Merge tag 'rxrpc-rewrite-20160824-2' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
David Howells says:
====================
rxrpc: Add better client conn management strategy
These two patches add a better client connection management strategy. They
need to be applied on top of the just-posted fixes.
(1) Duplicate the connection list and separate out procfs iteration from
garbage collection. This is necessary for the next patch as with that
client connections no longer appear on a single list and may not
appear on a list at all - and really don't want to be exposed to the
old garbage collector.
(Note that client conns aren't left dangling, they're also in a tree
rooted in the local endpoint so that they can be found by a user
wanting to make a new client call. Service conns do not appear in
this tree.)
(2) Implement a better lifetime management and garbage collection strategy
for client connections.
In this, a client connection can be in one of five cache states
(inactive, waiting, active, culled and idle). Limits are set on the
number of client conns that may be active at any one time and makes
users wait if they want to start a new call when there isn't capacity
available.
To make capacity available, active and idle connections can be culled,
after a short delay (to allow for retransmission). The delay is
reduced if the capacity exceeds a tunable threshold.
If there is spare capacity, client conns are permitted to hang around
a fair bit longer (tunable) so as to allow reuse of negotiated
security contexts.
After this patch, the client conn strategy is separate from that of
service conns (which continues to use the old code for the moment).
This difference in strategy is because the client side retains control
over when it allows a connection to become active, whereas the service
side has no control over when it sees a new connection or a new call
on an old connection.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>