From 9e4e948a3edafd2b7f4dc14c395e146ffd0d9611 Mon Sep 17 00:00:00 2001 From: Julian Anastasov Date: Wed, 9 Oct 2013 09:24:27 +0300 Subject: ipvs: avoid rcu_barrier during netns cleanup commit 578bc3ef1e473a ("ipvs: reorganize dest trash") added rcu_barrier() on cleanup to wait dest users and schedulers like LBLC and LBLCR to put their last dest reference. Using rcu_barrier with many namespaces is problematic. Trying to fix it by freeing dest with kfree_rcu is not a solution, RCU callbacks can run in parallel and execution order is random. Fix it by creating new function ip_vs_dest_put_and_free() which is heavier than ip_vs_dest_put(). We will use it just for schedulers like LBLC, LBLCR that can delay their dest release. By default, dests reference is above 0 if they are present in service and it is 0 when deleted but still in trash list. Change the dest trash code to use ip_vs_dest_put_and_free(), so that refcnt -1 can be used for freeing. As result, such checks remain in slow path and the rcu_barrier() from netns cleanup can be removed. Signed-off-by: Julian Anastasov Signed-off-by: Simon Horman --- include/net/ip_vs.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include') diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h index 1c2e1b9f6b86..cd7275f9c463 100644 --- a/include/net/ip_vs.h +++ b/include/net/ip_vs.h @@ -1442,6 +1442,12 @@ static inline void ip_vs_dest_put(struct ip_vs_dest *dest) atomic_dec(&dest->refcnt); } +static inline void ip_vs_dest_put_and_free(struct ip_vs_dest *dest) +{ + if (atomic_dec_return(&dest->refcnt) < 0) + kfree(dest); +} + /* * IPVS sync daemon data and function prototypes * (from ip_vs_sync.c) -- cgit v1.2.3