From e4db5b61c572475bbbcf63e3c8a2606bfccf2c9d Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 25 Jun 2018 17:26:02 +0200 Subject: xfrm: policy: remove pcpu policy cache Kristian Evensen says: In a project I am involved in, we are running ipsec (Strongswan) on different mt7621-based routers. Each router is configured as an initiator and has around ~30 tunnels to different responders (running on misc. devices). Before the flow cache was removed (kernel 4.9), we got a combined throughput of around 70Mbit/s for all tunnels on one router. However, we recently switched to kernel 4.14 (4.14.48), and the total throughput is somewhere around 57Mbit/s (best-case). I.e., a drop of around 20%. Reverting the flow cache removal restores, as expected, performance levels to that of kernel 4.9. When pcpu xdst exists, it has to be validated first before it can be used. A negative hit thus increases cost vs. no-cache. As number of tunnels increases, hit rate decreases so this pcpu caching isn't a viable strategy. Furthermore, the xdst cache also needs to run with BH off, so when removing this the bh disable/enable pairs can be removed too. Kristian tested a 4.14.y backport of this change and reported increased performance: In our tests, the throughput reduction has been reduced from around -20% to -5%. We also see that the overall throughput is independent of the number of tunnels, while before the throughput was reduced as the number of tunnels increased. Reported-by: Kristian Evensen Signed-off-by: Florian Westphal Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_state.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'net/xfrm/xfrm_state.c') diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 3803b6813fc5..e04a510ec992 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -735,10 +735,9 @@ restart: } out: spin_unlock_bh(&net->xfrm.xfrm_state_lock); - if (cnt) { + if (cnt) err = 0; - xfrm_policy_cache_flush(); - } + return err; } EXPORT_SYMBOL(xfrm_state_flush); -- cgit v1.2.3