Re: [PATCH] net/flow: remove sleeping and deferral mechanism from flow_cache_flush
From: Steffen Klassert <steffen.klassert@secunet.com>
Date: 2011-12-20 08:23:35
Subsystem:
networking [general], networking [ipsec], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Steffen Klassert, Herbert Xu, Linus Torvalds
On Tue, Sep 27, 2011 at 03:31:32PM -0400, David Miller wrote:
From: David Miller <davem@davemloft.net> Date: Tue, 27 Sep 2011 15:28:36 -0400 (EDT)quoted
afinfo->garbage_collect is the only other place __xfrm_garbage_collect is referenced, and that is completely unused and should thus be deleted (I'll take care of that in net-next).Nevermind I see how these are referenced directly via xfrm4_policy.c and xfrm6_policy.c, sigh...
Is there any progress in fixing this issue? I've seen this occasionally on some of our production systems, so I fixed it for us in the meantime with the patch below. I could submit this for inclusion if noone else wants to fix it in a different manner. ------ net: Add a flow_cache_flush_deferred function flow_cach_flush() might sleep but can be called from atomic context via the xfrm garbage collector. So add a flow_cache_flush_deferred() function and use this if the xfrm garbage colector is invoked from within the packet path. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> --- include/net/flow.h | 1 + net/core/flow.c | 12 ++++++++++++ net/xfrm/xfrm_policy.c | 18 ++++++++++++++---- 3 files changed, 27 insertions(+), 4 deletions(-)
diff --git a/include/net/flow.h b/include/net/flow.h
index a094477..57f15a7 100644
--- a/include/net/flow.h
+++ b/include/net/flow.h@@ -207,6 +207,7 @@ extern struct flow_cache_object *flow_cache_lookup( u8 dir, flow_resolve_t resolver, void *ctx); extern void flow_cache_flush(void); +extern void flow_cache_flush_deferred(void); extern atomic_t flow_cache_genid; #endif
diff --git a/net/core/flow.c b/net/core/flow.c
index 8ae42de..e318c7e 100644
--- a/net/core/flow.c
+++ b/net/core/flow.c@@ -358,6 +358,18 @@ void flow_cache_flush(void) put_online_cpus(); } +static void flow_cache_flush_task(struct work_struct *work) +{ + flow_cache_flush(); +} + +static DECLARE_WORK(flow_cache_flush_work, flow_cache_flush_task); + +void flow_cache_flush_deferred(void) +{ + schedule_work(&flow_cache_flush_work); +} + static int __cpuinit flow_cache_cpu_prepare(struct flow_cache *fc, int cpu) { struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 2118d64..9049a5c 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c@@ -2276,8 +2276,6 @@ static void __xfrm_garbage_collect(struct net *net) { struct dst_entry *head, *next; - flow_cache_flush(); - spin_lock_bh(&xfrm_policy_sk_bundle_lock); head = xfrm_policy_sk_bundles; xfrm_policy_sk_bundles = NULL;
@@ -2290,6 +2288,18 @@ static void __xfrm_garbage_collect(struct net *net) } } +static void xfrm_garbage_collect(struct net *net) +{ + flow_cache_flush(); + __xfrm_garbage_collect(net); +} + +static void xfrm_garbage_collect_deferred(struct net *net) +{ + flow_cache_flush_deferred(); + __xfrm_garbage_collect(net); +} + static void xfrm_init_pmtu(struct dst_entry *dst) { do {
@@ -2422,7 +2432,7 @@ int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo) if (likely(dst_ops->neigh_lookup == NULL)) dst_ops->neigh_lookup = xfrm_neigh_lookup; if (likely(afinfo->garbage_collect == NULL)) - afinfo->garbage_collect = __xfrm_garbage_collect; + afinfo->garbage_collect = xfrm_garbage_collect_deferred; xfrm_policy_afinfo[afinfo->family] = afinfo; } write_unlock_bh(&xfrm_policy_afinfo_lock);
@@ -2516,7 +2526,7 @@ static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void switch (event) { case NETDEV_DOWN: - __xfrm_garbage_collect(dev_net(dev)); + xfrm_garbage_collect(dev_net(dev)); } return NOTIFY_DONE; }
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1.7.0.4