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2025-05-13net: enable driver support for netmem TXMina Almasry
Drivers need to make sure not to pass netmem dma-addrs to the dma-mapping API in order to support netmem TX. Add helpers and netmem_dma_*() helpers that enables special handling of netmem dma-addrs that drivers can use. Document in netmem.rst what drivers need to do to support netmem TX. Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250508004830.4100853-7-almasrymina@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-14net: convert dev->rtnl_link_state to a boolJakub Kicinski
netdevice reg_state was split into two 16 bit enums back in 2010 in commit a2835763e130 ("rtnetlink: handle rtnl_link netlink notifications manually"). Since the split the fields have been moved apart, and last year we converted reg_state to a normal u8 in commit 4d42b37def70 ("net: convert dev->reg_state to u8"). rtnl_link_state being a 16 bitfield makes no sense. Convert it to a single bool, it seems very unlikely after 15 years that we'll need more values in it. We could drop dev->rtnl_link_ops from the conditions but feels like having it there more clearly points at the reason for this hack. Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250410014246.780885-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-10tcp: add LINUX_MIB_PAWS_TW_REJECTED counterJiayuan Chen
When TCP is in TIME_WAIT state, PAWS verification uses LINUX_PAWSESTABREJECTED, which is ambiguous and cannot be distinguished from other PAWS verification processes. We added a new counter, like the existing PAWS_OLD_ACK one. Also we update the doc with previously missing PAWS_OLD_ACK. usage: ''' nstat -az | grep PAWSTimewait TcpExtPAWSTimewait 1 0.0 ''' Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250409112614.16153-3-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-25tcp/dccp: remove icsk->icsk_ack.timeoutEric Dumazet
icsk->icsk_ack.timeout can be replaced by icsk->csk_delack_timer.expires This saves 8 bytes in TCP/DCCP sockets and helps for better cache locality. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250324203607.703850-3-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-25tcp/dccp: remove icsk->icsk_timeoutEric Dumazet
icsk->icsk_timeout can be replaced by icsk->icsk_retransmit_timer.expires This saves 8 bytes in TCP/DCCP sockets and helps for better cache locality. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250324203607.703850-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-24tcp: move icsk_clean_acked to a better locationEric Dumazet
As a followup of my presentation in Zagreb for netdev 0x19: icsk_clean_acked is only used by TCP when/if CONFIG_TLS_DEVICE is enabled from tcp_ack(). Rename it to tcp_clean_acked, move it to tcp_sock structure in the tcp_sock_read_rx for better cache locality in TCP fast path. Define this field only when CONFIG_TLS_DEVICE is enabled saving 8 bytes on configs not using it. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250317085313.2023214-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-04net: rename netns_local to netns_immutableNicolas Dichtel
The name 'netns_local' is confusing. A following commit will export it via netlink, so let's use a more explicit name. Reported-by: Eric Dumazet <edumazet@google.com> Suggested-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-02-26tcp: be less liberal in TSEcr received while in SYN_RECV stateEric Dumazet
Yong-Hao Zou mentioned that linux was not strict as other OS in 3WHS, for flows using TCP TS option (RFC 7323) As hinted by an old comment in tcp_check_req(), we can check the TSEcr value in the incoming packet corresponds to one of the SYNACK TSval values we have sent. In this patch, I record the oldest and most recent values that SYNACK packets have used. Send a challenge ACK if we receive a TSEcr outside of this range, and increase a new SNMP counter. nstat -az | grep TSEcrRejected TcpExtTSEcrRejected 0 0.0 Due to TCP fastopen implementation, do not apply yet these checks for fastopen flows. v2: No longer use req->num_timeout, but treq->snt_tsval_first to detect when first SYNACK is prepared. This means we make sure to not send an initial zero TSval. Make sure MPTCP and TCP selftests are passing. Change MIB name to TcpExtTSEcrRejected v1: https://lore.kernel.org/netdev/CADVnQykD8i4ArpSZaPKaoNxLJ2if2ts9m4As+=Jvdkrgx1qMHw@mail.gmail.com/T/ Reported-by: Yong-Hao Zou <yonghaoz1994@gmail.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250225171048.3105061-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-11tcp: add tcp_rto_max_ms sysctlEric Dumazet
Previous patch added a TCP_RTO_MAX_MS socket option to tune a TCP socket max RTO value. Many setups prefer to change a per netns sysctl. This patch adds /proc/sys/net/ipv4/tcp_rto_max_ms Its initial value is 120000 (120 seconds). Keep in mind that a decrease of tcp_rto_max_ms means shorter overall timeouts, unless tcp_retries2 sysctl is increased. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-02-11tcp: add the ability to control max RTOEric Dumazet
Currently, TCP stack uses a constant (120 seconds) to limit the RTO value exponential growth. Some applications want to set a lower value. Add TCP_RTO_MAX_MS socket option to set a value (in ms) between 1 and 120 seconds. It is discouraged to change the socket rto max on a live socket, as it might lead to unexpected disconnects. Following patch is adding a netns sysctl to control the default value at socket creation time. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-12-11tcp: Add sysctl to configure TIME-WAIT reuse delayJakub Sitnicki
Today we have a hardcoded delay of 1 sec before a TIME-WAIT socket can be reused by reopening a connection. This is a safe choice based on an assumption that the other TCP timestamp clock frequency, which is unknown to us, may be as low as 1 Hz (RFC 7323, section 5.4). However, this means that in the presence of short lived connections with an RTT of couple of milliseconds, the time during which a 4-tuple is blocked from reuse can be orders of magnitude longer that the connection lifetime. Combined with a reduced pool of ephemeral ports, when using IP_LOCAL_PORT_RANGE to share an egress IP address between hosts [1], the long TIME-WAIT reuse delay can lead to port exhaustion, where all available 4-tuples are tied up in TIME-WAIT state. Turn the reuse delay into a per-netns setting so that sysadmins can make more aggressive assumptions about remote TCP timestamp clock frequency and shorten the delay in order to allow connections to reincarnate faster. Note that applications can completely bypass the TIME-WAIT delay protection already today by locking the local port with bind() before connecting. Such immediate connection reuse may result in PAWS failing to detect old duplicate segments, leaving us with just the sequence number check as a safety net. This new configurable offers a trade off where the sysadmin can balance between the risk of PAWS detection failing to act versus exhausting ports by having sockets tied up in TIME-WAIT state for too long. [1] https://lpc.events/event/16/contributions/1349/ Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Link: https://patch.msgid.link/20241209-jakub-krn-909-poc-msec-tw-tstamp-v2-2-66aca0eed03e@cloudflare.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-09neighbour: Create netdev->neighbour associationGilad Naaman
Create a mapping between a netdev and its neighoburs, allowing for much cheaper flushes. Signed-off-by: Gilad Naaman <gnaaman@drivenets.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20241107160444.2913124-7-gnaaman@drivenets.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-29Merge tag 'wireless-next-2024-10-25' of ↵Jakub Kicinski
git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next Kalle Valo says: ==================== wireless-next patches for v6.13 The first -next "new features" pull request for v6.13. This is a big one as we have not been able to send one earlier. We have also some patches affecting other subsystems: in staging we deleted the rtl8192e driver and in debugfs added a new interface to save struct file_operations memory; both were acked by GregKH. Because of the lib80211/libipw move there were quite a lot of conflicts and to solve those we decided to merge net-next into wireless-next. Major changes: cfg80211/mac80211 * stop exporting wext symbols * new mac80211 op to indicate that a new interface is to be added * support radio separation of multi-band devices Wireless Extensions * move wext spy implementation to libiw * remove iw_public_data from struct net_device brcmfmac * optional LPO clock support ipw2x00 * move remaining lib80211 code into libiw wilc1000 * WILC3000 support rtw89 * RTL8852BE and RTL8852BE-VT BT-coexistence improvements * tag 'wireless-next-2024-10-25' of git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next: (126 commits) mac80211: Remove NOP call to ieee80211_hw_config wifi: iwlwifi: work around -Wenum-compare-conditional warning wifi: mac80211: re-order assigning channel in activate links wifi: mac80211: convert debugfs files to short fops debugfs: add small file operations for most files wifi: mac80211: remove misleading j_0 construction parts wifi: mac80211_hwsim: use hrtimer_active() wifi: mac80211: refactor BW limitation check for CSA parsing wifi: mac80211: filter on monitor interfaces based on configured channel wifi: mac80211: refactor ieee80211_rx_monitor wifi: mac80211: add support for the monitor SKIP_TX flag wifi: cfg80211: add monitor SKIP_TX flag wifi: mac80211: add flag to opt out of virtual monitor support wifi: cfg80211: pass net_device to .set_monitor_channel wifi: mac80211: remove status->ampdu_delimiter_crc wifi: cfg80211: report per wiphy radio antenna mask wifi: mac80211: use vif radio mask to limit creating chanctx wifi: mac80211: use vif radio mask to limit ibss scan frequencies wifi: cfg80211: add option for vif allowed radios wifi: iwlwifi: allow IWL_FW_CHECK() with just a string ... ==================== Link: https://patch.msgid.link/20241025170705.5F6B2C4CEC3@smtp.kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-14net: napi: Add napi_configJoe Damato
Add a persistent NAPI config area for NAPI configuration to the core. Drivers opt-in to setting the persistent config for a NAPI by passing an index when calling netif_napi_add_config. napi_config is allocated in alloc_netdev_mqs, freed in free_netdev (after the NAPIs are deleted). Drivers which call netif_napi_add_config will have persistent per-NAPI settings: NAPI IDs, gro_flush_timeout, and defer_hard_irq settings. Per-NAPI settings are saved in napi_disable and restored in napi_enable. Co-developed-by: Martin Karsten <mkarsten@uwaterloo.ca> Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca> Signed-off-by: Joe Damato <jdamato@fastly.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20241011184527.16393-6-jdamato@fastly.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-14net: napi: Make gro_flush_timeout per-NAPIJoe Damato
Allow per-NAPI gro_flush_timeout setting. The existing sysfs parameter is respected; writes to sysfs will write to all NAPI structs for the device and the net_device gro_flush_timeout field. Reads from sysfs will read from the net_device field. The ability to set gro_flush_timeout on specific NAPI instances will be added in a later commit, via netdev-genl. Signed-off-by: Joe Damato <jdamato@fastly.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20241011184527.16393-4-jdamato@fastly.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-14net: napi: Make napi_defer_hard_irqs per-NAPIJoe Damato
Add defer_hard_irqs to napi_struct in preparation for per-NAPI settings. The existing sysfs parameter is respected; writes to sysfs will write to all NAPI structs for the device and the net_device defer_hard_irq field. Reads from sysfs show the net_device field. The ability to set defer_hard_irqs on specific NAPI instances will be added in a later commit, via netdev-genl. Signed-off-by: Joe Damato <jdamato@fastly.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20241011184527.16393-2-jdamato@fastly.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-11tcp: move sysctl_tcp_l3mdev_accept to netns_ipv4_read_rxEric Dumazet
sysctl_tcp_l3mdev_accept is read from TCP receive fast path from tcp_v6_early_demux(), __inet6_lookup_established, inet_request_bound_dev_if(). Move it to netns_ipv4_read_rx. Remove the '#ifdef CONFIG_NET_L3_MASTER_DEV' that was guarding its definition. Note this adds a hole of three bytes that could be filled later. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Cc: Wei Wang <weiwan@google.com> Cc: Coco Li <lixiaoyan@google.com> Link: https://patch.msgid.link/20241010034100.320832-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-09doc: net: Fix .rst rendering of net_cachelines pagesDonald Hunter
The doc pages under /networking/net_cachelines are unreadable because they lack .rst formatting for the tabular text. Add simple table markup and tidy up the table contents: - remove dashes that represent empty cells because they render as bullets and are not needed - replace 'struct_*' with 'struct *' in the first column so that sphinx can render links for any structs that appear in the docs Signed-off-by: Donald Hunter <donald.hunter@gmail.com> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20241008165329.45647-1-donald.hunter@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-09Merge net-next/main to resolve conflictsJohannes Berg
The wireless-next tree was based on something older, and there are now conflicts between -rc2 and work here. Merge net-next, which has enough of -rc2 for the conflicts to happen, resolving them in the process. Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2024-10-08wifi: remove iw_public_data from struct net_deviceJohannes Berg
Given the previous patches, we no longer need the struct iw_public_data etc., it's only used by the old Intel drivers (and ps3_gelic creates it but then doesn't use it). Remove all of that, including the pointer in struct net_device. Link: https://patch.msgid.link/20241007213525.8b2d52b60531.I6a27aaf30bded9a0977f07f47fba2bd31a3b3330@changeid Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2024-10-07ipv4: remove fib_info_devhash[]Eric Dumazet
Upcoming per-netns RTNL conversion needs to get rid of shared hash tables. fib_info_devhash[] is one of them. It is unclear why we used a hash table, because a single hlist_head per net device was cheaper and scalable. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20241004134720.579244-5-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-04net: add IFLA_MAX_PACING_OFFLOAD_HORIZON device attributeEric Dumazet
Some network devices have the ability to offload EDT (Earliest Departure Time) which is the model used for TCP pacing and FQ packet scheduler. Some of them implement the timing wheel mechanism described in https://saeed.github.io/files/carousel-sigcomm17.pdf with an associated 'timing wheel horizon'. This patch adds dev->max_pacing_offload_horizon expressing this timing wheel horizon in nsec units. This is a read-only attribute. Unless a driver sets it, dev->max_pacing_offload_horizon is zero. v2: addressed Jakub feedback ( https://lore.kernel.org/netdev/20240930152304.472767-2-edumazet@google.com/T/#mf6294d714c41cc459962154cc2580ce3c9693663 ) v3: added yaml doc (also per Jakub feedback) Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20241003121219.2396589-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-05net: napi: Prevent overflow of napi_defer_hard_irqsJoe Damato
In commit 6f8b12d661d0 ("net: napi: add hard irqs deferral feature") napi_defer_irqs was added to net_device and napi_defer_irqs_count was added to napi_struct, both as type int. This value never goes below zero, so there is not reason for it to be a signed int. Change the type for both from int to u32, and add an overflow check to sysfs to limit the value to S32_MAX. The limit of S32_MAX was chosen because the practical limit before this patch was S32_MAX (anything larger was an overflow) and thus there are no behavioral changes introduced. If the extra bit is needed in the future, the limit can be raised. Before this patch: $ sudo bash -c 'echo 2147483649 > /sys/class/net/eth4/napi_defer_hard_irqs' $ cat /sys/class/net/eth4/napi_defer_hard_irqs -2147483647 After this patch: $ sudo bash -c 'echo 2147483649 > /sys/class/net/eth4/napi_defer_hard_irqs' bash: line 0: echo: write error: Numerical result out of range Similarly, /sys/class/net/XXXXX/tx_queue_len is defined as unsigned: include/linux/netdevice.h: unsigned int tx_queue_len; And has an overflow check: dev_change_tx_queue_len(..., unsigned long new_len): if (new_len != (unsigned int)new_len) return -ERANGE; Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Joe Damato <jdamato@fastly.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20240904153431.307932-1-jdamato@fastly.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-03netdev_features: convert NETIF_F_FCOE_MTU to dev->fcoe_mtuAlexander Lobakin
Ability to handle maximum FCoE frames of 2158 bytes can never be changed and thus more of an attribute, not a toggleable feature. Move it from netdev_features_t to "cold" priv flags (bitfield bool) and free yet another feature bit. Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-09-03netdev_features: convert NETIF_F_NETNS_LOCAL to dev->netns_localAlexander Lobakin
"Interface can't change network namespaces" is rather an attribute, not a feature, and it can't be changed via Ethtool. Make it a "cold" private flag instead of a netdev_feature and free one more bit. Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-09-03netdev_features: convert NETIF_F_LLTX to dev->lltxAlexander Lobakin
NETIF_F_LLTX can't be changed via Ethtool and is not a feature, rather an attribute, very similar to IFF_NO_QUEUE (and hot). Free one netdev_features_t bit and make it a "hot" private flag. Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-09-03netdevice: convert private flags > BIT(31) to bitfieldsAlexander Lobakin
Make dev->priv_flags `u32` back and define bits higher than 31 as bitfield booleans as per Jakub's suggestion. This simplifies code which accesses these bits with no optimization loss (testb both before/after), allows to not extend &netdev_priv_flags each time, but also scales better as bits > 63 in the future would only add a new u64 to the structure with no complications, comparing to that extending ::priv_flags would require converting it to a bitmap. Note that I picked `unsigned long :1` to not lose any potential optimizations comparing to `bool :1` etc. Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-08-30Documentation: Add missing fields to net_cachelinesJoe Damato
Two fields, page_pools and *irq_moder, were added to struct net_device in commit 083772c9f972 ("net: page_pool: record pools per netdev") and commit f750dfe825b9 ("ethtool: provide customized dim profile management"), respectively. Add both to the net_cachelines documentation, as well. Signed-off-by: Joe Damato <jdamato@fastly.com> Link: https://patch.msgid.link/20240829155742.366584-1-jdamato@fastly.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-03-19net: move dev->state into net_device_read_txrx groupEric Dumazet
dev->state can be read in rx and tx fast paths. netif_running() which needs dev->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 <edumazet@google.com> Cc: Coco Li <lixiaoyan@google.com> Reviewed-by: Jiri Pirko <jiri@nvidia.com> Link: https://lore.kernel.org/r/20240314200845.3050179-1-edumazet@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-02-28Documentations: correct net_cachelines title for struct inet_sockHaiyue Wang
The fast path usage breakdown describes the detail for 'inet_sock', fix the markup title. Signed-off-by: Haiyue Wang <haiyue.wang@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-02-12net-device: move lstats in net_device_read_txrxEric Dumazet
dev->lstats is notably used from loopback ndo_start_xmit() and other virtual drivers. Per cpu stats updates are dirtying per-cpu data, but the pointer itself is read-only. Fixes: 43a71cd66b9c ("net-device: reorganize net_device fast path variables") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Coco Li <lixiaoyan@google.com> Cc: Simon Horman <horms@kernel.org> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-02-12tcp: move tp->tcp_usec_ts to tcp_sock_read_txrx groupEric Dumazet
tp->tcp_usec_ts is a read mostly field, used in rx and tx fast paths. Fixes: d5fed5addb2b ("tcp: reorganize tcp_sock fast path variables") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Coco Li <lixiaoyan@google.com> Cc: Wei Wang <weiwan@google.com> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-02-12tcp: move tp->scaling_ratio to tcp_sock_read_txrx groupEric Dumazet
tp->scaling_ratio is a read mostly field, used in rx and tx fast paths. Fixes: d5fed5addb2b ("tcp: reorganize tcp_sock fast path variables") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Coco Li <lixiaoyan@google.com> Cc: Wei Wang <weiwan@google.com> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-01-03net-device: move xdp_prog to net_device_read_rxEric Dumazet
xdp_prog is used in receive path, both from XDP enabled drivers and from netif_elide_gro(). This patch also removes two 4-bytes holes. Fixes: 43a71cd66b9c ("net-device: reorganize net_device fast path variables") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Coco Li <lixiaoyan@google.com> Cc: Simon Horman <horms@kernel.org> Link: https://lore.kernel.org/r/20240102162220.750823-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-01-02net-device: move gso_partial_features to net_device_read_txEric Dumazet
dev->gso_partial_features is read from tx fast path for GSO packets. Move it to appropriate section to avoid a cache line miss. Fixes: 43a71cd66b9c ("net-device: reorganize net_device fast path variables") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Coco Li <lixiaoyan@google.com> Cc: David Ahern <dsahern@kernel.org> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2023-12-05Documentations: fix net_cachelines documentation build warningCoco Li
Original errors: Documentation/networking/net_cachelines/index.rst:3: WARNING: Explicit markup ends without a blank line; unexpected unindent. Documentation/networking/net_cachelines/inet_connection_sock.rst:3: WARNING: Explicit markup ends without a blank line; unexpected unindent. Documentation/networking/net_cachelines/inet_sock.rst:3: WARNING: Explicit markup ends without a blank line; unexpected unindent. Documentation/networking/net_cachelines/net_device.rst:3: WARNING: Explicit markup ends without a blank line; unexpected unindent. Documentation/networking/net_cachelines/netns_ipv4_sysctl.rst:3: WARNING: Explicit markup ends without a blank line; unexpected unindent. Documentation/networking/net_cachelines/snmp.rst:3: WARNING: Explicit markup ends without a blank line; unexpected unindent. Documentation/networking/net_cachelines/tcp_sock.rst:3: WARNING: Explicit markup ends without a blank line; unexpected unindent. Fixes: 14006f1d8fa2 ("Documentations: Analyze heavily used Networking related structs") Signed-off-by: Coco Li <lixiaoyan@google.com> Link: https://lore.kernel.org/r/20231204220728.746134-1-lixiaoyan@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-12-02Documentations: Analyze heavily used Networking related structsCoco Li
Analyzed a few structs in the networking stack by looking at variables within them that are used in the TCP/IP fast path. Fast path is defined as TCP path where data is transferred from sender to receiver unidirectionally. It doesn't include phases other than TCP_ESTABLISHED, nor does it look at error paths. We hope to re-organizing variables that span many cachelines whose fast path variables are also spread out, and this document can help future developers keep networking fast path cachelines small. Optimized_cacheline field is computed as (Fastpath_Bytes/L3_cacheline_size_x86), and not the actual organized results (see patches to come for these). Investigation is done on 6.5 Name Struct_Cachelines Cur_fastpath_cache Fastpath_Bytes Optimized_cacheline tcp_sock 42 (2664 Bytes) 12 396 8 net_device 39 (2240 bytes) 12 234 4 inet_sock 15 (960 bytes) 14 922 14 Inet_connection_sock 22 (1368 bytes) 18 1166 18 Netns_ipv4 (sysctls) 12 (768 bytes) 4 77 2 linux_mib 16 (1060) 6 104 2 Note how there isn't much improvement space for inet_sock and Inet_connection_sock because sk and icsk_inet respectively takes up so much of the struct that rest of the variables become a small portion of the struct size. So, we decided to reorganize tcp_sock, net_device, netns_ipv4 Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Coco Li <lixiaoyan@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
generated by cgit (git 2.34.1) at 2025-07-30 13:17:55 +0000