Commit Graph

1458 Commits

Author SHA1 Message Date
Xin Long 8a321cf7be net: add IFF_NO_ADDRCONF and use it in bonding to prevent ipv6 addrconf
Currently, in bonding it reused the IFF_SLAVE flag and checked it
in ipv6 addrconf to prevent ipv6 addrconf.

However, it is not a proper flag to use for no ipv6 addrconf, for
bonding it has to move IFF_SLAVE flag setting ahead of dev_open()
in bond_enslave(). Also, IFF_MASTER/SLAVE are historical flags
used in bonding and eql, as Jiri mentioned, the new devices like
Team, Failover do not use this flag.

So as Jiri suggested, this patch adds IFF_NO_ADDRCONF in priv_flags
of the device to indicate no ipv6 addconf, and uses it in bonding
and moves IFF_SLAVE flag setting back to its original place.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-12-12 15:18:25 -08:00
Jakub Kicinski dd8b3a802b ipsec-next-2022-12-09
-----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEEH7ZpcWbFyOOp6OJbrB3Eaf9PW7cFAmOS/ooACgkQrB3Eaf9P
 W7cOVA/+L8rHwLe78DDz/PNESyShtTVCYBDF/ngYMV8AIvjSfPresMbFV3NKqO5E
 3qbMl199QH2eWI7dhQaQ+edynSG0QCx5FmPai0UuHPLxATct1pNPJPpvBryO/4jC
 ZouYBIVjdMbq6Y8vD2gJ8UtA7TZpncP0HYOKTvYyDL9kQ+nUmu9KUYxcEcNHL5w+
 TjL9jJafR+GqczCRiwAoMKIFV7lUrTFzh7slfINNN5DVTuzN33H7Tp70z6IKOfVL
 1LATlZv7mqpLVF6dQuMXOt6kd/BEBl1y4ZHTHow5nstJvwu99P96iKwEfIXuOvWK
 fulhDU61eIik8D9QJWeM7TuZDbYewWI77plwVY/R/zRt0At4VLpq7I1m33CmLLMY
 Fb5fMxJPkM8YAtDID+BknYPrSAcxo8ji04BWFrVqQ6InPmtGfnP83XSSkYfxY7FB
 3hUfz4igsJpV5vrS1EFRhjklNwI+jY2yAvIggQtdkJ97ubSUY3E4ACfNqlJ5lJbv
 2KqWnSKlG21F9ZTR68VzcQVhFIQF6j/EuQqro+4TQUIdZswcml2iK32zrel0rs9C
 iAsgQQaMV9a2vEaScRZqdOJ4HENTbm9wD7Mso/i5vr+lnpr1ThKjQo8osU8YUlbC
 SDTMeWRRos+esFML6SP+YZ7SM/qXMluou204x/llJ/VDMXQ5e8k=
 =enQp
 -----END PGP SIGNATURE-----

Merge tag 'ipsec-next-2022-12-09' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next

Steffen Klassert says:

====================
ipsec-next 2022-12-09

1) Add xfrm packet offload core API.
   From Leon Romanovsky.

2) Add xfrm packet offload support for mlx5.
   From Leon Romanovsky and Raed Salem.

3) Fix a typto in a error message.
   From Colin Ian King.

* tag 'ipsec-next-2022-12-09' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next: (38 commits)
  xfrm: Fix spelling mistake "oflload" -> "offload"
  net/mlx5e: Open mlx5 driver to accept IPsec packet offload
  net/mlx5e: Handle ESN update events
  net/mlx5e: Handle hardware IPsec limits events
  net/mlx5e: Update IPsec soft and hard limits
  net/mlx5e: Store all XFRM SAs in Xarray
  net/mlx5e: Provide intermediate pointer to access IPsec struct
  net/mlx5e: Skip IPsec encryption for TX path without matching policy
  net/mlx5e: Add statistics for Rx/Tx IPsec offloaded flows
  net/mlx5e: Improve IPsec flow steering autogroup
  net/mlx5e: Configure IPsec packet offload flow steering
  net/mlx5e: Use same coding pattern for Rx and Tx flows
  net/mlx5e: Add XFRM policy offload logic
  net/mlx5e: Create IPsec policy offload tables
  net/mlx5e: Generalize creation of default IPsec miss group and rule
  net/mlx5e: Group IPsec miss handles into separate struct
  net/mlx5e: Make clear what IPsec rx_err does
  net/mlx5e: Flatten the IPsec RX add rule path
  net/mlx5e: Refactor FTE setup code to be more clear
  net/mlx5e: Move IPsec flow table creation to separate function
  ...
====================

Link: https://lore.kernel.org/r/20221209093310.4018731-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-12-09 20:06:35 -08:00
Leon Romanovsky f3da86dc2c xfrm: add support to HW update soft and hard limits
Both in RX and TX, the traffic that performs IPsec packet offload
transformation is accounted by HW. It is needed to properly handle
hard limits that require to drop the packet.

It means that XFRM core needs to update internal counters with the one
that accounted by the HW, so new callbacks are introduced in this patch.

In case of soft or hard limit is occurred, the driver should call to
xfrm_state_check_expire() that will perform key rekeying exactly as
done by XFRM core.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2022-12-05 10:38:31 +01:00
Leon Romanovsky 919e43fad5 xfrm: add an interface to offload policy
Extend netlink interface to add and delete XFRM policy from the device.
This functionality is a first step to implement packet IPsec offload solution.

Signed-off-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2022-12-05 10:33:13 +01:00
Heiner Kallweit d93607082e net: add netdev_sw_irq_coalesce_default_on()
Add a helper for drivers wanting to set SW IRQ coalescing
by default. The related sysfs attributes can be used to
override the default values.

Follow Jakub's suggestion and put this functionality into
net core so that drivers wanting to use software interrupt
coalescing per default don't have to open-code it.

Note that this function needs to be called before the
netdevice is registered.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-12-03 21:48:36 +00:00
Jakub Kicinski d6dc62fca6 bpf-next-for-netdev
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYIAB0WIQTFp0I1jqZrAX+hPRXbK58LschIgwUCY4AC5QAKCRDbK58LschI
 g1e0AQCfAqduTy7mYd02jDNCV0wLphNp9FbPiP9OrQT37ABpKAEA1ulj1X59bX3d
 HnZdDKuatcPZT9MV5hDLM7MFJ9GjOA4=
 =fNmM
 -----END PGP SIGNATURE-----

Daniel Borkmann says:

====================
bpf-next 2022-11-25

We've added 101 non-merge commits during the last 11 day(s) which contain
a total of 109 files changed, 8827 insertions(+), 1129 deletions(-).

The main changes are:

1) Support for user defined BPF objects: the use case is to allocate own
   objects, build own object hierarchies and use the building blocks to
   build own data structures flexibly, for example, linked lists in BPF,
   from Kumar Kartikeya Dwivedi.

2) Add bpf_rcu_read_{,un}lock() support for sleepable programs,
   from Yonghong Song.

3) Add support storing struct task_struct objects as kptrs in maps,
   from David Vernet.

4) Batch of BPF map documentation improvements, from Maryam Tahhan
   and Donald Hunter.

5) Improve BPF verifier to propagate nullness information for branches
   of register to register comparisons, from Eduard Zingerman.

6) Fix cgroup BPF iter infra to hold reference on the start cgroup,
   from Hou Tao.

7) Fix BPF verifier to not mark fentry/fexit program arguments as trusted
   given it is not the case for them, from Alexei Starovoitov.

8) Improve BPF verifier's realloc handling to better play along with dynamic
   runtime analysis tools like KASAN and friends, from Kees Cook.

9) Remove legacy libbpf mode support from bpftool,
   from Sahid Orentino Ferdjaoui.

10) Rework zero-len skb redirection checks to avoid potentially breaking
    existing BPF test infra users, from Stanislav Fomichev.

11) Two small refactorings which are independent and have been split out
    of the XDP queueing RFC series, from Toke Høiland-Jørgensen.

12) Fix a memory leak in LSM cgroup BPF selftest, from Wang Yufen.

13) Documentation on how to run BPF CI without patch submission,
    from Daniel Müller.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
====================

Link: https://lore.kernel.org/r/20221125012450.441-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-28 19:42:17 -08:00
Eric Dumazet 6c1c509778 net: add atomic_long_t to net_device_stats fields
Long standing KCSAN issues are caused by data-race around
some dev->stats changes.

Most performance critical paths already use per-cpu
variables, or per-queue ones.

It is reasonable (and more correct) to use atomic operations
for the slow paths.

This patch adds an union for each field of net_device_stats,
so that we can convert paths that are not yet protected
by a spinlock or a mutex.

netdev_stats_to_stats64() no longer has an #if BITS_PER_LONG==64

Note that the memcpy() we were using on 64bit arches
had no provision to avoid load-tearing,
while atomic_long_read() is providing the needed protection
at no cost.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-11-16 12:48:44 +00:00
Toke Høiland-Jørgensen 14d898f3c1 dev: Move received_rps counter next to RPS members in softnet data
Move the received_rps counter value next to the other RPS-related members
in softnet_data. This closes two four-byte holes in the structure, making
room for another pointer in the first two cache lines without bumping the
xmit struct to its own line.

Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20221108140601.149971-2-toke@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-15 09:00:27 -08:00
Jiri Pirko 3e52fba03a net: introduce a helper to move notifier block to different namespace
Currently, net_dev() netdev notifier variant follows the netdev with
per-net notifier from namespace to namespace. This is implemented
by move_netdevice_notifiers_dev_net() helper.

For devlink it is needed to re-register per-net notifier during
devlink reload. Introduce a new helper called
move_netdevice_notifier_net() and share the unregister/register code
with existing move_netdevice_notifiers_dev_net() helper.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-09 13:45:59 -08:00
Andy Ren bd039b5ea2 net/core: Allow live renaming when an interface is up
Allow a network interface to be renamed when the interface
is up.

As described in the netconsole documentation [1], when netconsole is
used as a built-in, it will bring up the specified interface as soon as
possible. As a result, user space will not be able to rename the
interface since the kernel disallows renaming of interfaces that are
administratively up unless the 'IFF_LIVE_RENAME_OK' private flag was set
by the kernel.

The original solution [2] to this problem was to add a new parameter to
the netconsole configuration parameters that allows renaming of
the interface used by netconsole while it is administratively up.
However, during the discussion that followed, it became apparent that we
have no reason to keep the current restriction and instead we should
allow user space to rename interfaces regardless of their administrative
state:

1. The restriction was put in place over 20 years ago when renaming was
only possible via IOCTL and before rtnetlink started notifying user
space about such changes like it does today.

2. The 'IFF_LIVE_RENAME_OK' flag was added over 3 years ago in version
5.2 and no regressions were reported.

3. In-kernel listeners to 'NETDEV_CHANGENAME' do not seem to care about
the administrative state of interface.

Therefore, allow user space to rename running interfaces by removing the
restriction and the associated 'IFF_LIVE_RENAME_OK' flag. Help in
possible triage by emitting a message to the kernel log that an
interface was renamed while UP.

[1] https://www.kernel.org/doc/Documentation/networking/netconsole.rst
[2] https://lore.kernel.org/netdev/20221102002420.2613004-1-andy.ren@getcruise.com/

Signed-off-by: Andy Ren <andy.ren@getcruise.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-11-09 13:08:12 +00:00
Jiri Pirko 77df1db80d net: remove unused ndo_get_devlink_port
Remove ndo_get_devlink_port which is no longer used alongside with the
implementations in drivers.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-03 20:48:36 -07:00
Jiri Pirko 02a68a47ea net: devlink: track netdev with devlink_port assigned
Currently, ethernet drivers are using devlink_port_type_eth_set() and
devlink_port_type_clear() to set devlink port type and link to related
netdev.

Instead of calling them directly, let the driver use
SET_NETDEV_DEVLINK_PORT macro to assign devlink_port pointer and let
devlink to track it. Note the devlink port pointer is static during
the time netdevice is registered.

In devlink code, use per-namespace netdev notifier to track
the netdevices with devlink_port assigned and change the internal
devlink_port type and related type pointer accordingly.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-03 20:48:33 -07:00
Hangbin Liu 1d997f1013 rtnetlink: pass netlink message header and portid to rtnl_configure_link()
This patch pass netlink message header and portid to rtnl_configure_link()
All the functions in this call chain need to add the parameters so we can
use them in the last call rtnl_notify(), and notify the userspace about
the new link info if NLM_F_ECHO flag is set.

- rtnl_configure_link()
  - __dev_notify_flags()
    - rtmsg_ifinfo()
      - rtmsg_ifinfo_event()
        - rtmsg_ifinfo_build_skb()
        - rtmsg_ifinfo_send()
	  - rtnl_notify()

Also move __dev_notify_flags() declaration to net/core/dev.h, as Jakub
suggested.

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-10-31 18:10:21 -07:00
Juhee Kang f3fb589aeb net: remove unused netdev_unregistering()
Currently, use dev->reg_state == NETREG_UNREGISTERING to check the status
which is NETREG_UNREGISTERING, rather than using netdev_unregistering.
Also, A helper function which is netdev_unregistering on nedevice.h is no
longer used. Thus, netdev_unregistering removes from netdevice.h.

Signed-off-by: Juhee Kang <claudiajkang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-10-30 21:56:39 +00:00
Jakub Kicinski fc8695eb11 Revert "net: fix cpu_max_bits_warn() usage in netif_attrmask_next{,_and}"
This reverts commit 854701ba4c.

We have more violations around, which leads to:

  WARNING: CPU: 2 PID: 1 at include/linux/cpumask.h:110 __netif_set_xps_queue+0x14e/0x770

Let's back this out and retry with a larger clean up in -next.

Fixes: 854701ba4c ("net: fix cpu_max_bits_warn() usage in netif_attrmask_next{,_and}")
Link: https://lore.kernel.org/all/20221014030459.3272206-2-guoren@kernel.org/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-10-15 11:17:12 +01:00
Linus Torvalds d4013bc4d4 bitmap patches for v6.1-rc1
From Phil Auld:
 drivers/base: Fix unsigned comparison to -1 in CPUMAP_FILE_MAX_BYTES
 
 From me:
 cpumask: cleanup nr_cpu_ids vs nr_cpumask_bits mess
 
 This series cleans that mess and adds new config FORCE_NR_CPUS that
 allows to optimize cpumask subsystem if the number of CPUs is known
 at compile-time.
 
 From me:
 lib: optimize find_bit() functions
 
 Reworks find_bit() functions based on new FIND_{FIRST,NEXT}_BIT() macros.
 
 From me:
 lib/find: add find_nth_bit()
 
 Adds find_nth_bit(), which is ~70 times faster than bitcounting with
 for_each() loop:
         for_each_set_bit(bit, mask, size)
                 if (n-- == 0)
                         return bit;
 
 Also adds bitmap_weight_and() to let people replace this pattern:
 	tmp = bitmap_alloc(nbits);
 	bitmap_and(tmp, map1, map2, nbits);
 	weight = bitmap_weight(tmp, nbits);
 	bitmap_free(tmp);
 with a single bitmap_weight_and() call.
 
 From me:
 cpumask: repair cpumask_check()
 
 After switching cpumask to use nr_cpu_ids, cpumask_check() started
 generating many false-positive warnings. This series fixes it.
 
 From Valentin Schneider:
 bitmap,cpumask: Add for_each_cpu_andnot() and for_each_cpu_andnot()
 
 Extends the API with one more function and applies it in sched/core.
 -----BEGIN PGP SIGNATURE-----
 
 iQGzBAABCgAdFiEEi8GdvG6xMhdgpu/4sUSA/TofvsgFAmNBwmUACgkQsUSA/Tof
 vshPRwv+KlqnZlKtuSPgbo/Kgswworpi/7TqfnN9GWlb8AJ2uhjBKI3GFwv4TDow
 7KV6wdKdXYLr4pktcIhWy3qLrT+bDDExfarHRo3QI1A1W42EJ+ZiUaGnQGcnVMzD
 5q/K1YMJYq0oaesHEw5PVUh8mm6h9qRD8VbX1u+riW/VCWBj3bho9Dp4mffQ48Q6
 hVy/SnMGgClQwNYp+sxkqYx38xUqUGYoU5MzeziUmoS6pZQh+4lF33MULnI3EKmc
 /ehXilPPtOV/Tm0RovDWFfm3rjNapV9FXHu8Ob2z/c+1A29EgXnE3pwrBDkAx001
 TQrL9qbCANRDGPLzWQHw0dwFIaXvTdrSttCsfYYfU5hI4JbnJEe0Pqkaaohy7jqm
 r0dW/TlyOG5T+k8Kwdx9w9A+jKs8TbKKZ8HOaN8BpkXswVnpbzpQbj3TITZI4aeV
 6YR4URBQ5UkrVLEXFXbrOzwjL2zqDdyNoBdTJmGLJ+5b/n0HHzmyMVkegNIwLLM3
 GR7sMQae
 =Q/+F
 -----END PGP SIGNATURE-----

Merge tag 'bitmap-6.1-rc1' of https://github.com/norov/linux

Pull bitmap updates from Yury Norov:

 - Fix unsigned comparison to -1 in CPUMAP_FILE_MAX_BYTES (Phil Auld)

 - cleanup nr_cpu_ids vs nr_cpumask_bits mess (me)

   This series cleans that mess and adds new config FORCE_NR_CPUS that
   allows to optimize cpumask subsystem if the number of CPUs is known
   at compile-time.

 - optimize find_bit() functions (me)

   Reworks find_bit() functions based on new FIND_{FIRST,NEXT}_BIT()
   macros.

 - add find_nth_bit() (me)

   Adds find_nth_bit(), which is ~70 times faster than bitcounting with
   for_each() loop:

	for_each_set_bit(bit, mask, size)
		if (n-- == 0)
			return bit;

   Also adds bitmap_weight_and() to let people replace this pattern:

	tmp = bitmap_alloc(nbits);
	bitmap_and(tmp, map1, map2, nbits);
	weight = bitmap_weight(tmp, nbits);
	bitmap_free(tmp);

   with a single bitmap_weight_and() call.

 - repair cpumask_check() (me)

   After switching cpumask to use nr_cpu_ids, cpumask_check() started
   generating many false-positive warnings. This series fixes it.

 - Add for_each_cpu_andnot() and for_each_cpu_andnot() (Valentin
   Schneider)

   Extends the API with one more function and applies it in sched/core.

* tag 'bitmap-6.1-rc1' of https://github.com/norov/linux: (28 commits)
  sched/core: Merge cpumask_andnot()+for_each_cpu() into for_each_cpu_andnot()
  lib/test_cpumask: Add for_each_cpu_and(not) tests
  cpumask: Introduce for_each_cpu_andnot()
  lib/find_bit: Introduce find_next_andnot_bit()
  cpumask: fix checking valid cpu range
  lib/bitmap: add tests for for_each() loops
  lib/find: optimize for_each() macros
  lib/bitmap: introduce for_each_set_bit_wrap() macro
  lib/find_bit: add find_next{,_and}_bit_wrap
  cpumask: switch for_each_cpu{,_not} to use for_each_bit()
  net: fix cpu_max_bits_warn() usage in netif_attrmask_next{,_and}
  cpumask: add cpumask_nth_{,and,andnot}
  lib/bitmap: remove bitmap_ord_to_pos
  lib/bitmap: add tests for find_nth_bit()
  lib: add find_nth{,_and,_andnot}_bit()
  lib/bitmap: add bitmap_weight_and()
  lib/bitmap: don't call __bitmap_weight() in kernel code
  tools: sync find_bit() implementation
  lib/find_bit: optimize find_next_bit() functions
  lib/find_bit: create find_first_zero_bit_le()
  ...
2022-10-10 12:49:34 -07:00
Yury Norov 854701ba4c net: fix cpu_max_bits_warn() usage in netif_attrmask_next{,_and}
The functions require to be passed with a cpu index prior to one that is
the first to start search, so the valid input range is [-1, nr_cpu_ids-1).
However, the code checks against [-1, nr_cpu_ids).

Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
2022-10-01 10:22:57 -07:00
Vladimir Oltean aac4daa894 net/sched: query offload capabilities through ndo_setup_tc()
When adding optional new features to Qdisc offloads, existing drivers
must reject the new configuration until they are coded up to act on it.

Since modifying all drivers in lockstep with the changes in the Qdisc
can create problems of its own, it would be nice if there existed an
automatic opt-in mechanism for offloading optional features.

Jakub proposes that we multiplex one more kind of call through
ndo_setup_tc(): one where the driver populates a Qdisc-specific
capability structure.

First user will be taprio in further changes. Here we are introducing
the definitions for the base functionality.

Link: https://patchwork.kernel.org/project/netdevbpf/patch/20220923163310.3192733-3-vladimir.oltean@nxp.com/
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Co-developed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-29 18:52:01 -07:00
Paolo Abeni dbae2b0628 net: skb: introduce and use a single page frag cache
After commit 3226b158e6 ("net: avoid 32 x truesize under-estimation
for tiny skbs") we are observing 10-20% regressions in performance
tests with small packets. The perf trace points to high pressure on
the slab allocator.

This change tries to improve the allocation schema for small packets
using an idea originally suggested by Eric: a new per CPU page frag is
introduced and used in __napi_alloc_skb to cope with small allocation
requests.

To ensure that the above does not lead to excessive truesize
underestimation, the frag size for small allocation is inflated to 1K
and all the above is restricted to build with 4K page size.

Note that we need to update accordingly the run-time check introduced
with commit fd9ea57f4e ("net: add napi_get_frags_check() helper").

Alex suggested a smart page refcount schema to reduce the number
of atomic operations and deal properly with pfmemalloc pages.

Under small packet UDP flood, I measure a 15% peak tput increases.

Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Suggested-by: Alexander H Duyck <alexanderduyck@fb.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Link: https://lore.kernel.org/r/6b6f65957c59f86a353fc09a5127e83a32ab5999.1664350652.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-29 18:48:15 -07:00
Jakub Kicinski b48b89f9c1 net: drop the weight argument from netif_napi_add
We tell driver developers to always pass NAPI_POLL_WEIGHT
as the weight to netif_napi_add(). This may be confusing
to newcomers, drop the weight argument, those who really
need to tweak the weight can use netif_napi_add_weight().

Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> # for CAN
Link: https://lore.kernel.org/r/20220927132753.750069-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-28 18:57:14 -07:00
Vladimir Oltean db01868bf2 net: introduce iterators over synced hw addresses
Some network drivers use __dev_mc_sync()/__dev_uc_sync() and therefore
program the hardware only with addresses with a non-zero sync_cnt.

Some of the above drivers also need to save/restore the address
filtering lists when certain events happen, and they need to walk
through the struct net_device :: uc and struct net_device :: mc lists.
But these lists contain unsynced addresses too.

To keep the appearance of an elementary form of data encapsulation,
provide iterators through these lists that only look at entries with a
non-zero sync_cnt, instead of filtering entries out from device drivers.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-09-20 10:32:35 +02:00
Jakub Kicinski c3f760ef12 net: remove netif_tx_napi_add()
All callers are now gone.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-09-02 12:41:43 +01:00
Eric Dumazet 977f1aa5e4 net: bql: add more documentation
Add some documentation for netdev_tx_sent_queue() and
netdev_tx_completed_queue()

Stating that netdev_tx_completed_queue() must be called once
per TX completion round is apparently not obvious for everybody.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-09-02 12:27:46 +01:00
Jakub Kicinski 880b0dd94f Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
  21234e3a84 ("net/mlx5e: Fix use after free in mlx5e_fs_init()")
  c7eafc5ed0 ("net/mlx5e: Convert ethtool_steering member of flow_steering struct to pointer")
https://lore.kernel.org/all/20220825104410.67d4709c@canb.auug.org.au/
https://lore.kernel.org/all/20220823055533.334471-1-saeed@kernel.org/

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-25 16:07:42 -07:00
Uros Bizjak b903078097 netdev: Use try_cmpxchg in napi_if_scheduled_mark_missed
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
napi_if_scheduled_mark_missed. x86 CMPXCHG instruction returns
success in ZF flag, so this change saves a compare after cmpxchg
(and related move instruction in front of cmpxchg).

Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails, enabling further code simplifications.

Cc: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Link: https://lore.kernel.org/r/20220822143243.2798-1-ubizjak@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-25 14:20:35 -07:00
Kuniyuki Iwashima a5612ca10d net: Fix data-races around sysctl_devconf_inherit_init_net.
While reading sysctl_devconf_inherit_init_net, it can be changed
concurrently.  Thus, we need to add READ_ONCE() to its readers.

Fixes: 856c395cfa ("net: introduce a knob to control whether to inherit devconf config")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-08-24 13:46:58 +01:00
Kuniyuki Iwashima af67508ea6 net: Fix data-races around sysctl_fb_tunnels_only_for_init_net.
While reading sysctl_fb_tunnels_only_for_init_net, it can be changed
concurrently.  Thus, we need to add READ_ONCE() to its readers.

Fixes: 79134e6ce2 ("net: do not create fallback tunnels for non-default namespaces")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-08-24 13:46:58 +01:00
Stephen Hemminger 1202cdd665 Remove DECnet support from kernel
DECnet is an obsolete network protocol that receives more attention
from kernel janitors than users. It belongs in computer protocol
history museum not in Linux kernel.

It has been "Orphaned" in kernel since 2010. The iproute2 support
for DECnet was dropped in 5.0 release. The documentation link on
Sourceforge says it is abandoned there as well.

Leave the UAPI alone to keep userspace programs compiling.
This means that there is still an empty neighbour table
for AF_DECNET.

The table of /proc/sys/net entries was updated to match
current directories and reformatted to be alphabetical.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: David Ahern <dsahern@kernel.org>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-08-22 14:26:30 +01:00
Jakub Kicinski 0d8730f07c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
drivers/net/ethernet/microchip/sparx5/sparx5_switchdev.c
  9c5de246c1 ("net: sparx5: mdb add/del handle non-sparx5 devices")
  fbb89d02e3 ("net: sparx5: Allow mdb entries to both CPU and ports")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-30 16:31:00 -07:00
Dan Carpenter 3b89b511ea net: fix IFF_TX_SKB_NO_LINEAR definition
The "1<<31" shift has a sign extension bug so IFF_TX_SKB_NO_LINEAR is
0xffffffff80000000 instead of 0x0000000080000000.

Fixes: c2ff53d804 ("net: Add priv_flags for allow tx skb without linear")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Link: https://lore.kernel.org/r/YrRrcGttfEVnf85Q@kili
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-24 16:45:40 -07:00
Eric Dumazet 9962acefbc net: adopt u64_stats_t in struct pcpu_sw_netstats
As explained in commit 316580b69d ("u64_stats: provide u64_stats_t type")
we should use u64_stats_t and related accessors to avoid load/store tearing.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-09 21:53:11 -07:00
Jakub Kicinski d62607c3fe net: rename reference+tracking helpers
Netdev reference helpers have a dev_ prefix for historic
reasons. Renaming the old helpers would be too much churn
but we can rename the tracking ones which are relatively
recent and should be the default for new code.

Rename:
 dev_hold_track()    -> netdev_hold()
 dev_put_track()     -> netdev_put()
 dev_replace_track() -> netdev_ref_replace()

Link: https://lore.kernel.org/r/20220608043955.919359-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-09 21:52:55 -07:00
Jakub Kicinski c304eddcec net: wrap the wireless pointers in struct net_device in an ifdef
Most protocol-specific pointers in struct net_device are under
a respective ifdef. Wireless is the notable exception. Since
there's a sizable number of custom-built kernels for datacenter
workloads which don't build wireless it seems reasonable to
ifdefy those pointers as well.

While at it move IPv4 and IPv6 pointers up, those are special
for obvious reasons.

Acked-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> # ieee802154
Acked-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-22 21:51:54 +01:00
Jakub Kicinski d7e6f58360 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
drivers/net/ethernet/mellanox/mlx5/core/main.c
  b33886971d ("net/mlx5: Initialize flow steering during driver probe")
  40379a0084 ("net/mlx5_fpga: Drop INNOVA TLS support")
  f2b41b32cd ("net/mlx5: Remove ipsec_ops function table")
https://lore.kernel.org/all/20220519040345.6yrjromcdistu7vh@sx1/
  16d42d3133 ("net/mlx5: Drain fw_reset when removing device")
  8324a02c34 ("net/mlx5: Add exit route when waiting for FW")
https://lore.kernel.org/all/20220519114119.060ce014@canb.auug.org.au/

tools/testing/selftests/net/mptcp/mptcp_join.sh
  e274f71540 ("selftests: mptcp: add subflow limits test-cases")
  b6e074e171 ("selftests: mptcp: add infinite map testcase")
  5ac1d2d634 ("selftests: mptcp: Add tests for userspace PM type")
https://lore.kernel.org/all/20220516111918.366d747f@canb.auug.org.au/

net/mptcp/options.c
  ba2c89e0ea ("mptcp: fix checksum byte order")
  1e39e5a32a ("mptcp: infinite mapping sending")
  ea66758c17 ("tcp: allow MPTCP to update the announced window")
https://lore.kernel.org/all/20220519115146.751c3a37@canb.auug.org.au/

net/mptcp/pm.c
  95d6865178 ("mptcp: fix subflow accounting on close")
  4d25247d3a ("mptcp: bypass in-kernel PM restrictions for non-kernel PMs")
https://lore.kernel.org/all/20220516111435.72f35dca@canb.auug.org.au/

net/mptcp/subflow.c
  ae66fb2ba6 ("mptcp: Do TCP fallback on early DSS checksum failure")
  0348c690ed ("mptcp: add the fallback check")
  f8d4bcacff ("mptcp: infinite mapping receiving")
https://lore.kernel.org/all/20220519115837.380bb8d4@canb.auug.org.au/

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-19 11:23:59 -07:00
Felix Fietkau cf2df74e20 net: fix dev_fill_forward_path with pppoe + bridge
When calling dev_fill_forward_path on a pppoe device, the provided destination
address is invalid. In order for the bridge fdb lookup to succeed, the pppoe
code needs to update ctx->daddr to the correct value.
Fix this by storing the address inside struct net_device_path_ctx

Fixes: f6efc675c9 ("net: ppp: resolve forwarding path for bridge pppoe devices")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-05-16 12:58:55 +02:00
Eric Dumazet 97e719a82b net: fix possible race in skb_attempt_defer_free()
A cpu can observe sd->defer_count reaching 128,
and call smp_call_function_single_async()

Problem is that the remote CPU can clear sd->defer_count
before the IPI is run/acknowledged.

Other cpus can queue more packets and also decide
to call smp_call_function_single_async() while the pending
IPI was not yet delivered.

This is a common issue with smp_call_function_single_async().
Callers must ensure correct synchronization and serialization.

I triggered this issue while experimenting smaller threshold.
Performing the call to smp_call_function_single_async()
under sd->defer_lock protection did not solve the problem.

Commit 5a18ceca63 ("smp: Allow smp_call_function_single_async()
to insert locked csd") replaced an informative WARN_ON_ONCE()
with a return of -EBUSY, which is often ignored.
Test of CSD_FLAG_LOCK presence is racy anyway.

Fixes: 68822bdf76 ("net: generalize skb freeing deferral to per-cpu lists")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-16 11:33:59 +01:00
Alexander Duyck 0fe79f28bf net: allow gro_max_size to exceed 65536
Allow the gro_max_size to exceed a value larger than 65536.

There weren't really any external limitations that prevented this other
than the fact that IPv4 only supports a 16 bit length field. Since we have
the option of adding a hop-by-hop header for IPv6 we can allow IPv6 to
exceed this value and for IPv4 and non-TCP flows we can cap things at 65536
via a constant rather than relying on gro_max_size.

[edumazet] limit GRO_MAX_SIZE to (8 * 65535) to avoid overflows.

Signed-off-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-16 10:18:56 +01:00
Eric Dumazet 34b92e8d19 net: limit GSO_MAX_SIZE to 524280 bytes
Make sure we will not overflow shinfo->gso_segs

Minimal TCP MSS size is 8 bytes, and shinfo->gso_segs
is a 16bit field.

TCP_MIN_GSO_SIZE is currently defined in include/net/tcp.h,
it seems cleaner to not bring tcp details into include/linux/netdevice.h

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-16 10:18:55 +01:00
Alexander Duyck 7c4e983c4f net: allow gso_max_size to exceed 65536
The code for gso_max_size was added originally to allow for debugging and
workaround of buggy devices that couldn't support TSO with blocks 64K in
size. The original reason for limiting it to 64K was because that was the
existing limits of IPv4 and non-jumbogram IPv6 length fields.

With the addition of Big TCP we can remove this limit and allow the value
to potentially go up to UINT_MAX and instead be limited by the tso_max_size
value.

So in order to support this we need to go through and clean up the
remaining users of the gso_max_size value so that the values will cap at
64K for non-TCPv6 flows. In addition we can clean up the GSO_MAX_SIZE value
so that 64K becomes GSO_LEGACY_MAX_SIZE and UINT_MAX will now be the upper
limit for GSO_MAX_SIZE.

v6: (edumazet) fixed a compile error if CONFIG_IPV6=n,
               in a new sk_trim_gso_size() helper.
               netif_set_tso_max_size() caps the requested TSO size
               with GSO_MAX_SIZE.

Signed-off-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-16 10:18:55 +01:00
Eric Dumazet 5b87be9e49 net: add include/net/net_debug.h
Remove from include/linux/netdevice.h helpers
that send debug/info/warnings to syslog.

We plan adding more helpers in following patches.

v2: added two includes, and 'struct net_device' forward declaration
    to avoid compile errors (kernel bots)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-11 12:43:10 +01:00
Gerhard Engleder 97dc7cd92a ptp: Support late timestamp determination
If a physical clock supports a free running cycle counter, then
timestamps shall be based on this time too. For TX it is known in
advance before the transmission if a timestamp based on the free running
cycle counter is needed. For RX it is impossible to know which timestamp
is needed before the packet is received and assigned to a socket.

Support late timestamp determination by a network device. Therefore, an
address/cookie is stored within the new netdev_data field of struct
skb_shared_hwtstamps. This address/cookie is provided to a new network
device function called ndo_get_tstamp(), which returns a timestamp based
on the normal/adjustable time or based on the free running cycle
counter. If function is not supported, then timestamp handling is not
changed.

This mechanism is intended for RX, but TX use is also possible.

Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-05-10 09:48:08 +02:00
Alaa Mohamed ca4567f1e6 rtnetlink: add extack support in fdb del handlers
Add extack support to .ndo_fdb_del in netdevice.h and
all related methods.

Signed-off-by: Alaa Mohamed <eng.alaamohamedsoliman.am@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-09 11:58:20 +01:00
Jakub Kicinski 744d49daf8 net: move netif_set_gso_max helpers
These are now internal to the core, no need to expose them.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-06 12:07:56 +01:00
Jakub Kicinski 14d7b8122f net: don't allow user space to lift the device limits
Up until commit 46e6b992c2 ("rtnetlink: allow GSO maximums to
be set on device creation") the gso_max_segs and gso_max_size
of a device were not controlled from user space.

The quoted commit added the ability to control them because of
the following setup:

 netns A  |  netns B
     veth<->veth   eth0

If eth0 has TSO limitations and user wants to efficiently forward
traffic between eth0 and the veths they should copy the TSO
limitations of eth0 onto the veths. This would happen automatically
for macvlans or ipvlan but veth users are not so lucky (given the
loose coupling).

Unfortunately the commit in question allowed users to also override
the limits on real HW devices.

It may be useful to control the max GSO size and someone may be using
that ability (not that I know of any user), so create a separate set
of knobs to reliably record the TSO limitations. Validate the user
requests.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-06 12:07:56 +01:00
Jakub Kicinski 6df6398f7c net: add netif_inherit_tso_max()
To make later patches smaller create a helper for inheriting
the TSO limitations of a lower device. The TSO in the name
is not an accident, subsequent patches will replace GSO
with TSO in more names.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-06 12:07:56 +01:00
Jakub Kicinski 58caed3dac netdev: reshuffle netif_napi_add() APIs to allow dropping weight
Most drivers should not have to worry about selecting the right
weight for their NAPI instances and pass NAPI_POLL_WEIGHT.
It'd be best if we didn't require the argument at all and selected
the default internally.

This change prepares the ground for such reshuffling, allowing
for a smooth transition. The following API should remain after
the next release cycle:
  netif_napi_add()
  netif_napi_add_weight()
  netif_napi_add_tx()
  netif_napi_add_tx_weight()
Where the _weight() variants take an explicit weight argument.
I opted for a _weight() suffix rather than a __ prefix, because
we use __ in places to mean that caller needs to also issue a
synchronize_net() call.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20220502232703.396351-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-03 17:26:10 -07:00
Pavel Begunkov c526fd8f9f net: inline dev_queue_xmit()
Inline dev_queue_xmit() and dev_queue_xmit_accel(), they both are small
proxy functions doing nothing but redirecting the control flow to
__dev_queue_xmit().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-04-30 12:58:44 +01:00
Jakub Kicinski 0e55546b18 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
include/linux/netdevice.h
net/core/dev.c
  6510ea973d ("net: Use this_cpu_inc() to increment net->core_stats")
  794c24e992 ("net-core: rx_otherhost_dropped to core_stats")
https://lore.kernel.org/all/20220428111903.5f4304e0@canb.auug.org.au/

drivers/net/wan/cosa.c
  d48fea8401 ("net: cosa: fix error check return value of register_chrdev()")
  89fbca3307 ("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>
2022-04-28 13:02:01 -07:00
Sebastian Andrzej Siewior 6510ea973d net: Use this_cpu_inc() to increment net->core_stats
The macro dev_core_stats_##FIELD##_inc() disables preemption and invokes
netdev_core_stats_alloc() to return a per-CPU pointer.
netdev_core_stats_alloc() will allocate memory on its first invocation
which breaks on PREEMPT_RT because it requires non-atomic context for
memory allocation.

This can be avoided by enabling preemption in netdev_core_stats_alloc()
assuming the caller always disables preemption.

It might be better to replace local_inc() with this_cpu_inc() now that
dev_core_stats_##FIELD##_inc() gained a preempt-disable section and does
not rely on already disabled preemption. This results in less
instructions on x86-64:
local_inc:
|          incl %gs:__preempt_count(%rip)  # __preempt_count
|          movq    488(%rdi), %rax # _1->core_stats, _22
|          testq   %rax, %rax      # _22
|          je      .L585   #,
|          add %gs:this_cpu_off(%rip), %rax        # this_cpu_off, tcp_ptr__
|  .L586:
|          testq   %rax, %rax      # _27
|          je      .L587   #,
|          incq (%rax)            # _6->a.counter
|  .L587:
|          decl %gs:__preempt_count(%rip)  # __preempt_count

this_cpu_inc(), this patch:
|         movq    488(%rdi), %rax # _1->core_stats, _5
|         testq   %rax, %rax      # _5
|         je      .L591   #,
| .L585:
|         incq %gs:(%rax) # _18->rx_dropped

Use unsigned long as type for the counter. Use this_cpu_inc() to
increment the counter. Use a plain read of the counter.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/YmbO0pxgtKpCw4SY@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-26 17:32:30 -07:00
Eric Dumazet 68822bdf76 net: generalize skb freeing deferral to per-cpu lists
Logic added in commit f35f821935 ("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>
2022-04-26 17:05:59 -07:00