Stephen Hemminger wrote:
On Mon, 30 Mar 2009 21:57:15 +0200
Eric Dumazet <dada1@xxxxxxxxxxxxx> wrote:
On normal machines, (no debugging spinlocks), patch uses an embedded
spinlock. We probably can use this even on 32bit kernels, considering
previous patch removed the rcu_head (8 bytes on 32bit arches) from
nf_conn :)
if LOCKDEP is on, size of a spinlock is 64 bytes on x86_64.
Adding a spinlock on each nf_conn would be too expensive. In this
case, an array of spinlock is a good compromise, as done in
IP route cache, tcp ehash, ...
I agree sizing of this hash table is not pretty, and should be
a generic kernel service (I wanted such service for futexes for example)
IMO having different locking based on lockdep and architecture is an invitation
to future obscure problems. Perhaps some other locking method or shrinking
ct entry would be better.
I agree. Do people enable lockdep on production machines? Otherwise
I'd say the size increase doesn't really matter.
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