Williem reported that in some scenarios the UDP protocol can keep a lot of
memory in use on an idle system. He also diagnosed the root cause in the
forward allocated memory bulk free.

This series addresses the issue adding memory pressure tracking for the UDP
protocol, and flushing the fwd allocated memory if the protocol is under
memory pressure.

The first two patches clean-up the current memory pressure helpers for UDP
usage, and the 3rd one is the actual fix.

Targeting the net tree, as this addresses a reported issue. I guess even
net-next can be considered a valid target, as this also changes slightly the
protocol behavior under memory pressure. Please advise on the preferred option.

Paolo Abeni (3):
  net: generic enter_memory_pressure implementation.
  net: add annotation to memory_pressure lockless access
  udp: avoid bulk memory scheduling on memory pressure.

 include/net/sock.h |  4 ++--
 include/net/udp.h  |  2 ++
 net/core/sock.c    | 10 +++++++---
 net/ipv4/udp.c     | 13 ++++++++++++-
 net/ipv6/udp.c     |  2 ++
 5 files changed, 25 insertions(+), 6 deletions(-)

-- 
2.21.0