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.
- local_ip / remote_ip / ipv6: the source and destination IP
addresses and the family selector for the same packets.
Every netpoll user that allocates a struct netpoll and 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.
The fix is to move 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 genuinely belongs to the generic poll/transmit
abstraction or what netpoll core still has to read itself.
Follow-ups
----------
local_ip, remote_ip and ipv6 are still in struct netpoll, as they are
left for a follow-up posting to keep each series focused on a single
responsibility transfer.
Signed-off-by: Breno Leitao <leitao@debian.org>
---
Breno Leitao (9):
netpoll: export refill_skbs(), refill_skbs_work_handler(), skb_pool_flush()
netconsole: take over skb pool lifecycle from netpoll
netconsole: move refill_skbs_work_handler() from netpoll
netconsole: move refill_skbs() and skb-pool sizing macros from netpoll
netconsole: move skb_pool_flush() from netpoll
netconsole: move skb_pool / refill_wq from struct netpoll to netconsole_target
netconsole: move local_port from struct netpoll to netconsole_target
netconsole: move remote_port from struct netpoll to netconsole_target
netconsole: move remote_mac from struct netpoll to netconsole_target
drivers/net/netconsole.c | 188 ++++++++++++++++++++++++++++++++++++-----------
include/linux/netpoll.h | 4 -
net/core/netpoll.c | 58 +--------------
3 files changed, 145 insertions(+), 105 deletions(-)
---
base-commit: 150061a2065192d77a4f6518b6238be81dfb8321
change-id: 20260514-netconsole_move_more-888fde03dfc7
Best regards,
--
Breno Leitao <leitao@debian.org>