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  1. 29 Mar, 2023 32 commits
  3. 28 Mar, 2023 8 commits
    • Saeed Mahameed's avatar
      net/mlx5e: Fix build break on 32bit · 163c2c70
      Saeed Mahameed authored 
      The cited commit caused the following build break in mlx5 due to a change
in size of MAX_SKB_FRAGS.

error: format '%lu' expects argument of type 'long unsigned int',
       but argument 7 has type 'unsigned int' [-Werror=format=]

Fix this by explicit casting.

Fixes: 3948b059 ("net: introduce a config option to tweak MAX_SKB_FRAGS")
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
Link: https://lore.kernel.org/r/20230328200723.125122-1-saeed@kernel.orgSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      163c2c70
    • Grygorii Strashko's avatar
      net: ethernet: ti: am65-cpsw: enable p0 host port rx_vlan_remap · 86e2eca4
      Grygorii Strashko authored 
      By default, the tagged ingress packets to the switch from the host port
P0 get internal switch priority assigned equal to the DMA CPPI channel
number they came from, unless CPSW_P0_CONTROL_REG.RX_REMAP_VLAN is enabled.
This causes issues with applying QoS policies and mapping packets on
external port fifos, because the default configuration is vlan_aware and
DMA CPPI channels are shared between all external ports.

Hence enable CPSW_P0_CONTROL_REG.RX_REMAP_VLAN so packet will preserve
internal switch priority assigned following the VLAN(priority) tag no
matter through which DMA CPPI Channels packets enter the switch.
Signed-off-by: default avatarGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: default avatarSiddharth Vadapalli <s-vadapalli@ti.com>
Link: https://lore.kernel.org/r/20230327092103.3256118-1-s-vadapalli@ti.comSigned-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
      86e2eca4
    • Grygorii Strashko's avatar
      net: ethernet: ti: am65-cpsw: add .ndo to set dma per-queue rate · 5c8560c4
      Grygorii Strashko authored 
      Enable rate limiting TX DMA queues for CPSW interface by configuring the
rate in absolute Mb/s units per TX queue.

Example:
    ethtool -L eth0 tx 4

    echo 100 > /sys/class/net/eth0/queues/tx-0/tx_maxrate
    echo 200 > /sys/class/net/eth0/queues/tx-1/tx_maxrate
    echo 50 > /sys/class/net/eth0/queues/tx-2/tx_maxrate
    echo 30 > /sys/class/net/eth0/queues/tx-3/tx_maxrate

    # disable
    echo 0 > /sys/class/net/eth0/queues/tx-0/tx_maxrate
Signed-off-by: default avatarGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: default avatarSiddharth Vadapalli <s-vadapalli@ti.com>
Link: https://lore.kernel.org/r/20230327085758.3237155-1-s-vadapalli@ti.comSigned-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
      5c8560c4
    • Paolo Abeni's avatar
      Merge branch 'allocate-multiple-skbuffs-on-tx' · d8b0c963
      Paolo Abeni authored 
      Arseniy Krasnov says:

====================
allocate multiple skbuffs on tx

This adds small optimization for tx path: instead of allocating single
skbuff on every call to transport, allocate multiple skbuff's until
credit space allows, thus trying to send as much as possible data without
return to af_vsock.c.

Also this patchset includes second patch which adds check and return from
'virtio_transport_get_credit()' and 'virtio_transport_put_credit()' when
these functions are called with 0 argument. This is needed, because zero
argument makes both functions to behave as no-effect, but both of them
always tries to acquire spinlock. Moreover, first patch always calls
function 'virtio_transport_put_credit()' with zero argument in case of
successful packet transmission.
====================

Link: https://lore.kernel.org/r/b0d15942-65ba-3a32-ba8d-fed64332d8f6@sberdevices.ruSigned-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
      d8b0c963
    • Arseniy Krasnov's avatar
      virtio/vsock: check argument to avoid no effect call · e3ec366e
      Arseniy Krasnov authored 
      Both of these functions have no effect when input argument is 0, so to
avoid useless spinlock access, check argument before it.
Signed-off-by: default avatarArseniy Krasnov <AVKrasnov@sberdevices.ru>
Reviewed-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
      e3ec366e
    • Arseniy Krasnov's avatar
      virtio/vsock: allocate multiple skbuffs on tx · b68ffb1b
      Arseniy Krasnov authored 
      This adds small optimization for tx path: instead of allocating single
skbuff on every call to transport, allocate multiple skbuff's until
credit space allows, thus trying to send as much as possible data without
return to af_vsock.c.
Signed-off-by: default avatarArseniy Krasnov <AVKrasnov@sberdevices.ru>
Reviewed-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
      b68ffb1b
    • Thomas Gleixner's avatar
      atomics: Provide rcuref - scalable reference counting · ee1ee6db
      Thomas Gleixner authored 
      atomic_t based reference counting, including refcount_t, uses
atomic_inc_not_zero() for acquiring a reference. atomic_inc_not_zero() is
implemented with a atomic_try_cmpxchg() loop. High contention of the
reference count leads to retry loops and scales badly. There is nothing to
improve on this implementation as the semantics have to be preserved.

Provide rcuref as a scalable alternative solution which is suitable for RCU
managed objects. Similar to refcount_t it comes with overflow and underflow
detection and mitigation.

rcuref treats the underlying atomic_t as an unsigned integer and partitions
this space into zones:

  0x00000000 - 0x7FFFFFFF	valid zone (1 .. (INT_MAX + 1) references)
  0x80000000 - 0xBFFFFFFF	saturation zone
  0xC0000000 - 0xFFFFFFFE	dead zone
  0xFFFFFFFF   			no reference

rcuref_get() unconditionally increments the reference count with
atomic_add_negative_relaxed(). rcuref_put() unconditionally decrements the
reference count with atomic_add_negative_release().

This unconditional increment avoids the inc_not_zero() problem, but
requires a more complex implementation on the put() side when the count
drops from 0 to -1.

When this transition is detected then it is attempted to mark the reference
count dead, by setting it to the midpoint of the dead zone with a single
atomic_cmpxchg_release() operation. This operation can fail due to a
concurrent rcuref_get() elevating the reference count from -1 to 0 again.

If the unconditional increment in rcuref_get() hits a reference count which
is marked dead (or saturated) it will detect it after the fact and bring
back the reference count to the midpoint of the respective zone. The zones
provide enough tolerance which makes it practically impossible to escape
from a zone.

The racy implementation of rcuref_put() requires to protect rcuref_put()
against a grace period ending in order to prevent a subtle use after
free. As RCU is the only mechanism which allows to protect against that, it
is not possible to fully replace the atomic_inc_not_zero() based
implementation of refcount_t with this scheme.

The final drop is slightly more expensive than the atomic_dec_return()
counterpart, but that's not the case which this is optimized for. The
optimization is on the high frequeunt get()/put() pairs and their
scalability.

The performance of an uncontended rcuref_get()/put() pair where the put()
is not dropping the last reference is still on par with the plain atomic
operations, while at the same time providing overflow and underflow
detection and mitigation.

The performance of rcuref compared to plain atomic_inc_not_zero() and
atomic_dec_return() based reference counting under contention:

 -  Micro benchmark: All CPUs running a increment/decrement loop on an
    elevated reference count, which means the 0 to -1 transition never
    happens.

    The performance gain depends on microarchitecture and the number of
    CPUs and has been observed in the range of 1.3X to 4.7X

 - Conversion of dst_entry::__refcnt to rcuref and testing with the
    localhost memtier/memcached benchmark. That benchmark shows the
    reference count contention prominently.

    The performance gain depends on microarchitecture and the number of
    CPUs and has been observed in the range of 1.1X to 2.6X over the
    previous fix for the false sharing issue vs. struct
    dst_entry::__refcnt.

    When memtier is run over a real 1Gb network connection, there is a
    small gain on top of the false sharing fix. The two changes combined
    result in a 2%-5% total gain for that networked test.
Reported-by: default avatarWangyang Guo <wangyang.guo@intel.com>
Reported-by: default avatarArjan Van De Ven <arjan.van.de.ven@intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230323102800.158429195@linutronix.de
      ee1ee6db
    • Thomas Gleixner's avatar
      atomics: Provide atomic_add_negative() variants · e5ab9eff
      Thomas Gleixner authored 
      atomic_add_negative() does not provide the relaxed/acquire/release
variants.

Provide them in preparation for a new scalable reference count algorithm.
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230323102800.101763813@linutronix.de
      e5ab9eff
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