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Date: Tue, 27 Jan 2015 11:40:28 +0000 From: Thomas Graf <tgraf@...g.ch> To: Herbert Xu <herbert@...dor.apana.org.au> Cc: David Miller <davem@...emloft.net>, David.Laight@...LAB.COM, ying.xue@...driver.com, kaber@...sh.net, paulmck@...ux.vnet.ibm.com, netdev@...r.kernel.org, netfilter-devel@...r.kernel.org Subject: Re: [PATCH 1/2] rhashtable: Introduce rhashtable_walk_* On 01/27/15 at 10:23pm, Herbert Xu wrote: > On Tue, Jan 27, 2015 at 11:16:04AM +0000, Thomas Graf wrote: > > > > No objection. I have a patch prepared which allows the user to > > provide ht->mutex himself so nfset can provide its own existing > > mutex to rhashtable and lock out the resizes from inserts, > > removals and dump iterations automatically That would restore the > > old behaviour of the nfset API without major surgery. > > If you take the mutex you might as well just make it synchronous. > There is zero difference. > > Maybe you misunderstood my email. I'm not making it synchronous > for everybody, just those that always take a lock on inserts/removals > and therefore don't need per-bucket locks. Understood. No objection, happy to review patches. I initially did keep sync/async separate and it lead to considerable code duplication and complexity. I figured that if a user needs sync insert they could provide their own locking. I missed to allow controlling the async resize though. Again, feel free to give a shot, no objections. This is unrelated to resize run control though, the reason is that I'm converting tcp_hashinfo et al and they require a hybrid approach. The tables may be too big to construct a parallel data structure, we don't want to hold off inserts or deletes while the expensive dump is underway. Even though we can't build a shadow structure while locking everybody else out, we still want to provide a way to somehow achieve consistent information. I think that NLM_F_INTR with fallback to restarting the dump is a good option and very easy to implement. In that case, we want to lock out resize from dumping iterations but still allow parallel insert/delete. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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