r/20220422201237.416238-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-25tcp: make sure treq->af_specific is initializedEric Dumazet1-0/+1
syzbot complained about a recent change in TCP stack, hitting a NULL pointer [1] tcp request sockets have an af_specific pointer, which was used before the blamed change only for SYNACK generation in non SYNCOOKIE mode. tcp requests sockets momentarily created when third packet coming from client in SYNCOOKIE mode were not using treq->af_specific. Make sure this field is populated, in the same way normal TCP requests sockets do in tcp_conn_request(). [1] TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 1 PID: 3695 Comm: syz-executor864 Not tainted 5.18.0-rc3-syzkaller-00224-g5fd1fe4807f9 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:tcp_create_openreq_child+0xe16/0x16b0 net/ipv4/tcp_minisocks.c:534 Code: 48 c1 ea 03 80 3c 02 00 0f 85 e5 07 00 00 4c 8b b3 28 01 00 00 48 b8 00 00 00 00 00 fc ff df 49 8d 7e 08 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 c9 07 00 00 48 8b 3c 24 48 89 de 41 ff 56 08 48 RSP: 0018:ffffc90000de0588 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff888076490330 RCX: 0000000000000100 RDX: 0000000000000001 RSI: ffffffff87d67ff0 RDI: 0000000000000008 RBP: ffff88806ee1c7f8 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff87d67f00 R11: 0000000000000000 R12: ffff88806ee1bfc0 R13: ffff88801b0e0368 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f517fe58700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffcead76960 CR3: 000000006f97b000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> tcp_v6_syn_recv_sock+0x199/0x23b0 net/ipv6/tcp_ipv6.c:1267 tcp_get_cookie_sock+0xc9/0x850 net/ipv4/syncookies.c:207 cookie_v6_check+0x15c3/0x2340 net/ipv6/syncookies.c:258 tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1131 [inline] tcp_v6_do_rcv+0x1148/0x13b0 net/ipv6/tcp_ipv6.c:1486 tcp_v6_rcv+0x3305/0x3840 net/ipv6/tcp_ipv6.c:1725 ip6_protocol_deliver_rcu+0x2e9/0x1900 net/ipv6/ip6_input.c:422 ip6_input_finish+0x14c/0x2c0 net/ipv6/ip6_input.c:464 NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:473 dst_input include/net/dst.h:461 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ipv6_rcv+0x27f/0x3b0 net/ipv6/ip6_input.c:297 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5405 __netif_receive_skb+0x24/0x1b0 net/core/dev.c:5519 process_backlog+0x3a0/0x7c0 net/core/dev.c:5847 __napi_poll+0xb3/0x6e0 net/core/dev.c:6413 napi_poll net/core/dev.c:6480 [inline] net_rx_action+0x8ec/0xc60 net/core/dev.c:6567 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097 Fixes: 5b0b9e4c2c89 ("tcp: md5: incorrect tcp_header_len for incoming connections") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Francesco Ruggeri <fruggeri@arista.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-04-25tcp: fix potential xmit stalls caused by TCP_NOTSENT_LOWATEric Dumazet1-0/+1
I had this bug sitting for too long in my pile, it is time to fix it. Thanks to Doug Porter for reminding me of it! We had various attempts in the past, including commit 0cbe6a8f089e ("tcp: remove SOCK_QUEUE_SHRUNK"), but the issue is that TCP stack currently only generates EPOLLOUT from input path, when tp->snd_una has advanced and skb(s) cleaned from rtx queue. If a flow has a big RTT, and/or receives SACKs, it is possible that the notsent part (tp->write_seq - tp->snd_nxt) reaches 0 and no more data can be sent until tp->snd_una finally advances. What is needed is to also check if POLLOUT needs to be generated whenever tp->snd_nxt is advanced, from output path. This bug triggers more often after an idle period, as we do not receive ACK for at least one RTT. tcp_notsent_lowat could be a fraction of what CWND and pacing rate would allow to send during this RTT. In a followup patch, I will remove the bogus call to tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED) from tcp_check_space(). Fact that we have decided to generate an EPOLLOUT does not mean the application has immediately refilled the transmit queue. This optimistic call might have been the reason the bug seemed not too serious. Tested: 200 ms rtt, 1% packet loss, 32 MB tcp_rmem[2] and tcp_wmem[2] $ echo 500000 >/proc/sys/net/ipv4/tcp_notsent_lowat $ cat bench_rr.sh SUM=0 for i in {1..10} do V=`netperf -H remote_host -l30 -t TCP_RR -- -r 10000000,10000 -o LOCAL_BYTES_SENT | egrep -v "MIGRATED|Bytes"` echo $V SUM=$(($SUM + $V)) done echo SUM=$SUM Before patch: $ bench_rr.sh 130000000 80000000 140000000 140000000 140000000 140000000 130000000 40000000 90000000 110000000 SUM=1140000000 After patch: $ bench_rr.sh 430000000 590000000 530000000 450000000 450000000 350000000 450000000 490000000 480000000 460000000 SUM=4680000000 # This is 410 % of the value before patch. Fixes: c9bee3b7fdec ("tcp: TCP_NOTSENT_LOWAT socket option") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Doug Porter <dsp@fb.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Neal Cardwell <ncardwell@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-04-22tcp: ensure to use the most recently sent skb when filling the rate samplePengcheng Yang1-0/+6
If an ACK (s)acks multiple skbs, we favor the information from the most recently sent skb by choosing the skb with the highest prior_delivered count. But in the interval between receiving ACKs, we send multiple skbs with the same prior_delivered, because the tp->delivered only changes when we receive an ACK. We used RACK's solution, copying tcp_rack_sent_after() as tcp_skb_sent_after() helper to determine "which packet was sent last?". Later, we will use tcp_skb_sent_after() instead in RACK. Fixes: b9f64820fb22 ("tcp: track data delivery rate for a TCP connection") Signed-off-by: Pengcheng Yang <yangpc@wangsu.com> Cc: Paolo Abeni <pabeni@redhat.com> Acked-by: Neal Cardwell <ncardwell@google.com> Tested-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/1650422081-22153-1-git-send-email-yangpc@wangsu.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-12net: remove noblock parameter from recvmsg() entitiesOliver Hartkopp1-1/+1
The internal recvmsg() functions have two parameters 'flags' and 'noblock' that were merged inside skb_recv_datagram(). As a follow up patch to commit f4b41f062c42 ("net: remove noblock parameter from skb_recv_datagram()") this patch removes the separate 'noblock' parameter for recvmsg(). Analogue to the referenced patch for skb_recv_datagram() the 'flags' and 'noblock' parameters are unnecessarily split up with e.g. err = sk->sk_prot->recvmsg(sk, msg, size, flags & MSG_DONTWAIT, flags & ~MSG_DONTWAIT, &addr_len); or in err = INDIRECT_CALL_2(sk->sk_prot->recvmsg, tcp_recvmsg, udp_recvmsg, sk, msg, size, flags & MSG_DONTWAIT, flags & ~MSG_DONTWAIT, &addr_len); instead of simply using only flags all the time and check for MSG_DONTWAIT where needed (to preserve for the formerly separated no(n)block condition). Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://lore.kernel.org/r/20220411124955.154876-1-socketcan@hartkopp.net Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-04-07tcp: Add tracepoint for tcp_set_ca_statePing Gan1-9/+3
The congestion status of a tcp flow may be updated since there is congestion between tcp sender and receiver. It makes sense to add tracepoint for congestion status set function to summate cc status duration and evaluate the performance of network and congestion algorithm. the backgound of this patch is below. Link: https://github.com/iovisor/bcc/pull/3899 Signed-off-by: Ping Gan <jacky_gam_2001@163.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20220406010956.19656-1-jacky_gam_2001@163.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-06tcp: add accessors to read/set tp->snd_cwndEric Dumazet1-4/+15
We had various bugs over the years with code breaking the assumption that tp->snd_cwnd is greater than zero. Lately, syzbot reported the WARN_ON_ONCE(!tp->prior_cwnd) added in commit 8b8a321ff72c ("tcp: fix zero cwnd in tcp_cwnd_reduction") can trigger, and without a repro we would have to spend considerable time finding the bug. Instead of complaining too late, we want to catch where and when tp->snd_cwnd is set to an illegal value. Signed-off-by: Eric Dumazet <edumazet@google.com> Suggested-by: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Link: https://lore.kernel.org/r/20220405233538.947344-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-03-09net: tcp: fix shim definition of tcp_inbound_md5_hashVladimir Oltean1-1/+1
When CONFIG_TCP_MD5SIG isn't enabled, there is a compilation bug due to the fact that the static inline definition of tcp_inbound_md5_hash() has an unexpected semicolon. Remove it. Fixes: 1330b6ef3313 ("skb: make drop reason booleanable") Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Link: https://lore.kernel.org/r/20220309122012.668986-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-03-09skb: make drop reason booleanableJakub Kicinski1-10/+11
We have a number of cases where function returns drop/no drop decision as a boolean. Now that we want to report the reason code as well we have to pass extra output arguments. We can make the reason code evaluate correctly as bool. I believe we're good to reorder the reasons as they are reported to user space as strings. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-03-02tcp: Remove the unused apiTao Chen1-5/+0
Last tcp_write_queue_head() use was removed in commit 114f39feab36 ("tcp: restore autocorking"), so remove it. Signed-off-by: Tao Chen <chentao3@hotmail.com> Link: https://lore.kernel.org/r/SYZP282MB33317DEE1253B37C0F57231E86029@SYZP282MB3331.AUSP282.PROD.OUTLOOK.COM Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-24net/tcp: Merge TCP-MD5 inbound callbacksDmitry Safonov1-0/+13
The functions do essentially the same work to verify TCP-MD5 sign. Code can be merged into one family-independent function in order to reduce copy'n'paste and generated code. Later with TCP-AO option added, this will allow to create one function that's responsible for segment verification, that will have all the different checks for MD5/AO/non-signed packets, which in turn will help to see checks for all corner-cases in one function, rather than spread around different families and functions. Cc: Eric Dumazet <edumazet@google.com> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Signed-off-by: Dmitry Safonov <dima@arista.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20220223175740.452397-1-dima@arista.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-20net: tcp: add skb drop reasons to tcp_add_backlog()Menglong Dong1-1/+2
Pass the address of drop_reason to tcp_add_backlog() to store the reasons for skb drops when fails. Following drop reasons are introduced: SKB_DROP_REASON_SOCKET_BACKLOG Reviewed-by: Mengen Sun <mengensun@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Menglong Dong <imagedong@tencent.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-02tcp: Use BPF timeout setting for SYN ACK RTOAkhmat Karakotov1-1/+1
When setting RTO through BPF program, some SYN ACK packets were unaffected and continued to use TCP_TIMEOUT_INIT constant. This patch adds timeout option to struct request_sock. Option is initialized with TCP_TIMEOUT_INIT and is reassigned through BPF using tcp_timeout_init call. SYN ACK retransmits now use newly added timeout option. Signed-off-by: Akhmat Karakotov <hmukos@yandex-team.ru> Acked-by: Martin KaFai Lau <kafai@fb.com> v2: - Add timeout option to struct request_sock. Do not call tcp_timeout_init on every syn ack retransmit. v3: - Use unsigned long for min. Bound tcp_timeout_init to TCP_RTO_MAX. v4: - Refactor duplicate code by adding reqsk_timeout function. Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-20tcp: Add a stub for sk_defer_free_flush()Gal Pressman1-0/+4
When compiling the kernel with CONFIG_INET disabled, the sk_defer_free_flush() should be defined as a nop. This resolves the following compilation error: ld: net/core/sock.o: in function `sk_defer_free_flush': ./include/net/tcp.h:1378: undefined reference to `__sk_defer_free_flush' Fixes: 79074a72d335 ("net: Flush deferred skb free on socket destroy") Reported-by: kernel test robot <lkp@intel.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Signed-off-by: Gal Pressman <gal@nvidia.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20220120123440.9088-1-gal@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-16tcp: defer skb freeing after socket lock is releasedEric Dumazet1-0/+10
tcp recvmsg() (or rx zerocopy) spends a fair amount of time freeing skbs after their payload has been consumed. A typical ~64KB GRO packet has to release ~45 page references, eventually going to page allocator for each of them. Currently, this freeing is performed while socket lock is held, meaning that there is a high chance that BH handler has to queue incoming packets to tcp socket backlog. This can cause additional latencies, because the user thread has to process the backlog at release_sock() time, and while doing so, additional frames can be added by BH handler. This patch adds logic to defer these frees after socket lock is released, or directly from BH handler if possible. Being able to free these skbs from BH handler helps a lot, because this avoids the usual alloc/free assymetry, when BH handler and user thread do not run on same cpu or NUMA node. One cpu can now be fully utilized for the kernel->user copy, and another cpu is handling BH processing and skb/page allocs/frees (assuming RFS is not forcing use of a single CPU) Tested: 100Gbit NIC Max throughput for one TCP_STREAM flow, over 10 runs MTU : 1500 Before: 55 Gbit After: 66 Gbit MTU : 4096+(headers) Before: 82 Gbit After: 95 Gbit Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-16tcp: annotate data-races on tp->segs_in and tp->data_segs_inEric Dumazet1-2/+6
tcp_segs_in() can be called from BH, while socket spinlock is held but socket owned by user, eventually reading these fields from tcp_get_info() Found by code inspection, no need to backport this patch to older kernels. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-03net: avoid double accounting for pure zerocopy skbsTalal Ahmad1-2/+6
Track skbs containing only zerocopy data and avoid charging them to kernel memory to correctly account the memory utilization for msg_zerocopy. All of the data in such skbs is held in user pages which are already accounted to user. Before this change, they are charged again in kernel in __zerocopy_sg_from_iter. The charging in kernel is excessive because data is not being copied into skb frags. This excessive charging can lead to kernel going into memory pressure state which impacts all sockets in the system adversely. Mark pure zerocopy skbs with a SKBFL_PURE_ZEROCOPY flag and remove charge/uncharge for data in such skbs. Initially, an skb is marked pure zerocopy when it is empty and in zerocopy path. skb can then change from a pure zerocopy skb to mixed data skb (zerocopy and copy data) if it is at tail of write queue and there is room available in it and non-zerocopy data is being sent in the next sendmsg call. At this time sk_mem_charge is done for the pure zerocopied data and the pure zerocopy flag is unmarked. We found that this happens very rarely on workloads that pass MSG_ZEROCOPY. A pure zerocopy skb can later be coalesced into normal skb if they are next to each other in queue but this patch prevents coalescing from happening. This avoids complexity of charging when skb downgrades from pure zerocopy to mixed. This is also rare. In sk_wmem_free_skb, if it is a pure zerocopy skb, an sk_mem_uncharge for SKB_TRUESIZE(skb_end_offset(skb)) is done for sk_mem_charge in tcp_skb_entail for an skb without data. Testing with the msg_zerocopy.c benchmark between two hosts(100G nics) with zerocopy showed that before this patch the 'sock' variable in memory.stat for cgroup2 that tracks sum of sk_forward_alloc, sk_rmem_alloc and sk_wmem_queued is around 1822720 and with this change it is 0. This is due to no charge to sk_forward_alloc for zerocopy data and shows memory utilization for kernel is lowered. With this commit we don't see the warning we saw in previous commit which resulted in commit 84882cf72cd774cf16fd338bdbf00f69ac9f9194. Signed-off-by: Talal Ahmad <talalahmad@google.com> Acked-by: Arjun Roy <arjunroy@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-01Revert "net: avoid double accounting for pure zerocopy skbs"Jakub Kicinski1-6/+2
This reverts commit f1a456f8f3fc5828d8abcad941860380ae147b1d. WARNING: CPU: 1 PID: 6819 at net/core/skbuff.c:5429 skb_try_coalesce+0x78b/0x7e0 CPU: 1 PID: 6819 Comm: xxxxxxx Kdump: loaded Tainted: G S 5.15.0-04194-gd852503f7711 #16 RIP: 0010:skb_try_coalesce+0x78b/0x7e0 Code: e8 2a bf 41 ff 44 8b b3 bc 00 00 00 48 8b 7c 24 30 e8 19 c0 41 ff 44 89 f0 48 03 83 c0 00 00 00 48 89 44 24 40 e9 47 fb ff ff <0f> 0b e9 ca fc ff ff 4c 8d 70 ff 48 83 c0 07 48 89 44 24 38 e9 61 RSP: 0018:ffff88881f449688 EFLAGS: 00010282 RAX: 00000000fffffe96 RBX: ffff8881566e4460 RCX: ffffffff82079f7e RDX: 0000000000000003 RSI: dffffc0000000000 RDI: ffff8881566e47b0 RBP: ffff8881566e46e0 R08: ffffed102619235d R09: ffffed102619235d R10: ffff888130c91ae3 R11: ffffed102619235c R12: ffff88881f4498a0 R13: 0000000000000056 R14: 0000000000000009 R15: ffff888130c91ac0 FS: 00007fec2cbb9700(0000) GS:ffff88881f440000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fec1b060d80 CR3: 00000003acf94005 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> tcp_try_coalesce+0xeb/0x290 ? tcp_parse_options+0x610/0x610 ? mark_held_locks+0x79/0xa0 tcp_queue_rcv+0x69/0x2f0 tcp_rcv_established+0xa49/0xd40 ? tcp_data_queue+0x18a0/0x18a0 tcp_v6_do_rcv+0x1c9/0x880 ? rt6_mtu_change_route+0x100/0x100 tcp_v6_rcv+0x1624/0x1830 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-01net: avoid double accounting for pure zerocopy skbsTalal Ahmad1-2/+6
Track skbs with only zerocopy data and avoid charging them to kernel memory to correctly account the memory utilization for msg_zerocopy. All of the data in such skbs is held in user pages which are already accounted to user. Before this change, they are charged again in kernel in __zerocopy_sg_from_iter. The charging in kernel is excessive because data is not being copied into skb frags. This excessive charging can lead to kernel going into memory pressure state which impacts all sockets in the system adversely. Mark pure zerocopy skbs with a SKBFL_PURE_ZEROCOPY flag and remove charge/uncharge for data in such skbs. Initially, an skb is marked pure zerocopy when it is empty and in zerocopy path. skb can then change from a pure zerocopy skb to mixed data skb (zerocopy and copy data) if it is at tail of write queue and there is room available in it and non-zerocopy data is being sent in the next sendmsg call. At this time sk_mem_charge is done for the pure zerocopied data and the pure zerocopy flag is unmarked. We found that this happens very rarely on workloads that pass MSG_ZEROCOPY. A pure zerocopy skb can later be coalesced into normal skb if they are next to each other in queue but this patch prevents coalescing from happening. This avoids complexity of charging when skb downgrades from pure zerocopy to mixed. This is also rare. In sk_wmem_free_skb, if it is a pure zerocopy skb, an sk_mem_uncharge for SKB_TRUESIZE(MAX_TCP_HEADER) is done for sk_mem_charge in tcp_skb_entail for an skb without data. Testing with the msg_zerocopy.c benchmark between two hosts(100G nics) with zerocopy showed that before this patch the 'sock' variable in memory.stat for cgroup2 that tracks sum of sk_forward_alloc, sk_rmem_alloc and sk_wmem_queued is around 1822720 and with this change it is 0. This is due to no charge to sk_forward_alloc for zerocopy data and shows memory utilization for kernel is lowered. Signed-off-by: Talal Ahmad <talalahmad@google.com> Acked-by: Arjun Roy <arjunroy@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-01tcp: rename sk_wmem_free_skbTalal Ahmad1-1/+8
sk_wmem_free_skb() is only used by TCP. Rename it to make this clear, and move its declaration to include/net/tcp.h Signed-off-by: Talal Ahmad <talalahmad@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Arjun Roy <arjunroy@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-28tcp: cleanup tcp_remove_empty_skb() useEric Dumazet1-1/+1
All tcp_remove_empty_skb() callers now use tcp_write_queue_tail() for the skb argument, we can therefore factorize code. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-26tcp: rename sk_stream_alloc_skbEric Dumazet1-0/+2
sk_stream_alloc_skb() is only used by TCP. Rename it to make this clear, and move its declaration to include/net/tcp.h Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-2/+3
Lots of simnple overlapping additions. With a build fix from Stephen Rothwell. Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-15tcp: md5: Allow MD5SIG_FLAG_IFINDEX with ifindex=0Leonard Crestez1-2/+3
Multiple VRFs are generally meant to be "separate" but right now md5 keys for the default VRF also affect connections inside VRFs if the IP addresses happen to overlap. So far the combination of TCP_MD5SIG_FLAG_IFINDEX with tcpm_ifindex == 0 was an error, accept this to mean "key only applies to default VRF". This is what applications using VRFs for traffic separation want. Signed-off-by: Leonard Crestez <cdleonard@gmail.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-15tcp: switch orphan_count to bare per-cpu countersEric Dumazet1-14/+3
Use of percpu_counter structure to track count of orphaned sockets is causing problems on modern hosts with 256 cpus or more. Stefan Bach reported a serious spinlock contention in real workloads, that I was able to reproduce with a netfilter rule dropping incoming FIN packets. 53.56% server [kernel.kallsyms] [k] queued_spin_lock_slowpath | ---queued_spin_lock_slowpath | --53.51%--_raw_spin_lock_irqsave | --53.51%--__percpu_counter_sum tcp_check_oom | |--39.03%--__tcp_close | tcp_close | inet_release | inet6_release | sock_close | __fput | ____fput | task_work_run | exit_to_usermode_loop | do_syscall_64 | entry_SYSCALL_64_after_hwframe | __GI___libc_close | --14.48%--tcp_out_of_resources tcp_write_timeout tcp_retransmit_timer tcp_write_timer_handler tcp_write_timer call_timer_fn expire_timers __run_timers run_timer_softirq __softirqentry_text_start As explained in commit cf86a086a180 ("net/dst: use a smaller percpu_counter batch for dst entries accounting"), default batch size is too big for the default value of tcp_max_orphans (262144). But even if we reduce batch sizes, there would still be cases where the estimated count of orphans is beyond the limit, and where tcp_too_many_orphans() has to call the expensive percpu_counter_sum_positive(). One solution is to use plain per-cpu counters, and have a timer to periodically refresh this cache. Updating this cache every 100ms seems about right, tcp pressure state is not radically changing over shorter periods. percpu_counter was nice 15 years ago while hosts had less than 16 cpus, not anymore by current standards. v2: Fix the build issue for CONFIG_CRYPTO_DEV_CHELSIO_TLS=m, reported by kernel test robot <lkp@intel.com> Remove unused socket argument from tcp_too_many_orphans() Fixes: dd24c00191d5 ("net: Use a percpu_counter for orphan_count") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Stefan Bach <sfb@google.com> Cc: Neal Cardwell <ncardwell@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-30tcp: adjust rcv_ssthresh according to sk_reserved_memWei Wang1-0/+11
When user sets SO_RESERVE_MEM socket option, in order to utilize the reserved memory when in memory pressure state, we adjust rcv_ssthresh according to the available reserved memory for the socket, instead of using 4 * advmss always. Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-24tcp: tracking packets with CE marks in BW rate sampleYuchung Cheng1-3/+6
In order to track CE marks per rate sample (one round trip), TCP needs a per-skb header field to record the tp->delivered_ce count when the skb was sent. To make space, we replace the "last_in_flight" field which is used exclusively for NV congestion control. The stat needed by NV can be alternatively approximated by existing stats tcp_sock delivered and mss_cache. This patch counts the number of packets delivered which have CE marks in the rate sample, using similar approach of delivery accounting. Cc: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Luke Hsiao <lukehsiao@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-23tcp: make tcp_build_frag() staticPaolo Abeni1-2/+0
After the previous patch the mentioned helper is used only inside its compilation unit: let's make it static. RFC -> v1: - preserve the tcp_build_frag() helper (Eric) Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-23tcp: expose the tcp_mark_push() and tcp_skb_entail() helpersPaolo Abeni1-0/+2
the tcp_skb_entail() helper is actually skb_entail(), renamed to provide proper scope. The two helper will be used by the next patch. RFC -> v1: - rename skb_entail to tcp_skb_entail (Eric) Acked-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>