We use napi_threaded_poll() in order to reduce our softirq dependency.
We can add a followup of 821eba962d ("net: optimize napi_schedule_rps()")
to further remove the need of firing NET_RX_SOFTIRQ whenever
RPS/RFS are used.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This will, after the next patch, hold only the core
drop reasons and minimal infrastructure. Fix a small
kernel-doc issue while at it, to avoid the move
triggering a checker.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Recent patches to mlx5 mentioned a regression when moving from
driver local page pool to only using the generic page pool code.
Page pool has two recycling paths (1) direct one, which runs in
safe NAPI context (basically consumer context, so producing
can be lockless); and (2) via a ptr_ring, which takes a spin
lock because the freeing can happen from any CPU; producer
and consumer may run concurrently.
Since the page pool code was added, Eric introduced a revised version
of deferred skb freeing. TCP skbs are now usually returned to the CPU
which allocated them, and freed in softirq context. This places the
freeing (producing of pages back to the pool) enticingly close to
the allocation (consumer).
If we can prove that we're freeing in the same softirq context in which
the consumer NAPI will run - lockless use of the cache is perfectly fine,
no need for the lock.
Let drivers link the page pool to a NAPI instance. If the NAPI instance
is scheduled on the same CPU on which we're freeing - place the pages
in the direct cache.
With that and patched bnxt (XDP enabled to engage the page pool, sigh,
bnxt really needs page pool work :() I see a 2.6% perf boost with
a TCP stream test (app on a different physical core than softirq).
The CPU use of relevant functions decreases as expected:
page_pool_refill_alloc_cache 1.17% -> 0%
_raw_spin_lock 2.41% -> 0.98%
Only consider lockless path to be safe when NAPI is scheduled
- in practice this should cover majority if not all of steady state
workloads. It's usually the NAPI kicking in that causes the skb flush.
The main case we'll miss out on is when application runs on the same
CPU as NAPI. In that case we don't use the deferred skb free path.
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Tested-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The RSS hash type specifies what portion of packet data NIC hardware used
when calculating RSS hash value. The RSS types are focused on Internet
traffic protocols at OSI layers L3 and L4. L2 (e.g. ARP) often get hash
value zero and no RSS type. For L3 focused on IPv4 vs. IPv6, and L4
primarily TCP vs UDP, but some hardware supports SCTP.
Hardware RSS types are differently encoded for each hardware NIC. Most
hardware represent RSS hash type as a number. Determining L3 vs L4 often
requires a mapping table as there often isn't a pattern or sorting
according to ISO layer.
The patch introduce a XDP RSS hash type (enum xdp_rss_hash_type) that
contains both BITs for the L3/L4 types, and combinations to be used by
drivers for their mapping tables. The enum xdp_rss_type_bits get exposed
to BPF via BTF, and it is up to the BPF-programmer to match using these
defines.
This proposal change the kfunc API bpf_xdp_metadata_rx_hash() adding
a pointer value argument for provide the RSS hash type.
Change signature for all xmo_rx_hash calls in drivers to make it compile.
The RSS type implementations for each driver comes as separate patches.
Fixes: 3d76a4d3d4 ("bpf: XDP metadata RX kfuncs")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/168132892042.340624.582563003880565460.stgit@firesoul
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Drivers call netdev_tx_completed_queue() right before
netif_txq_maybe_wake(). If BQL is enabled netdev_tx_completed_queue()
should issue a memory barrier, so we can depend on that separating
the stop check from the consumer index update, instead of adding
another barrier in netif_txq_maybe_wake().
This matters more than the barriers on the xmit path, because
the wake condition is almost always true. So we issue the
consumer side barrier often.
Wrap netdev_tx_completed_queue() in a local helper to issue
the barrier even if BQL is disabled. Keep the same semantics
as netdev_tx_completed_queue() (barrier only if bytes != 0)
to make it clear that the barrier is conditional.
Plus since macro gets pkt/byte counts as arguments now -
we can skip waking if there were no packets completed.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
A lot of drivers follow the same scheme to stop / start queues
without introducing locks between xmit and NAPI tx completions.
I'm guessing they all copy'n'paste each other's code.
The original code dates back all the way to e1000 and Linux 2.6.19.
Smaller drivers shy away from the scheme and introduce a lock
which may cause deadlocks in netpoll.
Provide macros which encapsulate the necessary logic.
The macros do not prevent false wake ups, the extra barrier
required to close that race is not worth it. See discussion in:
https://lore.kernel.org/all/c39312a2-4537-14b4-270c-9fe1fbb91e89@gmail.com/
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
There was a sort of rush surrounding commit 88c0a6b503 ("net: create a
netdev notifier for DSA to reject PTP on DSA master"), due to a desire
to convert DSA's attempt to deny TX timestamping on a DSA master to
something that doesn't block the kernel-wide API conversion from
ndo_eth_ioctl() to ndo_hwtstamp_set().
What was required was a mechanism that did not depend on ndo_eth_ioctl(),
and what was provided was a mechanism that did not depend on
ndo_eth_ioctl(), while at the same time introducing something that
wasn't absolutely necessary - a new netdev notifier.
There have been objections from Jakub Kicinski that using notifiers in
general when they are not absolutely necessary creates complications to
the control flow and difficulties to maintainers who look at the code.
So there is a desire to not use notifiers.
In addition to that, the notifier chain gets called even if there is no
DSA in the system and no one is interested in applying any restriction.
Take the model of udp_tunnel_nic_ops and introduce a stub mechanism,
through which net/core/dev_ioctl.c can call into DSA even when
CONFIG_NET_DSA=m.
Compared to the code that existed prior to the notifier conversion, aka
what was added in commits:
- 4cfab35667 ("net: dsa: Add wrappers for overloaded ndo_ops")
- 3369afba1e ("net: Call into DSA netdevice_ops wrappers")
this is different because we are not overloading any struct
net_device_ops of the DSA master anymore, but rather, we are exposing a
rather specific functionality which is orthogonal to which API is used
to enable it - ndo_eth_ioctl() or ndo_hwtstamp_set().
Also, what is similar is that both approaches use function pointers to
get from built-in code to DSA.
There is no point in replicating the function pointers towards
__dsa_master_hwtstamp_validate() once for every CPU port (dev->dsa_ptr).
Instead, it is sufficient to introduce a singleton struct dsa_stubs,
built into the kernel, which contains a single function pointer to
__dsa_master_hwtstamp_validate().
I find this approach preferable to what we had originally, because
dev->dsa_ptr->netdev_ops->ndo_do_ioctl() used to require going through
struct dsa_port (dev->dsa_ptr), and so, this was incompatible with any
attempts to add any data encapsulation and hide DSA data structures from
the outside world.
Link: https://lore.kernel.org/netdev/20230403083019.120b72fd@kernel.org/
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The fact that PTP 2-step TX timestamping is broken on DSA switches if
the master also timestamps the same packets is documented by commit
f685e609a3 ("net: dsa: Deny PTP on master if switch supports it").
We attempt to help the users avoid shooting themselves in the foot by
making DSA reject the timestamping ioctls on an interface that is a DSA
master, and the switch tree beneath it contains switches which are aware
of PTP.
The only problem is that there isn't an established way of intercepting
ndo_eth_ioctl calls, so DSA creates avoidable burden upon the network
stack by creating a struct dsa_netdevice_ops with overlaid function
pointers that are manually checked from the relevant call sites. There
used to be 2 such dsa_netdevice_ops, but now, ndo_eth_ioctl is the only
one left.
There is an ongoing effort to migrate driver-visible hardware timestamping
control from the ndo_eth_ioctl() based API to a new ndo_hwtstamp_set()
model, but DSA actively prevents that migration, since dsa_master_ioctl()
is currently coded to manually call the master's legacy ndo_eth_ioctl(),
and so, whenever a network device driver would be converted to the new
API, DSA's restrictions would be circumvented, because any device could
be used as a DSA master.
The established way for unrelated modules to react on a net device event
is via netdevice notifiers. So we create a new notifier which gets
called whenever there is an attempt to change hardware timestamping
settings on a device.
Finally, there is another reason why a netdev notifier will be a good
idea, besides strictly DSA, and this has to do with PHY timestamping.
With ndo_eth_ioctl(), all MAC drivers must manually call
phy_has_hwtstamp() before deciding whether to act upon SIOCSHWTSTAMP,
otherwise they must pass this ioctl to the PHY driver via
phy_mii_ioctl().
With the new ndo_hwtstamp_set() API, it will be desirable to simply not
make any calls into the MAC device driver when timestamping should be
performed at the PHY level.
But there exist drivers, such as the lan966x switch, which need to
install packet traps for PTP regardless of whether they are the layer
that provides the hardware timestamps, or the PHY is. That would be
impossible to support with the new API.
The proposal there, too, is to introduce a netdev notifier which acts as
a better cue for switching drivers to add or remove PTP packet traps,
than ndo_hwtstamp_set(). The one introduced here "almost" works there as
well, except for the fact that packet traps should only be installed if
the PHY driver succeeded to enable hardware timestamping, whereas here,
we need to deny hardware timestamping on the DSA master before it
actually gets enabled. This is why this notifier is called "PRE_", and
the notifier that would get used for PHY timestamping and packet traps
would be called NETDEV_CHANGE_HWTSTAMP. This isn't a new concept, for
example NETDEV_CHANGEUPPER and NETDEV_PRECHANGEUPPER do the same thing.
In expectation of future netlink UAPI, we also pass a non-NULL extack
pointer to the netdev notifier, and we make DSA populate it with an
informative reason for the rejection. To avoid making it go to waste, we
make the ioctl-based dev_set_hwtstamp() create a fake extack and print
the message to the kernel log.
Link: https://lore.kernel.org/netdev/20230401191215.tvveoi3lkawgg6g4@skbuf/
Link: https://lore.kernel.org/netdev/20230310164451.ls7bbs6pdzs4m6pw@skbuf/
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We want to make two optimizations in napi_schedule_rps() and
____napi_schedule() which require to know if these helpers are
called from net_rx_action(), instead of being called from
other contexts.
sd.in_net_rx_action is only read/written by the owning cpu.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Tested-by: Jason Xing <kerneljasonxing@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
When requesting a TX queue at a given index, warn on out-of-bounds
referencing if the index is greater than the allocated number of
queues.
Specifically, since this function is used heavily in the networking
stack use DEBUG_NET_WARN_ON_ONCE to avoid executing a new branch on
every packet.
Signed-off-by: Nick Child <nnac123@linux.ibm.com>
Link: https://lore.kernel.org/r/20230321150725.127229-2-nnac123@linux.ibm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add MDB net device operations that will be invoked by rtnetlink code in
response to received RTM_{NEW,DEL,GET}MDB messages. Subsequent patches
will implement these operations in the bridge and VXLAN drivers.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
That really was meant to be a per netns attribute from the beginning.
The idea is that once proper isolation is in place in the main
namespace, additional demux in the child namespaces will be redundant.
Let's make child netns default rps mask empty by default.
To avoid bloating the netns with a possibly large cpumask, allocate
it on-demand during the first write operation.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cited commit changed devlink to register its netdev notifier block on
the global netdev notifier chain instead of on the per network namespace
one.
However, when changing the network namespace of the devlink instance,
devlink still tries to unregister its notifier block from the chain of
the old namespace and register it on the chain of the new namespace.
This results in corruption of the notifier chains, as the same notifier
block is registered on two different chains: The global one and the per
network namespace one. In turn, this causes other problems such as the
inability to dismantle namespaces due to netdev reference count issues.
Fix by preventing devlink from moving its notifier block between
namespaces.
Reproducer:
# echo "10 1" > /sys/bus/netdevsim/new_device
# ip netns add test123
# devlink dev reload netdevsim/netdevsim10 netns test123
# ip netns del test123
[ 71.935619] unregister_netdevice: waiting for lo to become free. Usage count = 2
[ 71.938348] leaked reference.
Fixes: 565b4824c3 ("devlink: change port event netdev notifier from per-net to global")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230215073139.1360108-1-idosch@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
====================
pull-request: bpf-next 2023-02-11
We've added 96 non-merge commits during the last 14 day(s) which contain
a total of 152 files changed, 4884 insertions(+), 962 deletions(-).
There is a minor conflict in drivers/net/ethernet/intel/ice/ice_main.c
between commit 5b246e533d ("ice: split probe into smaller functions")
from the net-next tree and commit 66c0e13ad2 ("drivers: net: turn on
XDP features") from the bpf-next tree. Remove the hunk given ice_cfg_netdev()
is otherwise there a 2nd time, and add XDP features to the existing
ice_cfg_netdev() one:
[...]
ice_set_netdev_features(netdev);
netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
NETDEV_XDP_ACT_XSK_ZEROCOPY;
ice_set_ops(netdev);
[...]
Stephen's merge conflict mail:
https://lore.kernel.org/bpf/20230207101951.21a114fa@canb.auug.org.au/
The main changes are:
1) Add support for BPF trampoline on s390x which finally allows to remove many
test cases from the BPF CI's DENYLIST.s390x, from Ilya Leoshkevich.
2) Add multi-buffer XDP support to ice driver, from Maciej Fijalkowski.
3) Add capability to export the XDP features supported by the NIC.
Along with that, add a XDP compliance test tool,
from Lorenzo Bianconi & Marek Majtyka.
4) Add __bpf_kfunc tag for marking kernel functions as kfuncs,
from David Vernet.
5) Add a deep dive documentation about the verifier's register
liveness tracking algorithm, from Eduard Zingerman.
6) Fix and follow-up cleanups for resolve_btfids to be compiled
as a host program to avoid cross compile issues,
from Jiri Olsa & Ian Rogers.
7) Batch of fixes to the BPF selftest for xdp_hw_metadata which resulted
when testing on different NICs, from Jesper Dangaard Brouer.
8) Fix libbpf to better detect kernel version code on Debian, from Hao Xiang.
9) Extend libbpf to add an option for when the perf buffer should
wake up, from Jon Doron.
10) Follow-up fix on xdp_metadata selftest to just consume on TX
completion, from Stanislav Fomichev.
11) Extend the kfuncs.rst document with description on kfunc
lifecycle & stability expectations, from David Vernet.
12) Fix bpftool prog profile to skip attaching to offline CPUs,
from Tonghao Zhang.
====================
Link: https://lore.kernel.org/r/20230211002037.8489-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
If RPS is enabled, this allows configuring a default rps
mask, which is effective since receive queue creation time.
A default RPS mask allows the system admin to ensure proper
isolation, avoiding races at network namespace or device
creation time.
The default RPS mask is initially empty, and can be
modified via a newly added sysctl entry.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a Netlink spec-compatible family for netdevs.
This is a very simple implementation without much
thought going into it.
It allows us to reap all the benefits of Netlink specs,
one can use the generic client to issue the commands:
$ ./cli.py --spec netdev.yaml --dump dev_get
[{'ifindex': 1, 'xdp-features': set()},
{'ifindex': 2, 'xdp-features': {'basic', 'ndo-xmit', 'redirect'}},
{'ifindex': 3, 'xdp-features': {'rx-sg'}}]
the generic python library does not have flags-by-name
support, yet, but we also don't have to carry strings
in the messages, as user space can get the names from
the spec.
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Co-developed-by: Marek Majtyka <alardam@gmail.com>
Signed-off-by: Marek Majtyka <alardam@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/327ad9c9868becbe1e601b580c962549c8cd81f2.1675245258.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch introduces gso_ipv4_max_size and gro_ipv4_max_size
per device and adds netlink attributes for them, so that IPV4
BIG TCP can be guarded by a separate tunable in the next patch.
To not break the old application using "gso/gro_max_size" for
IPv4 GSO packets, this patch updates "gso/gro_ipv4_max_size"
in netif_set_gso/gro_max_size() if the new size isn't greater
than GSO_LEGACY_MAX_SIZE, so that nothing will change even if
userspace doesn't realize the new netlink attributes.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
