linux.git/net/core/dev.c, branch v5.18-rc2

net: move net_unlink_todo() out of the header

2022-03-28T21:40:08+00:00

There's no reason for this to be in netdevice.h, it's all
just used in dev.c. Also make it no longer inline and let
the compiler decide to do that by itself.

Signed-off-by: Johannes Berg 
Link: https://lore.kernel.org/r/20220325225023.f49b9056fe1c.I6b901a2df00000837a9bd251a8dd259bd23f5ded@changeid
Signed-off-by: Jakub Kicinski

net: Revert the softirq will run annotation in ____napi_schedule().

2022-03-21T19:07:05+00:00

The lockdep annotation lockdep_assert_softirq_will_run() expects that
either hard or soft interrupts are disabled because both guaranty that
the "raised" soft-interrupts will be processed once the context is left.

This triggers in flush_smp_call_function_from_idle() but it this case it
explicitly calls do_softirq() in case of pending softirqs.

Revert the "softirq will run" annotation in ____napi_schedule() and move
the check back to __netif_rx() as it was. Keep the IRQ-off assert in
____napi_schedule() because this is always required.

Fixes: fbd9a2ceba5c7 ("net: Add lockdep asserts to ____napi_schedule().")
Signed-off-by: Sebastian Andrzej Siewior 
Reviewed-by: Jason A. Donenfeld 
Link: https://lore.kernel.org/r/YjhD3ZKWysyw8rc6@linutronix.de
Signed-off-by: Jakub Kicinski

net: set default rss queues num to physical cores / 2

2022-03-18T19:00:35+00:00

Network drivers can call to netif_get_num_default_rss_queues to get the
default number of receive queues to use. Right now, this default number
is min(8, num_online_cpus()).

Instead, as suggested by Jakub, use the number of physical cores divided
by 2 as a way to avoid wasting CPU resources and to avoid using both CPU
threads, but still allowing to scale for high-end processors with many
cores.

As an exception, select 2 queues for processors with 2 cores, because
otherwise it won't take any advantage of RSS despite being SMP capable.

Tested: Processor Intel Xeon E5-2620 (2 sockets, 6 cores/socket, 2
threads/core). NIC Broadcom NetXtreme II BCM57810 (10GBps). Ran some
tests with `perf stat iperf3 -R`, with parallelisms of 1, 8 and 24,
getting the following results:
- Number of queues: 6 (instead of 8)
- Network throughput: not affected
- CPU usage: utilized 0.05-0.12 CPUs more than before (having 24 CPUs
  this is only 0.2-0.5% higher)
- Reduced the number of context switches by 7-50%, being more noticeable
  when using a higher number of parallel threads.

Suggested-by: Jakub Kicinski 
Signed-off-by: Íñigo Huguet 
Link: https://lore.kernel.org/r/20220315091832.13873-1-ihuguet@redhat.com
Signed-off-by: Jakub Kicinski

net: Add lockdep asserts to ____napi_schedule().

2022-03-14T10:09:28+00:00

____napi_schedule() needs to be invoked with disabled interrupts due to
__raise_softirq_irqoff (in order not to corrupt the per-CPU list).
____napi_schedule() needs also to be invoked from an interrupt context
so that the raised-softirq is processed while the interrupt context is
left.

Add lockdep asserts for both conditions.
While this is the second time the irq/softirq check is needed, provide a
generic lockdep_assert_softirq_will_run() which is used by both caller.

Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: David S. Miller

net: add per-cpu storage and net->core_stats

2022-03-12T07:17:24+00:00

Before adding yet another possibly contended atomic_long_t,
it is time to add per-cpu storage for existing ones:
 dev->tx_dropped, dev->rx_dropped, and dev->rx_nohandler

Because many devices do not have to increment such counters,
allocate the per-cpu storage on demand, so that dev_get_stats()
does not have to spend considerable time folding zero counters.

Note that some drivers have abused these counters which
were supposed to be only used by core networking stack.

v4: should use per_cpu_ptr() in dev_get_stats() (Jakub)
v3: added a READ_ONCE() in netdev_core_stats_alloc() (Paolo)
v2: add a missing include (reported by kernel test robot )
    Change in netdev_core_stats_alloc() (Jakub)

Signed-off-by: Eric Dumazet 
Cc: jeffreyji 
Reviewed-by: Brian Vazquez 
Reviewed-by: Jakub Kicinski 
Acked-by: Paolo Abeni 
Link: https://lore.kernel.org/r/20220311051420.2608812-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski

net: remove exports for netdev_name_node_alt_create() and destroy

2022-03-12T06:55:09+00:00

netdev_name_node_alt_create() and netdev_name_node_alt_destroy()
are only called by rtnetlink, so no need for exports.

Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20220310223952.558779-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

net: dev: use kfree_skb_reason() for __netif_receive_skb_core()

2022-03-04T12:17:11+00:00

Add reason for skb drops to __netif_receive_skb_core() when packet_type
not found to handle the skb. For this purpose, the drop reason
SKB_DROP_REASON_PTYPE_ABSENT is introduced. Take ether packets for
example, this case mainly happens when L3 protocol is not supported.

Signed-off-by: Menglong Dong 
Signed-off-by: David S. Miller

net: dev: use kfree_skb_reason() for sch_handle_ingress()

2022-03-04T12:17:11+00:00

Replace kfree_skb() used in sch_handle_ingress() with
kfree_skb_reason(). Following drop reasons are introduced:

SKB_DROP_REASON_TC_INGRESS

Signed-off-by: Menglong Dong 
Signed-off-by: David S. Miller

net: dev: use kfree_skb_reason() for do_xdp_generic()

2022-03-04T12:17:11+00:00

Replace kfree_skb() used in do_xdp_generic() with kfree_skb_reason().
The drop reason SKB_DROP_REASON_XDP is introduced for this case.

Signed-off-by: Menglong Dong 
Signed-off-by: David S. Miller

net: dev: use kfree_skb_reason() for enqueue_to_backlog()

2022-03-04T12:17:11+00:00

Replace kfree_skb() used in enqueue_to_backlog() with
kfree_skb_reason(). The skb rop reason SKB_DROP_REASON_CPU_BACKLOG is
introduced for the case of failing to enqueue the skb to the per CPU
backlog queue. The further reason can be backlog queue full or RPS
flow limition, and I think we needn't to make further distinctions.

Signed-off-by: Menglong Dong 
Signed-off-by: David S. Miller