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  1. 24 Mar, 2019 12 commits
    • David S. Miller's avatar
      Merge tag 'mlx5-updates-2019-03-20' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux · d64fee0a
      David S. Miller authored 
      Saeed Mahameed says:

====================
mlx5-updates-2019-03-20

This series includes updates to mlx5 driver,

1) Compiler warnings cleanup from Saeed Mahameed
2) Parav Pandit simplifies sriov enable/disables
3) Gustavo A. R. Silva, Removes a redundant assignment
4) Moshe Shemesh, Adds Geneve tunnel stateless offload support
5) Eli Britstein, Adds the Support for VLAN modify action and
   Replaces TC VLAN pop and push actions with VLAN modify

Note: This series includes two simple non-mlx5 patches,

1) Declare IANA_VXLAN_UDP_PORT definition in include/net/vxlan.h,
and use it in some drivers.
2) Declare GENEVE_UDP_PORT definition in include/net/geneve.h,
and use it in mlx5 and nfp drivers.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d64fee0a
    • David S. Miller's avatar
      Merge branch '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/jkirsher/next-queue · 071d08af
      David S. Miller authored 
      Jeff Kirsher says:

====================
100GbE Intel Wired LAN Driver Updates 2019-03-22

This series contains updates to ice driver only.

Akeem enables MAC anti-spoofing by default when a new VSI is being
created.  Fixes an issue when reclaiming VF resources back to the pool
after reset, by freeing VF resources separately using the first VF
vector index to traverse the list, instead of starting at the last
assigned vectors list.  Added support for VF & PF promiscuous mode in
the ice driver.  Fixed the PF driver from letting the VF know it is "not
trusted" when it attempts to add more than its permitted additional MAC
addresses.  Altered how the driver gets the VF VSIs instances, instead
of using the mailbox messages to retrieve VSIs, get it directly via the
VF object in the PF data structure.

Bruce fixes return values to resolve static analysis warnings.  Made
whitespace changes to increase readability and reduce code wrapping.

Anirudh cleans up code by removing a function prototype that was never
implemented and removed an unused field in the ice_sched_vsi_info
structure.

Kiran fixes a potential divide by zero issue by adding a check.

Victor cleans up the transmit scheduler by adjusting the stack variable
usage and added/modified debug prints to make them more useful.

Yashaswini updates the driver in VEB mode to ensure that the LAN_EN bit
is set if all the right conditions are met.

Christopher ensures the loopback enable bit is not set for prune switch
rules, since all transmit traffic would be looped back to the internal
switch and dropped.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      071d08af
    • David S. Miller's avatar
      Merge branch 'tcp-rx-tx-cache' · bdaba895
      David S. Miller authored 
      Eric Dumazet says:

====================
tcp: add rx/tx cache to reduce lock contention

On hosts with many cpus we can observe a very serious contention
on spinlocks used in mm slab layer.

The following can happen quite often :

1) TX path
  sendmsg() allocates one (fclone) skb on CPU A, sends a clone.
  ACK is received on CPU B, and consumes the skb that was in the retransmit
  queue.

2) RX path
  network driver allocates skb on CPU C
  recvmsg() happens on CPU D, freeing the skb after it has been delivered
  to user space.

In both cases, we are hitting the asymetric alloc/free pattern
for which slab has to drain alien caches. At 8 Mpps per second,
this represents 16 Mpps alloc/free per second and has a huge penalty.

In an interesting experiment, I tried to use a single kmem_cache for all the skbs
(in skb_init() : skbuff_fclone_cache = skbuff_head_cache =
                  kmem_cache_create("skbuff_fclone_cache", sizeof(struct sk_buff_fclones),);
qnd most of the contention disappeared, since cpus could better use
their local slab per-cpu cache.

But we can do actually better, in the following patches.

TX : at ACK time, no longer free the skb but put it back in a tcp socket cache,
     so that next sendmsg() can reuse it immediately.

RX : at recvmsg() time, do not free the skb but put it in a tcp socket cache
   so that it can be freed by the cpu feeding the incoming packets in BH.

This increased the performance of small RPC benchmark by about 10 % on a host
with 112 hyperthreads.

v2 : - Solved a race condition : sk_stream_alloc_skb() to make sure the prior
       clone has been freed.
     - Really test rps_needed in sk_eat_skb() as claimed.
     - Fixed rps_needed use in drivers/net/tun.c

v3: Added a #ifdef CONFIG_RPS, to avoid compile error (kbuild robot)
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      bdaba895
    • Eric Dumazet's avatar
      tcp: add one skb cache for rx · 8b27dae5
      Eric Dumazet authored 
      Often times, recvmsg() system calls and BH handling for a particular
TCP socket are done on different cpus.

This means the incoming skb had to be allocated on a cpu,
but freed on another.

This incurs a high spinlock contention in slab layer for small rpc,
but also a high number of cache line ping pongs for larger packets.

A full size GRO packet might use 45 page fragments, meaning
that up to 45 put_page() can be involved.

More over performing the __kfree_skb() in the recvmsg() context
adds a latency for user applications, and increase probability
of trapping them in backlog processing, since the BH handler
might found the socket owned by the user.

This patch, combined with the prior one increases the rpc
performance by about 10 % on servers with large number of cores.

(tcp_rr workload with 10,000 flows and 112 threads reach 9 Mpps
 instead of 8 Mpps)

This also increases single bulk flow performance on 40Gbit+ links,
since in this case there are often two cpus working in tandem :

 - CPU handling the NIC rx interrupts, feeding the receive queue,
  and (after this patch) freeing the skbs that were consumed.

 - CPU in recvmsg() system call, essentially 100 % busy copying out
  data to user space.

Having at most one skb in a per-socket cache has very little risk
of memory exhaustion, and since it is protected by socket lock,
its management is essentially free.

Note that if rps/rfs is used, we do not enable this feature, because
there is high chance that the same cpu is handling both the recvmsg()
system call and the TCP rx path, but that another cpu did the skb
allocations in the device driver right before the RPS/RFS logic.

To properly handle this case, it seems we would need to record
on which cpu skb was allocated, and use a different channel
to give skbs back to this cpu.
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      8b27dae5
    • Eric Dumazet's avatar
      tcp: add one skb cache for tx · 472c2e07
      Eric Dumazet authored 
      On hosts with a lot of cores, RPC workloads suffer from heavy contention on slab spinlocks.

    20.69%  [kernel]       [k] queued_spin_lock_slowpath
     5.64%  [kernel]       [k] _raw_spin_lock
     3.83%  [kernel]       [k] syscall_return_via_sysret
     3.48%  [kernel]       [k] __entry_text_start
     1.76%  [kernel]       [k] __netif_receive_skb_core
     1.64%  [kernel]       [k] __fget

For each sendmsg(), we allocate one skb, and free it at the time ACK packet comes.

In many cases, ACK packets are handled by another cpus, and this unfortunately
incurs heavy costs for slab layer.

This patch uses an extra pointer in socket structure, so that we try to reuse
the same skb and avoid these expensive costs.

We cache at most one skb per socket so this should be safe as far as
memory pressure is concerned.
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      472c2e07
    • Eric Dumazet's avatar
      net: convert rps_needed and rfs_needed to new static branch api · dc05360f
      Eric Dumazet authored 
      We prefer static_branch_unlikely() over static_key_false() these days.
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      dc05360f
    • David S. Miller's avatar
      Merge branch 'net-dev-BYPASS-for-lockless-qdisc' · 7c1508e5
      David S. Miller authored 
      Paolo Abeni says:

====================
net: dev: BYPASS for lockless qdisc

This patch series is aimed at improving xmit performances of lockless qdisc
in the uncontended scenario.

After the lockless refactor pfifo_fast can't leverage the BYPASS optimization.
Due to retpolines the overhead for the avoidables enqueue and dequeue operations
has increased and we see measurable regressions.

The first patch introduces the BYPASS code path for lockless qdisc, and the
second one optimizes such path further. Overall this avoids up to 3 indirect
calls per xmit packet. Detailed performance figures are reported in the 2nd
patch.

 v2 -> v3:
  - qdisc_is_empty() has a const argument (Eric)

 v1 -> v2:
  - use really an 'empty' flag instead of 'not_empty', as
    suggested by Eric
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      7c1508e5
    • Paolo Abeni's avatar
      net: dev: introduce support for sch BYPASS for lockless qdisc · ba27b4cd
      Paolo Abeni authored 
      With commit c5ad119f ("net: sched: pfifo_fast use skb_array")
pfifo_fast no longer benefit from the TCQ_F_CAN_BYPASS optimization.
Due to retpolines the cost of the enqueue()/dequeue() pair has become
relevant and we observe measurable regression for the uncontended
scenario when the packet-rate is below line rate.

After commit 46b1c18f ("net: sched: put back q.qlen into a
single location") we can check for empty qdisc with a reasonably
fast operation even for nolock qdiscs.

This change extends TCQ_F_CAN_BYPASS support to nolock qdisc.
The new chunk of code mirrors closely the existing one for traditional
qdisc, leveraging a newly introduced helper to read atomically the
qdisc length.

Tested with pktgen in queue xmit mode, with pfifo_fast, a MQ
device, and MQ root qdisc:

threads         vanilla         patched
                kpps            kpps
1               2465            2889
2               4304            5188
4               7898            9589

Same as above, but with a single queue device:

threads         vanilla         patched
                kpps            kpps
1               2556            2827
2               2900            2900
4               5000            5000
8               4700            4700

No mesaurable changes in the contended scenarios, and more 10%
improvement in the uncontended ones.

 v1 -> v2:
  - rebased after flag name change
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Tested-by: default avatarIvan Vecera <ivecera@redhat.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarIvan Vecera <ivecera@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ba27b4cd
    • Paolo Abeni's avatar
      net: sched: add empty status flag for NOLOCK qdisc · 28cff537
      Paolo Abeni authored 
      The queue is marked not empty after acquiring the seqlock,
and it's up to the NOLOCK qdisc clearing such flag on dequeue.
Since the empty status lays on the same cache-line of the
seqlock, it's always hot on cache during the updates.

This makes the empty flag update a little bit loosy. Given
the lack of synchronization between enqueue and dequeue, this
is unavoidable.

v2 -> v3:
 - qdisc_is_empty() has a const argument (Eric)

v1 -> v2:
 - use really an 'empty' flag instead of 'not_empty', as
   suggested by Eric
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarIvan Vecera <ivecera@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      28cff537
    • Soheil Hassas Yeganeh's avatar
      tcp: add documentation for tcp_ca_state · 576fd2f7
      Soheil Hassas Yeganeh authored 
      Add documentation to the tcp_ca_state enum, since this enum is
exposed in uapi.
Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Cc: Sowmini Varadhan <sowmini05@gmail.com>
Acked-by: default avatarSowmini Varadhan <sowmini05@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      576fd2f7
    • Eric Dumazet's avatar
      tcp: remove conditional branches from tcp_mstamp_refresh() · e6d14070
      Eric Dumazet authored 
      tcp_clock_ns() (aka ktime_get_ns()) is using monotonic clock,
so the checks we had in tcp_mstamp_refresh() are no longer
relevant.

This patch removes cpu stall (when the cache line is not hot)
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e6d14070
    • Florian Fainelli's avatar
      net: phy: Correct Cygnus/Omega PHY driver prompt · a7a01ab3
      Florian Fainelli authored 
      The tristate prompt should have been replaced rather than defined a few
lines below, rebase mistake.

Fixes: 17cc9821 ("net: phy: Move Omega PHY entry to Cygnus PHY driver")
Reported-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a7a01ab3
  3. 22 Mar, 2019 28 commits
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