[PATCH net-next v2 0/2] net: netpoll: Improve SKB pool management

[Breno Leitao <leitao@debian.org>]

The netpoll subsystem pre-allocates 32 SKBs in a pool for emergency use
during out-of-memory conditions. However, the current implementation has
several inefficiencies:

 * The SKB pool, once allocated, is never freed:
	 * Resources remain allocated even after netpoll users are removed
	 * Failed initialization can leave pool populated forever
 * The global pool design makes resource tracking difficult

This series addresses these issues through three patches:

Patch 1 ("net: netpoll: Individualize the skb pool"):
 - Replace global pool with per-user pools in netpoll struct

Patch 2 ("net: netpoll: flush skb pool during cleanup"):
- Properly free pool resources during netconsole cleanup

These changes improve resource management and make the code more
maintainable.  As a side benefit, the improved structure would allow
netpoll to be modularized if desired in the future.

What is coming next?

Once this patch is integrated, I am planning to have the SKBs being
refilled outside of hot (send) path, in a work thread.

Changelog:

v2:
 * Drop the very first patch from v1 ("net: netpoll: Defer skb_pool
   population until setup success") (Jakub)
 * Move skb_queue_head_init() to the first patch, where it belongs to
   (Jakub)

v1:
 * https://lore.kernel.org/all/20241025142025.3558051-1-leitao@debian.org/

Signed-off-by: Breno Leitao <leitao@debian.org>
---
Breno Leitao (2):
      net: netpoll: Individualize the skb pool
      net: netpoll: flush skb pool during cleanup

 include/linux/netpoll.h |  1 +
 net/core/netpoll.c      | 53 +++++++++++++++++++++++++++++++------------------
 2 files changed, 35 insertions(+), 19 deletions(-)
---
base-commit: 2575897640328d218e4451d2c6f2741ae894ed27
change-id: 20241107-skb_buffers_v2-f3e626100eda

Best regards,
-- 
Breno Leitao <leitao@debian.org>