Messages in this thread | | | Date | Sun, 10 Jan 2016 02:06:37 +0100 | From | Florian Westphal <> | Subject | Re: [PATCH] netfilter: nf_conntrack: use safer way to lock all buckets |
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Sasha Levin <sasha.levin@oracle.com> wrote: > When we need to lock all buckets in the connection hashtable we'd attempt to > lock 1024 spinlocks, which is way more preemption levels than supported by > the kernel.
You're right.
> Fix this by using a global lock and synchronize all buckets on it when we > need to lock them all. This is pretty heavyweight, but is only done when we > need to resize the hashtable, and that doesn't happen often enough (or at all).
> diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c > index 3cb3cb8..3c008ce 100644 > --- a/net/netfilter/nf_conntrack_core.c > +++ b/net/netfilter/nf_conntrack_core.c > @@ -66,6 +66,32 @@ EXPORT_SYMBOL_GPL(nf_conntrack_locks); > __cacheline_aligned_in_smp DEFINE_SPINLOCK(nf_conntrack_expect_lock); > EXPORT_SYMBOL_GPL(nf_conntrack_expect_lock); > > +spinlock_t nf_conntrack_locks_all_lock; > +bool nf_conntrack_locks_all;
Seems both of these can be static and __read_mostly too -- as you already note resizing virtually never happens.
Otherwise: Reviewed-by: Florian Westphal <fw@strlen.de>
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