peer: allocate in kmem_cache

With deployments having upwards of 600k peers now, this somewhat heavy
structure could benefit from more fine-grained allocations.
Specifically, instead of using a 2048-byte slab for a 1544-byte object,
we can now use 1544-byte objects directly, thus saving almost 25%
per-peer, or with 600k peers, that's a savings of 303 MiB. This also
makes wireguard's memory usage more transparent in tools like slabtop
and /proc/slabinfo.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/peer.h b/src/peer.h
index 8d53b68..76e4d31 100644
--- a/src/peer.h
+++ b/src/peer.h
@@ -80,4 +80,7 @@ void wg_peer_put(struct wg_peer *peer);
 void wg_peer_remove(struct wg_peer *peer);
 void wg_peer_remove_all(struct wg_device *wg);
 
+int wg_peer_init(void);
+void wg_peer_uninit(void);
+
 #endif /* _WG_PEER_H */