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Breno Leitao says:
====================
netconsole: stop charging netpoll users for netconsole-only data
This work continue to untangle netconsole and netpoll, improving
memory usage for netpoll users that are not netconsole.
struct netpoll is shared by every netpoll consumer in the tree:
bonding, bridge, team, vlan, macvlan, dsa and netconsole. The non-
netconsole users only need a per-port handle that lets them transmit
SKBs.
Yet struct netpoll has accumulated a pile of fields that exist only
to serve netconsole's printk path:
- skb_pool / refill_wq: the fallback skb pool find_skb() falls back
on when alloc_skb() returns NULL, plus the workqueue that refills
it.
- local_port / remote_port / remote_mac: the source and destination
UDP ports and the destination ethernet address used to build
outgoing log packets.
Every netpoll user that allocates a struct netpoll pays for all of
these fields, even though it never queues a single skb on the pool,
never sends a UDP frame and never looks at any of the addressing.
Move this netconsole-only state out of the shared struct into struct
netconsole_target, where its only consumer already lives.
After the series every passive netpoll consumer drops
sizeof(sk_buff_head) + sizeof(work_struct) + 2 * sizeof(u16) +
ETH_ALEN bytes per port (plus padding), and struct netpoll keeps only
what belongs to the generic poll/transmit abstraction or what netpoll
core still reads itself.
Follow-ups
----------
local_ip, remote_ip and ipv6 are still in struct netpoll. Moving the
addressing additionally requires relocating netpoll_setup() -- whose
only caller is netconsole -- and its IPv4/IPv6 helpers, so it is left
for a follow-up to keep this series focused on a single responsibility
transfer.
This is pure code motion with no functional change. The pre-existing
target/device teardown races reported against v1 have since been fixed
independently (as suggested by Jakub) and are already in the tree, so,
re-posting this one.
====================
Link: https://patch.msgid.link/20260710-netconsole_move_more-v3-0-6f63f76b28bc@debian.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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